Biology · Chemistry

Biomolecules and Enzymes

1,501 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 biology metabolism, cell respiration, and photosynthesis metabolism enzymes carbohydrate metabolism

Which of the following statements regarding enzyme inhibition is correct?

  1. Non-competitive inhibition of an enzyme can be overcome by adding large amount of substrate.

  2. Competitive inhibition is seen, when a substrate competes with an enzyme for binding to an inhibitor protein.

  3. Competitive inhibition is seen, when the substrate and the inhibitor compete for the active site on the enzyme.

  4. Non-competitive inhibitors often bind to the enzyme irreversibly.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A competitive inhibitor is a reversible inhibition where the inhibitor competes with the substrate for the active site of an enzyme. While the inhibitor occupies the active site it prevents binding of the substrate to the enzyme. Many competitive inhibitors are compounds that resemble the substrate and combine with the enzyme to form an enzyme inhibitor complex, but without leading to catalysis. Even fleeting combinations of this type will reduce the efficiency of the enzyme. By taking into account the molecular geometry of inhibitors that resemble the substrate, we can reach conclusions about which parts of the normal substrate bind to the enzyme. Competitive inhibition can be analyzed quantitatively by steady-state kinetics.

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 biology : an introduction introduction to organization of life signs of life what is living?

Sum of physical and chemical processes by which living matter is produced and maintained is called as

  1. Respiration

  2. Growth

  3. Metabolism

  4. Reproduction
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
The chemical processes that occur within a living organism in order to maintain life. There are two main types of metabolic processes namely catabolic and anabolic processes. The catabolic process involves breaking down of material for eg. proteins to amino acids. Whereas the anabolic process involves synthesizing materials for eg. sugars formation from carbon dioxide, water, and oxygen.
Hence correct answer is "metabolism".
Multiple choice biology biology : an introduction introduction to organization of life signs of life what is living?

Important inorganic molecules of living things are

  1. Water

  2. Salts

  3. Glucose

  4. Both A and B
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Water is a major component of many of the body’s lubricating fluids and transport of materials throughout an organism. Water also protects cells and organs from physical trauma.
Many other salts are important in the body. For example, bile salts produced by the liver helps break apart dietary fats, and calcium phosphate salts form the mineral portion of teeth and bones. Salts also help in maintaining pH level of body along with water and other components.
Hence correct option is "Both A and B".
Multiple choice biology concept of life theories of the origin of life origin of life the origin of cells and cell division

Which of these are considered most essential in the origin of life?

  1. Enzymes

  2. Nucleic acids

  3. Carbohydrates

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

Nucleic acids, specifically RNA in the RNA world hypothesis, are considered the most essential molecules in the origin of life because they can both store genetic information and catalyze reactions. While proteins, carbohydrates, and enzymes are vital, nucleic acids provide the foundational blueprint required for heredity and evolution.

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' .