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

Iron free compound of haemoglobin is

  1. haemotoxin

  2. bilirubin

  3. haematin

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

Haemoglobin consists of two components: heme (iron-containing porphyrin) and globin (protein). When iron is removed from haemoglobin, the remaining protein portion is called globin. This is distinct from bilirubin (a breakdown product) or haematin (an oxidized, iron-containing form).

Multiple choice

Which of the following statements is/are true about isoelectric point of a protein?

  1. All proteins with isoelectric point below pH 7.0 will have negative charge and move towards positive electrode.

  2. All proteins with isoelectric point above pH 7.0 will have positive charge and move towards negative electrode.

  3. At isoelectric point, the net charge of protein depends on the nature of aminoacid present in the protein.

  4. All of the above

  5. Only 1 and 2
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Options 1 and 2 are true, but 3 is false.

Multiple choice

Which of the following statements is incorrect about the mechanism of blood clotting?

  1. Blood platelets burst when they come in contact with environment.

  2. Thromboplastin forms prothrombinase, which activates heparin.

  3. Thrombin acts as a proteolytic enzyme and converts fibrinogen into fibrin monomers.

  4. The fibrin monomers polymerise to form long threads.

  5. The clot seals the wound and the platelets entrapped in the clot release more thromboplastin.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Thromobplastin forms an enzyme prothrombinase that inactivates heparin andconverts inactive plasma protein; prothrombin into thrombin, which converts fibrinogen into fibrin monomers that polymerise to form long threads to clot the blood.

Multiple choice

Which of the following is an example of multidrug resistance transporter protein?

  1. P type ATPase

  2. V type ATPase

  3. F type ATPase

  4. ABC transporter

  5. A type ATPase
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

ATP binding cassette transporters are transmembrane proteins that utilize the energy of ATP hydrolysis to carry out translocation of various substrates across membranes. It is also involved in eukaryotic development of resistance to multidrugs.

Multiple choice

Which plasma protein plays an important role in blood coagulation?

  1. Fibrinogen

  2. Albumin

  3. Globulin

  4. Prothrombin

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

Fibrinogen is one of the important plasma proteins, which plays an important role in blood coagulation where it is converted by thrombin to fibrin. This is achieved through processes in the coagulation cascade that activates the zymogen prothrombin to the serine protease thrombin, which is responsible for converting fibrinogen into fibrin.

Multiple choice

Which amino acid change causes sickle cell anaemia?

  1. Threonine to valine

  2. Glutamic acid to valine

  3. Glutamic acid to isoleucine

  4. Alanine to valine

  5. Glutamic acid to alanine
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The change of glutamic acid to valine in the sixth position of beta globin chain of haemoglobin causes sickle cell anaemia.