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

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).

Multiple choice

Which of the following is a pair of zinc-containing enzymes?

  1. Carboxypeptidase and ATPase

  2. Carbonic anhydrase and phosphoglucomutase

  3. Carbonic anhydrase and carboxypeptidase

  4. ATPase and phosphoglucomutase

  5. Phosphoglucomutase and carboxypeptidase
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

This option is correct because carboxypeptidase and carbonic anhydrase are zinc-containing enzymes.

Multiple choice

Match the following Fe containing proteins with the corresponding function and oxidation state of Fe.

   
Fe containing proteins
Function
Oxidation state of Fe
P. Haemoglobin i. Plasma O2 transport a. 2
Q. Myoglobin ii. Muscle O2 storage b. 3
R. Transferrin iii. Plasma Fe transport
S. Catalase iv. H2O2 metabolism

  1. P - ii - a, Q - iv - b, R - i - b, S - iii - b

  2. P - iii - a, Q - iv - a, R - ii - b, S - i - b

  3. P - i - a, Q - ii - a, R - iii - b, S - iv - a

  4. P - ii - b, Q - iii - b, R - iv - a, S - i - a

  5. P - i - b, Q - iii - b, R - ii - a, S - iv - b
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

This is the correct answer. Haemoglobin is a plasma O2 transport protein. Oxidation number of Fe in haemoglobin is 2. Myoglobin is a muscle O2 storage protein. Oxidation number of Fe in myoglobin is 2. Transferrin is a plasma Fe transport protein. Oxidation number of Fe in transferrin is 3. Catalase is an enzyme, which catalyses H2O2 metabolism. Oxidation number of Fe in catalase is 2.

Multiple choice

Which of the following statements is correct?

  1. Enzymes are nucleic acids.

  2. Repeating units of proteins are peptides.

  3. Saccharides are the most abundant biomolecules on the Earth.

  4. Primary structure of proteins represents linear sequence of amino acids joined together by ester linkage.

  5. Glycogen is a polymer of galactose and glucose.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

This option is correct because saccharides (carbohydrates) are the most abundant biomolecules on the Earth.

Multiple choice

Which of the following is a false statement?

  1. Nihydrin test is used for detection of α-amino acids.

  2. Denaturation leads to loss of primary and secondary structure of proteins.

  3. Keratin is an example of fibrous protein.

  4. Albumin is a globular protein.

  5. Isoelectric point is the pH at which no net migration of amino acid occurs under electric field.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This option is correct because the denatured protein has the same primary structure as the original. Denaturation leads to loss of secondary, tertiary and quarternary structures of proteins.