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

ATP contains _______ phosphate molecule/s in its molecule.

  1. 1

  2. 2

  3. 3

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

ATP (Adenosine Triphosphate) contains 3 phosphate molecules in its structure: adenine-ribose-phosphate-phosphate-phosphate. The 'Tri' in Triphosphate means 'three'. Breaking the bond to the third (terminal) phosphate releases energy for cellular work. ADP (Adenosine Diphosphate) has only 2 phosphates.

Multiple choice

The arthropod exoskeleton is composed of a

  1. mixture of several kinds of polysaccharides

  2. mixture of several kinds of proteins

  3. single-complex polysaccharide called chitin

  4. single-complex protein called arthropodin
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The arthropod exoskeleton is composed of a single-complex polysaccharide called chitin.

Multiple choice

The breakdown of proteins results in _________.

  1. sugars

  2. glycerol

  3. fatty acids

  4. amino acids
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Amino acids are the chemical units or building blocks of the body that make up proteins. Protein substances make up the muscles, tendons, organs, glands, nails, and hair. The final digestion products of proteins are amino acids.

Multiple choice

___________ are enveloped viruses.

  1. Omsk hemorrhagic fever viruses

  2. Orthomyxo viruses

  3. The Murray Valley Encephalitis Viruses (MVEV)

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

Orthomyxoviruses (influenza A, B, and C viruses) are enveloped viruses that contain single-stranded RNA in a helical array of nucleoprotein. Inserted in the lipid envelop are two glycoproteins- the hemagglutinin (HA) and the neuraminidase (NA).

Multiple choice

Which among the following mutations has no effect on the functioning of the protein?

  1. Silent mutations

  2. Nonsense mutations

  3. Missense mutations

  4. Non-conservative mutations

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

Silent mutations codes for the same amino acid. A silent mutation has no effect on the functioning of the protein. A single nucleotide can change, but the new codon specifies the same amino acid, resulting in an unmutated protein.

Multiple choice

The enzymes catalysing the reaction involveing a metal is known as

  1. serine proteases

  2. cysteine proteases

  3. metalloproteinases

  4. aspartic proteases

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

Metalloproteinases constitute a family of enzymes from the group of proteases, classified by the nature of the most prominent functional group in their active site. These are proteolytic enzymes whose catalytic mechanism involves a metal. Most metalloproteases are zinc-dependent, some use cobalt.

Multiple choice

The enzymes produced by cows is

  1. dextrinase

  2. nuclease

  3. chymosin

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

Chymosin or rennin is an enzyme found in rennet. It is produced by cows in the lining of the abomasum (the fourth and final, chamber of the stomach). Chymosin is produced by gastric chief cells in infants to curdle the milk they ingest, allowing a longer residence in the bowels and better absorption.

Multiple choice

Protein synthesis in its intial stages is inhibited by

  1. Aurin

  2. Aurintricarboxylic acid

  3. Brilliant Blue

  4. Brilliant Green

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

Aurintricarboxylic acid (ATA) is a form of dye that is used to inhibit protein biosynthesis in its initial stages. Nominally, it is used in biological experiments as a protein inhibitor, and as an ammonium salt (known as aluminon) it is used as a reagent to estimate  aluminium in water, biological tissue and foods.

Multiple choice

Which of the following destroys the activity of the catalyst?

  1. Ribozyme

  2. Catalytic poisons

  3. Catalytic promoters

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

Substances which destroy the activity of the catalyst by their presence are known as catalytic poisons. (i) For example, the presence of traces of arsenious oxide (As2O3) in the reacting gases reduces the activity of platinized asbestos which is used as catalyst in contact process for the manufacture of sulphuric acid.