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 is a database of protein-protein interactions, genetic interactions, chemical interactions, and post-translational modifications?

  1. BioGRID

  2. STRING

  3. Reactome

  4. SignaLink 2.0

  5. ModBase
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The Biological General Repository for Interaction Datasets (BioGRID) is a curated biological database of protein-protein interactions, genetic interactions, chemical interactions, and post-translational modifications created in 2003 (originally referred to as simply the General Repository for Interaction Datasets (GRID) by Mike Tyers, Bobby-Joe Breitkreutz, and Chris Stark at the Lunenfeld-Tanenbaum Research Institute at Mount Sinai Hospital.

Multiple choice

Identify the mismatched pairs among the following: A. Chaperones: infectious proteinaceous particles. B. Domains: Independently folded functional unit of a proteinC. C Prion: Proteins that assist in proper folding of proteins. D. Zinc finger: Small, functional, independently folded domain that coordinates one or more zinc ions to stabilize its structure.

  1. A and B only

  2. B and C only

  3. A and C only

  4. B and D only

  5. A, C and D only
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Chaperones are a functionally related group of proteins assisting proper protein folding in the cell under physiological and stress conditions. Prions are proteins that are unique in their ability to reproduce on their own and become infectious.

Multiple choice

Which of the following plays the crucial role in the tertiary structure of the protein?

  1. Disulfide bonds

  2. Fatty acids

  3. Esters

  4. Hemiacetals

  5. Peptide bonds
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A disulfide bond (Br.E. disulphide bond) is a covalent bond, usually derived by the coupling of two thiol groups. The linkage is also called an SS-bond or disulfide bridge. The overall connectivity is therefore R–S–S–R. The terminology is widely used in biochemistry.

Multiple choice

Which is the only glycosaminoglycan that is exclusively nonsulfated?

Glycosaminoglycans have high degrees of heterogeneity with regards to molecular weight, disaccharide construction and sulfation due to the fact that GAG synthesis, unlike proteins or nucleic acids, is not template driven, and dynamically modulated by processing enzymes. Members of the glycosaminoglycan family vary in the type of hexosamine, hexose or hexuronic acid unit they contain.

  1. Hyaluronan

  2. Heparin

  3. Keratan sulfate

  4. Heparan sulfate

  5. Dermatan sulfate
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Hyaluronan (also called hyaluronic acid or hyaluronate or HA) is an anionic, nonsulfated glycosaminoglycan distributed widely throughout  connective, epithelial and neural tissue.

Multiple choice

Which of the following proteoglycans are included in the small leucine - rich proteoglycan family?

Small leucine-rich proteoglycan (SLRP) family consists of a protein core containing leucine repeats with a glycosaminoglycan (GAG) chain consisting of either chondroitin sulfate (CS) or dermatansulfate (DS).

  1. Versican

  2. Decorin

  3. Aggrecan

  4. Perlecan

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

Decorin is a proteoglycan that is on average 90 - 140 kilodalton (kD) in molecular weight, included in the small leucine-rich proteoglycan family.

Multiple choice

Which of the following is not correct about proteins?

  1. It is known to form tissues in the body.

  2. Nitrogen is its main constituent.

  3. It can be directly stored in the body.

  4. It can release energy when the body is in its need.

  5. It gets converted into urea and excretes out of the body with urine.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The protein is not stored in the body. Hence, this statement is incorrect.

Multiple choice

To select for spontaneously arising histidine auxotrophs in a population, you would use a medium containing

  1. Histidine and penicillin

  2. Penicillin but no histidine

  3. Histidine and lysozyme

  4. Lysozyme but no histidine
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Penicillin kills actively growing cells (prototrophs). If you want to select for auxotrophs (which cannot grow without histidine), you provide histidine so they survive, while the prototrophs are killed by penicillin in the absence of histidine (or by using a counter-selection method).