Important Questions for Class 11 Biology 9th Chapter Biomolecules MCQ, Very Short, Short Type, Long Type
CBSE Class 11 Important Questions for Class 11 Biology Chapter 9 Biomolecules all MCQ Type, Very Short Type, Assertion Reason Type, Case Study, Short Type and Long Type Questions with Answers by Expert. Important Questions for Section A, B, C, D Class 11 Biology Chapter 9.
- MCQs
Q.1) Assertion: Generally, proteinsare made from a-amino acids
Reason: Amino acids are organic compounds containing an amino group andan acidic group as substituents on the same carbon i.e., the a-carbon.
a.) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
b.) Both Assertion and Reason are correct and Reason is not the correct explanation for Assertion.
c.) If assertion is true but the reason is false.
d.) If both assertion and reason are false.
Q.2) Assertion: Inorganic catalysts work efficiently at high temperaturesand high pressures, while enzymes get damaged at high temperatures.
Reason: enzymes isolated from organisms, normally living under extremely high temperatures (e.g., hot vents), are stable and retain their catalytic power even at hightemperatures (up to 80°-90°C).
a.) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
b.) Both Assertion and Reason are correct and Reason is not the correct explanation for Assertion.
c.) If assertion is true but the reason is false.
d.) If both assertion and reason are false.
Q.3) Lecithin is an example of
a) Monoglycerides
b) Phospholipid
c) Simple fatty acids
d) Waxes
Q.4) Assertion: If a phosphate group is also foundesterified to the sugar, they are called nucleotides. Reason: Adenosine, guanosine,thymidine, uridine and cytidine are nucleotides
a.) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
b.) Both Assertion and Reason are correct and Reason is not the correct explanation for Assertion.
c.) If assertion is true but the reason is false.
d.) If both assertion and reason are false.
Q.5) Assertion: Certain amino acids areessential for our health and they have to be supplied through our diet.
Reason: Due to this. dietary proteins are thesource of essential amino acids
a.) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
b.) Both Assertion and Reason are correct and Reason is not the correct explanation for Assertion.
c.) If assertion is true but the reason is false.
d.) If both assertion and reason are false.
Q.6) Assertion: Cellulose is a heteropolymer
Reason: Cellulose is apolymeric polysaccharide consisting of monosaccharide like glucose and fructose.
a.) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
b.) Both Assertion and Reason are correct and Reason is not the correct explanation for Assertion.
c.) If assertion is true but the reason is false.
d.) If both assertion and reason are false.
Q.7) The mostimportant form of energy currency in living systems is the bond energy in
a chemical called
a) adenosine triphosphate
b) guanine triphosphate
c) cytosine triphosphate
d) thiamine triphosphate
Q.8) Enzymes catalyzing hydrolysis of ester, ether, peptide,glycosidic, C-C, C-halide or P-N bonds belong to the class
a) Oxidoreductases/dehydrogenases
b) Transferases
c) Hydrolases
d) Lyases
Q.9) Organic compounds and their association withthe apoenzyme is only transient, during the course of catalysis
a) Co-enzymes
b) Prosthetic groups
c) Metal ions
d) All the above
Q.10) Assertion: When the inhibitor closely resembles the substrate in its molecular structure and inhibits the activity of the enzyme, it is known ascompetitive inhibitor.
Reason: Due to its close structural similarity with the substrate, the inhibitor competes with the substrate for the substratebindingsite of the enzyme.
a.) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
b.) Both Assertion and Reason are correct and Reason is not the correct explanation for Assertion.
c.) If assertion is true but the reason is false.
d.) If both assertion and reason are false.
- Answer in one sentence
Q.1) What are proteins?
Ans. Amino acids are the building blocks of proteins. Proteins are linear chains of amino acids linked by peptide bonds.
Q2) What is ash?
Ans. 1.) The inorganic elements like calcium, magnesium which remain after burning the living tissue is called ash.
2.) When living tissue is completely burned, all the carbon containg entities are converted to CO2 and water vapor while the remanent are called ash.
Q.3) What are secondary metabolites?
Ans. The metabolites which are not essential for the growth and development of are called secondary metabolites. They have ecological importance and used in human welfare.
Q.4) What are the tertiary protein structure?
Ans. The tertiary structure is formed when the long protein chain folds within itself to form domain like structures. This provides us with a three-dimensional view of a protein.Tertiary structure is vitally required for proteins to perform their numerous biological functions.
Q.5) Explain the structure of human hemoglobin?
Ans. Adult human hemoglobin is made up of four components.Two of them are identical subunits. As a result, human hemoglobin is made up of two subunits of the a type and two subunits of the b type (Hb).
Q.6) Describe DNA structure on the basis of Watson- crick model.
