Multiple Choice Questions (MCQs) on Endocrine Pancreas (Insulin and Glucagon): Biochemistry, endocrinology

Multiple Choice Question on Endocrine Pancreas (Insulin and Glucagon)

1) 'Pancreatic islets' in the pancreas consist of specialized cells that produce insulin, glucagon, and somatostatin and regulate blood sugar levels in the body. 

Which of the following cells produce insulin?
a) Alpha cells
b) Beta cells
c) Gamma cells
d) Delta cells

2) Pancreatic islets in the pancreas are made up of different types of cells. 

Which of the following cells produce glucagon?
a) Alpha cells
b) Beta cells
c) Gamma cells
d) Delta cells

3) Insulin activates cells by binding to which of the following receptor?
a) G protein Receptor
b) Tyrosine kinase Receptor
c) Nuclear receptor
d) None of the above

4) Once insulin engages with its receptor, all the following activities occur downstream, Except
a) Proteins with SH2 domains bind to the phosphotyrosine residue in the insulin receptor
b) Activation of phosphatidylinositol-3-kinase  (PI3 kinase)
c) Activation of p21ras encoded by ras gene
d) Activation of Protein Phosphorylase

5) Epinephrine prevents the secretion of which of the following hormone by inhibiting adenylate cyclase?
a) Gastrin
b) Glucagon
c) Insulin
d) None of the above

6) Insulin is synthesized as proinsulin. Within storage granules, a connecting peptide (C peptide) is removed by proteases to yield insulin. The C peptide is packaged and secreted along with insulin. Which of the following statement is true regarding the C peptide?
a) C-peptide is measured for the diagnosis of diabetes mellitus
b) C-peptide is used to monitor beta-cell function in patients receiving exogenous insulin
c) C-peptide facilitates the interaction of insulin with insulin receptor
d) All of the above

7) Which of the following factor decreases insulin secretion?
a) Epinephrine
b) Amino acids (Arginine, Lysine, Leucine)
c) Fatty Acid
d) Glucose-dependent insulinotropic peptide

8) Which of the following factor increases insulin secretion?
a) Somatostatin
b) Increased Blood glucose
c) Norepinephrine
d) All of the above

9) All the following statements are correct regarding the Insulin receptors, EXCEPT:
a) The insulin receptor is a tetramer consisting of two alpha and two beta subunits
b) The alpha subunits are located on the extracellular side and interact with insulin
c) The beta subunits span the cell membrane and have intrinsic tyrosine kinase activity
d) Binding of insulin to insulin receptors leads to dissociation of the tetrameric complex

10) Insulin acts on the liver, adipose tissue, and muscle to decrease blood glucose concentration. Identify the correct statements from the following:
a) Increases uptake of glucose into the target tissue by upregulating glucose transporter GLUT4. 
b) Increases promote the formation of glycogen and downregulation of glycogenolysis (glycogen breakdown.
c) Decreases gluconeogenesis and activating glycolysis in the liver
d) All of the above

11) Which of the following hormones do not increase protein synthesis (anabolic effect)?

a) Glucagon

b) Growth Hormone

c) Insulin

d) Thyroid Hormones

12) Insulin promotes glycogen synthesis by..................................................................?

a) Increasing activity of glucokinase

b) Increasing activity of glycogen synthetase

c) Increasing uptake of glucose into the cells

d) All of the above 

13) Insulin causes a positive nitrogen balance in the body by the following mechanism, EXCEPT

a) Increasing uptake and availability of amino acid 

b) Increasing protein synthesis

c) Increasing gluconeogenesis

d) Decreasing protein breakdown

14) Select the false statement regarding the effect of insulin on lipid metabolism:

a) Insulin increases the availability of triose phosphate required for fat synthesis

b) Insulin increases the activity of hormone-sensitive lipase and enhances the uptake of fatty acids in adipose tissues 

c) Insulin increases the activity of acetyl CoA carboxylase, a rate-limiting enzyme for the fatty acid synthesis

d) Insulin increases the activity of lipoprotein lipase and enhances the uptake of fatty acids in adipose tissues 

15) Identify the false statement regarding the control and secretion of insulin:

a) High blood glucose- the potent stimulator of insulin secretion, activates GLUT2

b) Increased glucose oxidation in islet cells increases intracellular ATP 

c) High Intracellular ATP opens the ATP-sensitive potassium ion channel 

d) Depolarization opens voltage-gated ion channel calcium channel

e) Increased Cytosolic Calcium ion causes exocytosis and release of insulin

16) Glucagon is a peptide hormone. It is secreted by the alpha cells of the pancreatic islets. The primary target for glucagon action is the liver, where its action is mediated by..............................................? 

a) cAMP
b) cGMP
c) Nuclear receptors
d) None of the above

17) Glucagon regulates blood glucose by following, EXCEPT: 

a) Increasing liver glycogenesis

b) Increasing liver gluconeogenesis 

c) Increasing liver glycolysis

d) All of the above 

18) Glucagon increases liver gluconeogenesis by which of the following mechanism?

a) It inhibits phosphofructokinase-2 (PFK-2), thereby reducing fructose 2-6 bisphosphate 

b) It enhances phosphoenolpyruvate carboxykinase

c) It stimulates glucose-6-phosphatase, thereby, releasing glucose into the blood. 

d) All of the above

19) Which of the following is not the metabolic effect of glucagon?

a) Decreased lipogenesis as a result of  inhibiting acetyl CoA carboxylase

b) Decreased ketogenesis as a result of decreasing availability of acetyl CoA

c) Increased Lipolysis as a result of the activation  of hormone-sensitive lipase

d) Increased ureagenesis 

20) Which of the following factor is a potent inhibitor of glucagon?

a) Hypoglycemia

b) Arginine

c) Lysine

d) Hyperglycemia

Answers:

1-b) Beta cells, these cells constitute the majority of the islet cells and are responsible for producing and releasing insulin.

2-a) Alpha cells, the hormone glucagon raises blood glucose levels by stimulating the liver to convert stored glycogen into glucose and release it into the bloodstream.

3-b) Tyrosine kinase Receptor
4-d) Activation of Protein Phosphorylase
5-c) Insulin
6)-b) C-peptide is used to monitor beta-cell function in patients receiving exogenous insulin
7-a) Epinephrine
8-b) Increased Blood glucose
9-d) Binding of insulin to insulin receptors leads to dissociation of the tetrameric complex
10-d) All of the above

11-a) Glucagon

12-d) All of the above 

13-c) Increasing gluconeogenesis

14-b) Insulin increases the activity of hormone-sensitive lipase and enhances the uptake of fatty acids in adipose tissues 

15-c) High Intracellular ATP opens the ATP sensitive potassium ion channel 

16-a) cAMP

17-c) Increasing liver glycolysis

18-d) All of the above

19-b) Decreased ketogenesis as a result of decreasing availability of acetyl CoA

20-d) Hyperglycemia