CBSE Class 12 Chemistry Biomolecules Worksheet Set A

1.Name the sugar present in milk.

A: Lactose,

2.How many monosaccharide units are present in it?

A: two monosaccharide units are present.

3. What are such oligosaccharides called?

A: Such oligosaccharides are called disaccharides

4. How do you explain the presence of all the six carbon atoms in glucose in a straight chain?

A: On prolonged heating with HI, glucose gives n-hexane.

4. Name the linkage connecting monosaccharide units in polysaccharides.

A: Glycosidic linkage.

5. Under what conditions glucose is converted to gluconic and saccharic acid?

A: Glucose is converted to gluconic acid by bromine water and to saccharic acid by conc. HNO3.

6. Which sugar is called invert sugar?

A: Sucrose.

7. During curdling of milk, what happens to sugar present in it?

A: It converts into Lactic acid.

8. . Monosaccharide contain carbonyl group hence are classified, as aldose or ketose. The number of carbon  atoms present in the monosaccharide moleculeare also considered for classification. In which class of monosaccharide willyou place fructose?

A:Fructose is a ketohexose.

Question. Which of the following is the correct order of priority of group in D-glyceraldehyde?
(a) OH(1), CHO(2), CH OH(3) 2 and H(4)
(b) OH(1), CH OH(2), 2 CHO(3) and H(4)
(c) CH OH(1), 2 CHO(2), OH(3) and H(4)
(d) CHO(1), OH(2), CH OH 2 (3) and H(4)
Answer. A

Question. Glucose on reaction with Fehling’s solution gives
(a) cupric oxide
(b) cuprous oxide
(c) saccharic acid
(d) Both (b) and (c)
Answer. B

Question. Glucose + Tollen’s reagent → Silver mirror, the above process shows
(a) presence of —COOHgroup
(b) presence of keto group
(c) presence of — CHOgroup
(d) presence of — CONH₂ group
Answer. C

Question. Glucose has difference from fructose in that it
(a) does not undergo hydrolysis
(b) gives silver mirror with Tollen’s reagent
(c) monosaccharide
(d) None of the above
Answer. B

Question. In a protein molecule various amino acids are linked together by
(a) b-glycosidic bond
(b) peptide bond
(c) dative bond
(d) a-glycosidic bond
Answer. B

Question. Which of the following compounds can form a Zwitter ion?
(a) Benzoic acid
(b) Acetanilide
(c) Aniline
(d) Glycine
Answer. D

Question. Which structure(s) of proteins remains(s) intact during denaturation process?
(a) Both secondary and tertiary structures
(b) Primary structure only
(c) Secondary structure only
(d) Tertiary structure only
Answer. B

Question. The correct statement regarding RNA and DNA, respectively is
(a) The sugar component in RNA is ribose and the sugar component in DNA is 2¢-deoxyribose
(b) The sugar component in RNA is arabinose and the sugar component in DNA is ribose
(c) The sugar component in RNA is 2¢-deoxyribose and the sugar component in DNA is arabinose
(d) The sugar component in RNA is arabinose and the sugar component in DNA is 2¢-deoxyribose
Answer. A

Question. A codon has a sequence of …A… and specifies a particular …B… that is to be incorporated into …C… . What are A, B, C ?
         A               B                   C
(a) 3 bases    Amino acid        Carbohydrate
(b) 3 acids     Carbohydrate    Protein
(c) 3 bases    Protein             Amino acid
(d) 3 bases    Amino acid       Protein
Answer. D

Question. Which is not the correct statement about RNA and DNA?
(a) DNA is active in virus whereas RNA never appears in virus
(b) DNA exists as dimer while RNA is usually single-stranded
(c) DNA contains deoxyribose as its sugar and RNA contains ribose
(d) RNA contains uracil in place of thymine (found in DNA) as a base
Answer. A

Question. The phenomenon of mutation is
(a) chemical change in DNA molecule
(b) production of macromolecules
(c) synthesis of micromolecules
(d) invasion of foreign microorganism
Answer. A

