Download Cell Signaling

Signaling an apoptotic moment for chapter 11
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) What could happen to target cells in an animal that lack receptors for local regulators?
A) They could compensate by receiving nutrients via an a factor.
B) They could develop normally in response to neurotransmitters instead.
C) They would divide but could never reach full size.
D) They would not be expected to multiply in response to growth factors from nearby cells.
E) Hormones would not be able to interact with target cells.
2) Paracrine signaling
A) involves secreting cells acting on nearby target cells by discharging a local regulator into the extracellular
fluid.
B) requires nerve cells to release a neurotransmitter into synapse.
C) occurs only in paracrine yeast cells.
D) has been found in plants but not animals.
E) involves mating factors attaching to target cells and causing production of new paracrine cells.
3) Which of the following is true of synaptic signaling and hormone signaling?
A) Hormone signaling occurs in animals only.
B) Hormone signaling is important between cells that are at greater distances apart than in synaptic
signaling.
C) Both use neurotransmitters, but hormone signaling is for adjacent cells in animals only.
D) Both are forms of paracrine signaling.
4) The old saying "one rotten apple spoils the whole barrel" comes from chemical signaling in plants
A) via an increased uptake of carbon dioxide during respiration in target cells.
B) via a local regulator for apple development.
C) via release of ethylene gas, a plant hormone for ripening.
D) via an a/a cell signal system in the rotten apple.
E) None of these explains the saying.
5) From the perspective of the cell receiving the message, the three stages of cell signaling are
A) the paracrine, local, and synaptic stages.
B) signal reception, signal transduction, and cellular response.
C) signal reception, nucleus disintegration, and new cell generation.
D) the alpha, beta, and gamma stages.
E) signal reception, cellular response, and cell division.
6) Which of the following are widely used second messengers in signal-transduction pathways?
A) calcium ions
B) cyclic AMP
C) nitric oxide
D)AandB
E)A, B, and C
7) A small molecule that specifically binds to a larger one
A) is called a signal transducer.
B) is a ligand.
C) is a polymer.
D) seldom is involved in hormone signaling.
E) usually terminates a signal reception.
8) Of the following, a receptor protein in a membrane that recognizes a chemical signal is most similar to
A) a specific catalytic site of an enzyme binding to a substrate.
B) DNA encoding a message into RNA.
C) a particular metabolic pathway operating within a specific organelle.
D) an enzyme with an optimum pH and temperature for activity.
E) genes making up a chromosome.
9) Which of the following signal systems use(s) G-protein-linked receptors?
A) yeast mating factors
B) epinephrine
C) neurotransmitters
D )Aand C
E)A,B,andC
10) Membrane receptors that attach phosphates to specific animo acids in proteins are
A) not found in humans.
B) called tyrosine-kinase receptors.
C) a class of GTP G-protein signal receptors.
D) associated with several bacterial diseases in humans,
E) important in yeast mating factors that contain amino acids.
11) The general name for an enzyme that transfers phosphate groups from ATP to a protein is
A) phosphorylase.
B) phosphatase.
C) protein kinase.
D)ATPase.
E) protease.
12) Up to 60% of all medicines used today exert their effects by influencing what structure in the cell membrane?
A) tyrosine-kinase receptors
B) gated ion-channel receptors
C) growth factors
D) G proteins
E) cholesterol
13) Testosterone functions inside a cell by
A) acting as a signal receptor that activates ion-channel proteins.
B) binding with a receptor protein that enters the nucleus and activates specific genes.
C) acting as a steroid signal receptor that activates ion-channel proteins.
D) becoming a second messenger that inhibits adenylyl cyclase.
E) coordinating a phosphorylation cascade that increases glycogen metabolism.
14) Chemical signal pathways
A) operate in animals, but not in plants.
B) are absent in bacteria, but are plentiful in yeast.
C) involve the release of hormones into the blood.
D) usually involve signal molecules binding to a target cell surface protein.
E) use hydrophilic molecules to activate enzymes.
15) A selective advantage of cell signaling is
A) that it allowed some organisms to evolve without having a nervous system.
B) to ensure proper timing of communication between cells in different parts of an organism.
C) to ensure that crucial activities occur in the right cells at the right time.
D)AandC.
E)A,B,andC.
16) The process of transduction usually begins
A) when the chemical signal is released from the alpha cell.
B) when the signal molecule changes the receptor protein in some way.
C) after the target cell divides.
D) after the third stage of cell signaling is completed.
E) when the hormone is released from the gland into the blood.
17) A plant deficient in calcium could experience several problems, including
A) poor response to signals of stress, drought, or cold.
B) decreased response to epinephrine.
C) overactive cyclic AMP responses.
D ) B an d C
E)A,B,andC.
18) An animal deficient in adenylyl cyclase
A) would not be able to transmit nerve impulses via a synapse.
B) could not convert GTP to ATP.
C) would lack plasma membrane-bound receptors.
D) would not respond properly to epinephrine.
E) would be unable to carry out all of the above activities.
19) Transcription factors
A) regulate the synthesis of DNA in response to a signal.
B) transcribe ATP into cAMP,
C) initiate the epinephrine response in animal cells.
D) control which genes are turned on to form mRNA.
E) are needed to regulate the synthesis of protein in the cytoplasm.
20) All of the following are true of cell communication systems except:
A) Cell signaling was an early event in the evolution of life.
B) Communicating cells may be far apart or close together.
C) Most signal receptors are bound to the outer membrane of the nuclear envelope.
D) Protein phosphorylation is a major mechanism of signal transduction.
E) In response to a signal, the cell may alter activities by changes in cytosol activity or in transcription of
RNA.
21) Which of the following events is necessary for the production of a malignant tumor?
A) activation of an oncogene in the cell
B) the inactivetion of tumor-suppressor genes within the cell
C) the presence of mutagenic substances within the cell's environment
D) the presence of a retrovirus within the cell
E) Both A and B are necessary.
22) The toxin of Vibrio cholerae causes profuse diarrhea because it
A) modifies a G protein involved in regulating salt and water secretion.
B) decreases the cytosolic concentration of calcium ions, which makes the cells hypotonic to the intestinal
cells.
C) binds with adenyl cyclase and triggers the formation of cAMP.
D) signals inositol triphosphate to become a second messenger for the release of calcium.
E) modifies calmodulin and activates a cascade of protein kinases.
Label and
pathways
The molecular mechanisms underlying apoptosis were worked out in detail by researchers studying
embryonic development of a small soil worm, a nematode called Caenorhabditis elegans (C. elegans).
What advantages are there in using this organism and what can we hope to gain from this research?
Why is P 53 considered the "the guardian of the genome"? what are two ways that it can be rendered
“ineffective”?
Of the 5 “divisions” or “classes” of oncogenes, what is a common “thread” of all of them? Why would
this be the case?
What 3 conditions can turn “normal” genes into “abnormal” (even cancerous) genes? Describe how each
would impact the cells “normal” or healthy environment.
You have just discovered an epitope (protein on the cell surface) that is unique to the particular cancer you
are studying. Describe how you might go about marketing an antibody to combat the cancer. Use this
diagram if you need to “visualize” how you are going to go about it.