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11th Class Chapter three Biology Short Questions

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Question: 1
What are enzymes?Give their importance?
Answer: 1
1-34
Enzymes are called biological catalyst the tremendously increase the rate of reaction,decrease the energy of activation and they are produced by the living organisms.
Importance:Enzyme control and catalyst chemical reaction in the living bodies or cell.Without enzymes reaction are not possible ultimately making life impossible.
Question: 2
What is NAD?
Answer: 2
2-34
NAD stands for nicotinamide adenine di nucleotide.It is and important enzyme.
Question: 3
Define apoenzyme and cofactor.
Answer: 3
3-34
Apoenzyme: The proteins of enzyme is called apoenzyme or enzyme without non protein part is called apoenzyme.
Question: 4
Give difference between prosthetic group and activator.
Answer: 4
4-34
Prosthetic Group:Covalently bounded non protein part is called prosthetic group.
Question: 5
What are cofactor?Give its types.
Answer: 5
5-34
Cofactors is a non proteins part of enzymes,which is essential for the proper functioning of the enzymes.Some enzymes consist of solely of proteins,Other have a non-proteins part known as cofactor.Types of cofactors are activators,prosthetic group and co-enzymes
Question: 6
Differentiate between apoenzyme and holoenzyme.
Answer: 6
6-34
Apoenzyme: The proteins part of enzyme is called apoenzyme or enzyme without non protein part is called apoenzyme.
Question: 7
Differentiate between cofactor and activator?
Answer: 7
7-34
Cofactor:Some enzymes consists of solely of proteins.Other have a non proteins part known as co-factor.which is essential for the proper functional of the enzymes..The cofactor usually acts as a bridge between the enzymes and its substrate,often it contributes directly to the chemical reaction which bring about catalysis.
Question: 8
Write four characteristics of enzyme.
Answer: 8
8-34
1.All enzymes are globular proteins.
2.They increase the rate of reaction without themselves being used up.
3.Their presence does not affect the nature of properties of end products.
4.Even a small amount of enzymes can bring about the change in large amount of the substrate.
Question: 9
What is cofactor?Give its role.
Answer: 9
9-34
Some enzymes consists of solely of proteins.Other have a non proteins part known as co-factor.which is essential for the proper functional of the enzymes..The cofactor usually acts as a bridge between the enzymes and its substrate,often it contributes directly to the chemical reaction which bring about catalysis.
Question: 10
Distinguish between prosthetic group and Co-enzyme.
Answer: 10
10-34
Prosthetic Group: If the non proteins parts are covalently bonded it is known as prosthetic group.
Question: 11
What is an activator?
Answer: 11
11-34
Some enzymes use metal ions as co factor like Mg2+etc.The detachable cofactor is known as activator if it is an inorganic ions like.
Question: 12
Differentiate between enzyme and co enzyme?
Answer: 12
12-34
Enzyme: Enzyme are called biological catalyst they tremendously increase the rate of reaction,decrease the energy of activation and the are produced by the living organisms.
Question: 13
How does high temperature effect enzyme activity?
Answer: 13
13-34
The rate of enzyme controlled reaction may increase with increase in temperature but up to a certain limit.All enzymes can work at their maximum rate at a specific temperature called optimum temperature.
Heat provide activation energy and therefore chemical reaction are accelerated at high temperature.
Question: 14
Give function of binding site and catalytic site of the active site of an enzyme.
Answer: 14
14-34
The binding sites helps the enzymes in the recognition and binding of a proper substrate to produce and ES complex.This reaction activities the catalytic site,Activated catalytic site catalyzes the transformation of the substrate into products.
Question: 15
What is role of enzyme concentration on the rate of enzyme action?
Answer: 15
15-34
The rate of reaction depends upon directly on the amount of enzyme present at a specific time at unlimited substrate concentration.If the amount of enzyme is increased by two fold the reaction is doubled.
Question: 16
Define optimum pH.
Answer: 16
16-34
Every enzyme function most efficiently over a narrow range of pH known as the optimum pH.
Question: 17
How enzyme catalyze series of chemical reaction?
Answer: 17
17-34
In certain cases enzymes act in a series of chemical reactions in a particular order to complete metabolic pathway such as respiration or photosynthesis.The successive enzymes containing these reactions are normally present together in a precise order of reaction.
Question: 18
What is induced fit model of enzyme action?
Answer: 18
18-34
On the basic of new evidences ,Koshland proposed modified form of lock and key model.This is known as induced fit model.He argued when a substance combines with an enzyme.It induced changes in the structure enables the enzyme to perform its catalytic activity more efficiently.This shows that enzymes are not rigid and flexible but are capable of considerable internal movement.
