NCERT Biomolecules questions,answers,solution,mcqs,pdfs NTA NEET

Biomolecules Mock Exam-5

Question No:1

In how many metabolic steps degradation of glucose to lactic acid occurs?

[A] 8
[B] 9
[C] 10
[D] 2



Question No:2

How do living organisms derive their energy? What strategies have they evolved? How do they store this energy and in what form? How do they convert this energy into work? These aspects are studied under a sub-discipline called

[A] Biowar
[B] Bioinformatics
[C] Bioenergetics
[D] Biosynthesis



Question No:3

Almost all enzymes are

[A] proteins
[B] nucleic acid
[C] carbohydrates
[D] vitamins



Question No:4

There are some nucleic acids that behaves like enzymes and are called

[A] DNA ase
[B] RNA ase
[C] endonuclease
[D] Ribozymes



Question No:5

………. of an enzyme is a crevices or pocket into which substrate fit.

[A] Inactive site
[B] Active site
[C] Allosteric site
[D] Any of the above



Question No:6

Select the incorrect statement from the following:

[A] Active enzyme has tertiary structure having many active sites (substrate binding sites)
[B] Enzymes are biocatalyst
[C] Enzymes occur in viruses
[D] Enzyme are mainly protein in nature



Question No:7

Select the correct statement from the following:

[A] Inorganic catalysts work efficiently at high temperature and high pressure while enzymes get damaged at high temperature (above 40℃)
[B] Ribozymes are nucleic acids behaving like enzyme
[C] Thermophilic organisms living in hot vents and sulphur springs have enzymes that are stable and retain their catalytic power even at high temperature (80-90℃)
[D] All



Question No:8

Select the incorrect statement from the following:

[A] A physical change simply refers to a change in shape without breaking of bonds
[B] Change is state of matter is also physical change
[C] Hydrolysis of starch into glucose is an inorganic chemical reaction
[D] Catalyzed reactions proceed at rates vastly higher than that of uncatalyzed ones



Question No:9

CO2+H2O<= 2CO3,
Carbonic acid Which one of the following statement is incorrect about the above reaction?

[A] In the absence of enzyme, the rate of H2CO3 formation is about 200 molecules per hour
[B] When carbonic anhydrase catalyses the same reaction, there is no change in the rate of H2CO3 formation
[C] The reaction catalyzed by the enzyme shows dramatically higher decrease speed about 600,000 molecules being formed every second, (rate becomes 10 million times more)
[D] The enzymes carbonic anhydrase occurs in abundance in RBC



Question No:10

Fill in the blanks in below statements:
A. A multistep chemical reaction, when each of the steps is catalyzed by the same enzyme complex or different enzymes, is called a………. ……… pathway B. In our skeletal muscle, under anaerobic conditions,………. ……… is formed. C. In yeast, during fermentation, the gylcolvtic pathway leads to the production of…………………………

[A] 1-metabolic pathway 2-acetic acid 3-ethanol
[B] 1-glycolytic pathway 2-lactic acid 3-ethanol
[C] 1-glycolytic pathway 2-ethanol 3-ethanol
[D] 1-metabolic pathway 2-lactic acid 3-ethanol



Question No:11

There could be many more ‘altered structural states’ (like transition state) between the stable substrate and the product in enzymatic reaction. These structural states are

[A] stable
[B] unstable
[C] metastable
[D] of lower energy then both substrate and product



Question No:12

Which one of the following statement about enzymes is true?
1) Enzymes are proteins whose three dimensional shape is key to their functions.
2) Enzymes speed up reactions by lowering activation energy.
3) Enzymes are highly specific for reactions.
4) Enzyme activity affected by change in temperature and pH.

[A] All except 2
[B] All except 1
[C] All except 3
[D] All



Question No:13

Which of the following is a unique feature about the enzyme?

[A] They are not consumed by the enzyme-mediated reaction
[B] They are not altered by the enzyme-mediated reaction
[C] They lower the activation energy
[D] All



Question No:14

The catalytic cycle of an enzyme action can be described in the following steps. Arrange them in sequence accordingly.
The binding of the substrate induces the enzyme to alter its shape, fitting more tightly around the substrate.
The substrate binds to the active site of the enzyme, fitting into the active site.
The enzyme releases the products of the reaction and the free enzyme is ready to bind to another molecule of the substrate and run through the catalytic cycle once again.
The active site of the enzyme, now in close proximity of the substrate breaks the chemical bonds of the substrate and the new enzyme product complex is formed,

[A] 1 -> 2 -> 3 -> 4
[B] 2 -> 1 -> 4 -> 3
[C] 1 -> 2 -> 4 -> 3
[D] 2 -> 1 -> 3 -> 4



Question No:15

Activation energy for given reaction is (i.e. reactant —»product):

[A] Energy of transition state — Energy of substrate
[B] Energy of transition state – Energy of product
[C] Threshold energy – Energy of transition state
[D] All are correct



Question No:16

Which one is correct?

[A] E + S -> ES -> EP -> EP
[B] E + S -> ES -> EP -> E + P
[C] E + S-> ES-> EP->E-P
[D] E + S-> ES-> EP-> E-P



Question No:17

Each enzyme shows its highest activity at particular temperature and pH called the(1) temperature and (2) pH. These (1) and (2) are respectively,

[A] optimum, optimum
[B] minimum, minimum
[C] maximum, maximum
[D] minimum, maximum



Question No:18

Select the correct statement:

[A] Low temperature preserves the enzyme in a temporarily inactive state
[B] Higher temperature destroys enzymatic activity because proteins are denatured by heat
[C] Activity of enzymes declines both below and above the optimum value
[D] All



Question No:19

Select the correct statement:

[A] Increase in substrate concentration, increases velocity of enzymatic reaction at first than it reaches maximum and further increment not occur
[B] In competitive inhibition inhibitor closely resembles the substrate in its molecular structure
[C] Competitive inhibition are often used in the control of bacterial pathogens
[D] All



Question No:20

The activity of an enzyme is also sensitive to the presence of specific chemicals that bind to the enzyme. When the binding of the chemical shuts off enzyme activity, the process is called………. and the chemical is called an………..

[A] activation, activator
[B] inhibition, inhibitor
[C] Inhibition, promoter
[D] activation, inhibitor