Deck 47: Chemical Signals in Animals

Question 1

Osteoporosis is a condition in which the density of bones is decreased so much that the individual is at a higher risk of fractures.The more calcium in the bones,the better the bone density.Which of the following would have the greatest effect on calcium levels in the bones?

A)calcitonin injection alone
B)calcitonin receptor blocker alone
C)calcitonin injection plus parathyroid hormone injection
D)calcitonin injection plus parathyroid hormone receptor blocker
E)calcitonin receptor blocker plus parathyroid hormone injection

Answer 1

D

Question 2

In experiments where researchers suspect that a hormone may be responsible for a certain physiological effect,they may cut the neurons leading to the organ where the effect being studied occurs.What is the purpose of cutting these neurons?

A)To make sure that the effect is not occurring through actions in the nervous system.
B)To make sure that the organ being effected cannot function unless the researchers stimulate it with an external electrical probe.
C)To impair the normal functions of the organ so that the hormonal effect can be more easily studied.
D)To numb the organ so that it can be probed without inducing pain in the lab animal.

Answer 2

A

Question 3

Predict the effects of a drug that increases adrenocorticotropic hormone (ACTH)synthesis.

A)increase in glucocorticoid production
B)increase in release of corticotropin-releasing hormone (CRH)
C)decrease in cortisol release
D)decrease in release of corticotropin-releasing hormone (CRH)
E)all of the above

Answer 3

A

Question 4

Which of these glands is located within the abdominal cavity?

A)thyroid
B)adrenal
C)parathyroid
D)pituitary
E)all of the above

Question 5

Removing which of the following glands would have the most wide-reaching effect on bodily functions of an adult human?

A)adrenal glands
B)pituitary gland
C)thyroid gland
D)ovaries (in female)or testes (in male)

Question 6

If a portion of the pancreas is surgically removed from a rat and the rat subsequently loses its appetite,one explanation is that the removed portion contains cells that secrete a chemical signal that somehow stimulates appetite.Given this scenario,what type of chemical signalling is occurring?

A)autocrine
B)paracrine
C)endocrine
D)neuroendocrine

Question 7

Coffee drinkers urinate more frequently than those who do not drink coffee or other caffeinated beverages.Which of the following is a reasonable hypothesis for the effect of caffeine on your body?

A)Caffeine stimulates the release of antidiuretic hormone (ADH).
B)Caffeine inhibits the release of antidiuretic hormone (ADH).
C)Caffeine stimulates the release of erythropoietin.
D)Caffeine inhibits the release of erythropoietin.

Question 8

What is the only type of chemical signal that is not intended to alter the physiology of the animal producing that signal?

A)neural
B)paracrine
C)neuroendocrine
D)pheromones
E)only A and C

Question 9

Which of these glands lies closest to the throat region?

A)thyroid
B)adrenal
C)hypothalamus
D)pituitary
E)pancreas

Question 10

All of the following are examples of amplification of a hormone signal EXCEPT

A)epinephrine initiates an enzyme cascade.
B)steroids bind hormone-response elements in the cell and initiate gene transcription.
C)0)09 mg of growth hormone leads to a 10,000-mg weight gain in a cow.
D)different cell types have different receptors capable of binding the same hormone.

Question 11

You have three strains of mice: A,B,and C.You experimentally manipulate each strain and find that all three show increased secretion of molecule X.Now you perform a parabiosis experiment with the three combinations of these mice: AB,AC,and BC.You perform the same experimental manipulation as above on one mouse of each pair without directly affecting the other mouse and look for effects on the other mouse.You find no detectable effect on the unmanipulated partner in any of the combinations.What is the logical conclusion based on these results?

A)The effect on molecule X is not mediated by hormones.
B)The effect on molecule X is not mediated by nerves.
C)The effect on molecule X was just an artifact of the first experiment.
D)The effect on molecule X is controlled by higher integrative centers of the brain.

Question 12

People with type II diabetes mellitus have defective insulin receptors that cannot respond to insulin properly.Relative to normal individuals,what would be the effect on blood glucose levels of chronic stress that kept blood cortisol levels high?

A)There would be a greater increase in blood glucose levels in individuals with type II diabetes mellitus than in normal individuals.
B)There would be less increase in blood glucose levels in individuals with type II diabetes mellitus than in normal individuals.
C)There would be a greater decrease in blood glucose levels in individuals with type II diabetes mellitus than in normal individuals.
D)There would be less decrease in blood glucose levels in individuals with type II diabetes mellitus than in normal individuals.
E)There would be about the same effect on blood glucose levels in both types of individuals.

Question 13

Polypeptides can have which of the following types of effects?

