Which series of terms is in the correct sequence of biological organization, from the simplest to the most complex?
a) tissue, organ system, organ, cell, organism
b) organisim, ecosystem, community, population, biosphere,
c)cell, tissue, organ, population, community
C is the correct answer
In an experimental procedure, repititiom of the procedures are necessary because________.
is necessary before concluding that a given set of results is correct
How is the information encoded in DNA actually used by organisms?
the information in DNA is transcribed to RNA and then translated into protein
Experimentation is only one part of the process of scientific inquiry, but it is a very important step because it _________.
allow rejection of a hypotheses when contradictory evidence emerges
Which of the following best demonstrates the unity among all organisms?
the structure and function of DNA
Which kingdom in the domain Eukarya is composed of organism that are generally unicellular?
Protista
Name and describe all the kingdoms of Domain Eukarya.
Kingdom Plantae- terrestrial multicellular eukaryotes that carry out photosynthesis
Kingdom fungi- eukaryotes that derive nutrients from the outside of their body.
Protist- unicellular eukaryotes and some relatively small multicellular relatives
Kingdom animialia- multicellular organism that digest other organisms
Pathway similarities suggest that ancestral signaling molecules evolved in ______and were modified later in eukaryote
prokaryotes
true or false. The concentration of signaling molecules with enviromental conditions allows bacteria to sense local population density
false. conditions have no effect; only concentration of signaling molecules ables qoutem sensing
define local regulators
messenger molecules that travel only short distances
true or false. A cell can respond to a signal without receptors
false. The ability of a cell to respond to a signal depends on whether or not it has a receptor specific to that signal
describe Earl W. Sutherland's experiment with epinephrine
discovered how epinephrine acts on cells, suggesting that cells receiving signals went through three processes
what is another name for protein receptor
ligand
A shape change in a receptor is often the initial transduction of the signal
Most ______ bind to specific sites on receptor proteins that span the plasma membrane
water-soluble signal molecules
name the three main types of membrane receptors
– G protein-coupled receptors
– Receptor tyrosine kinases
– Ion channel receptors
give three characteristics of G protein-coupled receptors (GPCRs)
• the largest family of cell-surface receptors
• A GPCR is a plasma membrane receptor that works with the help of a G protein
• The G protein acts as anon/off switch: If GDP isbound to the G protein, the G protein is inactiv
give three characteristics of Receptor tyrosine kinases (RTKs)
• Receptor tyrosine kinases (RTKs) are membrane receptors that attach phosphates to tyrosines
• A receptor tyrosine kinase can trigger multiple signal transduction pathways at once
• Abnormal functioning of RTKs is associated with many types of cancer
give two characteristics of ligand-gated ion channe
• A ligand-gated ion channel receptor acts as a gate when the receptor changes shape
• When a signal molecule binds as a ligand to the receptor, the gate allows specific ions, such as Na+or Ca2+, through a channel in the recepto
are Intracellular receptor proteins found in the cytosol or nucleus of target cell?
both
true or false. Small or hydrophobic chemical messengers can readily cross the membrane and activate receptor
true
give examples of hydrophobic chemical messenger
Examples of hydrophobic messengers are the steroid and thyroid hormones of animal
can An activated hormone-receptor complex act as a transcription factor, turning on specific gene?
yes
what are the benefits of multiple pathways in signal transduction?
• Multistep pathways can amplify a signal: A few molecules can produce a large cellular response
• Multistep pathways provide more opportunities for coordination and regulation of the cellular respons
true or false. The molecules that relay a signal from receptor to response are mostly lipids
false. proteins are the molecules most of the time
Like falling dominoes, the receptor activates another protein, which activates another, and so on, until the protein producing the response is activate
• In many pathways, the signal is transmitted by a cascade of protein phosphorylation
Protein kinase
transfer phosphates from ATP to protein, a process called phosphorylation
Protein phosphatases
remove the phosphates from proteins, a process called dephosphorylation
The ________ is a pathway’s “first messenger
extracellular signal molecule (ligand) that binds to the receptor
Second messengers
small, nonprotein, watersoluble molecules or ions that spread throughout a cell by diffusion
Second messengers participate in pathways ______.
initiated by GPCRs and RTK
name two common second messengers
Cyclic AMP and calcium ions
Adenylyl cyclas
an enzyme in the plasma membrane, converts ATP to cAMP in response to an extracellular signal
cAMP usually activates_______ , which phosphorylates various other protein
protein kinase A
Further regulation of cell metabolism is provided by _______ that inhibit adenylyl cyclase
G-protein systems
why are calcium ions important second messengers?
Calcium is an important second messenger because cells can regulate its concentration
Pathways leading to the release of calcium involve____________as additional second messengers
inositol triphosphate (IP3) and diacylglycerol (DAG)
trueor false. At each step of signal amplification, the number of activated products is much greater than in the preceding steps
true
true or false. Inactivation mechanisms are an essential aspect of cell signaling
true
Apoptosis
programmed or controlled cell suicide
how are cells undergo apotosis not take up space?
