a methylated guanine nucleotide added to the 5' end of eukaryotic mRNA. The cap is necessary to initiate translation of mRNA
The band of the sarcomere that extends the full length of the thick filament. The A band includes regions of thick and thin filament overlap
Absolute refractory period
A period of time following an action potential during which no additional action potential can be evoked regardless of the level of stimulation. (usually because Na+ channel closed whle K+ efflux)
The three glands in the male reproductive system that reproduce semen: the seminal vesicles
(1) In the GI tract
The neurotransmitter used throughout the parasympathetic nervous system as well as the neuromuscular junction.
The enzyme that breaks down acetylcholine in the synaptic cleft.
The first substrate in teh Krebs cycle
Enzymes that degrade various macromolecules and that require an acidic pH to function properly. Acid hydrolases are found within the lysosomes of cells.
Cells that make up exocrine galnds
A region at the head of a sperm cell that contains digestive enzyems which
A contractile protein. In skeletal and cardiac muscle
A localized change in a neruon's or musce cell's membrane potential that can propogate itself away from its point of origin. Action potentials are an all-or-none process mediated by the opening of voltage-gated Na+ and K+ channels when the membrane is brought to the threshold potential; opening of the Na+ channels causes a characteristic depolarization
Activation energy (Ea)
The amount of energy required to produce the transition state of a chemical reaction. If the activation energy for a reaction is very high
The 3D site of an enzyme where substrates (reactants) bind and a chemical reaction is facilitated.
The movement of molecules through the plasma membrane against their concentration gradients. Active transport requires input of cellular energy
One of the four aromatic bases found in DNA and RNA; also a component of ATP
anterior pituitary gland
The inner region of the adrenal gland. The adrenal medulla is part of the sympathetic nervous systme
A constant input to the arteries that keeps them somewhat constricted to maintain a basal level of blood pressure.
Adrenocoricotropic hormone (ACTH)
A trop hormone produced by the anterior pituitary gand that targets the adrenal cortex
The small artery that carries blood toward the capillaries of the glomerulus.
A neuron that arries information (action potentials) to the central nervous system; a sensory neuron.
A blood protein produced by the liver. Albumin helps to mantain blood osmotic pressure (oncotic pressure)
The principal mineralocorticoid secreted by teh adrenal cortex. This steroid hormone targets the kidney tubules and increases renal reabsorption of sodium [and excretion of potassium]. (this causes ADH to be secreted & increased water comes out
"Also known as the gastrointestinal (GI) tract of the digestive tract
The modifaction of enzyme activity through interactino of molecules with specific sites on the enzyme other than the active site (called allosteric sites)
(singular alveolus.) Tiny sacs
A version of a gene. For example
The monomer of a protein; amino acids hae an amio group on one end fo the molecule and a carboxylic acid group on the other
Amino acid acceptor site
The 3' end of a tRNA molecule that binds an amino acid. The nucleotide sequence at this end is CCA
A tRNA with an amino acid attached. This is made by an animoacyl-tRNA synthetase specific to the amino acid being attache.d
A sac filled with fluid (aminotic fluid) that surroudns and protects a developing embryo.
The characteristics of amolecule that has both polar (hydrophilic) and non-polar hydrophobic) regions
An enzyme that digests starch into disaccharides. Amylase is secreted by salivary glands and by the pancreas.
The process of bulidng complex structures out of simpler precursors
Physical structures in two different organism that have funcitonal similarity due to their evoluntion in a common environment
The valve that controls the release of feces from the recturm. It has an internal part made of smooth muscle (thus involuntary) and an external part made of skeletal muscle (thus voluntary).
The third phase of mitosis. During anaphase
The third phase of meiosis I. During anaphase I the rplicated homologous chromosomes are separated (the tetrad is split) and pulled to opposite sides of the cell.
The third phase of meiosis II. During anaphase II the sister chromatids are finally spearated at their centromeres and puled to opposite sides of teh cell. Note that anaphase II is identical to mitotic anaphase
Mal sex hormones. Testosteron is the primary androgen.
A normal blood protein produced by the liver
Something that acts to oppose the action of something else. For example
Anterioir pituitary gland
Also known as the adenohypophysis
Also called immunoblobins
A sequence of three nucleotides (found int he anticodon loop of tRNA) that is complementary to a specific codon in mRNA. The codon to which the anticodon is complementary specifies the amino acid that is carried by that tRNA.
Antidiuretic hormone (ADH)
Also called vasopressin
A molecule (usually a protein) capable of initiating an immune repsonse (antibody production).
Antigen presenting cell
"Cells that possess MHC II (B cells and macrophages) and are able to display bits of ingested antigen on their surface in order to activate T cells. See also ""MHC"""
The normal configuration of double-stranded DNA in which the 5' end of oen strand is paired with the 3' end of the other
A carrier protein that transports two molecules acrss the plasma membrane in opposite directions.
The largest artery in teh body; the aorta carries oxygenated blood away from the left ventricle of the heart.
A mass of lymphatic tissue at the befenning of the large intestine that helps trap ingested pathogens.
A function in the reproductive system
A blood vessel that carries blood away from the heart chambers. Arteries have muscular walls to regulate blood flow and are typically high-pressure vessles.
Amino-acyl tRNA site; the site on a ribosome where a new amino acid is added to a growing peptide.
A protein complex foudn in the inner membrane of the mitochondira. It is essentially a channel that llows H+ ions to flow from teh intermembrane space to the matrix (down teh gradeint produced by the enyzmes complexes of the electron transport chain); as the H= ions flow through the channel
Atrioventricular bundle (AV) bundle
Also known as the Bundle of His
Atrioventricular (AV) node
The second major node of the cardiac conduction system (after the SA node). The cardiac impulse is delayed slightly at teh AV node
The valves in the heart that separte the atria from teh ventricles. The tricuspid valve separates teh right atrium from the right ventricel
One of the two small chambers in the heart that receive blood and pass it on to the ventricles. The right atrium receives deoxygenated blood from teh body through the superior and inferiro vena cavae
The first step in viral infection. Attachemen of a virus to its host is very specific and is also known as adsorption.
The tube that connects the middle ear acity with the pharynx; also known as the Eustachian tube. Its fucntion is to equalize midle ear pressure with atmospheric pressure so that pressure on boths sides of the tympanic membrane is the same.
An immune reaction directed against normal (necessary ) cells.Fo example
Autonomic nervous system (ANS)
The division of the periperal nervsous system that innervates and cotnrols the visceral organs (everything but the skeletal muscles). It is also knowns as the involuntary nervous system and an be subdivided into the sympathetic and parasympathetic divisions.
A chromosome that does not determine gender (is not a sex chromosome). Humans have two sex chromsomes and 22 autosomes.
An organism that makes its own
"A bacterium that cannon survive on minimal medium (glucose alone) because it lacks the ability to syntheisze a molecule it needs to live (typically an amino acid). Auxotrphs must ave the needed substance (the auxiliary trophic substance) added to their medium in order to survive. The are typically denoted by teh susbstance they require followed by a ""-"" sign in superscript. For example
Lacking a blood supply; cartialge is an example of this
A long projection off the cell body of a neruon down which an action potential can be propagated.
A bacterium having a rod-like shaped (plural = bacilli).
A virus that infects a bacterium.
A sensory receptor that responds to hcanges in pressure; for example
A layer of collagen fibers that separates epithelial tissue from connective tisse (example of epithelial cells in digestive tract) - they are actual connective tissue.
The flexible membrane in teh chochlea that supports the organ of Corti (structure which contains the hearing receptors). The fibers of the basilar membrane are short and stiff near the oval windown and long and fleaxible near the apex of the cochlea. This difference in structure allows the basilar membrane to help trasnduce pitch.
A type of lymphocyte that can recognize (bind to) an antigen adn secrete an antibody specific for that antigen. When activated by binding an antigen
HCO3-. THis ion results from the dissociation of carbonic acid
A green fluid made from cholesterol and secreted by teh liver. It is stored and concentrated in the gallbladder. Bile isn an amphipathic molecule that is secreted itno the small intestine when fats are present
An asexual method of bacterial reproduction that serves only to increase the size of the population; ther is no introduciton of gnetic diversity. THe bacterium simply grows in size until it has doubled its cellular components
A neuron with a single axon and a single dendrite
A fluid-filled sphere formed about 5 days after fertilization of an ovum that is made up of an outer ring of cells and inner cell mass. THis is the structure that implants in the endometrium of the uterus.
The tendency of certain factors to stablize the hemoglobin in the tense conformation
A non-bony material that fills the hollow spaces inside bones. Red bone marrow is found in regiosn of spongy bone and is the site of blood cell (red and white) production. Yellow bone marrow is found in the diaphysis (shaft) of long bones
The region of the nephron that surrounds the glomerulus. The capsule ollects the plasma that is filtered from teh capillaries in the glomerulus.
Very small air tubes int eh respiratory system (diameter 0.5 - 1.0 mm). The walls of the bronchioles are made of smooth muscle (thus involunatry) to help regulate air flow.
Brush border enzymes
Enzymes secreted by the mucosal cells lining the intestine. The brush border enzymes are disaccharides adn dipeptidases taht digest the smallest peptides and carbohydrates into their respective monomers.
Small paired gland found inferior to the prostate in males and at the posterior end of the penile urethra. They secrete an alkaline mucus on sexual arousal that helps toneutralize any traces of acidic urine the urethra that might be harmful to sperm.
