metabolic processes carried out by green plantsand cynobacteria by which visible light is trapped and the energy used to convert CO2 into organic compounds.
organisms whose cell contain their genetic material inside a nucleus. includes all life other than the viruses, archaea, and bacteria
The theory that the eukaryotic cell evolved via the engulfing of one prokaryotic cell by another.
A change in the genetic material not cause by recombination
the complete DNA sequence for a particular organism or individual
Deoxyribonucleic acid (DNA)
The fundamental hereditary material of all living organisms. In eukaryotes, stored primarily in the cell nucleus. A nucleic acid using deoxyribose rather than ribose.
The sum total of the chemical reactions that occur in an organism, or some subset of that total ( as in respiratory metabolism)
the maintenance of a steady state, such as a constant temperature, by means of physiological or behavior feedback responses.
the differential contribution of offspring to the next generation by various genetics types belonging to the same population. the mechanism of evolution proposed by Charles Darwin.
In evolutionary biology, a particular structure, physiologial process, or behavior that makes an organism better able to survive and reproduce. Also, the evolutionary process that leads to the development or persistence of such a trait.
the smallest unit of a chemical element
A subatomic particle outside the nucleus carrying a negative charge and very little mass.
A subatomic particle with a single positive charge. the number of protons in the nucleus of an atom determine its element.
One of the three fundamental particles of matter, with mass slightly larger than that of a proton and no electrical charge.
A substance that cannot be converted to simpler substance by ordinary chemical means.
The number of protons in the nucleus of an atom; also equals the number of electrons around the nuetral atom. determins the chemical properties of the atom.
The region surrounding the atomic nucleus at a fixed energy level in which electrons orbit.
A Chemical substance made up of two or more atom joind by covalent bonds or ionic attractions.
an attractive force stably linking two atoms
An electrically charged particle that forms when an atom gains or loses one or more electrons
An ion with one or more positive charges
A negatively charged ion
Chemical bond based on the sharing of electrons between two atoms.
The tendency of an atom to attract electrons when it occurs as part of a compound.
Polar covalent bond
A covalent bond in which the electrons are drawn to one nucleus more than the other, resulting in an unequal distribution of charge
A weak electrosatic bond which arises from the attraction between the slight positive charge on a hydrogen atom and the slight negative charge on a nearby oxygen or nitrogen atom.
The tendency of molecules (or any substances) to stick together
Having an affinity for water (polar)
having no affinity for water (non-polar)
A small molecule, two or more of which can be combined to form oligomers (consisting of a few monomers) or polymers (consisting of many monomers)
A large molecule made up of similar or identical subunits called monomers.
A chemical reaction in which two molecules become connected by a covalent bond and a molecule of water is released
A chemical reaction that breaks a bond by inserting the components of water
Organic compounds containing carbon, hydrogen, and oxygen in the ration 1:2:1. Common examples are sugars, starch, and cellulose.
A simple sugar. Oligo-saccharides and poly-saccharides are made up of monosaccharides.
Bond between carbohydrate (sugar) molecules through an intervening oxygen atom.
a carbohydrate made up of two monosaccharides (simple sugars)
A macromolecule composed of many monosaccharides (simple sugars). Common examples are cellulose and starch.
Nonpolar, hydrophobic molecules that include fats, oils, waes, steroids, and the phospholipids that make up biological membranes.
A simple lipid in which three fatty acids are combined with one molecule of glycerol
a molecule made up of a long nonpolar hydrocarbon chain and a polar carboxyl group. found in may lipids.
Saturated Fatty Acids
a fatty acid in which all the bonds between carbon atoms in the hydrocarbon chains are single bonds- that is all the bonds are saturated with hydrogen atoms.
Unsaturated Fatty Acids
a fatty acid whose hydrocarbon chain contains one or more double bonds
of a molecule, having both hydrophilic and hydrophobic regions
a lipid containing a phoshate group; an important constituent of cellular membranes.
the basic structural unit of biological membranes; a sheet of phosopholipids two molecules thick in which the phospholipids are lined up with their hydrophobic "tails" packed tightly together and the hydrophilic, phosphate-containing "heads" facing outward. also called lipid bilayer
a synthetic reactions in which simple molecules are linked to form more complex ones; requires an input of energy and captures it in the chemical bonds that are formed.
a synthetic reaction in which complex molecules are broken down into simpler ones and the energy is released
the basic chemical unit in nucleic acids, consisting of a pentose sugar, a phosphate group, and a nitrogen-containing base.