Question. The spatial arrangement of two or more polypeptide chains with respect to each other is known as
(a) primary structure
(b) secondary structure
(c) tertiary structure
(d) quaternary structure
Answer. D

Question. Match correctly between Column I and Column II –
   Column I            Column II
A. Collagen       I. Glucose transport
B. Trypsin         II. Binding with some chemical like for small taste and hormones
C. Insulin          III. Hormones
D. Antibody       IV. Enzymes
E. Receptor      V. Intercellular ground substance
F. GLUT – 4      VI. Fight infectious agents
(a) A – V, B – IV, C – III, D – VI, E – II, F – I
(b) A – II, B – III, C – IV, D – V, E – VI, F – I
(c) A – VI, B – II, C – I, D – V, E – IV, F – III
(d) A – I, B – IV, C – III, D – VI, E – II, F – V
Answer. A

Question. In some places a protein molecule may be folded back on itself. This is called ________ structure and folds or coils are held together in place by ______.
(a) 2°, H – bonds
(b) 2°, Peptide bond
(c) 3°, H – bonds
(d) 1°, Peptide bond
Answer. A

Question. A protein has how many terminal amino acids are called _________?
(a) 2; N-terminal amino acid and C – terminal amino acid
(b) 3; N-terminal amino acid, C-terminal amino acid, R – terminal amino acid
(c) 1; C-terminal amino acid
(d) 4; N-terminal amino acid
Answer. A

Question. The primary structure of a protein is determined by its –
(a) Disulfide brides
(b) α-helix structure
(c) Order of amino acids
(d) 3D-structure
Answer. C

Question. A β-pleated sheet organization in a polypeptide chain is an example of –
(a) 1°structure
(b) 2° structure
(c) 3° Structure
(d) 4° structure
Answer. B

Question. The _____ structure of a protein relates to how separate polypeptides assemble together –
(a) 1°
(b) 2°
(c) 3°
(d) 4°
Answer. D

Question. An α helix is the example of which level of protein structure?
(a) 1°
(b) 2°
(c) 3°
(d) 4°
Answer. B

Question. The overall three dimensional shape of polypeptide is called the –
(a) 1° structure
(b) 2° structure
(c) 3° structure
(d) 4° structure
Answer. C

Question. Which is the highest structural organization found in all enzymes?
(a) 2°
(b) 3°
(c) 1°
(d) 4°
Answer. B

Question. Arachnidonic acid and palmatic acids have many carbons in each of them –
(a) 16, 16
(b) 16, 20
(c) 20, 16
(d) 18, 18
Answer. C

Question. 𝐶𝐻+ − (𝐶𝐻.)01 − 𝐶𝑂𝑂𝐻
The above is the formula
(a) Phospholipid
(b) Palmatic acid
(c) Triglyceride
(d) Arachidonic acid
Answer. B

Question. Lecithin is –
(a) Phospholipid
(b) Carbohydrate
(c) Protein
(d) Amino acid
Answer. A

Question. Plants produce an enormous diversity of substances that have no apparent roles in growth and development processes are classified under the heading of –
(a) Primary metabolites
(b) Secondary metabolites
(c) Necessary metabolites
(d) Tertiary metabolites
Answer. B

Question. Match the Column I with Column II correctly –
Column I (Category)      Column II (Secondary Metabolites)
A. Pigments                  I. Concanavalin A
B. Terpenoides             II. Monoterpenes, Diterpenes
C. Alkaloids                 III. Morphine, Cadeine
D. Lectins                    IV. Carotenoids, Anthocyanine
(a) A – IV, B – II, C – III, D – I
(b) A – IV, B – III, C – II, D – I
(c) A – I, B – IV, C – III, D – II
(d) A – I, B – III, C – II, D – IV
Answer. A

Question: Carbohydrate that cannot be hydrolysed further to give simpler unit of polyhydroxy aldehyde or ketone is called
a) monosaccharide
b) oligosaccharide
c) polysaccharide
d) sucrose