A hormone produced by the C-cells of the thyroid gland that decreases serum calcium levels. It targets teh bones (stimulates osteoblasts)
A hormone produced from vitamin D that acts in essentially the same manner as parathyroid hormone.
A cyoplasmic Ca2+-binding protein. Calmodulin is particularly important in smooth muscle cells
Very small tube or channel
An incrase in the fragility of the membranes of sperm cells when exposed to the female reproductive tract. Capacitation is required sot aht the acrosomal enzymes can be relased to faciliate fertilization.
The smalles of all blodo vessles
The outer protein coat of a virus (the whole coat)
Molecules made from monosaccharides that serve as the primary source of cellular energy
An enzyme present in erythrocytes (as well as in other places) that catalyzes the conversion of CO2 and H2O into carbonic acid (H2CO3).
Cardiac conduction system
The specialized cells of the heart that spontaneously initiate action potentials and transmit them to the cardiac muscle cells. The cells of the conduction system are essentially cardiac muscle cells
The muscle tissue of the heart Cardiac muscle is striated
The volume of blood pumped out of the heart in one minute (vol/min); the product of the stroke volume (vol/beat) and the heart rate (beat/min). Cardiac output is directly proportional to blood pressure**.
An integral membrane protein that undergoes a conformational change to move a molecule from one side of the membrane to another. See also 'uniporter'
A strong connective tissue with varying degrees of flexibility. (1) Elastic cartilage is the most flexible
The process of breaking down large molecules into smaller precursors
The primary enzyme in peroxisomes; catalse catalyzes the hydrolysis of hydrogen peroxide (H2O2) into water and oxygen.
Something that increases the rate of a chemical reaction by reducing the activation energy for that reaction. The free energy of reaction remains unchanged.
Complementary DNA. DNA produced synthetically by reverse trascribing mRNA. Because of eukaryotic mRNA splicing
The first part of the large intestine.
Cell surface receptor
An integral membrane proteint hat binds extracellular signaling molecules
The hollow center of an osteon
Receptors in the central nervous system that monitor the pH of cerebrospinal luid to help regulate ventilation rate.
Central Nervous System
The subdivision of the nervous system consisting of the brain and spinal cord.
A structure composed of a ring of nine microtube triplets
A structure near the middle of eukaryotic chromosomes to which the fibers of the mitotic spindle attach during cell division.
The region of teh brain that coordinates and smooth skeletal muscle activity.
A thin (4 mm) layer of gray matter on the surface of the cerebral hemispheres. The cerebral cortex is the conscious mind
A clear fluid the circulates around through the brain and spinal cord that helps to physially support teh brain and act as a shock absorber
A gland that secretes a waxy product
The opening to the uterus The ervix is typically plugged with a sticky acidic mucus during non-fertile times (to form a barrier against the entry of pathogens)
An integral protein that selectively allows molecules across the plasma membrane. See also entries under 'ion channel'
A type of synapse at which a chemical (a neurotransmitter) is released from teh axon of a neuron into the ysnaptic cleft where it binds to receptors on the next structure in sequence
A sensory receptor that responds to specific chemicals. Some examples are gustatory (taste) receptors
Movement that is directed by chemical gradients
An organism that relies on a chemical source of energy (such as ATP) instead of light (which phototrophs).
Pepsinogen-secreting cells foudn at teh bottom of the gastric glands
A poysaccharide found in the cell walls of fungi and in the exoskeletons of insects.
A hormone secreted by the samll intestine (duodenum) in response to the presence of fats. It promotes release of bile from the gallbladder and pancreatic juice from the pancreas
The portion of the placenta derived from the zygote.
The darkly pigmented middle layer of the eyeball
A single piece of double-stranded DNA; part of the genome of an organism. Prokaryotes have circular chromosomes and eukaryotes have linear chromosomes.
A type of lipoprotein; the form in which absorbed fats from the intestines are transported to the circulatory system.
One of the main pancreatic proteases; it is activated (from chymotrypsinogen) by trypsin.
A hair-like structure on teh cell surface composed of microtubules ina '9+2' arrangement (nine pairs of microtubles surrounding 2 single microtubules in the center). Teh microtubules are conneted with a contractile protien called dynein. Cilia beat in a repetitive sweeping motion
Muscles that help focus light on teh retin by controlling the curvature of the lens of the eye.
Circular smooth muscles
The inner layer of smooth muscle in the wall of the digestive tract. When the circular muscle contracts
A fibrous protein found on the intracellular side of the plasma membrane (also associated with the Golgi complex) that helps invaginate the membrane. Typically cel surface receptors are associated with clathrin-coated pits at the plasma membrane binding of the ligan to the receptor trigger invagination (example: cholesterol uptake via lipoprotein endocytosis).
The rapid mitotic division of a zygot that being within 24-36 hours after fertilization
A bacteria having a round shape (plural = cocci)
The curled structure in the inner ear that contains the membranes and hair cells that transduce sound waves into action potentials.
A situation in which a heterozygote displays the phenotype associated with each of the alleles
A group of three nucleotides taht is specific for a particular amino acid
An **organic molecuel taht associates non-covalently with an enzyme
An **inorganic molecule that associates non-covalently with an enzyme and that is required for the proper functioning of the enzyme
A protein fiber with a unique triple-helix that gives it great strength. Tissues with a lot of collagen fibers are typically very strong
The portion of the nephron where water reabsorption is regulated via antidiuretic hormone (ADH). Several nephrons empty into each collecting duct
Common bile duct
The duct that carries bile from the gallbladder and liver to the small intestine (duodenum).
An enzyme inhibitor that competes with substrate for binding at the active site of teh enzyme. When the inhibitor is bound
A group of blood proteins that bind non-specifically to the surface proteins of foreign cells (such as bacteria)
Photoreceptors in the retina of the eye that responds to bright light and provide color vision.
A form of genetic recombination in bacteria in which plasmid and/or genomic DNA is transferred from one bacterium to the toher through a conjugation bridge.
One of the four basic tissue types in the body (epithelial
A form of evolution in which different organisms are placed into the same environment and exposed to teh same selection pressures. This causes the organisms to evolve along similar lines. As a result
A type of substrate binding to a multi-active site enzyme
The clear portion of the tough outer layer of teh eye ball
The layer of granulosa cells taht surround an oocyte after is has been ovulated.
The blood vessels taht carry blood to and from cardiac muscle. The coronary arteries branch off teh aorta and carry oxygenated blood to the cardiac tissue. The coronary veins collect deoxygenated blood from teh cardiac tissue
The largest bundle of white matter (axons) connecting th two cerebral hemispheres.
'Yellow body.' The remnants of an ovarian follicle after ovulation has occurred. The cells enlarge and begin secreting progesterone
The outer layer of an organ
Steroid hormones secreted from the adrenal cortex. The two major classes are teh mineralocorticoids and glucocorticoids. Aldosterone is the principal mineralocorticoid
The principal glucocorticoid secreted from teh adrenal cortex. This steroid hormone is released ruing stress
An energy storage molecule used by muscle tissue. The phosphate from creatine phosphate can be removed and attached to an ADP to generate ATP quickly.
The folds of the inner membrane of a mitochondrion
The connection of a mosin head group to an actin filament during muscle contraction (the sliding filament theory).
The exchange of DNA between paired homologus chromosomes (tetrads) during *prophase I* of meiosis.
Cyclic AMP (cAMP)
A cyclic version of adenosine monophosphate
The phase of mitosis during which the cell physically splits into two daugter cells. Cytokinesis begins near the end of anaphase
One of the four aromatic bases found in DNA and RNA. Cytosine is a pyrimidine; it pairs with guanine.
A projection of the cell body of a neuron that recieves a nerve impulse form a different neuron and send the impulse to the cell body. Neurons can have one or several dendrites!
Dense connective tissue
Connective tissue with large amounts of either collagen fibers (making them strong) or elastic fibers
The movement of teh membrane potential of a cell away from rest potential in a more positive direction.
A layer of connective tissue underneath the epidermis of the skin. The dermis contains blood vessels
A general cell junction
The point during development at which a cell becomes committed to a particular fate (sensory
The primary muscle of inspiration. The diaphragm is stimulated to contract at regular intervals by the respiratory center in the medulla oblongata (via the phrenic nerve). Although it is made of skeletal muscle (and can therefore be voluntary controlled)
The shaft of a long bone. The diaphysis is hollow and is made entirely from compact bone.
The perio of time during which the ventricles of the heart are relaxed.
The pressure measured in the arteries while the ventricles are relaxed (during diastole).
The portion of theforebrain that includes the thalamus and hypothalamus.
The specialization of cell types
The movement of a particle (the solute) in a solution from its region of high concentration to its region of low concentration ( or down it concentration gradient).
An organism that has two copies of its genome it each cell. The paired genomes are said to be homologous.
A molecule composed of two monosaccharides. Common disaccharides include maltose
Distal convoluted tubule
The portion of the nephron tubule after the loop of Henle
A form of evolution in which the same organism is placed into different environments with different selection pressures. This causes organisms to evolve differently
Also called DNA pol
The allele in a heterozygous genotype that is expressed; the phenotype resulting from either a heterozygous genotype or a homozygous dominant genotype.
Dorsal root ganglion
A group of sensory neuron cell bodies found just posterior to the spinal cord on either side. A pair of root ganglia exists for each spinal nerve that expands from the spinal cord. The ganglia are part of the peripheral nervous system (PNS).
Toward the 3' end of an RNA transcript (the 3' end of the DNA coding strand). Stop codons and (in eukaryotes) the pol-A tail are found 'downstream.'
