BIOMOLECULES REVISION

1. The carbohydrates may be defined as optically active polyhydroxy aldehydes or ketones or the compounds which
produce such units on hydrolysis.
2. Classification of Carbohydrates:.
 Monosaccharides: A carbohydrate that cannot be hydrolysed further to give simpler unit of polyhydroxy aldehyde or
ketone is called a monosaccharide. examples are glucose, fructose, ribose, etc.
 Oligosaccharides: Carbohydrates that yield two to ten monosaccharide units, on hydrolysis, are called
oligosaccharidesFor example, sucrose on hydrolysis gives one molecule each of glucose and fructose whereas maltose
gives two molecules of glucose only .
 Polysaccharides: Carbohydrates which yield a large number of monosaccharide units on hydrolysis are called
polysaccharides. Some common examples are starch, cellulose, glycogen, gums, etc.
3. Reducing or Non-reducing sugars. All those carbohydrates which reduce Fehling’s solution and Tollens’ reagent are
referred to as reducing sugars. They contain free aldehydic or ketonic group. e.g.all monosaccharides.
4. Non-reducing sugars: All those carbohydrates which do not reduce Fehling’s solution and Tollens’ reagent are referred
to as non reducing sugars. They do not contain free aldehydic or ketonic group. sucrose
5. Reactions of Glucose:

6. Cyclic Structure of Glucose (Pyranose structure)

7. Anomers: The two cyclic hemiacetal forms of glucose differ only in the configuration of the hydroxyl group at C1, called
anomeric carbon (the aldehyde carbon before cyclisation). Such isomers, i.e., α-form and β-form, are called anomers.
8. The open chain structure could not following reactions: Despite having the aldehyde group, glucose does not give 2,4-
DNP test, Schiff’s test and it does not form the hydrogensulphite addition product with NaHSO3.
9. Glycosidic linkage: The two monosaccharides are joined together by an oxide linkage formed by the loss of a water
molecule. Such a linkage between two monosaccharide units through oxygen atom is called glycosidic linkage
10. Invert sugar: Hydrolysis of sucrose brings about a change in the sign of rotation, from dextro (+) to laevo (–) and the
product is named as invert sugar.
11. Product of Hydrolysis: (i)Sucrose : (glucose and fructose) Lactose: (galactose and glucose)
12. Starch: Starch is the main storage polysaccharide of plants. It is a polymer of α-glucose and consists of two
components— Amylose(water soluble component, long unbranched chain of α-D-glucose ) and Amylopectin(insoluble
in water, branched chain polymer of α-D-glucose)
13. Cellulose: Cellulose occurs exclusively in plants and it is the most abundant organic substance in plant kingdom. It is a
predominant constituent of cell wall of plant cells. Cellulose is a straight chain polysaccharide composed only of β-D-
glucose
14. Glycogen: The carbohydrates are stored in animal body as glycogen. It is also known as animal starch.
15. Importance of Carbohydrates: Carbohydrates are used as storage molecules as starch in plants and glycogen in animals.
Cell wall of bacteria and plants is made up of cellulose.
16. All proteins are polymers of α-amino acids. Amino acids contain amino (–NH2) and carboxyl (–COOH) functional groups.

17. Amino acids are classified as acidic, basic or neutral depending upon the relative number of amino and carboxyl groups
in their molecule. Equal number of amino and carboxyl groups makes it neutral; more number of amino than carboxyl
groups makes it basic and more carboxyl groups as compared to amino groups makes it acidic.

