CLASS XI
Biomolecules Worksheet
Very Short Answer Questions
Q.1. How many types of biomolecules are there?
A.1. There are four major classes of Biomolecules – Carbohydrates, Proteins, Nucleic acids and Lipids.
Q.2. Classify the following into one of the appropriate bonds – ester bond, peptide bond, glycosidic
bond, hydrogen bond.
a) Polysaccharide b) Protein c) Fat d) Water
A.2. a) Polysaccharide – glycosidic bond
b) Protein-peptide bond
c) Fat – ester bond
d) Water – hydrogen bond
Q.3. Name any one sugar, amino acid, fatty acid, nucleotide.
A.3. Sugar – Lactose
Amino acid – Leucine
Fatty acid – Palmitic acid
Nucleotide – Adenosine
Q.4. What is meant by ‘reducing sugars’?
A.4. Reducing sugar contains aldehydic or ketonic group in the hemiacetal and hemiketal forms and
can reduce
Tollen’s reagent or Fehing’s solution.
Q.5. What are monosaccharides?
A.5. These are the simplest carbohydrates which cannot be hydrolysed to smaller molecules. Their
general formula is (CH2O)n where n = 3 – 7
Example : glucose, fructose etc.
Q.6. What is a glycosidic linkage?
A.6. The two monosaccharide units are joined together through an etheral or oxide linkage formed
by loss of a molecule of water. Such a linkage between two monosaccharide units through oxygen
atom is called glycosidic linkage.
Q.7. Name the products of hydrolysis of sucrose.
A.7. Glucose and fructose are the products of hydrolysis of sucrose.
Q.8. Which component of starch is a branched polymer of a-glucose and insoluble in water?
A.8. Amylopectin.
Q.9. What are the products of hydrolysis of maltose?
A.9.
Q.10. Write the products of hydrolysis of lactose.
A.10. Lactose on hydroloysis gives an equimolar mixture of D-glucose and D-galactose.
Short Answer Questions
Q.11. Explain what is meant by
(i) a peptide linkage
(ii) a glycosidic linkage.
A.12. (i) Peptide linkage: A peptide linkage is an amide linkage formed between – COOH group of one
α-amino acid and NH2 group of the other a-amino acid by loss of a molecule of water.
(ii) Glycosidic linkage : The two monosaccharide units are joined together through an etheral or oxide
linkage formed by loss of a molecule of water. Such a linkage between two monosaccharide units
through oxygen atom is called glycosidic linkage.
Q.12. Name the four bases present in DNA. Which one of these is not present in RNA? (All India 2009)
A.12. The four bases present in DNA are :
(i) Adenine (A)
(ii) Guanine (G)
(iii) Cytosine (C)
(iv) Thymine (T)
In RNA, Thymine (T) is absent. It has Uracil (U) in place of Thymine.
Q.13. What are nucleosides and nucleotides. Explain with suitable diagrams.
A.13. Nucleoside : A nucleoside contains only two basic components of nucleic acids i.e. a pentose
sugar and a nitrogenous base. During their formation 1-position of the pyrimidine or 9-position of
the purine moitey is linked to C1 of the sugar (ribose or deoxyribose) by a β-linkage.
Nucleotides : A nucleotide contains all the three basic components of nucleic acids, i.e. a phosphoric
acid group, a pentose sugar and a nitrogenous base. These are formed by esterification of C5‘ – OH
of the sugar of the nucleoside with phosphoric acid.
Q.14. Explain the pyranose structure of glucose.
A.14. The six membered ring containing 5 carbon atoms and one oxygen atom because of its
resemblance with pyron is called the pyranose form.
Q.15. What are essential and non-essential amino acids? Give two examples of each.
Answer: Essential amino acids : Amino acids which the body cannot synthesize are called essential
amino acids. Example : Valine, leucine etc. Therefore they must be supplied in diet.
Non-essential amino acids : Amino acids which the body can synthesize are called non-essential
amino acids. Therefore, they may or may not be present in diet.
Example ; Glycine, alanine etc.