The first (approximately 5%) of the small intestinte.
A contractile protein connecting microtubules in the '9+2- arrangement of cilia and eukaryotic flagella. The contraction of dynein produces the characteristic movement of these structures.
One of the three primary (embryonic) germ layers formed during gastrulation. Ectoderm ultimately forms external structures such as the skin
Swelling of tissues
The organ that carries out teh command sent along a particular motor neuron
The small artery that carries blood away from the capillaries of the glomerulus.
A neuron that carries information (action potentials) away from the central nervous system; a motor neuron.
A subphase of male orgasm
The fraction of teh end-diastolic volume ejected from the ventricles in a single contraction of teh heart. THe ejection fraction is normally around 60% of the end diastolic volume.
A type of syanpse in which the cells are connected by gap junctions
Electron transport chain
A series of enzyme complexes found along the inner mitochondrial membrane. NADH and FADH2 are oxidized by tehse enzymes; the electrons are shuttled down the chain and are ultimately passed to oxygen and to produce water. The electron energy is used to pump H+ out of the mitochondrial membrane; the resulting H+ gradient is subsequently used to drive the production of ATP.
The period of human development from implantation through 8 weeks of gestation. Gastrulation
A subphase of male orgasm. Emission is the movement of sperm (via the vas deferens) and semen into the urtehra in prepartion for ejaculation.
A ductless gland that secretes a hormone into the blood
A systme of ductless glands taht secrete chemical messengers (into) the blood - has to be into the blood.
The uptake of material into a cell
One of the three primary (embryonic) germ layers formed during gastrulation. Endoderm ultimately forms internal structures
The 28 days of the menstrual cycle as they apply to the events in the uterus. The endometrial cycle is also known as the uterine cycle
The inner epithelial lining of the uterus that thickens and develops during the menstrual cycle
A bacterial structure formed in unfavorable growth conditions. Endospores have very rough outer shells made of peptidoglycan and can survive harsh conditions. The bacterium inside the endospore is essentially dormant and can become active (called germination) when conditions again become favorable.
the theory that mitochondria and chloroplasts originated as independent unicellular organsims living in symbiosis with larger cells
A normal component of the outer membrane of Gram-negative bacteria. Endotoxins produce extreme immune reactions (septic shock)
End plate potential
The depolarzation of the motor end plate on a muscle cell.
Enteric nervous system
The nervous system of the gastrointestinal tract. It controls secretion and motility within teh Gi tract
A hormone secreted by the small intestine (duodenum) in response to the presence of food. It decreases the rate at which chyme leaves the stomach and enters the small intestine.
A duodenal enzyme that activates trypsinogen (from the pancreas) to trypsin.
A lipid bilayer that surrounds the capsid of an animal virus. the envelope is acquired as teh virus buds out through the plasma membrane of its host cell. Not all annimal viruses possess and envelope.
A physiological catalyst. Enzymes are usually proteins
The outermost layer of teh skin. The epidermis is made of epithelial tissue that is constantly dividing at the bottom; teh cells migrate to teh surface (dying along the way) to be sloughed off at the suface.
A flexible piece of cartilage in the larynx that flips downward to seal teh trachea during swallowing.
A hormone produced and secreted by teh adrenal medulla that prolongs and increases teh effects of the sympathetic nervous system.
A band of carilage (hyaline) found between the diaphysis and epiphyses of long bones during childhood and adolescence. Cell proliferation in the middle of the eiphyseal plate essentially forces teh diaphysis and epiphyses further apart
One of the two ends of long bone (pl: eiphyses). The epiphyses have an outer shell made of compact bone and inner core of spongy bone. The spongy bone is filled with red bone marrow
A situation in which the expression of one gene prevents expression of all allelic forms of another gene
One of the four basic tissue types in the body (epithelial
The specific site on an antigenic molecule that binds to a T cell receptor or to an antibody.
Excitatory postsynaptic potential; a slight depolarization of a postsynaptic cell
Specialized tissue with a lot of space that can fill with blood upon proper stimulation
A red blood cell; they are filled with hemoglobin
A hormone produced and released by the kidney that stimulates the production of red blood cells by the bone marrow.
The primary female sex hormone. Estrogen stimulates the development of female secondary sex characteristics during puberty
DNA that is loosely packed around histones. This DNA is more accessible to enzymes and the genes in euchromatin can be activated if needed.
A cell characterized by the presence of a nucleus and other membrane-bound organelles. Eukaryotes can be unicellular (protists) or multicellular (fungi
The removal ( and usually the activation) of a viral genome from its host's genome.
The mechanism that ensures tehat skeletal muscle contraction does not occur without neural stimulation (excitation). A trest
The elimination of wastes from the body.
A gland that secretes its product into a duct
The secretion of a cellular product to the extracellular medium through a secretory vesicle.
A nucleotide sequence in RNA that contains protein-coding information. Exons are typically separated by introns (intervening sequences) that are spliced out prior to translation.
A toxin that secreted by a bacterium into its surrounding medium that help the bacterium compete with other species. Some exotoxins cause serious disease in humans (botulism
The movement of air out of the respiratory tract. Expiration can be passive (caused by relaxation of the diaphragm and elastic recoil of the lungs) or active (caused by contraction of the abdominal muscles
Movement of a hydrophilic molecuel across the plasma membrane of a cell
An organism that will use oxygen (aerobic metabolism) if it is available
The reduced from (carries electrons) of FAD (flavin adenine dinucleotide). this is the other main electron carrier in cellular respiration (NADH is the most common).
A bundle of skeletal muscle cells. Fascicles group together to form skeletal muscles.
Fast block to polyspermy
The depolarization of the egg plasma membrane upon fertilization
Also called negative feedback
The reduction of pyruvate to either ethanol or lactate in order to regenerate NAD+ from NADH. Fermentation occurs in the absence of oxygen
The fusion of a sperm with an ovum during sexual reproduction. Fertilization typically occurs in the uterine tubes and requires capacitation of the sperm and relase of the acrosomal enzymes. Fertilization is a species-specific process
F (fertility) factor
A bacterial extrachromosal elent that allows the bacterium to initati conjugation. Bacteria that possess teh F factor are known as F+ 'males'.
The period of human development beginning at 8 weeks of gestation and lasting until birth (38-42 weeks of gestation). During this stage the organs formed in the embryonic stage grow and mature. The developing baby is known as a fetus during this time period.
A blood protein essential to blood clotting. The conversion of fibrinogen to its active form (fibrin) is among the final steps in clot formation
A generic connective tissue cell that produces fibers; the progenitor of all other connective tissue cell types.
The movement of a substance across a membane via pressure. In the kidney
Fingerlike projection of the uterin (fallopian) tubes that drape over the ovary.
First law of Thermodynamics
The law of conservation of energy; the energy of the universe is constant
Fluid mosaic model
the current understanding of membrane structure
A developing oocyte and all of its surrounding (supporting) cells.
A tropic hormone produced by the anterior pituitary gland that targets the gonads. In females
The first phase of the ovarian cycle
The first generation of offspring from a given genetic cross.
The cellular elements of blood; erythrocytes
A mutation caused by an insertion or deletion of base pairs in a gene sequence in DNA such that the reading frame of the gene (and thus teh amino acid sequence of the protein) is altered.
Frank Starling mechanism
A mechanism by which the stroke volume of the heart is increased by increasing the venous return of the heart (thus stretching the ventricular muscle).
A tissue in which the cytoplasms of the cells are connected by gap junctions
A digestive accessory organ near the liver. The gallbladder stores and concentrates bile produced by the liver
The formation of haploid gametes (sperm or ova) via meiosis.
A clump of gray matter (unmyelinated neuron cell bodies) found in the peripheral nervous system.
A junction between cells
A phase in the cycle between mitosis and S phase (G1) or between S phase and mitosis (G2). During gap phases the cell undergoes normal activity and growth; G1 may include preparation for DNA replication and G2 includes preparation for mitosis. Note that non-dividing cells remain permanently in G1
A hormone released by teh G cells of the stomach in the presence of food. Gastrin promotes muscular activity of the stomach as well as secretion of hydrochloric acid
the division of the inner cell mass of a blastocyst (developing embryo) into the three primary germ layers. Gastrulation occurs during weeks 2-4 of gestation.
A portion of DNA that codes for some product
The sum of all genetic material in a population.
The 'language' of a molecular biology that specifies which amino acid corresponds to which three-nucleotide group (codon).
All the genetic information in an organism; all of an organism's chromosomes.
The combination of alleles of an organism carries. In a homozygous genotype
Gibbs free energy
The energy in a system that can be used to drive chemical reactions. If the change in free energy of a reaction (Delta G
The ball of capillaries at the beginning of the nephron where blood filtration takes place.
A peptide hormone produced and secreted by the alpha cells
A membrane lipid consisting of a glycerol molecule esteried to two fatty acid chains and a sugar molecule.
Unicellular exocrine glands found along the respiratory and digestive tracts taht secrete mucus.
A stack of membranes found near the rough ER in eukaryotic cells that is involved in the secretory pathway. The Golgi is involved in protein glycosylation (and other protein modification) and sorting and packagin proteins.
Gonadotropin releasing hormone (GnRH
A hormone released from the hypothalamus that triggers the anterior pituitary to secrete FSH and LH.
Anterior pituitary topic hormones FSH (follicle stimulating hormone) and LH (luteinizing homeon) that stimulates the gonads (testes and ovaries) to produce gametes and to secrete sex steroids.
