Endocrine and Cell Communication

Which of the following would likely not be observed in a person injected with epinephrine?

A) Decreased production of cAMP in liver cells

Which signaling mechanism listed above involve chemicals being secreted into the environment?

A) I and II

At which point on the graph above are insulin receptors on glucose carrier proteins least likely to contain the ligand?

A) Q

Cell signaling involves converting extracellular signals to specific responses inside the target cell. Which of the following best describes how a cell initially responds to a signal?

A) The cell experiences a change in receptor conformation.

The term steroid describes both hormones produced by the body and artificially produced medications that duplicate the action for the naturally occurring steroids. All of the following describe steroid hormones EXCEPT?

A) They bind with receptor proteins in the plasma membrane to trigger cellular responses.

Insulin, epinephrine, testosterone, follicle stimulating hormone, and estrogen are all capable of triggering the flow of communication in a signal transduction pathway. Which of the following terms best describes such molecules?

A) ligands

The data shown above was collected during an experiment designed to test the hypothesis that a second messenger mediates between receptor activation at the plasma membrane and enzyme activation in the cytoplasm. Liver tissue was homogenated and used to make three test solutions: a whole homogenate, a fraction containing plasma membrane, and a fraction containing cytoplasm but no plasma membrane. Which of the following would be a reasonable conclusion based on the data collected?

B) A soluble second messenger, produced by hormone-activated membranes,, is present in the solution and activates enzymes in the cytoplasm.

The dashed arrows indicate the pathway taken by chemical signals. Which of the following statements best describes this type of cell communication?

B) Cells communicate with each other through direct contact.

Which of the following represents the correct ordering of the molecules that are activated by a single molecule of epinephrine, from highest number of molecules to lowest number ofmolecules?

B) Glycogen phosphorylase, phosphorylasekinase, protein kinase A, cAMP

Which signaling mechanism is exemplified by food trail marking behaviors in insects such as ants and termites?

B) II

A transmembrane protein is a protein that goes from one side of a membrane through to the other side of the membrane. Which model pictured in the image above depicts a membrane protein serving as a ligand receptor in a signal transduction pathway?

B) II only

Which of the following best explains the difference between a hormone and a pheromone?

B) Pheromones are chemical signals between organisms while hormones communicate among the parts within the organism.

Adrenalin (epinephrine) is often released in response to environmental dangers and produces the fight or flight response. Which of the following explains why organisms with the adrenal gland arterial arrangement have a selective advantage over those with fewer arteries connected to the adrenal gland?

B) This arrangement allows adrenalin, a protein hormone, to enter the bloodstream quickly to be distributed throughout the body producing a rapid release of energy.

Testosterone is a cholesterol containing hormoneproduced by interstitial Leydig cells inside thetestes. Testosterone is circulated by the bloodstreamto a variety of target cells within the body includingthe Sertoli cells responsible for spermatogenesis.Which of the following statements is true regardingtestosterone?

B)Testosterone is a protein hormone involved inendocrine signaling

Investigations into the causes behind symptoms in Alzheimer's patients have led to the hypothesis that the disease maybe caused by excessive activity of IP3 second messengers in brain cells. When comparing cell samples of Alzheimer's patients to those taken from the control group, which of the following pieces of evidence would support this hypothesis?

C) A higher concentration of calcium ions in the cytosol of the Alzheimer cell samples.

In his research on cell signaling involving epinephrine, E.W. Sutherland determined glycogen phosphorylase was activated by epinephrine. Sutherland found that in vitro, in the lab setting, epinephrine was unable to activate phosphorylase. The reaction required live cells. Which of the following best explains why epinephrine reacted only in live cells?

C) Cell membrane proteins and molecules inside the cell must be involved in transmitting the signal.

Patients with Type 1 diabetes lack the hormone insulin. Injections of commercially produced insulin are used to treat the symptoms of this form of diabetes. Ideally, a relatively steady level of blood glucose is maintained by the body's regulatory mechanisms. The data shown above was collected during an investigation comparing two insulin therapy medicines, Insulin Glargine and NPH insulin. Which of the following conclusions is best supported by the data?

C) The rate of glucose uptake produced by Insulin Glargine remains constant for more than 18 hours after injection.

All of the following are enzymes involved in the signal transduction pathway shown EXCEPT

D) epinephrine

When epinephrine binds to cardiac (heart) musclecells, it speeds their contraction. When it binds to muscle cells of the small intestine, it inhibits their contraction. Which of the following best accounts for the fact that the same hormone can have different effects on muscle cells?

C) The two types of muscle cells have different signal transduction pathways for epinephrine and thus have different cellular responses.

Which of the following best describes the role in which the G protein is most intimately involved in the process shown above?

C) Transduction of the signal.

Which of the following statements is supported by the information depicted in the stress hormone feedback loop shown above?

C)Increased cortisol production by the adrenalcortex will result in decreased corticotropinreleasing hormone.

Which of the following best describes a benefit of the many steps involved in a protein kinasecascade?

D) All of the above.

Which of the following molecules act as a second messenger in the cascade by which epinephrine stimulates the activation of the enzyme glycogen phosphorylase?

D) Cyclic AMP

Which kingdoms contain organisms that employ cell-to-cell communication? I. EubacteriaII. Fungi III. Animalia IV. Plantae

D) I, II, III and IV

I. Induce a rapid response II. Result in a slow change III. Composed of amino acid monomers IV. Synthesized from cholesterol V. Act as long distance chemical messengersWhich of the characteristics listed above best describe a steroid hormone?

D) II, IV and V only

Each of the following numbered processes are involved in signal transduction pathways: I. Response II. AmplificationIII. Reception IV. TransductionWhich of the following represents the sequence of events in a typical signal transduction pathway?

D) III, IV, II, I

All of the following statements about ligand-receptor complexes are true EXCEPT

D) Ligand-receptor complexes are most often formed in cell communication pathways in which participating cells are in direct contact.

Blood calcium plays a role in the processes of blood clot formation, muscle contraction and signal conduction in neurons. Negative feedback mechanisms regulate the release of the paired hormones that maintain the blood calcium levels. Which of the following statements correctly describes this regulatory process?

D) Parathyroid glands release PTH which stimulates the release of calcium from bones when the blood calcium levels are lower than the set point.