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

Consider the following statements: (i) Parasites secrete digestive juices on the matter they live and convert it into a solution and then absorb it. (ii) Hydroponics is a method of growing plants using mineral nutrient solutions in water without soil.

Which of the given statements is/are correct?

  1. Only (i)

  2. Only (ii)

  3. Both (i) and (ii)

  4. Neither (i) nor (ii)
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

(I) Statement (1) is wrong. Those organisms which live in or on other organisms and depend on them for their nutrition are called parasites. (II) Statement (2) is correct. It is a method of hydroculture in which plants are grown using mineral nutrient solutions in water without soil.

Multiple choice

Which of the following plasma proteins functions by maintaining the colloidal osmotic pressure?

  1. Albumin

  2. Globulin

  3. Fibrinogen

  4. Thrombin

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

Albumin produced only in the liver is the major plasma protein that circulates in the bloodstream. One of the functions of albumin is to maintain intravascular oncotic (colloid osmotic) pressure. To facilitate movement of fluid throughout the body the average capillary pressure is 15 to 25 mm Hg, greater at the arterial end than at the venous end. Serum albumin carries and delivers important nutrients to cells. It binds toxins to avoid toxic effects, binds excessive proteins to act as a buffer and binds hormones and growth peptides to keep them stable.

Multiple choice

Which of the following is the best evidence for the Lock and Key theory of enzyme action?

  1. All isolated enzymes have been identified as proteins.

  2. Compounds similar in structure to substrate a molecule may inhibit the reaction.

  3. Enzymes speed up and determine the direction of a reaction.

  4. Enzymes are found only in cytoplasm of a cell.

  5. Enzymes are found only in the vacuoles of a cell.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

According to Lock and key Theory, the active site of an enzyme is static in nature. It has a specific geometric shape where in the substrate molecule fits. It is just like a key and its particular lock in which levers of key act like active site of the enzyme to open a particular lock (substrate).

Multiple choice

An enzyme is a protein which differs from an inorganic catalyst in that is highly specific. This specificity of the enzyme is associated with the ___________.

  1. insoluble nature of the protein molecule

  2. high molecular weight of the protein molecule

  3. surface configuration of the protein molecule

  4. absence of metallic ions in the protein molecule

  5. soluble nature of the protein molecule
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The specificity of the enzyme is associated with the surface configuration of the protein molecule.

Multiple choice

The monopoly of proteins to form enzymes is now not universal. Certain catalytic RNA (RNA enzymes) like Ribozyme discovered by RNAse- P (Ribonucleases P ) discovered by Altman are not proteins but act as catalysts. These RNA enzymes differ from protein enzymes in _______.

  1. that they catalyse only RNA molecules

  2. that they catalyse only nucleic acid molecules

  3. that they catalyse only phosphoprotein molecules

  4. both 2 and 3

  5. both 1 and 3
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

RNA enzymes only  catalyse only RNA molecules whereas protein enzymes helps to catalyse nucleic acid molecules, phosphoprotein molecules,  etc.

Multiple choice

Enzymes are able to accelerate a reaction because ___________.

  1. reacting substances are brought into highly specific relations with each other

  2. energy is added to the system

  3. molecules of the reactants are speeded up so that random encounters are more

  4. products of the reaction are removed simultaneously

  5. metallic ions are absent in the protein molecules
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Enzymes are able to accelerate a reaction because reacting substances are brought into highly specific relations with each other.