G-protein linked receptor
A cell surface receptor associated with an intracellular protein that binds and hydrolyzes GTP. When GTP is bound
Bacteria that have a thin peptidoglycan cell wall covered by an outer plasma membrane. They stain very lightly (pink) in Gram stain. Gram-negative bacteria are typically more resistant to antibiotics than Gram-positive bacteria.
Bacteria that have a thick peptido glycan cell wall
the majority of the cells surrouding an oocyte in a follicle. Granulosa cells secrete estrogen during the follicular phase of the ovarian cycle (before ovulation).
Unmyelinated neuron cell bodies and short unmyelinated axons.
A hormone released by the anterior pituitary that targets all cells in the body. Growth hormone stimulates whole body growth in children and adolescents
One of the four aromatic bases found in DNA and RNA. Guanine is a purine; it pairs with cytosine.
Chemoreceptors on the tongue that respond to chemicals in a food.
A prokaryotic enzyme used to twist teh single circular chromosome of prokaryotes upon itself to form supercois. Supercoiling helps to compact prokaryotic DNa and make it sturdier.
Sensory receptors found in the inner ear. Cochlear hair cells respond to vibration in the cochlea caused by sound waves and vestibular hair cells respond to changes in position and acceleration (used for balance).
An organism that has only a single copy of its genome in each of its cells. Haploid organisms possess no homolous chromosomes.
A law of population genetics that states that the frequencies of alleles in a given gene pool do not change over time. There are five assumptions required for this law to hold true: there must be no mutation
Human Chorionic Gonadotropin
An enzyme that unwinds the double helix of DNA and separates the DNA strands in preparation for DNA replication.
The percentage of wholeblood made up of erythrocytes The typical hematocrit value is between 40-45%.
The synthesis of blood cells (occurs in the red bone marrow)
A gene appearing in a single copy in diploid organisms
A four-subunit protein found in red blood cells that binds oxygen. Each subunit contains a heme group
An X-linked recessive disorder in which blood fails to clot properly
The stoppage of bleeding; blood clotting.
Hepatic portal vein
A vein connecting the capillary bed of the intestines with the capillary bed of the liver. This allows amino acids and gluocse absorbed from the intestines to be delivered first to the liver for processing before being transported throughout the circulatory system.
DNA that is densely packed around histones. The genes in heterochromatin are generally inaccessible to enzymes and are turned off.
An organism that cannot make its own food
A genotype in which two different alleles are possessed for a given gene.
The enzymes that catalyzes the phosphorylation of glucose to form glucose-6-phosphate in the first step of glycolysis. This is one of the ain regulatory steps of this pathway. Hexokinase is feedback-inhibited by glucose-6-P.
High frequency of recombination bacterium An F+ bacterium that has the fertility factor integrated into its chromosome. When conjugation takes place
Globular protein that assist in DNA packaging in eukaryotes. Histones form octamers around which DNA is wound to form a nucleosome.
Heterogeneous nuclear RNA; the primary transcript made in eukaryotes before splicing.
The maintenance of relatively constant internal conditions (such as temperature
A pair of similar chromosomes that have the same genes in the same order
Physical structures in two different organisms that have structural similarity due to a common ancestor
A genotype in which two identical alleles are possessed for a given gene. The allelles can both be dominant (homozygous dominant) or both be recessive (homozygous recessive)
Specif ic defense of the body by antibodies
Hardy crystals consisting of calcium and phosphate that form the bone matrix.
The movement of the membrane potential of a cell away from rest potential in a more negative direction.
Aso called a subcutaneous layer
The pituitary gland.
Hypothalamic-pituitary portal system
A set of veins that connect a capillary bed in the hypothalamus (the primary capillary plexus) with a capillary bed in the anterior pituitary gland (the secondary capillary bed). Releasing and inhibiting factors from the hypothalamus travel along the veins to directly affect cells in the anterior pituitary.
The portion of the diencephalon involved in maintaining body homeostasis. the hypothalamus also controls the release of hormones from the pituitary gland.
The region at the center of an A band of a sarcomere that is made up of myosin only. The H zone gets shorter (and may disappear) during muscle contraction.
The regino of the sarcomere made up only of thin filaments. The I band is bisected by a Z line. I bands alternate with A bands to give skeletal and cardiac muscle a striated appearance. I bands get shorter (and may disappear completely) during muscle contraction.
The sphincter that separates the final part of the small intestine (the ileum) from the fron part of the large intestine (the cecum). It is typically kept contracted (closed) so that chyme can remain in the small intestine as long as possible. The ileocecal valve is stimulated to relax by the presence of food in the stomach.
The final section (approximately 55%) of the small intestine.
The burrowing of a blastocyst (a developing embryo) into the endometrium of the uterus
A situation in which a heterozygot displays a blended version of the pheotypes associated with each allele
An enzyme whose transcription can be stimulated by an abundance of its substrate (as opposed to repressible enzyme). Usually in catabolism.
The process by which neighboring cells can influence the determination (and subsequent differentiation) of a cell.
An irritation of a tissue caused by infection or injury. Inflammation is characterized by four cardinal symptoms; redness (rubor)
A protein hormone secreted by sustenacular cells of the testes that acts to inhibit the release of FSH and LH from the anterior pituitary.
Inner cell mass
The mass of cells in the blastocyst that ultimately give rise to the embryo and other embryonic structues (the amion
The movement of air into the respiratory tract. Inspiration is an *active process*
A peptide hormone produced and secreted by the Beta cells of the pancreas. Insulin targets cells in the body
Integral membrane protein
A protein embedded in the lipid bilayer of a cell. These are typicallly cell surface receptors
The division between neighboring cardiac muscle cells. Intercalcated discs include gap junctions
Muscles located in between the ribs that play a role in ventilation.
A chemical secreted by a T cell (usually the helper Ts) that stimulates activation and proliferation of other immune system cells.
Cytoskeletal filaments with a diameter in between that of the microtubule and the microfilament. Intermediate filaments are composed of many different proteins and tend to play structural roles in cells.
A neuron found completely within the central nervous system. Interneous typically connect sensory and motor neurons
The portion of the cardiac conduction system between the SA node and the AV node.
All of the cell cycle except for mitosis. Interphase includes G1
Also called Leydig cells
A nucleotide sequence that intervenes between protein-coding sequences. In DNA
A protein channel in a cell membrane that is specific for a particular ion
Inhibitory postsynaptic potential; a slight hyperpolarization of the postysynaptic cell
A pigmented membrane found just in from the lens of the eye. In the center of iris is the pupil
Islets of Langerhans
"Also called simply
The middle (approximtely 40%) of the small intestine.
Juxtaglomerular apparatus (JGA)
A contact point between the afferent arteriole of the glomerulus and the distal convoluted tubule of the nephron. It is involved in regulating blood pressure.
The cells of the afferent artery at the juxtaglomerular apparatus. They are baroreceptors that secrete renin upon sensing a decrease in blood pressure.
A protein-based substance secreted by cells of the epiderms as they migrate outward. The keratin makes the cells tougher (better able to withstand abrasion) and helps make the skin waterproof.
An enzyme that phosphorylates something else. Kinases are frequently used in regulatory pathways
The third stage of cellular respiration
The folds of skin that enclose the vaginal and urethral openings of females.
Strong contractions of the uterus (stimulated by oxytoncin) that force a baby out of the mother's baby during childbirth. Labor contractions are part of a positive feedback cycle
Specialized lymphatic capillaries in the intestines that take up lipids as well as lymph.
Produced in muscle cells from the reduction of pyruvate (under anaerobic conditions) to regenerate NAD+ so that glycolysis can continue. A rise in lactic acid usually accompanies an increase in physical activity.
Small cavities in the bone or cartilage that hold individual bones or cartilage cells.
The newly forming daughter strand of DNA that is replicated in a discontinuous fashion
A short period of time **prior to exponential growth of a bacterial population during which no
The final phase of the digestive tract
A rigid structure at the top of the trachea (so it is part of trachea
Law of Independent Assortment
Mendel's seond law. States that genes found on different chromosomes
Law of Segregation
Mendels' first law. The Law of Segregation states that the two alleles of a given gene will be separate from one another during gamete formation (meiosis).
A dense grwoth of bacteria that covers the surface of a petri dish.
The newly forming daughter strand of DNA that is replicated in a continuous fasion; the daughter strand that is replicated in thes aem direction that parental DNA is unwinding.
An ion channel that is constitutively open
The relationship of muscle length to its ability to generate strong contractions. Maximum tension (contraction strength) is achieved at sarcomere lengths between 2.0 and 2.2 microns. Tension decreases outside of this range <-- remember.
A type of white blood cell; leukocytes are either B or T cells and are involved in disease defense.
A strong band of connective tissue that connets bones to one another.
The specific molecule that binds to a receptor.
Ligand-gated ion channel
An ion channel that is opened or closed based on the binding of a specific ligand to teh channel. Once opened
An enzyme that connects two fragments of DNA to make a single fragment; also called DNA ligase. This enzyme is usedd during DNA replication and is also used in recombinant DNA research.
Large conglomerations of proteins
The failure of two separate genes to boey the Law of Independent Assortment
A hydrophobic molecule
The largest organ in the abdominal cavity. The liver has many roles
The ability of tissues to regulate their own blood flow in the absence of neural stiulation. THis is generally accomplished via metabolic wastes (such as CO2) that act as vasodilators.
The period of exponential growth of bacterial population.
