Biomolecules | Unit Test - 4 Sets of PDF QPs in one page with answer key I Class 11

➡️ Unit Test - 4 Sets of PDF QPs Download

Set A - Max. score: 15

1. A triglyceride is formed of 3 fatty acids and a ………………. (1)
2. In a protein, amino acids are linked by ………………. bond. (1)
3. What is meant by primary metabolites? Give any two examples. (2)
4. Lipid is not strictly a macromolecule as its molecular weight does not exceed 800 Da. But it comes under acid insoluble fraction. Justify. (2)
5. 1. Name two levels of protein structure which are not three dimensional.
   2. Give an example for protein having quaternary structure and justify your answer. (2)
6. Distinguish between Lyases and Ligases. (2)
7. Identify the molecules A and B. (2)
   

   

8. Explain the following reactions showing a catalytic cycle. (3)
   
   E + S ➔ ES ➔ EP ➔ E + P

Set A - ANSWER KEY

1. Glycerol (trihydroxy propane).
2. Peptide bond.
3. The biomolecules that have identifiable functions in physiological processes and necessary for life are called Primary metabolites.
   E.g. amino acids, sugars, nucleic acids, lipids, vitamins etc. (Any two)
4. Lipids have small molecular weights (< 800 Da) and are present in cell membranes. During tissue grinding, membranes are broken down into pieces and form water-insoluble vesicles. These vesicles do not pass into the acid-soluble pool and are filtered into the acid-insoluble fraction.
5. 1. Primary structure and Secondary structure.
   2. Example: Haemoglobin.
      Justification: It consists of 4 subunits (two identical α-chains and two identical β-chains) arranged together architecture-wise.
6. Lyases: Enzymes that catalyse removal of groups from substrates by mechanisms other than hydrolysis leaving double bonds.
   Ligases: Enzymes that catalyse the linking together of two compounds (e.g., C-O, C-S, C-N, P-O bonds).
7. 1. A: Glucose (C₆H₁₂O₆)
   2. B: Glycine (amino acid)
8. 1. Substrate (S) binds to the active site of the enzyme (E), fitting into the active site to form the Enzyme-Substrate complex (ES).
   2. The binding of the substrate induces the enzyme to alter its shape, fitting more tightly around the substrate.
   3. The active site breaks the chemical bonds of the substrate, forming the Enzyme-Product complex (EP).
   4. The enzyme releases the products (P), and the free enzyme (E) is ready to bind another molecule of substrate.

Set B - Max. score: 15

1. ………………. are substituted methanes. (1)
2. Name a protein enables glucose transport into cells. (1)
3. Give any four examples for polysaccharides. (2)
4. What is meant by competitive inhibitor? Mention its action with suitable example. (2)
5. Distinguish between Transferases and Hydrolases. (2)
6. Fill in the blanks: (2)

   Base	Nucleoside	Nucleotide
   Adenine	Adenosine	Adenylic acid
   Guanine	a	Guanylic acid
   b	Cytidine	Cytidylic acid
   Thymine	c	d

7. Identify the molecules A and B. (2)
   

   

8. 1. Explain the effect of concentration of substrate on enzyme activity.
   2. Differentiate apoenzyme and coenzyme. (3)

Set B - ANSWER KEY

1. Amino acids.
2. GLUT-4.
3. Cellulose, Starch, Glycogen, Inulin, Chitin. (Any four)
4. When a chemical substance closely resembles the substrate in its molecular structure and inhibits the activity of the enzyme, it is called a competitive inhibitor.
   Example: Inhibition of succinic dehydrogenase by malonate, which closely resembles the substrate succinate in structure.
5. Transferases: Enzymes catalysing the transfer of a group (other than hydrogen) between a pair of substrates.
   Hydrolases: Enzymes catalysing hydrolysis of ester, ether, peptide, glycosidic, C-C, or P-N bonds.
6. a: Guanosine
   b: Cytosine
   c: Thymidine
   d: Thymidylic acid
7. 1. A: Serine (hydroxy methyl group containing amino acid)
   2. B: Cholesterol
8. 1. With the increase in substrate concentration, the velocity of the enzymatic reaction rises initially until it reaches a maximum velocity (V_max). It does not increase further because enzyme molecules are saturated with substrate.
   2. Apoenzyme: The protein portion of the enzyme.
      Coenzyme: The non-protein organic cofactor that is loosely and transiently attached to the apoenzyme (e.g., NAD, NADP).

