Exam 7: Cell Communication and Multicellularity

Refer to the figure below. The figure shows a receptor protein that functions in a signal transduction pathway.The portion of this receptor protein that transmits a signal to another molecule in response to ligand binding is labeled _______.

Which statement about the insulin receptor is false?

Which example illustrates how a paracrine signal functions in the human body?

If a person is being treated for shock and receives an injection of epinephrine to aid recovery, you would expect to see all of the following except

Refer to the table below. Compound X is the natural ligand that binds to a receptor and stimulates a signal transduction pathway associated with the receptor.Based on the information given in the table, what are the roles of compounds A, B, and C?

Located inside the cell, _______ receptors bind to physical or chemical signals that diffuse across the cell membrane.

Which of the following would be best to use in an investigation about the role of plasmodesmata in a plant?

Which statement explains how gap junctions provide a biological advantage to animals?

The small molecule acetylcholine acts to signal different cellular responses in many different cell types, including skeletal muscle cells, heart muscle cells, cells lining blood vessels, liver cells, and pancreatic cells.In each case, there is a membrane receptor that specifically binds acetylcholine.Upon binding, acetylcholine triggers a _______ to elicit a specific cellular response.

Refer to the graph below. The graph shows results from an investigation using living cartilage cells extracted from slaughtered cows.The cells were treated so that they took up a fluorescent dye in their cytosols without losing viability.(This dye undergoes a change in fluorescence intensity upon binding calcium ions.) The treated cells were then exposed to forces that mimic the forces on cartilage during weight-bearing exercise.This experiment was then repeated with cells that were pretreated with a calcium ion channel inhibitor before exposure to forces of weight-bearing exercise.This inhibitor is specific for intracellular calcium ion channels.Which statement is consistent with the results shown in the graph?

Refer to the graphs below. Human cells taken from the large intestine were cultured in dishes and divided into control and experimental groups.Control cells were incubated for 1 hour in a buffered solution, while experimental cells were incubated for 1 hour in a buffered solution that also contained 10 M dibutyryl cyclic AMP (db-cAMP).Dibutyryl cyclic AMP has biological activity similar to that of cyclic AMP (cAMP) but readily diffuses through the cell membrane.Following the incubations, researchers isolated a protein known to act as a transcription factor from the cells.They measured both the protein quantity (graph A) and the amount of phosphorylation of the protein (graph B).Which statement is consistent with these results?

The figure below shows the oxytocin signal transduction pathway in uterine smooth muscle cells.The abbreviation "CaM" refers to calmodulin, and "MLCK" refers to myosin light chain kinase, an enzyme that phosphorylates the light chains of myosin, stimulating smooth muscle contractions. Which two components of this pathway share a similar mechanism in transmitting a biological signal by causing a conformation change in a target protein?

A deer smells a predator as it passes by and quickly bounds to safety.Which sequence represents the correct order of steps in the signal transduction pathway that is involved?

A species of algae consists of aggregates of cells that have different functions.Researchers suspect that the outer, motile cells of this species produce a chemical signal that travels to the inner reproductive cells, causing them to lose their flagella and divide.Which experimental approach would best provide evidence in support of a chemical signaling agent acting to cause the observed change in cells?

In a signal transduction pathway, the signal molecule that binds to a receptor site of a receptor protein to initiate a cellular response is known as a(n) _______.

Biologists have found numerous genes in a single cell that encode cAMP-binding proteins.Based on what you know about cAMP as a second messenger in signal transduction pathways, which statement makes a reasonable claim?

Inositol trisphosphate (IP₃) is released into the cytoplasm when phosphatidyl inositol-bisphosphate (PIP₂) is hydrolyzed.IP₃ is one type of molecule that can directly

Epinephrine stimulates a G protein-mediated cascade within liver cells, resulting in phosphorylation of two enzymes: glycogen synthase, which is _______, and glycogen phosphorylase, which is _______.This results in _______ glucose being released to the blood and _______ glycogen being stored.

Refer to the table below. Listed are dissociation constants for ligands and inhibitors of five different membrane receptors.In which case is the receptor's affinity for an inhibitor much greater than the receptor's affinity for its ligand?

Aldosterone is a steroid compound synthesized in the adrenal glands that binds to receptors in kidney cells.How would aldosterone be classified?