11th Class Biology Chapter 3 Enzymes Short Questions Answer

The catalytic activity of enzymes is restricted to a small portion of the enzymes know as the active site.

Some enzymes also have a non-protein part know as a co-factor.

If the non-protein part is covalently bonded to protein part of enzyme it is know as a prosthetic group. If it is loosely attached to the protein part it is known as coenzyme.

An activated enzyme consisting of polypeptide chain and a cofactor is known as holoenzyme.

An enzyme and its substrate react with each other through definite charge bearing sites called active sites.

The active site of the enzyme is made up of two definite regions i.e.,the binding site and the catalytic site.

Emil Fischer (1890) proposed a lock and key model to visualize substrate and enzyme interaction.

Koshland (1959) proposed Induce fit model. He argued that when a substrate combines with an enzyme it induces changes in the enzyme structure the change in structure enables the enzyme to perform its catalytic activity more effectively

Ans: Any factor that can alter the chemistry and shape of an enzyme affect its rate of catalysis such as temperature pH etc.

If the amount of enzyme is increased by two fold the reaction rate doubled.

For enzymes of human body 37ᵒC is the optimum temperature.

Extreme changes in pH cause the bonds in the enzyme to break resulting in the enzyme denaturation.

An inhibitor is a chemical substance which can react with the enzyme but is not transformed into product and thus blocks the active site.

Irreversible inhibitors occupy the active sites by forming covalent bonds or they may physically block the active sites

The detachable co-factor is known as an activator if it is an inorganic ion e.g., metal-ions like Mg2+,Cu2+,& Zn2+ etc.

The temperature at which enzyme can work best is called optimum temperature.

The pH at which enzyme can work best is called its optimum pH.

An enzyme with its coenzyme or prosthetic group removed is designated as apoenzyme.

An enzyme is a protein which can catalyze a biological reaction while the non protein part that is loosely attached to the protein part of enzyme it is known as coenzyme. The coenzyme helps the enzyme to carry out the reaction.

Any substance such as proteins carbohydrates lipids etc. which is acted upon by the enzymes is called substrate.

The value of a factor at which the reaction is carried out best is called its optimal or optimum value.

They check the reaction rate by occupying the active sites of destroying the globular structure. Irreversible inhibitors occupy the active sites by forming covalent bonds or they may physically block the active sites.

If the enzyme concentration is increased by two fold the reaction rate is doubled. By increasing the enzyme molecules an increase in the number of active sites takes place.

Butter solidifies at room temperature because butter is saturated fatty acid and saturated fatty acids are solid at room temperature and mustered oil is unsaturated fatty acid this is why it usually liquid at room temperature.

Nucleotides of DNA contains Adenine, Guanine, Cytosine and Thy mine where nucleotides of RNA contain Adenine, Guanine, Cytosine and Uricil.

lipids are used to store energy because of higher proportion of C-H bonds and very low proportion of oxygen and they store double amount of energy as compared to any carbohydrate.

DNA considered as genetic material because it contains genes and genes contains heredity characters which are transferred into new generation.

Proteins are called nitrogenous compounds because they contain nitrogen.

Carbohydrates are called as hydrated carbons because they contain the ratio of hydrogen and oxygen is the same as in water.

When two different groups of biomolecules are combined together, conjugated molecules are formed.

Glycolipids are also called as cerborsides because these are found in brain.

These are also called as simple sugars because they cannot further hydrolyzed into simple sugars.

Phospholipids are most important class of lipids because these are present in all living cells and are associated with membranes and related with vital functions of cell.

Water requires higher amount of energy to change into vapors or ice because water contains hydrogen bonding which holds the water molecules together and gives stability to water molecules also.

Water molecules are considered as amphoteric molecules because water acts both an acid and a base.

There twenty essential amino acids are found in the body of living organisms.

Mononucleotides do not work independently as genetic material because they are not associated with RNA or DNA and they are found singly in the cell or as a part of other molecules.

Lipids would be most advantageous organic molecules for energy storage because lipids have higher proportion of C-H bonds and very low proportion of oxygen: Lipids store double the amount of amount of energy as compared to carbohydrates.