Vidaara.orgClass 11 · Mathematics
CodeVID-M11-WS
Biomolecules — Practice Worksheet
Name: ____________________
Roll No.: __________
Date: ____________
General Instructions
- All questions are compulsory.
- Choose the correct option (A, B, C or D) for each question.
- The answer key is at the end — try the paper first!
Section A — Multiple Choice (1 mark each)
15 × 1 = 15 marks
1.
The most abundant molecule by weight in a living cell is:
- A.Protein
- B.Water
- C.Lipid
- D.DNA
2.
Substances like alkaloids and pigments, not directly essential for growth, are:
- A.Primary metabolites
- B.Secondary metabolites
- C.Water
- D.Minerals
3.
The chief source of energy in the body is:
- A.Carbohydrates
- B.Nucleic acids
- C.Vitamins
- D.Minerals
4.
Cellulose, found in plant cell walls, is a:
- A.Monosaccharide
- B.Disaccharide
- C.Polysaccharide
- D.Lipid
5.
Lipids are made of glycerol and:
- A.Amino acids
- B.Fatty acids
- C.Nucleotides
- D.Sugars only
6.
The building blocks of proteins are:
- A.Fatty acids
- B.Amino acids
- C.Nucleotides
- D.Glucose
7.
The bond that joins amino acids in a protein is the:
- A.Peptide bond
- B.Glycosidic bond
- C.Ester bond
- D.Hydrogen bond
8.
Loss of a protein's normal shape due to heat or pH is called:
- A.Denaturation
- B.Digestion
- C.Hydrolysis
- D.Respiration
9.
The monomers of nucleic acids are:
- A.Amino acids
- B.Nucleotides
- C.Fatty acids
- D.Monosaccharides
10.
In DNA, adenine (A) pairs with:
- A.Guanine
- B.Cytosine
- C.Thymine
- D.Uracil
11.
RNA differs from DNA in having the base:
- A.Thymine
- B.Uracil
- C.Adenine
- D.Guanine
12.
Biological catalysts that speed up reactions are:
- A.Vitamins
- B.Enzymes
- C.Hormones
- D.Minerals
13.
The specific pocket of an enzyme where the substrate binds is the:
- A.Active site
- B.Cristae
- C.Nucleoid
- D.Grana
14.
Which factor does NOT directly affect enzyme activity?
- A.Temperature
- B.pH
- C.Substrate concentration
- D.Colour of the container
15.
Deficiency of vitamin C causes:
- A.Rickets
- B.Scurvy
- C.Night blindness
- D.Goitre
Section B — Challenge / Olympiad (2 marks each)
6 × 2 = 12 marks
16.
Per gram, fats store more energy than carbohydrates, which is why the body uses fat for:
- A.Long-term energy storage
- B.Immediate quick energy
- C.Genetic information
- D.Catalysing reactions
17.
An enzyme acts only on one specific substrate because:
- A.Only that substrate fits its active site (lock-and-key)
- B.It has no active site
- C.All substrates fit
- D.It is a carbohydrate
18.
Boiling a solution of the enzyme amylase stops it digesting starch because heat:
- A.Denatures the enzyme, destroying its active site
- B.Adds more substrate
- C.Lowers the pH
- D.Makes more enzyme
19.
Pepsin works best in the stomach and trypsin in the intestine. This shows that enzymes have an optimum:
- A.pH
- B.Colour
- C.Mass
- D.Size
20.
Increasing substrate concentration speeds up an enzyme reaction up to a point, after which the rate levels off because:
- A.All the enzyme active sites become occupied (saturated)
- B.The enzyme is used up
- C.The substrate disappears
- D.The temperature falls
21.
Many B-complex vitamins are needed in tiny amounts because they act as:
- A.Coenzymes that help enzymes function
- B.Main energy fuels
- C.Structural proteins
- D.Genetic material
Answer Key
Section A — Multiple Choice (1 mark each)
- (B) Water
- (B) Secondary metabolites
- (A) Carbohydrates
- (C) Polysaccharide
- (B) Fatty acids
- (B) Amino acids
- (A) Peptide bond
- (A) Denaturation
- (B) Nucleotides
- (C) Thymine
- (B) Uracil
- (B) Enzymes
- (A) Active site
- (D) Colour of the container
- (B) Scurvy
Section B — Challenge / Olympiad (2 marks each)
- (A) Long-term energy storage
- (A) Only that substrate fits its active site (lock-and-key)
- (A) Denatures the enzyme, destroying its active site
- (A) pH
- (A) All the enzyme active sites become occupied (saturated)
- (A) Coenzymes that help enzymes function
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