A)autocrine
B)paracrine
C)endocrine
D)all of the above
E)only A and C

Question 14

Which of the following is similar in structure to cholesterol?

A)testosterone
B)estradiol
C)cortisol
D)all of the above
E)only A and B

Question 15

A cluster of tumor cells that produces and secretes growth factors to induce surrounding cells to grow and divide are showing which type of cell-to-cell signalling?

A)autocrine
B)paracrine
C)endocrine
D)neuroendocrine

Question 16

Which of the following statements is not true of hormones?

A)All are organic molecules.
B)All are secreted from the cells where they are synthesized.
C)Some have only local effects on nearby cells.
D)Some are derived from amino acids.
E)They have large effects on target tissues relative to their concentrations.

Question 17

The regulation of blood sugar levels and our stress responses are controlled in part by a negative feedback loop involving cortisol,ACTH,and CRH.What would likely be the result during times of stress if cortisol receptors in the hypothalamus were nonfunctional?

A)Blood sugar levels would rise to dangerous levels.
B)Blood sugar levels would be unaffected.
C)ACTH production would cease.
D)CRH production would cease.
E)Cortisol production would cease.

Question 18

You are dissecting a fish in your biology laboratory section.Your teaching assistant points out a long oval structure and tells you it is an endocrine gland.Which of the following is true about this structure?

A)It secretes a product that is carried in the bloodstream or other fluids to target cells.
B)The gland's product will interact with receptors on the cell membrane or inside target cells.
C)The gland's product is secreted into the cavity of some organ,outside of the circulatory system.
D)Only answers A and B apply.
E)Only answers B and C apply.

Question 19

When partially digested food enters the small intestine from the stomach,several events must occur to protect the intestine and allow for the continued digestion of the food.One hormone in particular performs two of these functions.What intestinal hormone is responsible for causing the pancreas to release digestive enzymes and the gall bladder to release bile salts into the intestine?

A)secretin
B)cholecystokinin
C)insulin
D)epinephrine
E)corticosterone

Question 20

In human embryonic development,which of the following pairs of hormones are released by the developing testes and result in development of the male reproductive tract and inhibition of the female reproductive tract?

A)testosterone and estrogen
B)estrogen and progesterone
C)testosterone and Mullerian inhibitory substance
D)estradiol and estrogen
E)testosterone and estradiol

Question 21

Which of the following is true during a typical cAMP-type signal transduction event?

A)The second messenger is the last part of the system to be activated.
B)The hormone activates the second messenger by directly binding to it.
C)The second messenger amplifies the hormonal response by attracting more hormones to the cell being affected.
D)Adenylyl cyclase is activated after the hormone binds to the cell and before phosphorylation occurs.

Question 22

In the cAMP pathway,a signalling molecule binds to and activates the cell surface receptor but the adenylyl cyclase remains inactivated.What is the most likely reason for this?

A)GDP was not replaced by GTP on the G protein.
B)Phosphodiesterase did not convert cAMP to AMP.
C)Protein kinase A was not activated.
D)The cell surface receptor did not undergo a conformational change.

Question 23

What condition would exist in a patient whose thyroid gland cannot sequester iodine?

A)thyroid cancer
B)goiter
C)overstimulation of thyroid hormone
D)all of the above

Question 24

How can a single hormone can have multiple effects?

A)There could be different types of receptors in different target tissues.
B)There could be different second messengers in different target tissues.
C)There could be different signaling cascades in different target tissues.
D)All of the above answers apply.
E)Only answers A and B apply.

Question 25

Tadpoles must undergo a major metamorphosis to become frogs.This change includes reabsorption of the tail,growth of limbs,calcification of the skeleton,increase in rhodopsin in the eye,development of lungs,change in hemoglobin structure,and reformation of the gut from the long gut of an herbivore to the short gut of a carnivore.Amazingly,all of these changes are induced by thyroxine.What is the most likely explanation for such a wide array of effects of thyroxine?

A)There are many different forms of thyroxine,each specific to a different tissue.
B)Different tissues have different types of receptors.
C)Some tissues have membrane receptors for thyroxine,while other tissues have thyroxine receptors within the nucleus.
D)Different releasing hormones release thyroxine to different tissues.
E)Answers B and C both apply.

Question 26

The vast majority of obese individuals have high leptin levels (db),while only a few rare obese individuals (ob)do not produce leptin.Which of the following hypotheses explains why leptin can cure obese individuals who produce no leptin (ob)while having no effect on other obese individuals (db)?