The most common class of bone in the body
The outer layer of smooth muscle in the wall of the digestive tract. When the longitudinal muscle contracts the tube shortens.
Loop of Henle
The loop of the nephron that dips downward into the renal medulla. The loop of Henle sets up a concentration gradient in the kidney such that from the cortex to the renal pelvis osmolarity increases. The descending limb of the loop of Henle is permeable to water
Loose connective tissue
Connective tissue that lacks great amount of collagen or elastic fibers (hence
Lower esophageal sphincter
Formerly called the cardiac sphincter
The inside of the a hollow organ (e.g.
The third phase of the ovarian cycle
Luteinizing Hormone (LH)
A tropic hormone produced by the anterior pituitary gland that targets the gonads. In females LH triggers ovulation and the development of a corpus luteum during the menstrual cycle; in males
A set of vessels in the body that runs alongside the vessels of the circulatory system. It is a one-way system
A concentrated region of white blood cells found along the vessels of the lympatic system.
The second most common of the five classes of leukocytes. Lymphocytes are involved in specific immunity and include two cell types
A chemical secreted by a T cell (usually the helper Ts) that stimulates activation and proliferation of other immune system cells.
A viral life cycle in which the viral genome is incorporated into the host genome where it can remain dormant for an unspecified period of time. Upon activation
A eukaryotic organelle filled with digestive enzymes (acid hydrolases) that is involved in digestion of macromolecules such as worng organelles or material ingested by phagocytosis.
An enzyme that lyses bacterial cell walls. Lysozyme is produced in the end stages of the lytic cycle so that new viral particles can escape their hosst; it is also found in human tears and human saliva.
"A viral life cycle in which the host is turned into a ""virus factory"" and ultimately lysed to release the new viral particles."
The cells of the distal tubule at the juxtaglomerular apparatus. They are receptors that monitor filtrate osmolarity as a means of regulatin filtration rate. If a drop is osmolarity is sensed
Genes that are inherited only from the mother
The interior of a mitochondrion (the region bounded by the inner membrane).
A sensory receptor that responds to mechanical disturbances
The environment in which or upon which bacteria grow. It typically contains a sugar source and any other nutrients that bacteria may require. 'Minimal medium' contain nothing but glucose.
The inner region of an organ
The portion of the hindbrain that controls respiratory and blood pressure
A type of cell division (in diploid cells) that reduces the number of chromosomes by half. Meiosis usualy produces haploid gametes in organisms that undergo sexual reproduction. It consists of a single interphase (G1
A pigment produced by melanocytes in teh bottom cell layer of the epidermis. Melanin production is increased on sun exposure and helps prevent cllular damage due to UV radiation.
A cell produced when a B cell is activated by antigen. Memory cells do not actively fight the current infection
The perio dof tim ein a woman's life when ovulation and menstruation cease. Menopause typically begins in the late 40s.
The first phase of the uterine (endometrial) cycle
One of the three primary (embryonic) germ layers formed during gastrulation. Mesoderm ultimately forms 'middle' structures such as bones
The secon phase of mitosis. During metaphase chromosomes align at the center of the ell (the metaphase plate).
The second phase of meiosis I. During metaphase I the paired homologous chromsomes (tetrads) align at the center of the cell (the metaphase plate).
The second phase of meiosis II. Metaphase II is identical to mitotic metaphase
"Major Histocompatability complex
The cytoskeleton filaments with the smallest diameter. Microfilaments are composed of the contractile protein actin. They are dynamic filaments
The largest of the cytoplasmic filaments. Microtubules are composed of two types of protein
Microscopic outward folds of the cells lining the small intestine; microvilli serve to increase the surface area of the small intestine for absorption.
The portion of the brain responsible for visual and auditory startle reflexes.
The release of milk from the mammary glands via contraction of ducts within the glands. Contraction is stimulated by oxytocin
A point mutation in which a codon that specifies an amino acid is mutated into a codon that specifies a different amino acid.
An organelle surrounded by a double=membrane (two lipid bilayers) where ATP production takes place. The interior (matrix) is where PDC and the Krebs cycle occur
The phase of the cell cycle during which the replicated genome is divided. Mitosis has four phases (prophase
mRNA that codes forsingle type of protein
The monomer of a carbohydrate. Monosaccharides have the general chemical formula CnH2nOn
A solid clump of cells resulting from cleavage in the early embryo. Because there is very little growth of these cells during cleavage
Motor end plate
The portion of the cell membrane at the neuromusclar junction; essentially the postsynaptic membrane at the synapse.
A motor neuron and all the all the skeletal muscle cells it innervates. Large motor units are typically found in large muscles (e.g.
Motor unit recruitment
A mechanism for increasing tension (contractile length) in a muscle by activating more motor units.
Messenger RNA; the type of RNa that is read by a ribosome to synthesize protein.
The layer of ciliated
The layer of epithelial tissue that lines body cavities in contact with the outside environment (respiratory
Earlier embryonic ducts that can develop into femal internal genitalia in the absence of testosteron.
Mullerian inhibiting factor (MIF)
A substance secreted by embryonic testes that causes the regression of the Mullerian ducts.
A neuron with a single axon and multiple dendrites; the most common type of neuron in the nervous system.
A form of symbiosis in which both organisms involved benefit from the association.
An insulating layer of membranes wrapped around the axons of almost all neurons in the body. Myelin is essentially the plasma membranes of specialized cells; Schwann cells in the peripheral nervous system
A skeletal muscle cell
A string of sarcomeres with a skeletal muscle cell (hence smaller than myofiber). Each muscle cell contains hundreds of myofibirils.
A globular protein found in muscle tissue that has the ability to bind oxygen. Myoglobin helps to store oxygen in the muscle for use in aerobic respiration (it does not move
The muscuar layer of the uterus. The myometrium is made of smooth muscles that retains its ability to divide in order to accomodate the massive size increases that occur during pregnancy. The myometrium is stimulated to contract during labor by the hormone oxytocin.
One of the contractie proteins in muscle tissue. In skeletal and cardiac muscles
Myosin light-chain kinase (MLCK)
A kinase in smooth muscle cells activated by calmodulin the presence of Ca2+. As its name implies
The reduced form of NAD+ (nicotinamide adenine dinucleotide). This is the most common electron carrier in cellular respiration.
A protein found in the plasma membrane of all cells in the body that uses the energy of an ATP (hydrolyzes ATP) to move three Na+ ions out of the cell and two K+ ions into the cell
The mechanism described by Charles Darwin that drives evolution. Through mutation
The function unit of the kidney. Each kidney has about a million nehprons; this is where blood filtration and subsequent modification of the filtrate occurs. The nephron empties into collecting ducts
The basic functional and structural unit of the nervous system. The neuron is a highly specialized cell
The synapse between a motor neuron and a muscle cell. At the NMJ
A chemical released by the axon of a neuron in response to an action potential that binds to receptors on a postsynaptic cell and causes that cell to either depolarize slightlly (EPSP) or hyperpolarize slightly (IPSP). Examples are acetylcholine
The formatino of the nervous system during weeks 5-8 of gestation. Neuralation begins when a section of the ectoderm invaginates and pinches off to form the neural groove
Pain receptors. Nociceptors are found everywhere in the body except for the brain.
Nodes of Ranvier
Gaps in the myelin sheath of the axons of peripheral neruons. Action potentials can 'hump' from node to node
An enzyme inhibitor that binds at a site other than the active sit of an enzyme (binds at an allosteric site). THis changes the three-dimensional shape of the enzyme such that it can no longer catalyze the reaction
The failure of homologous chromosomes or sister chromatids to separate properly during cell division. This could ocur during *anaphase I of meiosis (homologous chromosomes) [--> leaving 2 gametes w/ 2 copies and 2 gametes w/ no copies of chromosome]
A point mutation in which a condon that specifies an amino acid is mutated into a stop (nonsense) codon.
The neurotransmitter used by the sympathetic division of the ANS at the postganglionic (organ-level ) synapse.
The membrane surrounding the DNA in eukaryotic cells made of two lipid bilayers.
Nuclear localization sequence
A sequence of amino acids (usually basic) that directs a protein to the nuclear envelope
A protein channel in the nuclear envelope that llows the free passage of molecules smaller than 60 kD.
A region within the nucleus where rRNA is transribed and ribosomes are partially assembled.
A structure composed of a ribose molecule linked to one of the aromatic bases. In a deoxynucleoside
A structure composed of two coils of DNA wrapped around an octet of histone proteins. The nucleosome is the primary form of packagin of eukaryotic DNA.
A nucleoside with one or more phosphate gropus attached. Nucleoside triphosphates (NTPs) are the building blocks of RNA and are also used as energy molecules
An organelle bounded by a double membrane (double lipid bilayer) called the nuclear envelope. The nucleus contains the genome and is the site of replication and transcription.
The string between beads of DNA on histones. They are also wrapped around a single histone
An organism that requires oxygen to survive (aerobic metabolism only).
An organism that can only survive in the absence of oxygen (anaerobic metabolism); oxygen is toxic to obligate anaerobes.
Small fragments of DNa produced on the lagging strand during DNa replication
Chemoreceptors in the upper nasal cavity that respond to odo chemicals.
The osmotic pressure in the blood vessels due only to plasma proteins (primarily albumin) --> causes water to rush back into capillaries at end.
A *precursor* cell that undergoes mitosis during fetal development to produce more oogonium. These cells are then activated to produce primary oocytes
A specific DNA nucleotide sequence where transcriptional regulatory proteins can bind.
