Question 1

Each of the following statements about adrenal cortical steroid hormones is correct EXCEPT which one?

Accepted Answer

A)   The formation of pregnenolone from cholesterol is a rate controlling step in adrenal steroid hormone synthesis.
B)   The reactions which lead to the formation of pregnenolone from cholesterol take place in mitochondria.
C)   Progesterone is formed from pregnenolone through a series of hydroxylation reactions which require NADPH.
D)   Progesterone is a precursor for aldosterone.
E)   Adrenocorticotropic hormone (ACTH)  stimulates the conversion of cholesterol to pregnenolone through mechanisms involving cyclic AMP.F) None of the above
G) A) and D)

Question 2

The estradiol receptor Erb can inhibit the activity of ERA. What is the mechanism of this inhibition?

Accepted Answer

A)   Blockage of transport of ERa into the nucleus
B)   Dissociation of the ligand from ERa
C)   ERb binds the ERa ligand
D)   Formation of heterodimers of the two receptors
E)   Inhibition of synthesis of ERaF) All of the above
G) A) and E)

Question 3

All of the following statements regarding the second messenger concept of hormone action are true EXCEPT which one?

Accepted Answer

A)   The hormone itself is the first messenger.
B)   Hormones act through receptors to stimulate the production of the second messenger.
C)   Cyclic AMP is a leading candidate for the second messenger of lipid-soluble hormones such as steroids.
D)   None of the above are exceptions; all statements are true.E) A) and C)
F) B) and D)

Question 4

The major actions of parathyroid hormone are

Accepted Answer

A)   enhancement of calcium excretion by direct effect on the kidney tubules
B)   direct promotion of bone resorption with increased osteoclastic activity
C)   enhancement of renal clearance of phosphate
D)   A and C above
E)   B and C aboveF) B) and D)
G) C) and D)

Question 5

Estrogen is thought be exert its metabolic effects by which one of the following?

Accepted Answer

A)   Decreasing the production of cyclic AMP.
B)   Increasing the permeability of cell membranes to molecules such as glucose and amino acids.
C)   Reaction with a specific receptor protein which in turn affects DNA metabolism.
D)   Alteration of the phosphorylation of histones.E) C) and D)
F) All of the above

Question 6

Tissue specificity in the action of steroid hormones is determined at the level of

Accepted Answer

A)   non-histone (acidic)  protein.
B)   DNA.
C)   histone proteins.
D)   RNA polymerase.
E)   the nuclear membrane.F) B) and E)
G) None of the above

Question 7

Which one of the following statements concerning the metabolism of testosterone is FALSE?

Accepted Answer

A)   The rate of testosterone formation in the stroma of the ovary is regulated by the activity of side chain cleavage enzyme.
B)   After removal of the testes (castration)  the granulosa cells of the adrenal Can compensate by the conversion of cholesterol to testosterone.
C)   Testosterone is converted to the more active 5-alpha-dihydro- testosterone in peripheral target tissues of the adult.
D)   Testosterone is a member of the C-l9 androgen class of steroids.
E)   Testosterone affects the rate of bone maturation.F) A) and D)
G) C) and D)

Question 8

Which group of steroids in the male has a pronounced general anabolic effect?

Accepted Answer

A)   Estrogens
B)   Mineralocorticoids
C)   Glucocorticoids
D)   Adrenal androgens
E)   Testicular androgensF) A) and C)
G) A) and E)

Question 9

Parathyroid hormone

Accepted Answer

A)   produces, in intestinal epithelial cells, new mRNA which codes for calcium ion transport protein
B)   lowers the concentration of free calcium ion in blood
C)   stimulates reabsorption of phosphate by the kidney
D)   stimulates osteoclasts to break down bone mineral
E)   counteracts the effect of the active metabolite of vitamin D on the kidneyF) A) and B)
G) None of the above

Question 10

The most prominent second messenger involved in the actions of LH, FSH and ACTH is

Accepted Answer

A)   Ca2+
B)   cGMP
C)   inositol triphosphate (IP3) 
D)   steroid receptor protein
E)   cAMPF) A) and B)
G) A) and C)

Exam 22: Biochemistry of Hormones

The estradiol receptor Erb can inhibit the activity of ERA. What is the mechanism of this inhibition?

Correct Answer
verified

Tissue specificity in the action of steroid hormones is determined at the level of

Correct Answer
verified

The most prominent second messenger involved in the actions of LH, FSH and ACTH is

Correct Answer
verified

The major actions of parathyroid hormone are

Correct Answer
verified

Which one of the following statements concerning the metabolism of testosterone is FALSE?

Correct Answer
verified

All of the following statements regarding the second messenger concept of hormone action are true EXCEPT which one?

Correct Answer
verified

Which group of steroids in the male has a pronounced general anabolic effect?

Correct Answer
verified

Estrogen is thought be exert its metabolic effects by which one of the following?

Correct Answer
verified

Each of the following statements about adrenal cortical steroid hormones is correct EXCEPT which one?

Correct Answer
verified

Parathyroid hormone

Correct Answer
verified

Exam 22: Biochemistry of Hormones

The estradiol receptor Erb can inhibit the activity of ERA. What is the mechanism of this inhibition?

Correct AnswerverifiedShow Answer

Tissue specificity in the action of steroid hormones is determined at the level of

Correct AnswerverifiedShow Answer

The most prominent second messenger involved in the actions of LH, FSH and ACTH is

Correct AnswerverifiedShow Answer

The major actions of parathyroid hormone are

Correct AnswerverifiedShow Answer

Which one of the following statements concerning the metabolism of testosterone is FALSE?

Correct AnswerverifiedShow Answer

All of the following statements regarding the second messenger concept of hormone action are true EXCEPT which one?

Correct AnswerverifiedShow Answer

Which group of steroids in the male has a pronounced general anabolic effect?

Correct AnswerverifiedShow Answer

Estrogen is thought be exert its metabolic effects by which one of the following?

Correct AnswerverifiedShow Answer

Each of the following statements about adrenal cortical steroid hormones is correct EXCEPT which one?

Correct AnswerverifiedShow Answer

Parathyroid hormone

Correct AnswerverifiedShow Answer

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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