Set C - Max. score: 15

1. Which of the following is not a pyrimidine? (1)
   Guanine, Cytosine, Uracil, Thymine
2. Insulin: Protein      Inulin: ………………. (1)
3. Mention any four functions of proteins. (2)
4. Distinguish between Primary metabolites and secondary metabolites. (2)
5. Briefly explain the 3 components of a nucleotide. (2)
6. What is meant by zwitterion? Draw its structure. (2)
7. Give reason: (2)
   1. Starch gives blue colour with iodine (I₂).
   2. Cellulose does not give blue colour with iodine.
8. Observe the graph given below. (3)
   

   

   1. Identify the graph.
   2. Define activation energy.
   3. Mention the role of enzyme in this process.

Set C - ANSWER KEY

1. Guanine.
2. Polysaccharide.
3. • Transport nutrients across cell membrane (e.g., GLUT-4).
   • Fight infectious organisms (Antibodies).
   • Act as hormones (e.g., Insulin).
   • Act as biocatalysts/enzymes (e.g., Trypsin).
   • Intercellular ground substance (e.g., Collagen). (Any four)
4. Primary metabolites: Have identifiable functions and play known roles in normal physiological processes (e.g., sugars, amino acids).
   Secondary metabolites: Products whose direct physiological functions in host organisms are unknown, but many are useful to human welfare or have ecological importance (e.g., alkaloids, flavonoids, rubber, antibiotics).
5. 1. Nitrogenous base: Adenine, Guanine, Cytosine, Uracil, or Thymine.
   2. Pentose sugar: Ribose (in RNA) or 2'-deoxyribose (in DNA).
   3. Phosphate group
6. It is an ionic form of an amino acid where the amino group carries a positive charge (-NH₃⁺) and the carboxyl group carries a negative charge (-COO^-) at a specific pH.
   Structure:
   

   

7. 1. Starch forms helical secondary structures that can hold iodine molecules in the helical portion, forming a blue colour.
   2. Cellulose does not contain complex helices and cannot hold iodine molecules.
8. 1. Concept of activation energy / Progress of an enzymatic reaction showing activation energy.
   2. The difference in average energy content of 'S' from that of its transition state / the minimum energy required to start a chemical reaction.
   3. Enzymes lower the activation energy, thereby increasing the rate of reaction.

Set D - Max. score: 15

1. Which of the following is not a secondary metabolite? (1)
   Terpenoids, Vitamins, Lectins, Alkaloids
2. Name the most abundant protein in animal world. (1)
3. Identify the given biomolecule. How is it formed? (2)
   

   

4. Distinguish between Nucleoside and nucleotide. (2)
5. Give one example each for acidic, basic, neutral and aromatic amino acids. (2)
6. Mention any 4 factors that affect enzyme activity. (2)
7. Identify and explain given structural level of protein. (2)
   

   

8. Non-protein constituents called cofactors are bound to the enzyme to make the enzyme catalytically active. (3)
   1. Name the protein portion of the enzyme.
   2. What happens to the catalytic activity when the cofactor is removed from the enzyme?
   3. Mention any 2 kinds of cofactors with examples.

Set D - ANSWER KEY

1. Vitamins.
2. Collagen.
3. Triglyceride (Triacylglycerol).
   It is formed by the esterification of three molecules of fatty acids with one molecule of glycerol.
4. Nucleoside: Formed by a nitrogenous base attached to a pentose sugar. (e.g., Adenosine, Guanosine).
   Nucleotide: Formed by a nitrogenous base, a pentose sugar and a phosphate group. (e.g., Adenylic acid, Guanylic acid).
5. • Acidic: Glutamic acid / Aspartic acid
   • Basic: Lysine / Arginine
   • Neutral: Valine / Glycine / Alanine
   • Aromatic: Tyrosine / Phenylalanine / Tryptophan
6. 1. Temperature
   2. pH
   3. Concentration of substrate
   4. Presence of inhibitors.
7. Quaternary structure.
   Here, more than one polypeptide chains form tertiary structure and each chain functions as subunits of protein. E.g. Haemoglobin. It has 4 subunits (2 α subunits & 2 β subunits).
8. 1. Apoenzyme.
   2. The catalytic activity is lost.
   3. • Prosthetic groups: Organic compounds tightly bound to the apoenzyme (e.g., Haem in peroxidase and catalase).
      • Co-enzymes: Organic compounds whose association with apoenzyme is transient (e.g., NAD, NADP).
      • Metal ions: Form coordination bonds with side chains at active site (e.g., Zinc for carboxypeptidase). (Any two)