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Cell Molecules Part 4 - Enzymes

Cell Molecules Part 4 - Enzymes:

Structure of enzyme:

  • Enzymes contain protein and non-protein part, where protein part is known as apoenzyme and non protein part is known as co-enzyme or prosthetic group.
  • Enzymes act on specific substance which is called as reactants or substrate.

Properties of enzyme:

  • It reacts with reactants and converts them into product.
  • It performs their activities at a specific temperature range.
  • They are specific for one reaction and is not useful in another reaction
  • They are pH dependent catalyst.

Mechanism of action:

Enzyme contains a specific region is their structure which is called as ‘active site’ which reacts with reactant and forms enzyme-substrate complex. The enzyme-substrate complex acts as a catalyst and increases the activation energy level and helps in formation of product. After completion of reaction, enzyme remains in its origin form.

Enzyme + Substrate → Enzyme-substrate complex → Enzyme + product

Types of enzyme:

Enzymes are classified on the basis of their action as a catalyst.

  1. Hydrolases: Enzymes that causes hydrolysis.
  2. Tranferases: Enzyme causes transfer of radical.
  3. Oxido-reductase: Enzyme causes oxidation and reduction reaction
  4. Isomerases: Enzyme causes change in geometry of substance
  5. Lipases: Enzyme that digest fat

Biological importance of enzyme:

  • They maintain life by taking part in various biochemical reactions in cells at normal concentration of reactants at normal temperature.
  • They act as a biological catalyst and remain in their origin form at the end of reaction.


Structure of vitamins:

  • Vitamins are the specific organic compound present in extremely small amount in the body.
  • Animal cell can not prepare the vitamin but obtained from their food.
  • Plants and bacteria synthesize vitamin their own.

Types of vitamins:

  1. Water soluble vitamin: Vitamin B Complex and vitamin C
  2. Fat soluble vitamin: Vitamin A, D, E and K.

Biological importance of vitamin:

  • Regulates various metabolic activities.
  • Essential for activities of enzyme.
  • Act as antioxidant and protect genetic material and cell organelles from foreign matter.
  • Deficiency of vitamins leads to various disease.

Self study:

Example-1: Protein component of enzymes are called as ……………..
a)  Co-factor
b)  Co-enzyme

c)  apoenzyme
d)  prosthetic group

Answer: Protein component of enzymes are called as apoenzyme

Example-2:  Match the following

Enzyme Vitamin B complex
Water soluble vitamin Vitamin A, D, E and K
Fat soluble vitamin Substance on which enzyme acts
Substrate Biological catalyst


Enzyme Biological catalyst
Water soluble vitamin Vitamin B complex
Fat soluble vitamin Vitamin A, D, E and K
Substrate Substance on which enzyme acts

Example-3: Which of the following component remains in is original form at the end of reaction?
a)  Enzyme
b)  Protein
c)  Carbohydrate
d)  Vitamins

Answer: Nucleic acids are the building blocks of proteins. © 2024 | Contact us | Terms of Use | Privacy Policy | Yellow Sparks Network
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