Ribonucleic Acid (RNA)
an often sigle-stranded nucleic acid whose necleotides use ribose rather than deoxyribose and in which the base uracil replaces thymine found in DNA. serves as genome from some viruses.
one of the two types of nitrogenou bases in nucleic acids. each of the pyrimidines-cytosine, thymine, and uracil- pairs with a specific purine.
one of the two types of nitrogenous bases in nucleic acids. each of the purines-adenine and guanine- pairs with a specific pyrimidine.
the connection in a nucleic acid strand, formed by linking two nucleotides
Complementary Base Pairing
the AT (or AU in RNA), TA, CG, and GC pairing of bases in double-stranded DNA, in transcription, and between tRNA and mRNA.
an organic compound containing both NH2 and COOH groups. proteins are polymers of amino acids
the distinguishing group of atoms of a particula amino acid; also known as a side chain
the covalent bond between two sulfur atoms linking two molecules or remote parts of the same molecule
the bond between amino acids in a protein; formed between a carboxyl group and amino group with the loss of water molecules
the specific sequence of amino acids in a protein
of a protein, localized regularities of structure, such as the helix and the B-pleated sheet
a prevalent type of secondary protein structure; a right-handed spiral.
Beta Pleated Sheet
a type of protein secondary structure; results from hydrogen bonding between polypeptide regions running antiparallel to each other
a chemical substance that accelerates a reaction without itself being consumed in the overall course of the reaction. Catalyst lower the activation energy of a reaction. enzymes are biological catalyst
in an enzyme-catalyzed reaction, the reactive condition of the substrate after there has been sufficient input of energy (activation energy) to initiate the reaction
the energy barrier that blocks the tendency for a chemical reaction to occur
the molecule or molecules on which an enzyme exerts catalytic action
The region on the surface of an enzyme or ribozyme where the substrate binds, and where catalysis occurs
a nonsubstrate that binds to the active site of an anzyme and thereby inhibits binding of its substartes
regulation of the activity of a protein (usually an enzyme) by the binding of an effector molecule to a site other than the active site.
a mechanism for regulating a metabolic pathway in which the end product of the oathway can bind to and inhibit the enzyme that catalyzes the first commited step in the pathway. also called endoproduct inhibition.
states that cells are the basic structual and physiological units of all living organisms and that all cells come from preexisting cells.
the membrane that surrounds the cell, regulating the entry and exit of molecules and ions. every cell has a plasma membrane
in cells, the centrally located compartment of eukaryotic cells taht is bounded by a double membrane and contains the chromosomes.
the contents of the cell, excluding the nucleus
the fluid portion of the cytoplasm, excluding the organelles and the other solids
a small particle in the cell that is the site of protein synthesis
long whiplike appendages that propel cells. prokaryotic flagella differ sharply from those found in eukaryotes.
a system of intracellular membranes that exchange material with one another, consisting of the golgi apparatus, endoplasmic reticulum, and lysosmes when present
within the cytoplasm, a membrane-enclosed compartment that is associated with other organelles; the Golgi complex is one example
Endoplasmic Reticulum (ER)
a system of membrane tube and flattened sacs found in the cytoplasm of eukaryotes. exist intwo forms:rough ER, studded with ribosmes; ans smooth ER, lacking ribosmes
Rough Endoplasmic Reticulum (RER)
the portion of the endoplasmic reticulum whose cuter surface has attached ribosmes
Sooth Endoplasmic Rteiculum (SER)
portion of the endoplasmic reticulum that lacks ribosmes and has a tubular appearance
a syatem of concentrically folded membranes found in the cytoplasm of eukaryotic cells; functions in secretion from the cell by exocytosis
an organelle in the eukaryotic cells that contains the enzymes of the citric acid cycle, the respiratory chain, and the oxidative phosphorylation
an organelle bounded by a double membrane containing the enzyme and pigments that perform photosynthesis. Chloroplast occur only in eurkaryotes
Membrane-enclose organelle in plant cells that can function for storage, water concentration for turgor, or hydrolysis of stored macromolecule
compnents of the cytoskeleton whose diameters fall between those of the larger microtubules and those of the smaller microfilaments
tubular structures found in the centrioles, spindle apparatus, cilia, flagella, and cytooskeleton of eukaryotic cells. these tubules play roles in the motion and maintenance of shape of the eukaryotic cells
hairlike organelles used for locomotion by many unicellular organisms and for moving water and mucus by many multicellular orgainisms. Generally shorter than a flagellum
