Chapter 2 Enzymes Short Questions 1st Year Biology Sindh Textbook board.

Q.1 Why enzymes are specific in nature?

Ans

Each different type of enzyme will usually act on only one substrate to catalyse one biological reaction. Enzymes are specific because different enzymes have differently shaped active sites. The shape of the active site of an enzyme is complementary to the shape of its specific substrate. This means they are the correct shapes to fit together.

Q.2 why enzymes activity is directly proportional to enzymes concentration?

Ans

The answer is that if there are more enzymes available the more substrate will get a chance to participate in the reaction hence the more product will be formed.

So if there are more enzymes more product will be formed as long as enzymes increases, if enzymes are in limited amount or enzymes decrease the reaction will also be decreased

Q.3 Why enzymes are called temperature sensitive

Ans

The proteins in enzymes are usually globular. The intra- and intermolecular bonds that hold proteins in their secondary and tertiary structures are changed by changes in temperature because the higher the temperature higher will be the kinetic energy of molecules. This affects shapes and so the catalytic activity of an enzyme is temperature sensitive.

Q.4 how enzymes reduces the energy activation?

Ans

Activation energy is the minimum energy required for the activation of atoms or molecules to undergo a chemical transformation/reaction.

They bring reactants close enough so that they don’t need to dissipate extra energy when they collide at random.

Binding reactants at the active site, allows the molecules to interact with less energy.

Reactions also occur via a different mechanism to lower activation energy.

Enzyme activities depend on the nature of substrate, temperature, ionic concentration, and pH of the surroundings.

e.g Digestive enzymes secreted in the acidic environment (low pH) of the stomach help break down proteins into smaller molecules,

Trypsin (pH 8) is another enzyme in the digestive system, which breaks protein chains in food into smaller parts.

Q.5 How enzyme activity effect on substrate concentration?

Ans

Initially, an increase in substrate concentration leads to an increase in the rate of an enzyme-catalyzed reaction. As the enzyme molecules become saturated with substrate, this increase in reaction rate levels off. The rate of an enzyme-catalyzed reaction increases with an increase in the concentration of an enzyme

Q.6 what do you mean by prosthetic group?

Ans 

A prosthetic group is a tightly bound, specific non-polypeptide unit required for the biological function of some proteins. The prosthetic group may be organic (such as a vitamin, sugar, or lipid) or inorganic (such as a metal ion), but is not composed of amino acids.

Q.7 Differentiate between the activator and inhibitor?

Ans

Activator

1) Molecule that binds to enzymes to increase the enzymatic activity

2) can be either protein, peptide, lipid, small organic molecules or metal ions

3) eg: calcium and magnesium ions, fructose 2-6 biphosphate and glucokinase etc

Inhibitor 

1) the molecule that binds to enzymes to decrease the enzymatic activity

2) they can be reversible inhibitor (competitive and non competitive) or irreversible inhibitor (group-specific reagents and suicide inhibitor)

3) eg: penicillin and aspirin and protease inhibitors