Chapter 11 Cell Communication
1) When yeast cells release mating factors, what happens?
A) The mating factors induce changes in the cells that lead to cell fusion.
B) The affected cells produce more of the a factor as a positive feedback.
C) One cell nucleus binds the mating factors and produces a new nucleus in the opposite cell.
D) The mating factors stimulate cell membrane disintegration, releasing the mating factors and leading to new yeast cells.
E) The cells in turn release a growth factor that stimulates mitosis in both cells.
Answer: A
Type: MC
Topic: Concept 11.1
Skill: Knowledge/Comprehension
2) What is most likely to happen to an animal’s target cells that lack receptors for local regulators?
A) They might compensate by receiving nutrients via a factor.
B) They could develop normally in response to neurotransmitters instead.
C) They could divide but never reach full size.
D) They might not be able to grow and multiply in response to growth factors from nearby cells.
E) Cells do not need local regulators.
Answer: D
Type: MC
Topic: Concept 11.1
Skill: Application/Analysis
3) What does yeast cell mating factor do?
A) acts on the same cell that secreted the mating factor, changing its development
B) passes through the membranes of neighboring cells, binds to DNA, and initiates transcription
C) binds to receptors on the membranes of other types of yeast cells
D) diffuses through the membranes of distant cells, causing them to produce factors that initiate long-distance migrations
E) allows two cells with the same mating factor (e.g. a) to mate
Answer: C
Type: MC
Topic: Concept 11.1
Skill: Knowledge/Comprehension
4) Which of the following is characterized by a cell releasing a signal molecule into the environment, followed by a number of cells in the immediate vicinity responding?
A) hormonal signalling
B) autocrine signalling
C) paracrine signalling
D) endocrine signalling
E) synaptic signalling
Answer: C
Type: MC
Topic: Concept 11.1
Skill: Knowledge/Comprehension
5) In the formation of biofilms, such as those forming on unbrushed teeth, cell signalling serves which function?
A) formation of mating complexes
B) secretion of apoptotic signals
C) aggregation of bacteria
D) secretion of substances that inhibit foreign bacteria
E) digestion of unwanted parasite populations
Answer: C
Type: MC
Topic: Concept 11.1
Skill: Knowledge/Comprehension
6) In yeast signal transduction, the yeast cells
A) must physically and directly interact.
B) produce signal molecules that change themselves so they can interact with one another.
C) produce response molecules that diffuse to other yeast cells.
D) secrete molecules that result in response by other yeast cells.
E) mate, after which the new cells secrete hybrid signals.
Answer: D
Type: MC
Topic: Concept 11.1
Skill: Knowledge/Comprehension
7) In which of the following ways do plant hormones differ from hormones in animals?
A) Plant hormones interact primarily with intracellular receptors.
B) Plant hormones may travel in air or through vascular systems.
C) Animal hormones are found in much greater concentration.
D) Plant hormones are synthesized from two or more distinct molecules.
E) Animal hormones are primarily for mating and embryonic development.
Answer: B
Type: MC
Topic: Concept 11.1
Skill: Knowledge/Comprehension
8) When a neuron responds to a particular neurotransmitter by opening gated ion channels, the neurotransmitter is serving as which part of the signal pathway?
A) receptor
B) relay molecule
C) transducer
D) signal molecule
E) endocrine molecule
Answer: D
Type: MC
Topic: Concept 11.1
Skill: Application/Analysis
9) Of the following, a receptor protein in a membrane that recognizes a chemical signal is most similar to
A) the active site of an allosteric enzyme that binds to a specific substrate.
B) tRNA specifying which amino acids are in a polypeptide.
C) a metabolic pathway operating within a specific organelle.
D) an enzyme having an optimum pH and temperature for activity.
E) an antibody in the immune system.
Answer: A
Type: MC
Topic: Concept 11.2
Skill: Knowledge/Comprehension
10) Which of the following is true for the signalling system in an animal cell that lacks the ability to produce GTP?
A) It would not be able to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane.
B) It could activate only the epinephrine system.
C) It would be able to carry out reception and transduction but would not be able to respond to a signal.
D) It would use ATP instead of GTP to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane.
E) It would employ a transduction pathway directly from an external messenger.
Answer: A
Type: MC
Topic: Concept 11.2
Skill: Application/Analysis
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