This set of Molecular Endocrinology Multiple Choice Questions & Answers (MCQs) focuses on “Insulin – Set 2”.
1. Which among the following is the gluconeogenic enzyme that is inhibited by insulin?
a) Phosphoenol-pyruvate carboxy kinase (PEPCK)
b) Phosphofructokinase
c) Pyruvate kinase
d) Pyruvate dehydrogenase
View Answer
Explanation: Insulin reduces the transcription of the gene involved in phosphoenol-pyruvate carboxy kinase (PEPCK) enzyme synthesis, which is the main enzyme for gluconeogenesis. Whereas it induces the synthesis of phosphofructokinase and pyruvate kinase necessary for glycolysis.
2. What is the role of insulin in the permissive effect of protein metabolism?
a) Prevents the permissive effect
b) Induces the permissive effect
c) Maintains the permissive effect
d) Spare some cells from permissive effect
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Explanation: Adequate insulin supply is needed for the anabolic protein effect of GH (Permissive effect). Insulin enhances protein production by controlling gene transcription by having more amino acids in the cells. The effects of insulin on the metabolism of proteins take place independently of the transport into the cell of glucose or amino acids; of the synthesis of glycogen; and of the stimulation of the production of high energy phosphates.
3. Which ribosomal translation enzyme is induced by insulin hormone?
a) Pyruvate decarboxylase
b) Pyruvate dehydrogenase
c) Ornithine decarboxylase
d) Polymerase
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Explanation: Ribosomal translation control is achieved by increasing the synthesis of polyamines. This is accomplished by increasing the synthesis of key and rate-limiting ornithine decarboxylase enzymes. A main enzyme in polyamine biosynthesis, ornithine decarboxylase (ODC), is a highly inducible protein whose expression involves a complex and variable array of regulatory mechanisms.
4. Insulin increases the conversion of pyruvate to acetyl-CoA in TCA cycle.
a) True
b) False
View Answer
Explanation: Insulin dephosphorylates the complex of pyruvate dehydrogenase (PDH), which is then converted to the ‘active form. Aerobic oxidative decarboxylation of pyruvate to acetyl-CoA is increased by insulin through this process.
5. Insulin increases the mechanism of glycogenolysis.
a) True
b) False
View Answer
Explanation: By dephosphorylating the key and rate limiting enzyme glycogen phosphorylase and by converting it into “inactive form”, insulin reduces glycogenolysis. It also represses the glucose-6-phosphatase enzyme.
6. Which among the following is an activity carried out by insulin for the regulation of ribosomal translation?
a) Decrease the synthesis of polyamines
b) Increase the synthesis of polyamines
c) Block the synthesis of polyamines
d) Dephosphorylation of 6S ribosome
View Answer
Explanation: Insulin Increases the synthesis of polyamines needed for the synthesis of ribosomal RNA to control the translation of ribosomes. This is achieved by increasing the synthesis of key and rate-limiting ornithine decarboxylase enzymes.
7. Which among the following is an example of a molecule that is influenced by insulin for growth and cell replication?
a) Fibroblast growth factor
b) Somatostatin
c) Growth hormone
d) Ghrelin
View Answer
Explanation: Insulin has been shown to trigger fibroblast growth factor (FGF), platelet-derived growth factor (PDGF) and epidermal growth factor (EGF) etc. In certain organs, such as the liver, the results of growth and cell proliferation are expressed with this effect on growth factors.
8. Insulin like growth factors are produced by which tissues?
a) Pancreatic tissues
b) Liver tissues
c) skeletal tissues
d) Brain tissues
View Answer
Explanation: Recently two insulin like growth factors, IGF-I and IGF-II, were discovered. They are not of pancreatic origin, liver and other connected tissues produce them. A main enzyme in polyamine biosynthesis, ornithine decarboxylase (ODC), is a highly inducible protein whose expression involves a complex and variable array of regulatory mechanisms.
9. What is the name of the process that helped in the synthesize of insulin analogues with pharmacologic advantages?
a) Computer modelling
b) Wobbler design
c) Software modelling
d) Clean design
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Explanation: ‘Computer modelling’ has recently made significant breakthroughs in the development of insulin analogues with pharmacological benefits. Relevant improvements in the molecular structure required to modify the stability, self-association and pharmacological function of insulin are made possible by this programme.
10. What is the name of the technology used for the synthesis of insulin altered through computer modelling?
a) Recombinant DNA technology
b) CRISPR technology
c) RNA editing
d) Gene mapping
View Answer
Explanation: The altered insulin molecules are synthesized by “Recombinant DNA technology.” Three types of insulin analogues were prepared using the technique, including short, intermediate and long-acting analogues.
11. Which among the following is a short acting analogue of insulin developed through rDNA technology?
a) B9 Asp B27 Glu
b) Diarginyl insulin
c) DES 64, 65 HPI (D PRO)
d) Novosol basal
View Answer
Explanation: B9 Asp B27 Glu is a short acting fast analogue of insulin developed through recombinant DNA technology. This analogue is absorbed by ordinary people 2 to 3 times faster than soluble human insulin.
12. Which among the following is an example of intermediate analogue of insulin developed through rDNA technology?
a) B9 Asp B27 Glu
b) Diarginyl insulin
c) Lys (B28), Pro (B29)
d) Novosol basal
View Answer
Explanation: Diarginyl insulin is an intermediate analogue of insulin developed through rDNA technology. In the bioconversion of proinsulin to insulin, this acts as an intermediary metabolite. Arginine does not induce the secretion of insulin in the amount likely to be consumed in a high-protein meal, but attenuates the rise in glucose when treated with glucose.
13. Which among the following is an example of long-acting analogue of insulin developed through rDNA technology?
a) B9 Asp B27 Glu
b) Diarginyl insulin
c) Lys (B28), Pro (B29)
d) Novosol basal
View Answer
Explanation: Novosol basal is an example of long-acting analogue of insulin developed through rDNA technology. In this, threonine substitution with arginine at position B27, and amidation of the B-chain ‘C’ terminal adds two positive charges and increases the isoelectric point (pI) from 5.4 to 6.8.
14. Which among the following analogues of insulin is otherwise known as Lispro insulin?
a) B9 Asp B27 Glu
b) Diarginyl insulin
c) Lys (B28), Pro (B29)
d) Novosol basal
View Answer
Explanation: Lys (B28), Pro (B29) is otherwise known as Lispro insulin. Studies have shown that the hypoglycemic activity after the administration of this analogue is shorter. So, this is an example of short acting analogue of insulin.
15. Which insulin analogue acts as a ‘subcutaneous depot’ in its site of administration?
a) B9 Asp B27 Glu
b) Diarginyl insulin
c) Lys (B28), Pro (B29)
d) Novosol base
View Answer
Explanation: Novosol base functions as a subcutaneous depot from which insulin is gradually extracted. As a result, this analogue is a long-acting analogue of insulin produced through rDNA technology. “Insulin” analogues are analogues that have been engineered to replicate the normal insulin release pattern of the body.
Sanfoundry Global Education & Learning Series – Molecular Endocrinology.
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