Biomolecules NEET MCQ

1. Which biomolecule serves as the primary source of energy for cellular activities?

a) Proteins
b) Carbohydrates
c) Lipids
d) Nucleic acids

Answer:

b) Carbohydrates

Explanation:

Carbohydrates, particularly glucose, are primarily used by cells to derive energy through processes like glycolysis and cellular respiration.

2. Which of the following is not a polysaccharide?

a) Starch
b) Cellulose
c) Glycogen
d) Fructose

Answer:

d) Fructose

Explanation:

Fructose is a monosaccharide, whereas the others listed are complex carbohydrates or polysaccharides.

3. The primary structure of a protein is determined by:

a) Hydrogen bonds
b) Disulfide bridges
c) Peptide bonds
d) Ionic interactions

Answer:

c) Peptide bonds

Explanation:

The primary structure of a protein is its sequence of amino acids, which are linked by peptide bonds.

4. DNA differs from RNA because DNA:

a) Contains ribose sugar
b) Is double-stranded
c) Contains uracil
d) Is found only in the nucleus

Answer:

b) Is double-stranded

Explanation:

DNA is typically double-stranded while RNA is single-stranded.

5. Which enzyme is responsible for the replication of DNA?

a) Helicase
b) RNA polymerase
c) DNA ligase
d) DNA polymerase

Answer:

d) DNA polymerase

Explanation:

DNA polymerase synthesizes the new DNA strand during replication.

6. Which of the following is a pyrimidine base?

a) Adenine
b) Guanine
c) Cytosine
d) None of the above

Answer:

c) Cytosine

Explanation:

Cytosine is a pyrimidine base, while adenine and guanine are purines.

7. Enzymes are which type of biomolecule?

a) Carbohydrates
b) Lipids
c) Proteins
d) Nucleic acids

Answer:

c) Proteins

Explanation:

Enzymes are specialized proteins that act as catalysts in various biochemical reactions.

8. The bond between two amino acids is called:

a) Glycosidic bond
b) Ester bond
c) Peptide bond
d) Phosphodiester bond

Answer:

c) Peptide bond

Explanation:

A peptide bond is formed between the carboxyl group of one amino acid and the amino group of another.

9. Which vitamin is water-soluble?

a) Vitamin A
b) Vitamin D
c) Vitamin E
d) Vitamin C

Answer:

d) Vitamin C

Explanation:

Vitamin C is water-soluble, while the others listed are fat-soluble vitamins.

10. Which biomolecule is responsible for the storage and transfer of genetic information?

a) Carbohydrates
b) Lipids
c) Proteins
d) Nucleic acids

Answer:

d) Nucleic acids

Explanation:

DNA and RNA, both nucleic acids, are responsible for the storage and transfer of genetic information.

11. Which of the following is not a function of lipids?

a) Energy storage
b) Insulation
c) Catalysis of reactions
d) Protection of organs

Answer:

c) Catalysis of reactions

Explanation:

Lipids are not involved in catalysis; enzymes (proteins) play that role.

12. In RNA, which nucleotide base pairs with adenine?

a) Thymine
b) Cytosine
c) Guanine
d) Uracil

Answer:

d) Uracil

Explanation:

In RNA, adenine pairs with uracil, while in DNA, adenine pairs with thymine.

13. Which carbohydrate is commonly referred to as "fruit sugar"?

a) Glucose
b) Galactose
c) Fructose
d) Lactose

Answer:

c) Fructose

Explanation:

Fructose is commonly found in fruits and is referred to as "fruit sugar."

14. Which type of lipid is primarily used for long-term energy storage?

a) Phospholipids
b) Steroids
c) Triglycerides
d) Waxes

Answer:

c) Triglycerides

Explanation:

Triglycerides, which consist of three fatty acid chains linked to glycerol, are primarily used for long-term energy storage.

15. Which amino acid contains a sulfur atom?

a) Glycine
b) Aspartic acid
c) Cysteine
d) Valine

Answer:

c) Cysteine

Explanation:

Cysteine contains a thiol group (-SH) which has sulfur.

16. Which enzyme breaks down starch into maltose?

a) Lipase
b) Amylase
c) Ribonuclease
d) Protease

Answer:

b) Amylase

Explanation:

Amylase is responsible for breaking down starch into simpler sugars like maltose.

17. Which is the storage form of glucose in animals?

a) Starch
b) Cellulose
c) Glycogen
d) Fructose

Answer:

c) Glycogen

Explanation:

Glycogen is a polysaccharide that serves as the storage form of glucose in animals.

18. Which of the following is a disaccharide?

a) Glucose
b) Fructose
c) Lactose
d) Ribose

Answer:

c) Lactose

Explanation:

Lactose, commonly known as milk sugar, is a disaccharide made up of glucose and galactose.

19. What is the molecular building block of proteins?

a) Nucleotide
b) Fatty acid
c) Amino acid
d) Monosaccharide

Answer:

c) Amino acid

Explanation:

Proteins are made up of chains of amino acids.

20. In which biomolecule can the α-helix structure be found?

a) DNA
b) Starch
c) Proteins
d) Lipids

Answer:

c) Proteins

Explanation:

The α-helix is a common secondary structure found in proteins.

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