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Biomolecules (Biology) · Question 44

NEET 2017MCQEasy📈 Topic in 62% papers+4−1
1

Which of the following statements is correct with reference to enzymes?

  1. Holoenzyme = Apoenzyme + Coenzyme
  2. Coenzyme = Apoenzyme + Holoenzyme
  3. Holoenzyme = Coenzyme + Co-factor
  4. Apoenzyme = Holoenzyme + Coenzyme

Answer

(1) Holoenzyme = Apoenzyme + Coenzyme

Solution

As per NCERT, the protein portion of an enzyme is called the apoenzyme, and the non-protein constituent bound to it is the co-factor (e.g. a coenzyme).

⇒ When the co-factor is removed from the enzyme, catalytic activity is lost.

⇒ The complete, catalytically active enzyme (holoenzyme) = apoenzyme + co-factor (coenzyme).

∴ Holoenzyme = Apoenzyme + Coenzyme.

Answer: (1)

NEET 2017

Keep practising — Biomolecules (Biology)

2

Which of the following are not polymeric?

  1. Proteins
  2. Polysaccharides
  3. Lipids
  4. Nucleic acids
NEET 2017
3

A typical fat molecule is made up of

  1. one glycerol and one fatty acid molecule
  2. three glycerol and three fatty acid molecules
  3. three glycerol molecules and one fatty acid molecule
  4. one glycerol and three fatty acid molecules.
NEET 2016 (Phase 1)
4

Which one of the following statements is wrong?

  1. Uracil is a pyrimidine.
  2. Glycine is a sulphur containing amino acid.
  3. Sucrose is a disaccharide.
  4. Cellulose is a polysaccharide.
NEET 2016 (Phase 1)
5

A non-proteinaceous enzyme is

  1. lysozyme
  2. ribozyme
  3. ligase
  4. deoxyribonuclease.
NEET 2016 (Phase 2)
6

Which of the following is the least likely to be involved in establishing the three-dimensional folding of most proteins?

  1. Hydrogen bonds
  2. Electrostatic interaction
  3. Hydrophobic interaction
  4. Ester bonds
NEET 2016 (Phase 2)
7

Which of the following describes the given graph correctly? [figure]

  1. Endothermic reaction with energy A in presence of enzyme and B in absence of enzyme.
  2. Exothermic reaction with energy A in presence of enzyme and B in absence of enzyme.
  3. Endothermic reaction with energy A in absence of enzyme and B in presence of enzyme.
  4. Exothermic reaction with energy A in absence of enzyme and B in presence of enzyme.
NEET 2016 (Phase 2)
8

The chitinous exoskeleton of arthropods is formed by the polymerisation of

  1. N-acetyl glucosamine
  2. lipoglycans
  3. keratin sulphate and chondroitin sulphate
  4. D-glucosamine.
AIPMT 2015
9

Which of the following biomolecules does have a phosphodiester bond?

  1. Amino acids in a polypeptide
  2. Nucleotides in a nucleic acid
  3. Fatty acids in a diglyceride
  4. Monosaccharides in a polysaccharide
AIPMT 2015
10

Which one of the following statements is incorrect?

  1. The competitive inhibitor does not affect the rate of breakdown of the enzyme-substrate complex.
  2. The presence of the competitive inhibitor decreases the Km of the enzyme for the substrate.
  3. A competitive inhibitor reacts reversibly with the enzyme to form an enzyme-inhibitor complex.
  4. In competitive inhibition, the inhibitor molecule is not chemically changed by the enzyme.
AIPMT 2015 (Cancelled)
11

Select the option which is not correct with respect to enzyme action.

  1. Substrate binds with enzyme at its active site.
  2. Addition of a lot of succinate does not reverse the inhibition of succinic dehydrogenase by malonate.
  3. A non-competitive inhibitor binds the enzyme at a site distinct from that which binds the substrate.
  4. Malonate is a competitive inhibitor of succinic dehydrogenase.
AIPMT 2014

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