Answer: a

Question: In sucrose, the two monosaccharides are held together by a glycosidic linkage. The linkage is between
a) C₁ of α-D-glucose and C₂ of β-D-fructose
b) C₂ of α-D-glucose and C₁ of β-D-fructose
c) C₁ of β-D-glucose and C₂ of β-D-fructose
d) C₁ of β-D-glucose and C₂ of β-D-fructose

Answer: a

Question: Which of the following is not an example of polysaccharide?
a) Starch
b) Cellulose
c) Glycogen
d) Maltose

Answer: d

Question: Which of the following act as epimeric pair?
a) Glucose and fructose
b) Fructose and mannose
c) Glucose and mannose
d) Glucose and sucrose

Answer: c

Question: Invert sugar is a mixture of
a) D-glucose + D-fructose
b) L-glucose + D-fructose
c) L-glucose + D-glucose
d) L-glucose + L-glucose

Answer: a

Question: Which of the following is known as animal starch?
a) Amylose
b) Amylopectin
c) Glycogen
d) Cellulose

Answer: c

Question: Which of the following amino acids can be synthesised in the body?
a) Valine
b) Leucine
c) Lysine
d) Glycine

Answer: d

Question: The spatial arrangement of the two or more polypeptide chains with respect to each other is known as
a) primary structure
b) secondary structure
c) tertiary structure
d) quaternary structure

Answer: d

Question: Which of the following structure of protein is formed when polypeptide in a protein has amino acids linked with each other in a specific sequence?
a) primary structure
b) secondary structure
c) tertiary structure
d) quaternary structure

Answer: a

Question: Which of the following is/are example(s) of denaturation of protein?
a) Coagulation of egg white
b) Clotting of blood
c) Curdling of milk
d) Both (a) and (c)

Answer: d

Question: What is the common name given to the enzyme which catalyse the oxidation of one substrate with simultaneous reduction of another substrate?
a) Reductioxidase
b) Oxidonductase
c) Oxidoreductase
d) Reductoxides

Answer: c

Question: Which of the following combination is correct between nucleic acid and its respective sugar base?
a) DNA →β-D-3-deoxyribose
b) DNA →β-D-1-deoxyribose
c) RNA →β-D-ribose
d) RNA →β-D-3-deoxyribose

Answer: c

Question: Name the product which is formed by the oxidation of glucose and gluconic acid with nitric acid.
a) Rhamnose
b) Saccharic acid
c) Citric acid
d) Oxalic acid

Answer: b

Question: Which of the following is a fat soluble vitamin?
a) Vitamin A
b) Vitamin B₆
c) Vitamin C
d) Vitamin B₂

Answer: a

Question: The total number of amino acids to form protein in human body is
a) 25
b) 100
c) 20
d) 10

Answer: c

Question: Water soluble vitamin is
a) vitamin C
b) vitamin D
c) vitamin E
d) vitamin K

Answer: a

Question: Pyridoxine is also known as
a) vitamin B₂
b) vitamin B₆
c) vitamin B₁₂
d) vitamin B₁

Answer: b

Question: Which of the following disease is caused by the deficiency of vitamin E?
a) Beri-beri
b) Rickets
c) Scurvy
d) Muscular weakness

Answer: d

Question: Which one of the following does not constitute the nucleic acid?
a) Uracil
b) Ribose sugar
c) Phosphoric acid
d) Guanidine

Answer: d

Question: Which of the following is not a hormone?
a) Insulin
b) Endorphins
c) Norepinephrine
d) Thymine

Answer: d

Question: Which of the following is a type of RNA?
a) m-RNA
b) t-RNA
c) r-RNA
d) All of these

Answer: d

Question: The major role of insulin is
a) to decrease the glucose level in human body
b) to keep the blood glucose level within the narrow limit
c) to regulate growth
d) to transport minerals

Answer: b

 ONE MARK QUESTIONS
1. What are the three types of RNA molecules which perform different functions? 
2. What type of bonding helps in stabilizing the𝛼−ℎ𝑒𝑙𝑖𝑥structure of proteins? 
3. Name the products of hydrolysis of lactose.
4. What is denaturation of protein?

