Saturday, November 7, 2020

Biomolecules | Class 11 | Previous Years Questions and Answers (2015 to 2020)

 BIOMOLECULES

2020 MARCH


1. Which among the following is a primary metabolite? (Score 1)

Alkaloids, Antibiotics, Amino acids, Flavonoids 

✔️Answer: Amino acids

2. When substrate concentration increases, the velocity of enzymatic reaction increases at first. After attaining a maximum velocity, it cannot be exceeded by further addition of substrates. Why? (Score 2)

✔️Answer:

Because enzyme molecules are fewer than the substrate molecules i.e. No free enzyme molecules to bind with additional substrate molecules.


2019 JULY


1. Match the following: (Score 3)

Classification of Enzymes

Reactions

A

B

Hydrolases

Oxidation-reduction reactions

Lyases

Linking together of molecules

Oxidoreductases

Transfer of a group

Isomerases

Interconversion of molecules

Ligases

Removal of groups

Transferases

Hydrolysis of bonds


✔️Answer:

Classification of Enzymes

Reactions

Hydrolases

Hydrolysis of bonds

Lyases

Removal of groups

Oxidoreductases

Oxidation-reduction reactions

Isomerases

Interconversion of molecules

Ligases

Linking together of molecules

Transferases

Transfer of a group


2019 MARCH


1. Observe the diagram A and B given below:


a. What is ‘A’ and ‘B’?
b. Mention the other two levels of protein structure. (Score 2)

✔️Answer::

(a) A= Secondary structure of protein, B= Tertiary structure of protein.
(b) Primary structure and quaternary structure.

2. ........... is the most abundant protein in the animal world. (Score 1)

✔️Answer: Collagen

2019 MODEL


1. General formula of amino acid is given below: (Score 3)


a. Prepare the amino acid serine using this formula.
b. Proteins carry many functions in living organism. List any four.
c. Give one word.
(i) The nucleic acid that behave like enzymes.
(ii) The organic compound tightly bound to the apoenzyme.
(iii) The non-protein organic compound that are tightly bound to the apoenzyme.
(iv) The protein part of the enzyme.

✔️Answer:

(a)

 
(b) o For growth and tissue repair.
    o Transport nutrients across cell membranes.
    o Acts as intercellular ground substance.
    o Acts as antibodies.
(c) (i) Ribozymes
    (ii) Prosthetic group
    (iii) Cofactor
    (iv) Apoenzyme

2018 AUGUST


1. Observe the graph given below. (Score 3)

 

a) Identify the graph.
b) Mention the role of enzyme in this process.

✔️Answer:

a) Concept of activation energy.
b) Enzymes lower the activation energy and thereby increases the speed of chemical reactions.

2018 MARCH


1. The molecular structure of 2 amino acids are given below. Name them. (Score 2)


 

✔️Answer:

(a) Serine
(b) Alanine

2. a) Complete the diagrammatic representation showing the nature of enzyme action: (Score 3)


    b) List out any two factors affecting enzyme activity.
    c) Based on the reaction formulae given below, identify the classes of the enzymes.

i) S reduced + S’ oxidised → S oxidised + S’ reduced

     X    Y
      |      |
ii) C – C → X – Y + C = C

✔️Answer:

a) (a) EP, (b) P
b) Temperature, pH, concentration of substrate etc.
c) (i) Oxidoreductases (Dehydrogenases).
              (ii) Lyases.

2018 MODEL


1. a) Effect of change in concentration of substrate on enzyme activity is graphically represented. After reaching a maximum velocity (Vmax), the reaction is not exceeded by any further rise in concentration of substrate. Explain.

    b) Mention any 2 other factors that affect enzyme activity? (Score 3)


✔️Answer:

(a) Because enzyme molecules are fewer than the substrate molecules i.e. No free enzyme molecules to bind with additional substrate molecules.
(b) Temperature and pH.

2. Fill in the blanks suitably. (Score 2)
  • In a proteins amino acids are linked by ….(a)…
  • In a polysaccharide, individual monosaccharides are linked by…….(b)…..
✔️Answer:

(a) Peptide bond.
(b) Glycosidic bond.

2017 MARCH


1. Identify the given biomolecules. (Score 3)


 

✔️Answer:

(A) Serine, (B) Adenylic acid, (C) Cholesterol

2. Select the wrongly matched pair from the following: (Score 1) 

Collagen

Intercellular ground substance

Insulin

Hormone

Antibody

Sensory reception

Trypsin

Enzyme


✔️Answer:

Antibody: Sensory reception.

2016 MARCH


1. Metabolites are organic compounds constantly utilized in various metabolic activities in the cells. (Score 2)

a) What are the two types of metabolites in cells?
b) Give an example for each type of metabolites.

✔️Answer:

(a) Primary metabolites & Secondary metabolites.
(b) Primary metabolites: E.g. Glucose.
      Secondary metabolites: E.g. Terpenoids.

2. Enzymes are biocatalysts which regulate various biochemical reactions. Illustrate the following reactions. (Score 2)

E+S → ES → E+P 

✔️Answer:

· The substrate binds to the active site of enzyme (E+S).
· The substrate is tightly bound with active site of enzyme to form enzyme- substrate complex (ES).
· The active site breaks chemical bonds of substrate to form enzyme- product complex (EP).
· The enzyme releases the products (E+P).

SEPTEMBER 2015 (IMPROVEMENT)


1. Complete the following sequence with appropriate words. (Score 1)

Amino acids: ….. (a) …..bond: Proteins

….. (b)…..: Glycosidic bond: Polysaccharides

✔️Answer:

(a) Peptide
(b) Glucose (Monosaccharides)

2. Based on the graph given below, explain the effect of concentration of substrate on enzyme activity. (Score 2)


✔️Answer:

With the increase in substrate concentration, the velocity of enzyme action rises at first and reaches a maximum velocity (Vmax). This is not exceeded by further rise in concentration because enzyme molecules are fewer than the substrate molecules i.e. No free enzyme molecules to bind with additional substrate molecules.

2015 MARCH


1. Identify the protein structures, (A) and (B) from the following figure. (Score 1)


✔️Answer:

(A) Secondary structure.
(B) Tertiary structure.

2. Analyse the graph showing the activity of an enzyme, influenced by temperature.

 

a. What is meant by optimum temperature?
b. Why does the enzyme activity decline at too low and too high temperature? (Score 2)

✔️Answer:

(a) It is the temperature at which enzyme action is maximum.
(b) o At low temperature, enzyme temporarily inactive.
      o At high temperature, enzymes destroy because proteins are denatured by heat.

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