Biomolecules Intext Questions with Answer NIOS

Biomolecules Intext Questions with Answer NIOS National Institute of Open Schooling | NIOS

Biomolecules Intext Questions with Answer NIOS

National Institute of Open Schooling (NIOS)
Sr. Secondary, Module-7
Lession-29: Biomolecules Intext Questions with Answer NIOS


1. Name three constituents of your diet which provide carbohydrates.

Cereals, fruits and sugar are three constituents of our diet which provide carbohydrates.

2. How are carbohydrates produced in nature?

Plants produce carbohydrates during photosynthesis.

3. What are the hydrolysis products of starch and sucrose?

Starch on hydrolysis gives glucose whereas sucrose on hydrolysis gives glucose and fructose.

4. Write the linear and ring forms of D-glucose.

linear and ring forms of D-glucose


1. What do you understand by primary structure of protein ?

Information regarding the sequence of amino acids in a protein chain is called its primary structure.

2. What do you mean by a peptide bond?

Proteins are made up of many α-amino acids which join together by the formation of an amide bond between –NH2 group of one amino acid and –COOH group of another. When two amino acids combine in this way, the resulting product is called a dipeptide and the amide bond between them is called a peptide bond.
peptide bond

3. Write the general structural formula of an a-amino acid?

Amino Acid

4. What are conjugated proteins ?

Conjugated proteins are complex proteins that, when hydrolyzed, release amino acids, inorganic, and organic components. The prosthetic group is the non-amino acid portion of conjugated proteins.
The chemical composition of the prosthetic group can be used to further divide conjugated proteins. They are –
1. Lipoproteins – proteins and lipid
2. Phosphoproteins – proteins with a phosphoric acid group
3. Nucleoproteins – protein and nucleic acid
4. Metalloproteins – metal-binding proteins with zinc, iron, or copper
5. Mucoproteins and glycoproteins – protein and carbohydrates
6. Chromoproteins – proteins and a colored pigment


1. What are lipids?

Biomolecules which are insoluble in water and soluble in organic solvents like benzene, ether or chloroform are called lipids. In the human body, these molecules can be synthesized in the liver and are found in oil, butter, whole milk, cheese, fried foods and also in some red meats.

2. What are the products of hydrolysis of an oil?

Oils on hydrolysis give glycerol and long chain fatty acids.

3. Name two important types of compound lipids.

Two types of compound lipids are phospholipids and glycolipids.

4. What is the basic difference between fats and oils?

A triglyceride which is solid at room temperature is called a fat and if it is liquid then it is called an oil.


1. What is a nucleotide?

A nucleotide is the basic building block of nucleic acids. RNA and DNA are polymers made of long chains of nucleotides. A nucleotide consists of three subunits which are-
(i) a nitrogen containing heterocyclic aromatic compound, also called a base
(ii) a pentose sugar (ribose or 2-deoxy ribose)
(iii) a molecule of phosphoric acid.

2. Why structure DNA is called a 'double helix'?

In DNA, two chains are wound around each other in the form of helix, hence the structure is called a double helix.

3. Write two main structural differences between DNA and RNA.

Two main structural differences between DNA and RNA are-
(i) DNA molecules are double stranded whereas RNA are single strand molecules.
(ii) In DNA molecules, the sugar moiety is 2-deoxyribose whereas in RNA molecules, it is ribose.


1. Name two important classes of steroid hormones.

Sex hormones and adrenocortical hormones.

2. What is oxytocin? Give its role.

Oxytocin is a female hormone. It stimulates uterine contraction during child birth.


1. Match the following vitamins mix their deficiency symptoms:
(i) Vitamin C
(ii) Vitamin B2
(iii) Vitamin B6
(a) Anemia
(b) Bleeding guns
(c) Scaly skin

(i) – (b) (ii) – (c) (iii) – (a)

2. What is night blindness? Why is it caused?

Night blindness is a deficiency symptom. It is caused by the deficiency of vitamin A.

3. How do enzymes increase the rate of a reaction?

Enzymes bind to the active site of substrate forming an enzyme-substrate complex. This reduces the activation energy of the reaction through the bending of bonds and the formation of the transition state. The decreased activation energy allows more substrate molecules to have sufficient energy to reach the transition state. Through this process, the enzyme increases the rate of reaction, permitting reactions that may have been to slow to proceed.

4. What do you understand by lock and key arrangement?

A mechanism proposed in 1890 by Emil Fischer (1852–1919) to explain binding between the active site of an enzyme and a substrate molecule. There is a particular enzyme for each substrate and they are said to have lock and key arrangement. It is said that first the substrate molecule binds to the active site of the enzyme which results in the formation of an enzyme-substrate complex. In this complex, the substrate is placed in the right orientation to facilitate a given reaction (Fig.29.6). This complex then breaks to give the molecule of the product and regenerates the enzyme for the next molecule of the substrate.

NIOS Sr. Secondary Chemistry Intext Questions of All Chapters with Answer