A nucleotide sequence on DNA that contians three elemtns: a coding sequence for one or more enzymes
The 'blind spot' of the eye
The nerve extending from the back of teh eyeball to teh brain that carries visual information. The ptic nerve is made up of the axons of the ganglion cells of the retina.
Organ of Corti
The structure in the cochlea of the inner ear made up of the basilar membrane
The stage of human development during which the organs are formed. Organogenesis begins after gastrulation and is completed by the eight week of gestation.
A function of the reproductive system controlled by the sympathetic nervous system. In males
Origin of replication
The specific location on a DNa strand where replication begins.. Prokaryotes typically have a single origin of replication
The movement of water (the solvent) from its region of high concentration to its region of low concentration. NOte that the water concnetration gradient is opposite to the solute concentration gradient
The force required to resist the movement of water by osmosis. Osmotic pressure is essentialy a measure of the concentration of a solution. A solution that is hyighly concnetrated has a strong tendency to draw water into itself
The three small bones found in the middle ear (the malleus
A cell that produces bone.
A phagocytic-like bone cell that breaks down bone matrix to release calcium and phosphate into the bloodstream.
The unit of combact bone
The portion of the ear consisting of the pinna and the external auditory canal. The outer ear is separated from the middle ear by the tympanic membrane (the eardrum).
The membrane that separates the middle ear from the inner ear.
The 28 days of the menstrual cycle as they apply to events in the ovary. The ovarian cycle has three subphases: the follicular phase
The female primary sex organ. The ovary produces female gametes (ova) and secretes estrogen and progesterone.
The release of a secondary oocyte (along with some granulosa cells) from the ovary at the approximate midpoint of the menstrual cycle (typically around day 14). Ovulation is triggered by a surge in LH.
A four-carbon molecule that binds with the two-carbon acetyl unit of acetyl-CoA to form citric acid in the first step of the Krebs cycle.
To attach oxygen
The oxidation of high-energy electron carriers (NADH and FADH2) coupled to the phosphorylation of ADP
A hormone released by the posterior pituitary that stimulates uterine contractions during childbirth and milk ejection during breastfeeding.
A self-initiating action potential that occurs in the conduction system of the heart and triggers action potentials (and thus contraction) in the cardiac muscle cells Tee pacemaker potential is triggered by the regular
An organs in the abdominal cavity with two roles. The first is an exocrine role: to produce digestive enzymes and bicarbonate
The main duct of the pancreas. The pancreatic duct carries the exocrine secretions of the pancreas (enzymes and bicarbonate) to the small intestine (dueodenum).
An organism that requires the aid of a host organism to survive
Parasympathetic nervous system
The division of the autonomic nervous system known as the 'resting and digesting' system. It causes a general decrease in body activities such as heart rate
Parathyroid hormone (PTH)
A hormone produced and secreted by the parathyroid glands that increases serum calcium levels. It targets the bones (stimulates osteoclasts)
Cells found in gastric glands that secrete hydrochloric acid (for hydrolysis of ingested food) and gastric intrinsic factor (for absorption of vitamin B-12).
The contribution of an individual gas to the total ppressure of a mixture of gases. Partial pressures are used to describe the amounts of the various gases carried in the bloodstream.
Movement across the membrane of a cell that does not require energy input from the cell. Passive transport relies on concentration gradients to provie the driving force for movement
The percentage of individuals with a particular genotype that actually displays the phenotype associated with the genotype.
The second step in viral infection
A protein-digesting enzyme secreted by the chief cells of the gastric glands. Pepsin is secreted in its inactive form (pepsinogen) and is activated by gastric acid. It is unusual in that its pH optimum is around 1-2; most of these enzymes in the body function best at neutral pHs
The bond formed between the carboxyl group of one amino acid and the amino group of another.
A hormone made of amino acids (in some cases just a single
A complex polymer of sugars and amino acids; the substance from which bacterial ell walls are made.
The flow of blood through a tissue; ischeia is when there is no blood flow
Receptors in the carotid arteries and the aorta that monitor blood pH to help regulate ventilation rate.
Peripheral membrane protein
A protein that is associated with the plasma membrane of a cell
Periperal nervous system
All parts of the nervous system except for the brain and spinal cord.
The resistance to blood flow in the systemic circulation. Peripheral resistance increases if arteries constrict (diameter decreases)
The spac0e between the inner and outer cell membranes in Gram-negative bactera. The peptidoglycan cell wall is found in the periplasmic space
A wave of contraction that sweeps along a muscular tube
Small organelles that contain the hydrogen peroxide produced as a byproduct of lipid metabolism. Peroxisomes convert hydrogen peroxide to water and oxygen by way of the enzyme catalase.
The non-specific uptake of solid material by a cell accomplished by englufing the particle with plasma membrane and drawing it into the cell.
A passageway leading from behind the nasal cavity to the trachea. The pharynx is divided into three regions
The physical characterisitcs resulting from the genotype. Phenotypes are usually described as dominant or recessive.
The enzyme that catalyzes the phosphorylation of fructose-6-phosphate to form fructose-1-6-bisphosphate in the third step of glycolysis. This is the main regulatory step of glycolysis. PFK is feedback-inhibited by ATP.
The primary membrane lipid. Phospholipids consist of a glycerol molecule esterified to two fatty acid chains and a phosphate molecule. Additional
A receptor that responds to light
An organism that utilizes light as its primary energy source.
A long projection on a bacterial surface involved in an attachment
The non-specific uptake of liquid particles into a cell by invagination of the plasma membrane and subsequent 'pinching off' a small bit of the extracellular fluid.
An organ that develops during pregnacy
Zygot-derived projections that extend into the endometrium of the uterus during pregnancy. Fetal capillaries grow into the placental villi
A clear area in a lawn of bacteria. Plaques represent an area where bacteria are lysing (dying) and usually caused by a lytic virus.
The liquid portion of blood; plasma contains water
An activated B cell that is secreting antibody.
Extremely small pseudo-cells in the blood
A gene that has effects on several different characteristics.
The membranes that line the surface of the lungs (visceral pleura) and the inside wall of the chest cavity (parietal pleura).
The pressure in the (theoretical) space between the lung surface and the inner wall of the chest cavity.
A type of mutation in DNa where a single base is substituted for another.
A small cell with extremely little cytoplasm that results from the unequal cytoplasmic divsion of the primary (produces the first polar body) and the secondary (produces the second polary body) oocytes during meiosis (oogenesis). The polar bodies degenerate.
A string of several hundred adenine nucletodies added to the 3' end of the eukaryotic mRNA.
mRna that codes for several different proteins by utliizing different reading frames
A molecule formed by joining many monosaccharides together. POlysaccharides are typically energy-storage molecules (glycogen in animals
The fertilization of an oocyte by more than one sperm. This occurs in some animals
A subset of a species consisting of members that mate and reproduce with one another.
A pathway through a plasma membrane that restrics passage based only on the size of the molecules. Pore are made from porin proteins.
A system of blood vessels where the blood passes from arteries to capillaries to veins
Posterior pituitary gland
Also known as the neurohyophysis
In the autonomic division of the PNS
Potassium leak channel
An ion channel specific for potassium found in the plasma membrane of all cells in the body. Leak channels are constitutively open and allow their specifi ion to move across the membrane according to its gadient. Potassium leak channels allow potassium to leave the cell.
The step in the sliding filament theory during which yosin undergoes a conformaitonal change to its low energy state
In the autonomic divison of the PNS
Primary active transport
Active transport that relies directly on the hydrolysis of ATP.
The first branches of the trachea. There are two primary bronchi
Primary immune response
The first encounter with an antigen
Diploid cells resulting from the activation of anoogoium; primary oocytes are ready to enter meiosis I. remember: cyte means ready to undergo meiosi
Diploid cells resultinf rom the activation of a spermatogoium; primary spermatocytes are ready to enter meiosis I. remember: cyte means ready to undergo meiosis.
An RNA polymerase that creates a primer (made of RNA) initiate DNa replication. DNA pol binds to the primer and elongates it.
A life cycle of animal viruses in which the mature viral particles bud from the host cell
A steroid hormone produced by the corpus luteum in the ovary during the second half of the menstrual cycle Progesterone maintains and enhances the uterine lining for the possible implantation of a fertilized ovum. It is the primary hormone secreted during pregnancy.
An organism that lacks a nucleus or any other memrane-bound organelles. All prokaytes belong to the Kingdom Monera (not protista!)
A hormone secreted by the anterior pituitary that tarets the mammary glands stimulating them to produce breastmilk.
The second phase of the uterine (endometrial) cycle
The sequence of nucleotides on a chromosome that activates RNA polymerase so that transcription can take place. The promoter is found upstream of the start site
The first phase of mitosis. During prophase the replicated chromosomes condense
The first phase of meiosis I. During prophase I the replicated chromosomes condense
The first phase of meiosis II. Prophase II is identical to mitotic prophase
A receptor that responds to changes in body position
A small gland encircling the male urethra just inferior to the bladder (only reproductive structure not paired). Its secretion contain nutrients and enzymes and account for approximately 35% of the ejaculate volume.
Molecules made by connecting amino acids via peptide bonds. Proteins are synthesized (translated) by ribosomes
Proximal convoluted tubuel
The first portion of the nephron tubuel after the glomerulus. THe PCT is the site of most reabsorption; all filtered nutrients are reabsorbed here as well as most of the filtered water.
Peptidyl-tRNA site; the stie on a ribosome where the growing peptide (attached to a tRNA) is found during translation.