A)Leptin has no role in regulating weight gain.
B)Leptin is involved in a negative feedback system that regulates the rate of fat metabolism.
C)Ob individuals have dysfunctional leptin receptors in the brain.
D)All of the above answers are consistent with the data.

Question 27

Why would most of the females in a college dormitory tend to have their menstrual cycles synchronized after living together for an extended period of time?

A)The sight of blood tends to induce menstruation in females.
B)Since females tend to be very social,communicating about bodily physiology induces changes in other females' physiology.
C)Pheromones released during the menstrual cycle bind to a receptor in other females that alters their normal menstrual cycle.
D)Steroidal hormones released from the gonads can induce physiological changes in other females if direct physical contact occurs.

Question 28

Which of the following statements correctly describes the relationship between the hypothalamus (H)and the anterior (AP)and posterior (PP)lobes of the pituitary?

A)The H is the neural system that releases hormones directly into the AP and communicates with the PP only through the circulation.
B)The AP regulates the H through negative feedback mechanisms while the PP regulates the H through positive feedback.
C)The H communicates directly with the PP and indirectly with the AP through the circulatory system.
D)The H regulates secretions from the PP,which then regulates all secretions from the AP.

Question 29

A weightlifter decides to try taking steroids to improve his performance level.Following a month of use,he notes that the steroids have had no effect on his performance.Which of the following is the most likely reason for this?

A)The steroid hormone did not bind to the receptors at the cell surface and no signal transduction cascade was initiated.
B)The steroid hormone did not enter the nucleus and could not bind to the hormone response element.
C)The protein needed to transport the steroid hormone into the cell was not present at the cell membrane.
D)The steroid hormone did no bind to the hormone receptor and the hormone response element was not activated.

Question 30

Of the following types of molecules,which can function as both neurotransmitters and hormones?

A)glucocorticoids
B)second messengers
C)catecholamines
D)adipocytes

Question 31

What changes might you predict/expect if a mutation caused a change in the timing of juvenile hormone,such that it remained high throughout the lifetime of the organism?

A)The organism would undergo metamorphosis at an earlier time.
B)The organism would maintain its juvenile state for the remainder of its life.
C)The organism would mature reproductively.
D)The organism would form structures that allowed it to respond to stress.

Question 32

How can the body prevent a hormone with different effects on different tissues from acting on inappropriate cells at inappropriate times?

A)Shunt blood supply to the desired tissues.
B)Internalize receptors on nontargeted cells.
C)Change the conformation of receptors on nontargeted cells.
D)All of the above answers apply.

Question 33

You spend two months in the mountains of Peru at ~ 3500 m altitude.After returning to Toronto,you notice that you can run your regular 10 k route significantly more easily than before you left.What is the reason for this burst of fitness?

A)You were in the mountains,so you must have been hiking every day and got in better shape.
B)Due to lower oxygen concentrations at high altitudes,low blood oxygen levels stimulated release of EP,which stimulated the production of red blood cells.This increased the oxygen binding capacity of your blood.
C)The time you spent at a high altitude resulted in an increased lung capacity and therefore extra oxygen intake.This extra oxygen stimulated the release of EP and in turn the production of red blood cells.
D)The time spent at a high altitude resulted in an increased active metabolic rate and therefore increased ATP production.

Question 34

Which of the following is not considered a second messenger?

A)cAMP
B)IP3
C)norepinephrine
D)DAG

Question 35

When an ant locates a food source,it leaves a trail that other ants can follow to locate the same food source.What type of chemical signalling is this an example of?

A)neural
B)paracrine
C)pheromones
D)autocrine

Question 36

Signal transduction occurs when a chemical message at the cell surface elicits a response inside the cell.Which one of the following events is not associated with signal transduction?

A)protein phosphorylation
B)cell-surface receptor binding
C)internal receptor binding
D)second messenger activation

Question 37

Which of the following best describes the neuroendocrine-to-endocrine pathway of hormone action?

A)a neural organ that produces hormones regulates another gland through the release of hormones into the circulation that travel to the effected gland
B)a neural organ that produces hormones releases its hormones directly into another gland that it regulates
C)a gland that releases hormones directly into a neural structure,thus regulating neural functions
D)a gland that exhibits negative feedback on the nervous system by releasing hormones into neural tissue both directly and indirectly through the circulation

Question 38

The posterior pituitary is anatomically and developmentally an extension of the hypothalamus.Which of the following is a true statement about the posterior pituitary?

A)The posterior pituitary's many hormone products and their diverse functions have led to it being called by the term master gland.
B)The posterior pituitary's hormones are actually produced in neurosecretory cells that originate in the hypothalamus.
C)None of the above answers apply.
D)Both answers A and B apply.