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

_______ are distinct low molecular weight nuclear acids.

  1. Virus

  2. Viroids

  3. Epsilon

  4. Preens

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Viroids are infectious agents composed solely of a short, circular, single-stranded RNA molecule, which is a low molecular weight nucleic acid. They lack the protein coat found in viruses.

Multiple choice

Which element is not always present in proteins?

  1. H

  2. S

  3. O

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

Proteins are composed of amino acids, which always contain Carbon, Hydrogen, Oxygen, and Nitrogen. Sulfur is present in some amino acids (like cysteine) but not all proteins.

Multiple choice

Separation of amino acid into amino and carboxyl group is known as

  1. deamination

  2. excretion

  3. amination

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

 Separation of amino acid into amino and carboxyl group is known as deamination.In the human body, deamination takes place primarily in the liver, however glutamate is also deaminated in the kidneys.

Multiple choice

Which of the following statements is/are correct?

A. Organic compounds are compounds of carbon. R. Carbohydrates and proteins are inorganic compounds.

  1. Both A and R are true and R is the correct explanation of A.

  2. Both A and R are true but R is not the correct explanation of A.

  3. A is true but R is false.

  4. A is false but R is true.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Organic compounds are compounds of carbon. Carbohydrates and proteins are organic compounds.

Multiple choice

Match the entries in Group-I (essential amino acids) with those in Group-II (corresponding functional groups/side chains) ||| |---|---| |Group-I |Group-II| |P. Histidine|1. hydroxy| |Q. Leucine|2. isobytyl| |R. Threonine|3. imidazole| |S. Tryptophan|4. indole|

  1. P - 3, Q - 2, R - 1, S - 4

  2. P - 3, Q - 4, R - 1, S - 2

  3. P - 3, Q - 4, R - 2, S - 1

  4. P - 1, Q - 2, R - 3, S - 4

  5. P - 2, Q - 1, R - 3, S - 4
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Histidine is an alpha amino acid, the conjugate acid of the imidazole side chain. Leucine is a branched-chain α-amino acid with the chemical formula HO2CCH(NH2)CH2CH(CH3)2. Because of the presence of aliphatic isobutyl side chain, Leucine is hydrophobic in nature. Threonine is an α-amino acid with the chemical formula HO2CCH(NH2)CH(OH)CH3. This essential amino acid is classified as polar. Together with serine, threonine is one of two proteinogenic amino acids bearing an alcohol group (-OH group). Tryptophan is one of the 22 standard amino acids and is an essential amino acid in the human diet. It has indole as fuctional group. Hence, the correct match of codes is P - 3, Q - 5, R - 1, S - 4.

Multiple choice

Which of the following sets of proteins provide protection and support, forming connective tissue, tendons, bone matrices, and muscle fiber?

  1. Hemoglobin, Myoglobin, Neuroglobin

  2. Collagen, Elastin, Neuroglobin

  3. Keratin, Collagen, Cytoglobin

  4. Neuroglobin, Fibroin, Elastin

  5. Collagen, Elastin, Keratin
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

This option is correct because this set of proteins provides protection and support, forming connective tissue, tendons, bone matrices, and muscle fiber. Keratin - A fibrous scleroprotein that occurs in the outer layer of the skin and in horny tissues, such as hair, feathers, nails, and hooves Collagen - A fibrous scleroprotein in bone and cartilage and tendon and other connective tissue; yields gelatin on boiling Elastin - A fibrous scleroprotein found in elastic tissues, such as the walls of arteries

Multiple choice

Which of the following statements are FALSE?

  1. Synteny refers to local conservation of gene order.
  2. The helix content of a protein can be determined using circular dichromism spectroscopy.
  3. In zinc finger proteins, the amino acid residues that coordinate zinc are cys and met.
  4. The production of secondary metabolites in plant cell cultures is enhanced by the addition of elicitors.

  1. 1 and 2

  2. 1 and 3

  3. 2 and 3

  4. 2 and 4

  5. 3 and 4
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Correct answer. Both are false statements. Synteny refers to gene duplication from a common ancestor. This is the condition in which two or more gene loci are present on the same chromosome. During evolution, rearrangements may cause the loss of synteny, else it will be retained. Translocations can cause gain of synteny. In zinc finger proteins, the amino acid residues that coordinate zinc are cys and his. Zinc fingers coordinate zinc ions with a combination of cysteine and histidine residues. They can be classified by the type and order of these zinc coordinating residues (e.g. cys2his2, cys4, and cys6).