Biology ยท 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

The signal transduction pathway databases are __________

  1. Reactome and NetPath

  2. Reactome and MetaCyc

  3. Netpath and MANET

  4. Netpath and MetaCyc

  5. Reactome and MANET
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This option is correct because NetPath is a manually curated resource of human signal transduction pathways and Reactome is a navigable map of human biological pathways, ranging from metabolic processes (metabolic pathways) to hormonal signalling (signal transduction pathways).

Multiple choice

The phylogenetic database is _______

  1. InterPro

  2. ModBase

  3. RefSeq

  4. SIMAP

  5. TreeFam
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

TreeFam is a database of phylogenetic trees of animal genes which aims at developing a curated resource that gives reliable information about ortholog and paralog assignments and evolutionary history of various gene families.

Multiple choice

Which of the following characteristics best applies to the allosteric effector?

  1. It competes with the substrate for the catalytic site.

  2. It binds to a site other than the catalytic site.

  3. It changes the nature of the product formed.

  4. It changes the substrate specificity of the enzyme.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Allosteric enzyme, upon binding an effector, changes its shape, which in turn changes its affinity towards its product. The effector never binds with the catalytic site of the enzyme.

Multiple choice

GABA is derived from which amino acid?

  1. Tryptophan

  2. TYrosin

  3. Glutamate

  4. Serine
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

GABA is systhesised from glutamate by the enzyme glutamic acid decarboxylase. It is an inhibitory neurotransmitter.

Multiple choice

Alanine on transamination gives rise to

  1. pyruvic acid

  2. para-hydroxyphenylpyruvate

  3. phenylpyruvate

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

Alanine transaminase transfers its amino group, which forms pyruvate.

Multiple choice

Two proteins are having the same molecular mass and identical pH of 7. The best way to separate them will be

  1. SDS polyacrylamide gel electrophoresis

  2. Native gel electrophoresis

  3. Cation exchange chromatography

  4. Anion exchange chromatography
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

SDS PAGE is not used in if a particular protein has to be separated in the basis of their biological activity. As there is no treatment with SDS, all the proteins will carry their own charge at the pH and will move according to their different electrophoretic mobilities.

Multiple choice

In an enzyme mixture, both substrates and inhibitors have been added. Both of them interact with the same binding site of enzyme What is true in this situation?

  1. Substrate will bind to the active site of the enzyme with no inhibition.

  2. Both substrate and the inhibitor will compete for binding to the catalytic site of the enzyme.

  3. Substrate can never bind itself to the enzyme.

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

As both the substrate and the inhibitor share the same binding site in the enzyme, they will compete with each other in binding. This will exert an competitive inhibition. If substarte concentration is increased to a greater level, then the inhibition will be released.

Multiple choice

Which of the following statements is true?

  1. Both cytosolic and extracellular proteins have similar amount of disulphide bonds.

  2. Cytosolic proteins lack disulphide bonds, whereas extracellular proteins have more disulphide bonds.

  3. Extracellular proteins lack disulphide bonds, whereas cytosolic proteins have more disulphide bonds.

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The cytosol is a reducing environment whereas the extracellular milieu is an oxidising environment. Disulphide bonds are formed as a result of oxidation of thiol group and it requires an oxidising environment.

Multiple choice

Pfu polymerase is better than Taq polymerase because

  1. it has more efficient polymerse activity

  2. it has proof reading activity

  3. both 1 and 2

  4. none of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Pfu polymerase has proof reading activity, so if there is any mispaired binding, it will repair this base pairing so that there will be no mispairing. Proof reading activity is absent in Taq polymerase, so it cannot repair any mispairing.