a relatively rigid structure that encloses cells of plants, fungi, many protist, and most prokaryotes, and which gives these cells their shape and limits their explansion in hypotonic media
a cytoplasmic strand connecting two adjacent plant cells
a material of heterogeneous composition surrounding cells and performing many functions including adhesion of cells
Specialized structures associated with the plasma membran of the epithelial cells. some contribute to cell adhesion, other to intercellular communication
Fluid Mosaic Model
a molecular model for the structue of biological membranes consisting of a fluid phospholipid bilayer in which suspended proteins are free to move in the plane of the bilayer
Peripheral Membrane Proteins
proteins associated with but not embedded within the plasma membrane
Integral Membrane Protein
protein that are at least partially embedded in the plasma membrane
an integral membrane protein that spans the phospholipid bilayer
allowing certain substances to pass through while other substances are excluded; a characteristic of membranes
diffusion across a membrane; may or may not require a channel or a carrier protein
the energy-dependent transport of a substance across a biological membrane against a concentration gradient-that is, from a region of low concentration (of that substance) to one of high concentration
random movement of molecules or other particles, resulting in even distribution of the particles when no barriers are present
an integral membrane protein that forms an aqueous passageway across the membrane in which it is inserted and through which specific solutes may pass
Passive movement through a membrane involving a specific carrier protein; does not proceed against a concentration gradient
a transport protein in plant and animal cell membranes through which water passes in osmosis
anti-porter responsible for primary active transport; it pumps sodium ions out of the cells and potassium ions into the cell, both against their concentration gradients. also called a sodium potassium ATPase
endocytosis initiated by macromolecular binding to a specific membrane receptor
Signal Transduction pathway
the series of biochemical steps wherby a stimulus to a cell (such as a hormone or neutrotransmitter binding to a receptor) is translated into a response of the cell
Cyclic AMP (cAMP)
A compound formed from ATP that acts as a second messenager
a chemical reaction in which one reactant becomes oxidized and the other becomes reduced
Gain og electron by a chemical reactant; any reduction is accompanied by an oxidation
relative loss of electrons in a chemical reaction; either outright removal to form an ion or the sharing of electrons with substances having a greater affinity for them, such as oxygen. most oxidations, including biological ones, are associated with the liberation of energy
ATP formation in the mitochondrion, associated with flow of electrons through the respiratory chain
formation of ATP in mitochondria and chloroplasts, resulting from a pumping of protons across a membrane ( against a gradient of electrical charge and a pH), followed by the return of the protons through a protein channel with ATP synthase activity.
In the presence of oxygen; requiring oxygen
the enzymatic breakdown of glucose to pyruvic acid
conversion pf pyruvate to acetyl CoA and CO2 that occurs in the mitochindrial matrix in the presence of O2
Citric Acid Cycle
in cellular respiration, a set of chemical reactions whereby acetyl CoA is oxidized to carbon dioxide and hydrogen atoms are stored as NADH and FADH2 also called the Krebs cycle
the passage of electron through a series of proteins with a release of energy which may be captures in a concentration gradient or in a chemical form such as NADH or ATP
occurring without the use of molecular oxygen
The anaerobic degradation of a substance such as glucose to smaller molecules such a slactic acid or alcohol with the extraction of energy
the inital phase of photosynthesis, in which light energy is converted into chemical energy
a self-propagating wave that travels through space and has both electrical and magnetic properties
the distance between successive peaks of a wave train, such as electromagnetic radiation
a quantum of visible radiation; a packet of light energy
a substance that absorbs visible light
any of several green pigment assiciated with chloroplast or with certain bacterial membranes; responsible for trapping light energy for photosynthesis
in photosynthesis, a group of different molecules that coorperate to absorb light energy and transfer it to a reaction center. also called antenna system
in photosynthesis, the complex that absorbs light at 700 nm, passing electron to ferrodoxin and thence to NADPH
in photsynthesis the complex that absorbs light at 688nm passing electrons transport chain in the chloroplast
Cyclic Electron transport
in photosyntheis light reactions the flow of electron that produces ATP but no NADPH or O2
the stage of photosynthesis in which CO2 reacts with RuBP to form 3PG, 3PG is reduced to a sugar and RuBP is regenerated, while othe rproducts are released to the rest of the plant. also known as the Calvin-Benson cycle