Biology · Chemistry

Biomolecules and Enzymes

1,432 Questions

This topic focuses on biomolecules, specifically proteins, enzymes, and amino acids. It includes questions on enzyme structures, protein folding, and catalysis. These concepts are crucial for medical and biology competitive exams.

Enzyme catalysisProtein structuresAmino acid synthesisPolypeptide chainsBiomolecule properties

Biomolecules and Enzymes Questions

Multiple choice zoology classification of living beings hierarchy of classification different types of classifications introduction to classification of living organisms

Organic compound first evolved on earth and required for origin of life were :

  1. Urea and amino acids

  2. Proteins and nucleic acids

  3. Proteins and amino acids

  4. Urea and nucleic acid
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  • Proteins and nucleic acids are the two most basic compounds for the sustenance of life. 
  • Proteins provided a limiting membrane and boundary to primitive entities and nucleic acids were important information molecules, which were required to build self-replicating entities. Option B is correct
Multiple choice biology digestive system oesophagus and stomach -intermediate digestion in human beings organs systems in animals

Read the following reactions and choose the correct option:
$Pepsinogen {}\overset{HCl}{\rightarrow}Pepsin$
$Proteins{}\overset{pepsinogen}{\rightarrow}Proteoses + Peptones$
$Trypsinogen{}\overset{HCl}{\rightarrow}Trypsin$
$Chymotrypsinogen  {}\overset{enterokinase}{\rightarrow}Chymotrypsin$
$Peptones{}\overset{trypsin}{\rightarrow}Dipeptides$

  1. i alone is correct

  2. i and v alone are correct

  3. iii and v alone are correct

  4. ii, iv and v alone are correct

  5. ii alone is correct
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Reaction (i) is correct as HCl activates pepsinogen to pepsin. Reaction (v) is correct as trypsin breaks down peptones into dipeptides. Reaction (ii) is incorrect because pepsinogen is not the enzyme acting on proteins; pepsin is. Reaction (iii) is incorrect because enterokinase, not HCl, activates trypsinogen. Reaction (iv) is correct, but the option set identifies (i) and (v) as the intended answer.

Multiple choice zoology applications of biotechnology genetically engineered insulin application of biology in therapy and vaccine application of biotechnology in medicine

Insulin has 51 amino acids arranged in

  1. Single polypeptide

  2. Two polypeptides of 21 and 30 amino acids

  3. Two polypeptides of 25 and 26 amino acids

  4. Three polypeptides having 15, 16 and 20 amino acids
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Insulin consists of two polypeptide chains: the A-chain (21 amino acids) and the B-chain (30 amino acids), linked by disulfide bridges.

Multiple choice zoology applications of biotechnology genetically engineered insulin application of biology in therapy and vaccine application of biotechnology in medicine

Assertion: Humilin synthesizes in the form of proinsulin.

Reason: C - peptide is not seen in mature insulin.

  1. A and R both are correct. Where R is explanation of A

  2. A and R both are correct. Where R is not explanation of A

  3. A is correct white R is correct

  4. A is incorrect white R is correct
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Insulin in human body is synthesized in the form of proinsulin . Proinsulin is a molecule which has 24 amino acids , B-chain peptide , C-chain peptide and A-chain peptide . The C-chain peptide of precursor insulin molecule has two amino acids . In mature insulin the C-chain peptide is cleaved off which results in the joining of A-chain peptide and B-chain peptide and form its active form. 

So the correct answer is ' A and R both are correct . Where R is the explanation of A ' .

Multiple choice zoology applications of biotechnology genetically engineered insulin application of biology in therapy and vaccine application of biotechnology in medicine

Globular protein of ~ 6kDaconsisting of 51 amino acids arranged in two polypeptide chains held by disulphide bridge is

  1. Insulin

  2. Fibrinogen

  3. Glucagon

  4. Keratin
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Insulin is a small globular protein consisting of 51 amino acids arranged in two chains (A and B) connected by disulfide bridges.

Multiple choice zoology applications of biotechnology genetically engineered insulin application of biology in therapy and vaccine application of biotechnology in medicine

Maturation of proinsulin into insulin takes place after

  1. Joining of c-peptide

  2. Removal of c-peptide

  3. Removal of disulphide bridge

  4. Addition of disulphide bridge
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Proinsulin is synthesized as a single polypeptide chain that must undergo post-translational processing, specifically the removal of the C-peptide, to become mature, active insulin.

Multiple choice zoology applications of biotechnology genetically engineered insulin application of biology in therapy and vaccine application of biotechnology in medicine

Identify the wrong statement with reference to the structure of human insulin :

  1. Insulin is synthesised as a pre-hormone which contains an extra stretch called C-peptide

  2. A and B chains are combined by disulphide bonds to form humulin

  3. Human insulin is made up of 51 amino acids arranged in two polypeptide chains

  4. In these, chain A is made up of 30 amino acids and chain B is made up of 21 amino acids
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Human insulin consists of 51 amino acids, but the distribution is 21 amino acids in chain A and 30 amino acids in chain B. The option stating 30 in A and 21 in B is incorrect.

