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 evs - i constituents of food minerals in our diets types of nutrients nutrients and deficiency

The non-protein component in enzymes, which is necessary for its biological activity, is called:

  1. nucleic acid

  2. lipid

  3. phosphoric acid

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

The non-protein component in enzymes, which is necessary for its biological activity, is called coenzyme. The activity of an enzyme depends, at the minimum, on a specific protein chain. In many cases, the enzyme consists of the protein and a combination of one or more non-protein parts called coenzymes. Coenzymes can be either inorganic or organic compounds. They include NADH, NADPH and ATP. These molecules transfer chemical groups between enzymes.

Multiple choice evs - i constituents of food minerals in our diets types of nutrients nutrients and deficiency

Which biomolecule is made up of long chain of amino acids?

  1. Lipids

  2. Proteins

  3. Carbohydrates

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

Proteins are the polymers of amino acids held together by peptide bonds. Carbohydrates are polyhydroxy aldehyde or ketones or their derivatives. Nucleic acids are polymers of nucleotides held together by phosphodiester bonds. Lipids are the chemically diverse group and mostly have long hydrocarbon chain. Thus, the correct answer is B.

Multiple choice evs - i constituents of food minerals in our diets types of nutrients nutrients and deficiency

Amino acids form the monomeric units of 

  1. Amylase

  2. Glycogen

  3. Phospholipid

  4. Polysaccharide

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

Amylase is peptide hormone and consists of amino acids as monomer subunit. Glycogen is homopolysaccharide of D-glucose while lipids having attached phosphate groups are called as phospholipids. Polysaccharides are polymers of simple sugars (single polyhydroxy aldehyde or ketone unit). Ribonucleic acid is a polymer of ribonucleotide monomers. Thus, the correct answer is A.

Multiple choice enzymes and catalysts catalysis adsorption and colloids surface chemistry chemistry adsorption theory of heterogeneous catalysis

The structural resemblence of substrate and inhibitor leads to______________ inhibition.

  1. non-competitive

  2. competitive
  3. both $A$ and $B$

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

Competitive Inhibitor - A competitive inhibitor is any compound which closely resembles the chemical structure and molecular geometry of the substrate.

Non-competitive Inhibitor - A non-competitive inhibitor is a substance that interacts with the enzyme, but usually not at the active site. The noncompetitive inhibitor reacts either remote from or very close to the active site.

Multiple choice evs a seeds tells a farmer's story manure manures and fertilisers water absorption organ

Function of leghaemoglobin (a red pigment) in root nodules of leguminous plants is

  1. to regulate $O _2$ supply in cells
  2. to regulate $CO _2$ supply in cells

  3. to regulate production of phenolic compounds

  4. to regulate the Mo supply in cells.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Leghemoglobin supports the centralization of free oxygen in the cytoplasm of contaminated plant cells to guarantee the best possible capacity of root knobs. Its capacity is to help give oxygen to the breathing harmonious bacterial cells in root nodules of leguminous plants in a way practically equivalent to hemoglobin transporting oxygen to breathing tissues in creatures.

Thus, the correct answer is 'to regulate O$ _2$ supply in cells.'

Multiple choice evs a seeds tells a farmer's story manure manures and fertilisers water absorption organ

Leghaemoglobin is formed for

  1. Respiration

  2. Photosynthesis

  3. Nitrogen fixation

  4. Fatty acid synthesis
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
The root nodules of the leguminous plants contain an oxygen-binding heme protein called leghemoglobin. Leghemoglobin is present in the cytoplasm of infected nodule cells at high concentrations 
This leghemoglobin has a high affinity for oxygen, (approximately, ten times higher than the ß chain of human hemoglobin). The function of leghemoglobin is to help transport oxygen to the respiring symbiotic bacterial cells in a manner analogous to hemoglobin transporting oxygen to respiring tissues in animals which helps in the fixation of nitrogen.
Thus, the correct answer is option (C). 
Multiple choice evs a seeds tells a farmer's story manure manures and fertilisers water absorption organ


The pigments essential for $N _2$ fixation by leguminous plants is leghaemogiobin