TWO MARK QUESTIONS
1. Write the important structural difference between DNA and RNA. Of the two bases, thymine and uracil, which one is present in DNA?
2. Name the products obtained on reaction of glucose with a) HI b) HNO₃
3. State what you understand by primary structure and secondary structure of proteins. 
4. What are essential and non-essential amino acids? Give one example of each type. 

THREE MARKQUESTIONS
1. Differentiate between
a) Amylose and amylopectin
b) Fibrous and globular proteins
c) Nucleoside and nucleotide

2. Name a disease that is caused due to the deficiency of the following vitamins:
a) Thiamine (b) Riboflavin (c) D

3. The two strands in DNA are not identical but are complementary. Explain.

FIVE MARKS QUESTIONS
1. a) What is glycogen? How is it different from starch? How is starch structurally different from cellulose? b) Explain what is meant by the following: i) Peptide linkage ii) Pyranose structure of glucose (2012)

VALUE BASED QUESTION
1. A person in Mahesh’s neighbourhood was suffering from bleeding gums. Mahesh suggested him to include citrus fruits in the diet.
a) Which disease was the person in Mahesh’s neighbourhood suffering from?
b) What is the cause of this disease?
c) What are vitamins?
d) Mention the value associated with Mahesh.

Q1. What are carbohydrates? What are sugars and non sugars?

Q2. How is glucose prepared commercially?

Q3. Give one chemical test to justify that:-
(a) glucose has five hydroxyl groups
(b) glucose contains a carboxyl gp.
(c) glucose contains one primary alcoholic gp.
(d) In glucose all six C atoms are linked by a linear chain.

Q4. How would you convert: - (a) glucose to gluconic acid (b) glucose to saccharic acid.

Q5. What does ‘D’ and ‘L’ signify? Draw Fischer projection formula of D(+) and L(+) glucose.

Q6. How does D-glucose react with excess of phenyl hydrazine?

Q7. Fructose doesn’t contain an aldehydic gp. yet it reduces fehling and tollen’s reagant in alkaline medium why ?

Q8. What are anomers? Draw Haworth projection of α-D (+) glucopyranose E-β-D(+) glucopyranoose.

Q9. What is meant by “inversion” of sugar?

Q10. Give the products of hydrolysis of: - (a) sucrose (b) lactose (c) maltose

Q11. What is composition of invert sugar?

Q12. Sucrose on hydrolysis produces glucose and fructose both of which reduce tollen’s’ and Fehling solun yet sucrose doesn’t reduce tollen’s and Fehling solu. Why?

Q13 What is glycosidic linkage? Give example of substances constituting α- glycosidic linkage and β- glycosidic linkage?

Q14. Why cellulose is not digestible?

Q15. Starch constitutes two polysaccharides, amylase and amyl pectin. What is the difference between the two?

Q16. Why is glycogen called animal starch?

Q17. What forces hold β-pleated structures? Why is it less stable than α-helix structure?

Q18. Two samples of DNA; A and B have Tm 340 K and 380K respectively. What conclusion can be drawn from its value regarding their base content?

Q19. How are nucleotides and nucleic acids related?

Q20. Classify the following as fibrous / globular proteins – insulin, haemoglobin, fibroin, collagen, albumin, myosin.

Q21. Give terms used to describe the following:-
(a) A molecule with full positive & full negative charge on different parts of molecule.
(b) A sub formed by condensing together of a number of amino acids.
(c) The change which occurs when a solution of protein is heated.
(d) Linkage that holds nucleotides together. (e) Sub. That sends message for protein synthesis.

Q22. Construct the daughter strands that will be formed on the given DNA strands:-
Show clearly the bonds between the bases on the complementary strands;-