Multiple choice zoology applications of biotechnology genetically engineered insulin application of biology in therapy and vaccine application of biotechnology in medicine

Which of the following statements regarding the structure of proinsulin and mature insulin are not correct?
(i) Proinsulin is made up of three polypeptide chains A, B, and C.
(ii) C-polypeptide chain with 33 amino acids is removed prior to insulin formation.
(iii) Mature insulin is made up of 51 amino acids and arranged in two polypeptide chains-A and B.
(iv) Polypeptide chain A has 30 amino acids and polypeptide chain B has 21 amino acids.
(v) Polypeptide chains A and B are interconnected by only one S-S linkage.

  1. (i) and (ii)

  2. (iii) and (iv)

  3. (iv) and (v)

  4. (iii), (iv) and (v)
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Human insulin is made up of 51 amino acids arranged in two polypeptide chains: A, having 21 amino acids and B, with 30 amino acids. The two polypeptide chains are interconnected by two disulphide bridges. The two polypeptide chains are interconnected by two disulphide briges. The hormone develops from a storage product called pronsulin. Proinsulin has three chains: A, B and C, C-chain with 33 amino acids is removed prior to insulin formation.
So, the correct answer is '(iv) and (v)'.
Multiple choice zoology applications of biotechnology genetically engineered insulin application of biology in therapy and vaccine application of biotechnology in medicine

Insulin is a/an.

  1. Polysaccharide

  2. Protein

  3. Amino acid derivative

  4. Lipid
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Insulin is a large popylpeptide hormone and is insoluble in lipids, therefore, it cannot enter the target cell. It acts at the cell surface. It operates through extracellular membrane bound receptor, a heterotetrameric protein (extrinsic protein) on the target cell.

Multiple choice zoology applications of biotechnology genetically engineered insulin application of biology in therapy and vaccine application of biotechnology in medicine

__________ is a globular protein of $\sim 6\, kDa$ consisting of $51$ amino acids, arranged in $2$ polypeptide chains held together by disulphide bridge.

  1. Insulin

  2. Keratin

  3. Glucagon

  4. Fibrinogen
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Insulin is composed of two peptide chains referred to as the A chain and B chain. A and B chains are linked together by two disulfide bonds, and an additional disulfide is formed within the A chain. In most species, the A chain consists of 21 amino acids and the B chain of 30 amino acids.

Although the amino acid sequence of insulin varies among species, certain segments of the molecule are highly conserved, including the positions of the three disulfide bonds, both ends of the A chain and the C-terminal residues of the B chain. These similarities in the amino acid sequence of insulin lead to a three dimensional conformation of insulin that is very similar among species, and insulin from one animal is very likely biologically active in other species. Indeed, pig insulin has been widely used to treat human patients.

So the correct option is 'Insulin'.
Multiple choice zoology applications of biotechnology genetically engineered insulin application of biology in therapy and vaccine application of biotechnology in medicine

During the processing of proinsulin into mature insulin

  1. C-peptide is added to proinsulin

  2. C-peptide is removed from proinsulin

  3. B-peptide is added to proinsulin

  4. B-peptide is removed from proinsulin.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Insulin is used for diabetes which is synthesised by a pro-hormone present in humans. The prohormone needs to be processed to become a fully mature and functional hormone as it contains an extra stretch called the C peptide which is not present in the mature insulin. 

So, the correct option is 'Option B' .

Multiple choice biology selection and evolution theory of natural selection natural selection evidence for evolution

Nucleoprotein gave most probably the first sign of 

  1. Life

  2. Amino acid

  3. Soil

  4. Sugar
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • The giant nucleoprotein molecules were formed by the union of nucleic acid and protein molecules. These nucleoprotein particles were described as free-living genes. Nucleoproteins gave most probably the first sign of life.
  • Hence Nucleoprotein gave most probably the first sign of life.
  • So, the correct answer is 'Life'.
Multiple choice biology selection and evolution theory of natural selection natural selection evidence for evolution

The simple organic compounds that may have first evolved in the direction of origin of life on earth may have been

  1. Protein and amino acid

  2. Protein and nucleic acid

  3. Urea and nucleic acid

  4. Urea and amino acid
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Nucleic acids were formed in a primitive hot soup of sea by the formation of pyrimidine-sugar –phosphate and purine-sugar-phosphate. RNA has the ability of self replication and to catalyze other chemical reactions. Thus, RNA served as an enzyme as well as genetic material in first life forms. Amino acids were formed by condensation, polymerization and redox reactions of hydrocarbons, ammonia and water in Primitive Ocean under influence of energy from UV rays, radiations and lightening. RNA catalyzed polymerization of these amino acids formed polypeptides. The nucleic acid came before proteins. Urea was synthesized as excretory material much later during the evolution of land animals as ammonia is very toxic and requires more water to serve as excretory material. Thus, the correct answer is option B.