Ans. DNA is made up of two strands that connect to form a double helix. Polynucleotide strands are antiparallel, which means they run in opposite directions. The sugar phosphate-sugar chain forms the backbone. The nitrogen bases are oriented perpendicular to the backbone but face inward. A and G on one strand must always base pair with T and C on the other strand.
- Answer in short
Q.1) Describe the enzyme structure.
Ans. 1.) An enzyme, like any other protein may have secondary and tertiary structures.
2) The tertiary structure of protein is the backbone of the protein chain folds into itself, the chain crisscrosses itself, and so multiple crevices or pockets are formed.
3) The ‘active site’ is one such pocket of an enzyme.
4) An enzyme’s active site is a fissure or pocket into which the substrate fits.
5) Thus, enzymes catalyze processes at a high pace via their active site.
Q.2) What are co-factors? State its types and significance
Ans. 1.) The non- protein part of an enzyme is called a co-factor.
2.) Prosthetic groups, co-enzymes, and metal ions are the three types of cofactors.
3.) Catalytic activity is lost when the co-factor is removed from the enzyme, indicating that they play an important part in the enzyme’s catalytic activity.
Q.3) Name the different classes of enzymes.
Ans. The 6 different classes of enzymes are
- Oxidoreductases/dehydrogenases
- Transferases
- Hydrolases
- Lyases
- Isomerases
- Ligases
Q.4) State the factors affecting enzyme activity
Ans. the factors affecting enzyme activity
1) Temperature
2) pH
3) concentration
4) binding of inhibitors or enhancers
Q.5) Describe simple chemical reaction which can be performed to determine type organic compounds are found in living organisms?
Ans. 1.) When living tissue is mixed with trichloroacetic acid (Cl3CCOOH) and strained through cheesecloth two fractions are obtained namely acid fraction and acid insoluble fraction
2.) The acid insoluble fraction is known to contain organic substance like carbohydrates, proteins etc.
3.) There are just four types of organic substances in the acid insoluble fraction: proteins, nucleic acids, polysaccharides, and lipids. With the exception of lipids, these groups of chemicals have molecular weights in the tens of thousands of daltons or higher.
Q.6) What is the difference between Nucleotides and Nucleoside?
Ans. 1.) Nitrogen bases are known as nucleosides when they are found linked to a sugar.
2.) Nucleosides include adenosine, guanosine, thymidine, uridine, and cytidine.
3.) Nucleotides are formed when a phosphate group is esterified to a sugar is attached to a nitrogen base.
4.) Nucleotides include adenylic acid, thymidylic acid, guanylic acid, uridylic acid, and cytidylic acid.
- Answer in Brief
Q.1) Distinguish between prosthetic group and coenzyme with example.
Ans. A.) Prosthetic groups
i) They are chemical molecules that are strongly attached to the apoenzyme, distinguishing them from other cofactors.
ii) For example, heam is the prosthetic group in peroxidase and catalase, which catalyze the breakdown of hydrogen peroxide to water and oxygen.
iii) It is also a component of the enzyme’s active site.
B.) Co-enzymes
(i) They are organic substances as well, although their relationship with the apoenzyme is only temporary, usually happening during catalysis.
(ii) Furthermore, co-enzymes act as cofactors in a variety of enzyme-catalyzed processes.
(iii) Many coenzymes’ key chemical components are vitamins; for example, the coenzymes nicotinamide adenine dinucleotide (NAD) and NADP contain the vitamin niacin.
Q.2) Explain in brief the steps in catalytic cycle of an enzyme action.
Ans. 1.) The substrate first binds to the enzyme’s active site, fitting into it.
2.) Substrate binding causes the enzyme to change shape, causing it to fit more closely around the substrate.
3.) The enzyme’s active site, now in close proximity to the substrate, breaks the chemical bonds of the substrate, resulting in the formation of the new enzyme-product complex.
4.) The enzyme releases the reaction products, and the free enzyme is ready to bind to another substrate molecule and repeat the catalytic cycle.
Q.3) Write short note on lipids
Ans. 1.) In general, lipids are insoluble in water.
2.) Lipids comprises fatty acids with a carboxyl group linked to a R group.
3.) The R group could be methyl (–CH3), ethyl (–C2H5), or a combination of –CH2 groups (1 carbon to 19 carbons).
4.) Saturated fatty acids (those with no double bonds) and unsaturated fatty acids (those with one or more C=C double bonds) are both possible. Glycerol, which is trihydroxy propane, is another simple lipid.
5.) Glycerol and fatty acids are found in many lipids. The fatty acids are esterified with glycerol here. They can then be classified as monoglycerides, diglycerides, or triglycerides.
6.) Based on their melting point, these are also known as fats and oils. Oils with lower melting points.
7.) Phospholipids include phosphorus as well as a phosphorylated organic molecule.
8.) They can be located in the cell membrane. One example is lecithin.
9.) Lipids with more complicated structures are found in some tissues, particularly brain tissues.