The blood vessel that carries deoxygenated from the right ventricle of the heart to the lungs.
The flow of blood from the heart
The collection of fluid in the alveoli
One of several vessels that carry oxygenated blood from the lungs to the left atrium of the heart.
A hole in the center of the iris of the eye that allows light to enter the eyeball. The diameter of pupil is controlled by the iris in response to the brightness of the light.
Aromatic bases found in DNA and RNA that are derived from purine. They have a double rightn structure and include adenine and guanine.
The smallest (and final) fibers in the cardiac conduction system. The Purkinje fibers transmit the cardiac impulse to the ventricular muscle.
The valve that regulates the passage of chyme from the stomach into the small intestine.
Aromatic bases found in DNa and RNA that have a single-ring structure. They include cytosine
Pyruvate dehydrogenase complex
A group of three enzymes that decarboxylates pyruvate
The product of glycolysis; 2 pyruvic acid (pyruvate) molecules are produced from a single glucose molecule. In the absence of oxygen
A highly specific cellular uptake mechanism. The molecule to be taken up must bind to cell surface receptor found in a clathrin-coated pit.
The allele in a heterozygou genotype that is not expressed; the phenotype resulting from possession of two recessive alleles (homozygous recessive).
The RF value
The final portion of the large intestine.
To remove oxygen
A relatively direct connection between a sensory neuron and a motor neuron that allows an extremely rapid response to a stimulus
Relative refractory period
The period of time following an action potential when it is possible
A cytoplasmic protein that binds to a stop codon where it appears in the A-site of the ribosome. Release factors modify the peptidyl transferase activity of the ribosome
The movement of a substance from the filtrate (in the renal tuble) bak into the bloodstream. Reabsorption reduces the amount of a substance in the urine.
The portion of the nephron after the glomerulus and apsule; the region of the nephron where the filtrate is modified along its path to becoming urine.
An enzyme secreted by the juxtaglomerular cells when blood pressure decreases. Renin onverts angiotensinogen to angiotensin I.
The duplication of DNA
The site(s) where the parental DNA double helix unwinds during replication.
Multiple sites of replication found on large
The return of membrane potential to normal resting values after a depolarization of hyperpolarization.
An enzyme whose transcription can be stopped by an abundance of its product (as opposed to inducible enzymes). Usually part of anabolism of product.
A regulatory protein that binds DNA at a specific nucleotide sequence (sometimes known as the operator) to prevent transcription of downstream genes.
The volume of air remaining in the lungs after a maximal forced exhalation
A function the reproductive system (conrolled by the sympathetic nervous system) that returns the body to its normal resting state after sexual arousal and orgasm.
A drop in blood pH due to hypoventilation (too little breathing) and a resulting accumulation of Co2.
Arise in blood pH due to hyperventilation (excessive breathing) and a resulting decrease in CO2.
Resting membrane potential
An electrical potential established across the plasma membrane of all cells by the Na+/K+ ATPase and the K+ leak channels. IN most cells
A bacterial enzyme that recognizes a specific DNA nucleotide sequence and that cuts the double helix at a specific site within the sequence.
The innermost layer of the eyeball. The retina is made up of a layer of photoreceptors
A chemical derived from vitamin A found in the pigment proteins of the rod photoreceptors of the retina. Retinal changes conformation when it absorbs light
A virus with an RNA genome (e.g. HIV) that undergoes a lysogenic life cycle in a host with a double stranded DNA genome. In order to integrate its genome with the host cell genome
An enzyme that polymerizes a strand of DNA by reading an RNA template (an RNA dependent DNa polymerase); used by retrovirus in order to integrate their genome with the host cell genome.
A structure made of two protein subunits and rRNA; this is the site of protein synthessis (translation) in a cell. Prokaryotic ribosomes (also known as 70S ribosomes) are smaller than eukaryotic ribosome (80S ribosomes). The S value refers to the sedimentation rate during centrifugation.
RNA dependent RNA polymerase
A viral enzyme that makes a strand of RNA by reading a strand of RNa . All prokaryotic and eukaryotic RNa polymerases are DNa dependent; they make a strand of RNa by reading a strand of DNA.
An enzyme that transcribes RNa. Prokaryotes have a single RNA pol
Photoreceptors in the retina of the eye that respond to dim light and provide us with black and white vision.
Rough endoplasmic reticulum
A large system of folded membranes within a eukaryotic cell that has ribosomes bound to it
Ribosomal RNA; the type of RNA that associates with ribosomal proteins to make a functional ribosome. It is thought that the rRNA has the peptidyl transferase activity.
Rule of addition
A statistical rule stating that the probability of either of two indpendent (and mutually exclusive) events ocuring is the sum of their individual probabilities minus the probability of them both occuring together.
Rule of multiplication
A statistical rule stating that the probability of two independent events occuring together is the product of their individual probabilities.
A rapid from of action potential conduction along the axon of a neuron in which the action potential appears to jump from nodde of Ranvier to node of Ranvier.
An organism (such as a fungus) that feeds of dead plants and animals.
The plasma membrane of a muscle cell.
The unit of muscle contraction. Sarcomeres are bounded by Z lins
The smooth ER of a muscle cell
One of the two peripheral nervous system supporting (glial) cells. Schwann cells from he myelin sheath on axons of peripheral neurons.
The white portion of teh tough outer layer of the eyeball
Oil-forming glands found all over the body
Seondary active transport
Active transport that releies on an established concentration gradient
Secondary immune response
"A subsequent immune response to previously encountered antigen that results in antibody production and T cell activation. The secondary immune response is mediated by memory cells (produced during the primary immune respone) and is much faster and stronger than the rpimary response
A haploid cell resulting from the first meiotic division of oogenesi (not that the cytoplasmic division in this case is unequal
Haploid cells resulting from the first meiotic division of spermatogenesis. Secondary spermatocytes are ready to enter meiosis II.
Secondary sex characteristics
The set of adult characteristics that develop during puberty under the control of the sex steroids. In males the secondary sex characteristics include enlargement and maturation of the genitalia
Second Law of Thermodynamics
The entropy (disorder) of the universe (or system) tends to increase.
An intracellular chemical signal (such as cAMP ) that relays instructions from the cell surface to enzymes in the cytosol.
A hormone secreted by the small intestine (duodenum) in response to low pH (e.g.
(1) The secretion of useful substances from a cell
The third phase of the uterin (endometrial) cycle
Three loop-like structures in the inner ear that contain sensory receptors to monitor balance.
DNA replication in which each of the parental strands is read to make a complementary daughter strand
The valves in the heart that separate the ventricles from the arteries. The pulmonary semilunar valve separates the right ventricle from the pulmonary artery
Paired glands found on the posterior external wall of the bladder in males. Their secretions contain an alkaline mucus and fructose
Small convoluted tubules in the testes where spermatogenesis takes place.
Cells that form the walls of the seminiferous tubules and help in spermatogenesis Sertoli cells are also called susenacular cells.
Plasma with the *clotting factors removed*. Serum is often used in diagnostic tests because it does not clot.
A triat determined by a gen on either the X or Y chromosomes (the sex chromosomes).
The prokaryotic ribosome-binding site on mRNA
Signal recognition particle (SRP)
A cytoplasmic protein that recognizes the signal sequences of proteins destined to be translated at the rough ER. It binds first to the ribosome translating the protein with the signal sequence then to an SRP receptor on the rough ER>
A short sequence of amino aids
The intracellular process triggered by the binding of a ligand to its receptor on the cell surface. Typically this activates seond messenger pathways.
A point mutation in which a codon that specifies an amino acid is mutated into a new codon that specifies the same amion acid.
The movement of a hydrophobic molecule across the plasma membrane of cell
Single strand binding proteins
Proteins that bind to and stabilize the signle strands of DNA exposed when helicase unwinds the double helix in preparation for replication.
Sinoatrial (SA) node
A region of specialized cardiac muscle cells in the right atrium of the heart that initiate the impules of heart contraction; for this reason the SA node is knownas the 'pacemaker' of the heart.
Identical copies of a chromosome
Muscle tissue that is attached to the bones. SKeletal muscle is striated multinucleate
Siding filament theory
The mechanism of contraction in skeletal and cardiac muscl cells. It is a series of four repeated steps: (1) myosin binds actin
Slow block to polyspermy
Also known as the cortical reaction
The regino of the digestive tract where virtually al digestion and absorption occur. It is subdivided into three regions: the duodenum
Smooth Endoplasmic Reticulum
A network of membranes inside eukarytoic cells invovled in lipid synthesis (steroid in gonads)
Muscle tissue found in the walls of hollow organs
The cell body of a neuron.
Somatic nervous system
The division of the peripheral nervous system that innervates and controls the skeletal muscles; also known as the voluntary nervous system.
Integration by a postsynaptic neuron of inputs (EPSPs and IPSPs) from multiple sources.
A haploid but immature cell resulting from the second meiotic division f spermatogenesis. Spermatids undergo significant physical changes to become mature sperm (spermatozoa).
Sperm production; occurs in human males on a daily basis from puberty until death. Spermatogenesis results in the production of four mature gametes (sperm) from a single precursor cell (spermatogonium). For maximum sperm viability
A diploid cell that can undergo mitosis to form more spermatogonium
The phase of the cell cycle during which the genome is replicated.
Sphincter of Oddi
The valvecontrolling release of bile and pancreatic juice into the bloodstream.