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • Leghaemoglobin is an oxygen carrier and hemoprotein found in the nitrogen-fixing root nodules of leguminous plants. 
  • Leghaemoglobin reduce the amount of free oxygen, and thereby to protect the nitrogen-fixing enzyme nitrogenase, which is irreversibly inactivated by oxygen.
  • Hence The pigments essential for $N _2$ fixation by leguminous plants is leghaemoglobin is a true statement.
  • So, the correct answer is 'True'.
Multiple choice zoology living and non living characteristics of life attributes of living organisms signs of life biology : an introduction living world and classification

Select the appropriate statement


Most common constitutes of organic compounds found in organism are

  1. C , H, O, P

  2. C , H, O

  3. C, H, N ,P

  4. C , H, O, N, P
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • Organic compounds are macromolecules or compounds associated with life processes such as carbohydrates, proteins, lipids, nucleic acids.
  • The main constituents of this organic compond are Carbon, hydrogen, oxygen and phosphorous.
  • In carbohydrates, the main components are carbon, hydrogen and oxygen atoms.
  • Eg- Glucose- is a single-unit carbohydrate or monosaccharide with six carbon atoms, 12 hydrogen atoms, and six oxygen atoms.
  • In proteins,  the main components are carbon, hydrogen, oxygen, and nitrogen atoms.
  • Eg- Any amino acid has a basic amino group (−NH2), an acidic carboxyl group (−COOH), and an organic R group (or side chain).
  • Nucleic acids contains carbon atoms, phosphate and nitrogenous base.
Multiple choice biology control and coordination in living organisms enzymes and hormones hormones coordination in human beings- chemical control

Mark the wrong statement about enzymes

  1. enzymes are biological catalysts

  2. each enzyme can catalyse a number of similar reactions

  3. enzymes are very efficient catalysts

  4. enzymes are needed only in very small amounts for their action
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Option (B) is incorrect. Enzymes are efficient and biological catalysts which are needed only in very small amounts for their action but each enzyme can catalyse only a specific selective reactions. This is often referred to as "the lock and key" model.

Multiple choice chemistry biomolecules enzymes and hormones hormones coordination in human beings- chemical control

Point out the wrong statement about proteins.

  1. They are nitrogenous organic compounds of high molecular mass.

  2. They on hydrolysis by enzymes give aminoacids.

  3. Many of them are enzymes.

  4. They do not contain polypeptide .
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Proteins are nitrogenous organic compounds of high molecular mass which on hydrolysis by enzymes give amino acids. All proteins are enzymes. They do not contain polypeptide but are bonded by peptide linkage.

Multiple choice chemistry biomolecules enzymes and hormones hormones coordination in human beings- chemical control

One insulin molecule contains:


  1. Three peptide chains, two persulphide linkages.

  2. Two peptide chains, two persulphide linkages.

  3. Two peptide chains, three persulphide bonds.

  4. Three peptide chains, three persulphide bonds.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

One insulin molecule contains two peptide chains, joined by three persulphide bonds. Insulin is a hormone made by the pancreas that allows your body to use sugar (glucose) from carbohydrates in the food that you eat for energy or to store glucose for future use. Insulin helps keeps your blood sugar level from getting too high or too low.

Multiple choice chemistry biomolecules enzymes and hormones hormones coordination in human beings- chemical control

The total number of amino acids in a molecule of the Hypoglycemic hormone is:

  1. 30

  2. 21

  3. 51

  4. 27
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The total number of amino acids in a molecule of the Hypoglycemic hormone is 51. The human hormone insulin is composed of 51 amino acids. It is a dimer of an A-chain consisting of 21 amino acids, and a B-chain consisting of 30 amino acids, which are linked together by disulphide bonds.

Multiple choice chemistry biochemistry enzymes and hormones hormones coordination in human beings- chemical control

Coenzyme is :

  1. the non-protein component of an enzyme which is loosely held by the enzyme and necessary for its biological activity

  2. the protein component of an enzyme which is loosely held by the enzyme and necessary for its biological activity

  3. the non-protein or protein component of an enzyme which is loosely held by the enzyme and necessary for its biological activity

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

A coenzyme is an organic non-protein compound that binds with an enzyme to catalyze a reaction. A coenzyme cannot function alone, but can be reused several times when paired with an enzyme. Without coenzymes or cofactors, enzymes cannot catalyze reactions effectively.