1. Which of the following is a major function of hormones in the body?
A) Transport of oxygen
B) Regulation of metabolic processes
C) Formation of blood cells
D) Protein synthesis
Answer: B) Regulation of metabolic processes
2. Which type of receptor is involved in the action of steroid hormones?
A) G-protein coupled receptors
B) Tyrosine kinase receptors
C) Intracellular receptors
D) Ligand-gated ion channels
Answer: C) Intracellular receptors
3. What is the first step in the signaling pathway for peptide hormones?
A) Hormone binding to intracellular receptors
B) Activation of second messengers
C) Hormone binding to cell surface receptors
D) Gene transcription initiation
Answer: C) Hormone binding to cell surface receptors
4. Which of the following is a second messenger involved in hormone action?
A) ATP
B) cAMP
C) DNA
D) RNA
Answer: B) cAMP
5. Which of the following is a characteristic of steroid hormones?
A) They act by binding to intracellular receptors.
B) They are derived from amino acids.
C) They are water-soluble.
D) They activate second messenger pathways.
Answer: A) They act by binding to intracellular receptors.
6. The binding of a hormone to a G-protein coupled receptor leads to the activation of which enzyme?
A) Adenylyl cyclase
B) DNA polymerase
C) ATP synthase
D) Phospholipase C
Answer: A) Adenylyl cyclase
7. What is the role of cAMP in hormone action?
A) It activates protein kinase A (PKA).
B) It degrades the hormone.
C) It transports hormones across the membrane.
D) It serves as a transcription factor.
Answer: A) It activates protein kinase A (PKA).
8. What happens when a steroid hormone binds to its receptor?
A) The receptor is internalized into the cell.
B) The receptor undergoes a conformational change and enters the nucleus.
C) The receptor is degraded.
D) The receptor activates a second messenger cascade.
Answer: B) The receptor undergoes a conformational change and enters the nucleus.
9. Which type of hormones require a second messenger for action?
A) Steroid hormones
B) Amino acid-derived hormones
C) Peptide hormones
D) All hormones
Answer: C) Peptide hormones
10. Which of the following is the primary function of protein kinase A (PKA)?
A) Activation of protein synthesis
B) Phosphorylation of target proteins
C) Conversion of ATP to cAMP
D) Degradation of second messengers
Answer: B) Phosphorylation of target proteins
11. What is the effect of insulin binding to its receptor?
A) It increases glucose uptake by cells.
B) It decreases protein synthesis.
C) It inhibits lipid metabolism.
D) It activates cAMP production.
Answer: A) It increases glucose uptake by cells.
12. Which of the following hormones acts through a receptor that is a tyrosine kinase?
A) Insulin
B) Estrogen
C) Thyroid hormone
D) Cortisol
Answer: A) Insulin
13. Which of the following is true about the action of thyroid hormones?
A) They act via second messenger systems.
B) They bind to nuclear receptors.
C) They increase cAMP levels in the cell.
D) They activate G-protein coupled receptors.
Answer: B) They bind to nuclear receptors.
14. Which of the following is an effect of glucagon?
A) Decreased glucose production
B) Increased protein synthesis
C) Increased breakdown of glycogen
D) Increased lipid synthesis
Answer: C) Increased breakdown of glycogen
15. Which enzyme does cAMP activate?
A) Adenylyl cyclase
B) Protein kinase A
C) Phospholipase C
D) Protein kinase C
Answer: B) Protein kinase A
16. How do peptide hormones typically affect their target cells?
A) By binding to intracellular receptors
B) By increasing gene expression
C) By activating second messenger systems
D) By inhibiting protein synthesis
Answer: C) By activating second messenger systems
17. What is the role of phosphatases in hormone signaling?
A) They phosphorylate target proteins.
B) They degrade second messengers.
C) They dephosphorylate proteins, turning off signaling pathways.
D) They synthesize ATP.
Answer: C) They dephosphorylate proteins, turning off signaling pathways.
18. Which of the following statements is true about protein hormones?
A) They are lipid-soluble and can pass through the cell membrane.
B) They bind to receptors on the surface of the target cell.
C) They do not require a receptor for action.
D) They act by binding directly to DNA.
Answer: B) They bind to receptors on the surface of the target cell.
19. What is the primary function of the G-protein coupled receptor (GPCR) in hormone signaling?
A) To degrade hormones
B) To activate adenylate cyclase
C) To activate cAMP
D) To transport the hormone inside the cell
Answer: B) To activate adenylate cyclase
20. Which of the following hormones is derived from amino acids?
A) Estrogen
B) Insulin
C) Thyroxine
D) Glucagon
Answer: C) Thyroxine
21. What is the result of the activation of G-protein coupled receptors (GPCRs)?
A) Activation of cAMP or IP3
B) Degradation of the hormone
C) Production of tyrosine kinase
D) Increase in the number of receptors
Answer: A) Activation of cAMP or IP3
22. Which of the following is the role of the receptor tyrosine kinase in hormone signaling?
A) It activates second messenger systems.
B) It catalyzes phosphorylation of tyrosine residues on target proteins.
C) It synthesizes DNA.
D) It transports hormones to their target cells.
Answer: B) It catalyzes phosphorylation of tyrosine residues on target proteins.
23. Which of the following is NOT a characteristic of peptide hormone action?
A) They bind to receptors on the cell membrane.
B) They use second messengers to activate target enzymes.
C) They are lipid-soluble.
D) They trigger signal transduction cascades.
Answer: C) They are lipid-soluble.
24. How do steroid hormones affect gene expression?
A) By binding to G-protein coupled receptors
B) By directly interacting with DNA in the nucleus
C) By activating cAMP levels
D) By releasing second messengers
Answer: B) By directly interacting with DNA in the nucleus
25. Which of the following is a second messenger involved in hormone signaling?
A) DNA
B) cAMP
C) ATP
D) Glucose
Answer: B) cAMP
26. What is the function of cyclic AMP (cAMP) in the hormonal signaling cascade?
A) To act as a transcription factor
B) To break down lipids
C) To activate protein kinase A (PKA)
D) To degrade the hormone
Answer: C) To activate protein kinase A (PKA)
27. What happens when insulin binds to its receptor?
A) The receptor activates adenylate cyclase.
B) The receptor is internalized into the cell.
C) The receptor phosphorylates tyrosine residues on itself.
D) The receptor activates the cAMP pathway.
Answer: C) The receptor phosphorylates tyrosine residues on itself.
28. What is a key difference between peptide and steroid hormones?
A) Peptide hormones are hydrophobic, while steroid hormones are hydrophilic.
B) Steroid hormones bind to intracellular receptors, whereas peptide hormones bind to cell surface receptors.
C) Steroid hormones are derived from amino acids, whereas peptide hormones are derived from lipids.
D) Peptide hormones act on the gene expression, while steroid hormones activate second messengers.
Answer: B) Steroid hormones bind to intracellular receptors, whereas peptide hormones bind to cell surface receptors.
29. Which of the following processes is activated by the binding of a hormone to its receptor?
A) DNA replication
B) Signal transduction cascade
C) Cell division
D) Protein synthesis
Answer: B) Signal transduction cascade
30. What is the primary role of the hormone receptor in cellular signaling?
A) To synthesize proteins
B) To transmit the signal from the extracellular environment to the cell’s interior
C) To transport nutrients into the cell
D) To degrade the signal molecule
Answer: B) To transmit the signal from the extracellular environment to the cell’s interior
These MCQs provide a broad understanding of the biochemical basis of hormone action, encompassing various types of hormones, receptors, signaling pathways, and their effects on cellular functions.