A blood pressure cuff
A bacterium having a spiral shape (plural = spirochetes)
An abdominal organ that is considered part of the immune system. THe spleen has four functions: (1) it filters antigen from the blood (2) it is the site of B cell maturation
One type of eukaryotic mRNA processing in which introns are removed from the primary transcript and exons are ligated together. SPlicing of transcripts can be different in different tissues.
The location on a chromosome where transcription begins.
A hormone derived from cholesterol. Steroids are generally hydrophobic and can easily cross the plasma membrane of cells
The portion of the digestive tract that stores and grinds food. Limited digestion occurs in the somach
A group of nucleotides that does not specify a particular amino acid
The volume of blood pumped out the heart in a single contraction.
The layer of connective tissue directly under the mucosa of an open body cavity.
The reactants in an enzyme-catalyzed reaction. Substrate binds at the active site of an enzyme.
A sweat gland located in the dermis of the skin. Sweat consists of water and ions (including Na+ and urea) and is secreted with temperatures rise.
(1) The integration of input (EPSPs and IPSPs) from many presynaptic neruons by a single postsynaptic neuron
A method of DNA protection utilized by prokaryotes in which their large circular chromosome is coiled upon itself.
An amphipathic molecule secreted by cells in the alveoli (type 2 alveolar cells) tha reducs surface tension on the inside of the alveolar walls. This prevents the alveoli from collapsing upon exhale and sticking together
Sympathic nervous system
"The division of the autonomic nervous system known as the ""fright or flight"" system. It causes a genera increase in body activities such as heart rate
A carrier protein that transports two molecules across the plasma membrane in the same direction. For example
Pairing of homologus chromosomes in a diploid cell
A microscopic space between the axon of one neuron and the cell body or dendrites of a secon neruon
A large multinucleate cell
Something that works together with another thing to augment the the second thing's activity. For example
The flow of blood from the heart
The period of time during which the ventricles of the heart are contracted.
The pressure measured in the arteries during contraction of the ventricles (during systole).
A type of lymphocyte. The major subtypes of T cells are the helper T cells (CD4) and the killer T cells (CD8
The cerebral hemispheres.
A specialized region at the ends of eukaryotic chromosmes that contains several repeats of a particular DNA sequence. These ends are maintained (in some cells) with the help of a special DNA poymerase called telomerase. In cells that lack telomerase
The fourth (and final) phase of mitosis. During telophase the nuclear envelope reforms
The fourth of meiosis I. Telophase I is identical to mitotic telophase
The fourth and final phase of meiosis II. Telophase II is identical to mitotic telophase
Summation by a postsynaptic cell of input (EPSPs or IPSPs) from a single source over time.
Strong bands of connective tissue that connect skeletal muscle to bone.
A genetic cross between an organism displaying a recessive phenotype (homozygous recessive) and an organism displaying a dominant phenotype (for whic the genotype is unknown)
The primary male sex organ. The testes are suspended outside the body cavity in the scrotum and have two functions (1) produce sperm
The primary androgen (male sex steroid). Testosterone is a steroid hormone produced and secreted by the interstitial cells of the testes. It triggers the development of secondary male sex characteristics during puberty (including spermatogenesis) and maintains those characteristics during adulthood.
A smooth sustained muscle contraction
A pair of replicated homologous chromosomes. Tetrads form during prophase I of meiosis so that homologous chromosomes can exchange DNA in a process known as 'crossing over.'
The central structure of the diencephalon of the brain. the thalamus acts as a relay station and major integrating area for sensory impulses.
A layer of cells surroudning the granulosa cells of the follicles in an ovary. Thecal cells help produce the estrogen secreted from the follicle during the first phase of the ovarian cycle.
A receptor that responds to changes in temperature.
DNA replication in prokaryotes
In skeletal and cardiac muscle tissue
In skeleta and cardiac muscle tissue
A blood clot that forms in an unbrokened blood vessel. Thrombi are dangerous they can break free and begin travelin in the bloodstream (become an embolus). Emboli ultimately become stuck in a small vessel and prevent adequate blood delivery to tissues beyond the sticking point
One of the four aromatic bases found in DNA. Thymine is a pyrimidine; it pairs with adenine.
An immune organ located near the heart. THe thymus is the site of T cell maturation and is larger in children and adolescents.
Thyroid stimulating hormone (TSH)
A tropic hormone produced by the anterior pituitary gland that targets the thyroid gland
Also called thryoid hormone
The volume of air inhaled and exhaled in a normla
Also called occluding junctions
An organism that can survive in the presence of oxygen (oxygen is not toxic)
Paired masses of lymphatic tissue near the back of the throat that help trap inhaled or swallowed pathogens.
An enzyme that cuts one or both strands of DNa to relieve the excess tension caused by the unwinding of the helix by helicase during replication.
Total lung capacity
The maximal volume of air that the lungs can contain. Total lung capacity is the sum of the vital capacity and the residual volume
Having the ability to become anything; a zygote is totipotent.
The main air tube leading into the respiratory system. The trachea is made of alternating rings of cartilage and connective tissue.
The enzymatic process of reading a strand of DNA to produce a complemenetary strand of RNA
The transfre by a lysogenic virus of a portion of a host cell genome to a new host.
A point mutation in which a pyrimidine is susbstituted for a pyrimidine
The process of reading a strand of mRNA to synthesize protein. Protein translation takes place on a ribosome.
The portion of an integral membrane protein that passes through the lipid bilayer.
A point mutation in which a pyrimidine is substitued for a purine
Transfer RNA; the type of RNA that carries an amino acid from the cytoplasm to the ribosome for incorporation into a growing protein.
The attachment of an amino acid to a tRNA (not that this a specific interaction). tRNa loading requires two high-energy phosphate bonds.
The outer ring of cells of a blastocyst. The trophoblast takes part in the formation of the placenta.
A hormone tha tcontrols the release of another hormone.
A helical protein that winds around actin helices in skeletal and cardiac muscle cells to form the thin filament of the sarcomere. In the absence of Ca2+
A globular protein that ssociated with tropomyosin as part of the thin filament of the sarcomere. Troponin binds Ca2+
The main protease secreted by the pancreas; trypsin is activated (from trypsinogen) by enterokinase
Also called transverse tubules
The membrane that separate the outer ear from the middle ear. The tympanic membrane is also known as the eardrum.
The cord that connects the embryo of a developing mammal to the placenta in the uterus of the mother. The umbilical cord contains fetal arteries (carry blood toward the placenta) and veins (carry blood away from the placenta). The umbilical vessels derive from the allantois
A carrier protein that transports a single molecule across the plasma membrane.
A person with blood type AB+. Because this person's red blood cells possess all of the typical blood surface proteins
A person with blood type O-. Because this person's red blood cells possess none of the typical blood suface proteins
Toward the 5' end of an Rna transcript (the 5' end of the DNA coding strand). The promoter and start sites are upstream.
One of the four aromatic bases found in RNA. Uracil is pyrimidine; it pairs with adnenine.
A waste product of protein dbreakdown
The tubes that carry urine from the kindeys to the bladder.
The tube that carries urine from the bladder to the to outside of the body. In males it also carries semen and sperm during ejaculation.
The valve that controls the release of urine from the bladder. It has an internal part made of smooth muscle (thus involuntary) and an external part made of skeletal muscle (thus voluntary).
Also called falopian tubes
The muscular femal organ
The deliberate exposure of a person to an antigen in order to provoke the primary immune response and memory cell production. Typically the antigens are those normally associated with pathogens
The constant inhibition provided to the heart by the vagus nerve. Vagal tone reduces the intrinsic firing rate of teh SA node from 120 beats/minute to around 80 beats/minute.
The birth canal; the stretchy
Cranial nerve pair X. The vagus nerves are very large mixed nerves (They carry both sensory input and motor input) that innervate virtually every visceral organ. They are especially important in transmitting parasympathetic input to the heart and digestive smooth muscle.
The capillaries that surround the tubules of the nephron. The vasa recta reclaims reabsorbed substances
A thick muscular tube that connects the epididymis of the testes to the urethra. Muscular contractions of the vas deferns during ejaculation ehp propel the sperm outward. Severing of the vas deferens (vasectomy) results in sterility of the male.
A blood vessel that carries blood toward the heart chambers. Veins do not have muscular walls
One of two large vessels (superior and inferior) that return deoxygenated blood to the right atrium of the heart.
The amount of blood returned to heart by the vena cavae.
One of two large chambers in the heart. The ventricles receive blood from the atria and pump it out of the lungs of the heart. The right ventricle has thing walls and pumps deoxygenated blood to the lungs through the pulmonary artery. The left ventricle has thick walls and pumps deoxygenated blood the body through the aorta.
Paired glands near the posterior side of the vaginal that secrete an alkaline mucus upon sexual arousal. The mucus helps to reduce the acidity of the vagina (which could be harmful to sperm) and lubricates the vagina to facilitate penetration.
(Singular:villus). Folds of the intestinal mucosa that project into the lumen of the intestine; vili serve to increase the surface area of the intestine for absorption.
The maximum amount of air that can be forcibly exhaled from the lungs after filling them to their maximum level
One of several different nutrietns that must be consumed in the diet
Voltage-gated ion channel
An ion channel that is oepend or closed based on the electrical potential across the plasma membrane. Once opened
Early embryonic ducts that can develop into male internal genitalia under the proper stimulation (testosterone).
An embryonic structure particularly important in egg-laying animals because it contains the yolk
The ends of a saromere.
A diploid cell formed by the fusion of two gametes during sexual reproduction.