Question: 19
Define active site of enzyme and write only names of its two regions.
Answer: 19
19-34
An enzyme and its substrate react with each other through definite charge bearing site called active site.The active site of an enzyme is a three dimensional cavity bearing a specific charge by which the enzyme reacts with its substrate.
Active sites have two regions:
1.Binding Site
2.Catalytic site
Question: 20
What is the role of pH on enzyme activity?
Answer: 20
20-34
A slight change in pH can change the ionization of the amino acid at the active site.Moreover it may effect the ionization of the substrate.Under these changed condition enzyme activity is either retarded blocked completely.
Question: 21
Discuss lock and key model of enzyme action.
Answer: 21
21-34
Emil Fischer in 1890 proposed lock and key model to visualize enzyme substrate interaction.According ti this model as only a specific key fits in a particular lock to open it,Similarly a specific enzyme can transform only one substrate in product.
According to lock and key model the active site is a rigid site is rigid structure.There is no key modification or flexibility in the active site before,during and after the enzyme action and it is used only as a template.
Question: 22
What is active site of an enzyme?
Answer: 22
22-34
An enzyme and its substrate react with each other through definite charge bearing site called active site.The active site of an enzyme is a three dimensional cavity bearing a specific charge by which the enzyme reacts with its substrate.
Question: 23
Who proposed induced fit model of enzyme action?
Answer: 23
23-34
Koshland's proposed induced fit model.
Question: 24
Differentiate between reversible and irreversible inhibitors.
Answer: 24
24-34
Reversible inhibitors: They form weak linkages with the enzyme.Their effect can be neutralized completely or partly by an increase on the concentration of the substrate.
Question: 25
Define inhibitors with example.
Answer: 25
25-34
An inhibitors is an chemical substance that can react with the enzyme but is not transferred in to product and thus block the active site temporarily or permanently.For Example: poisons like cyanide,antibodies,anti metabolites,some drugs and pesticides etc.
Question: 26
What is enzyme to enzyme chain?
Answer: 26
26-34
In certain cases enzyme act in series of chemical reaction in a particular order to complete the metabolic pathway such as respiration or photosynthesis.The successive enzyme containing these reactions are normally present together in a precise order of reaction such that substrate molecule can be literally handed on form one enzyme to another forming a enzyme,coenzyme chain.
Question: 27
Compare competitive and non competitive inhibitors.
Answer: 27
27-34
Competitive inhibitors:Such inhibitors have structural similarity with the substrate both of which compete for same active sites of the enzyme.Because of the structural similarity with the substrate they may be selected by the binding sites,
Question: 28
Define optimum temprature,Give optimum temprature of human.
Answer: 28
28-34
All enzymes can work at their maximum rate at a specific temperature called as optimum temperature,For enzymes of human body 37 Degree is the optimum temperature.
Question: 29
Give the role of pH in enzyme action.Give the optimum pH values for any two enzyme actions.
Answer: 29
29-34
Optimum pH for pepsin is 2.00 and for sucrose is 5.50.
Question: 30
Give the optimum pH values of enzyme pepsin and pancreatic lipase.
Answer: 30
30-34
Optimum pH for pepsin is 2.00 and that for pancreatic lipase is 9.00.
Question: 31
How extreme change in pH affect enzyme?
Answer: 31
31-34
A slight change in pH can change the ionization of the amino acids at the active site.Moreover it may affect the ionization of the substrates.Under these change condition enzyme activity is either retarded blocked completely.Extreme change in pH cause the bonds in the enzymes to break,resulting in the enzyme denaturation.
Question: 32
At high substrate level,rate of enzyme action is not increased.Give reason.
Answer: 32
32-34
If the enzyme concentration is kept constant and the amount of substrate is increased a point is reached when further increase in the substrate s does not increase the rate of reaction any more,This is because at high substrate level all the active sites of enzyme are saturated with example.
Question: 33
Why enzymes are denatured at high temperature?
Answer: 33
33-34
At high temperature heat provides activation energy and therefore,chemical reaction are accelerated at high temperature.Heat also supplies kinetic energy to the reacting molecules causing them to move rapidly.Thus the reactant move rapidly and chance of their collision with each other also increased.
Question: 34
In what way,substrate concentration affects the rate of reaction?
Answer: 34
34-34
1.At low substrate concentration is kept constant and the amount of substance is increased,a point is reached when a further in the substrate does not increased the rate of reaction any more.This is because at high substrate level all the active sites of enzyme are saturated with substrate,After this the rate of enzyme reaction becomes steady and addition of substrate will not have the positive effect.

11th Class Biology Chapters Short Questions