Components of the cell are chopped up and packaged into vesicles that are digested by scavenger cells
what is a benefit of apoptosis besides recycling useless cells?
Apoptosis prevents enzymes from leaking out of a dying cell and damaging neighboring cells
_____________ are the main proteases (enzymes that cut up proteins) that carry out apoptosis
Caspases
name three triggers of apoptosis
– An extracellular death-signaling ligand
– DNA damage in the nucleus
– Protein misfolding in the endoplasmic reticulu
Apoptosis may be involved in some diseases (for example, ______’s);
Parkinson’s, cancer, and Alzheimer
true or false. Prokaryotes and eukaryotes alter gene expression in response to their changing environmen
true
In multicellular eukaryotes, gene expression __________
regulates development and is responsible for differences in cell types
RNA molecules play many roles in _______
regulating gene expression in eukaryote
Gene expression orchestrates _________
the developmental programs of animal
The transformation from zygote to adult results from :
cell division, cell differentiation, and morphogenesis
Cell differentiation
the process by which cells become specialized in structure and function
morphogenesis
The physical processes that give an organism its shape constitute
________ results from genes being regulated differently in each cell type
Differential gene expression
true or false An egg’s cytoplasm contains RNA, proteins, and other substances that are distributed evenly in the unfertilized egg
false. unevenly
Cytoplasmic determinante
maternal substances in the egg that influence early development
true or false. As the zygote divides by mitosis, cells contain different cytoplasmic determinants, which lead to different gene expression
true
The other important source of developmental information is the environment around the cell, especially signals from nearby embryonic cells
induction
signal molecules from embryonic cells cause transcriptional changes in nearby target cells
true or false. interactions between cells during embryonic develepoment induce differentiation of specialized cell type
true
Determination
commits a cell to its final fate
Cell differentiation is marked by ______
the production of tissue-specific protein
function of Myoblast
produce muscle-specific proteins and form skeletal muscle cells
name and describe MyoD
one of several “master regulatory genes” that produce proteins that commit the cell to becoming skeletal muscle
• The MyoD protein is a transcription factor that binds to enhancers of various target gene
Pattern formation
the development of a spatial organization of tissues and organs
• In animals, pattern formation begins with the establishment of the major axe
Positional information
the molecular cues that control pattern formation, tells a cell its location relative to the body axes and to neighboring cell
Pattern formation has been extensively studied in the fruit fly _________
Drosophila melanogaster
true or false. In Drosophila and humans, cytoplasmic determinants in the unfertilized egg determine the axes before fertilization
false. not in humans
homeotic genes
control pattern formation in late embryo, larva, and adult stages
embryonic lethals
causing death during embryogenesi
Maternal effect gene
encode for cytoplasmic determinants that initially establish the axes of the body of Drosophila
eggpolarity genes
they control orientation of the egg and consequently the fly
Ribozymes
catalytic RNA molecules that function as enzymes and can splice RNA
Spliceosomes
consist of a variety of proteins and several small nuclear ribonucleoproteins(snRNPs) that recognize the splice sites
RNA splicing
removes introns and joins exons, creating an mRNA molecule with a continuous coding sequence
exon
noncoding regions eventually expressed, usually translated into amino acid sequence
introns
These noncoding regions are called intervening sequence
A cell translates an mRNA message into protein with the help of_____
transfer RNA (tRNA)
tRNAs transfer ______
amino acids to the growing polypeptide in a ribosom
• The three stages of translation
– Initiation
– Elongation
– Termination
true or false.only two stages require protein “factors” that aid in the translation proces
false. all tree
What is the terminology for unequal separation of chromosomes
nondisjunction
What is the alternation of chromosome structure called when the reverse orientation of a chromosome occurs within a segment
inversion
What is the only viable monosomy in humans? (Hint: these patients are sterile and always female)
turner's syndrome; XO
True or False: A centimorgan, known as a map unit, represents 1% recombination frequency
true
What is the enzyme that “unzips” double stranded DNA during replication
Helicase
What is the term for highly condensed DNA and proteins that will not be involved in transcription or replication
heterochromatin
DNA is synthesized in what direction
5' to 3'
in a single word, what was the result of the Avery, McCarty, and Macleod experiment involving the mice?
Transformation
What was the point of the Hershey and Chase experiment?
Something along the lines of
What is the name of the genetic material that is “cut out” of the pre-mRNA strand to yield mRNA?
introns
What are the 3 stop codons?
uag uga uaa
What type of mutation has no effect on the amino acid produced by a codonbecause of redundancy of the genetic code
silent mutation
What specific region of the promoter is necessary for the RNA polymerase to recognize and crucial in the formation of the initiation complex in transcription?