Kalra sir, 09462305605,kalra1977@gmail.com 1

18. The amino acids, which can be synthesised in the body, are known as non essential amino acids.e.g. Glycine , Alanine
(R=CH3)On the other hand, those which cannot be synthesised in the body and must be obtained through diet, are
known as essential amino acids.e.g. Phenylalanine.
19. Zwitter ion: In aqueous solution, the carboxyl group can lose a proton and amino group can accept a proton, giving rise
to a dipolar ion known as zwitter ion.
20. Peptide bond or Peptide linkage. Chemically, peptide linkage is an amide formed between –COOH group and –NH2
group. peptide bond –CO–NH– Involves of elimination of a water.
21. ‘When the number of such amino acids is more than ten, then the products are called polypeptides.
22. Primary structure of proteins: It tells us sequence of ά-amino acids present in the polypeptide chains. Each protein has
a specific sequence of ά-amino acids.
23. Secondary structure of proteins:It refers to shape in which long polypeptide chain exists.A protein may assume α-helix
and β-pleated sheet structure.
24. α-Helix results due to regular coiling of polypeptide chain which is stablised by intramolecular hydrogen
bonding.e.g.Keratin
25. In β-structure all peptide chains are stretched out to nearly maximum extension and then laid side by side which are
held together by intermolecular hydrogen bonds.e.g Silk
26. Tertiary structure of proteins: The tertiary structure of proteins represents overall folding of the polypeptide chains i.e.,
further folding of the secondary structure. The main forces which stabilise the 2° and 3° structures of proteins are
hydrogen bonds, disulphide linkages, van der Waals and electrostatic forces of attraction.
27. Globular proteins : This structure results when the chains of polypeptides coil around to give a spherical shape.They are
soluble in water.e.g. Insulin and albumins
28. Fibrous proteins: The molecules have long and thread like structures. They are insoluble in water. examples are keratin
(present in hair, wool, silk)
29. Quaternary structure of proteins: Some of the proteins are composed of two or more polypeptide chains referred to as
sub-units. The spatial arrangement of these subunits with respect to each other is known as quaternary structure
30. Denaturation of Proteins: When a protein in its native form, is subjected to physical change like change in temperature
or chemical change like change in pH, the hydrogen bonds are disturbed. This is called denaturation of protein. During
denaturation 2° and 3° structures are destroyed but 1º structure remains intact. Examples : coagulation of egg white on
boiling, curdling of milk
31. Vitamins are Organic compounds required in the diet in small amounts to perform specific biological functions for
normal maintenance of optimum growth and health of the organism.
32. Classification of Vitamins : (a) Fat soluble vitamins: These are vitamins A, D, E and K. They are stored in liver and
adipose (fat storing) tissues. (b)Water soluble vitamins: B group vitamins and vitamin C
33. Water soluble vitamins must be supplied regularly in diet because they are readily excreted in urine and cannot be
stored (except vitamin B12) in our body
34. Some important Vitamins & Deficiency Diseases: Vitamin A: Xerophthalmia, Night blindness (b) Vitamin B1: Beri beri
(c)Vitamin B2 Cheilosis (d)Vitamin B6 Convulsions (e)Vitamin B12 Pernicious anaemia (f) Vitamin C: Scurvy (g) Vitamin D:
Rickets & osteomalacia (h) Vitamin E: Sterility (i)Vitamin K: Increased blood clotting
35. Enzymes are Biocatalyst produced by living cells which catalysis the biological reactions.
36. Nucleic acids : The particles in nucleus of the cell, responsible for heredity, are called chromosomes which are made up
of proteins and another type of biomolecules called nucleic acids.
37. Nucleosides: It consists of nitrogen containing bases and four carbon sugar. Base + Sugar  Nucleosides
38. Nucleotides: It consists of nitrogen containing bases ,four carbon sugar and phosphate unit.
Base + Sugar + Phosphate  Nucleotides.
39. RNA molecules are of three types and they perform different functions. They are named as messengerRNA
(m-RNA), ribosomal RNA (r-RNA) and transfer RNA (t-RNA).
40. DNA & RNA
DNA RNA
It contains β-D-2-deoxyribose sugar. It Contains β-D-ribose sugar.
It Contains adenine (A), guanine (G), It Contains adenine (A), guanine (G), cytosine
cytosine (C) and thymine (T) as bases. (C), uracil (U). as bases
It has double helix structure It has single helix structure
It Can replicate It Can not replicate
It is present in the nucleus cell. It is present in the cytoplasm of the cell.

Kalra sir, 09462305605,kalra1977@gmail.com 2

(Questions related to carbohydrates)
1. ●Define carbohydrates. How are carbohydrates classified on the basis of their behaviour on hydrolysis?
2. What are reducing and non reducing sugars?
3. ●●How is Glucose prepared? Write the reactions when D-Glucose reacts with following: (a)Hydrocyanicacid,
HCN (b) acetic anhydride (c)Tollen reagent(d)HI(e)ConcHNO3 (f)PhenylHydrazine (g)Hydroxlamime
(h)Bromine
4. ●Explain the structure of glucose. Enumerate the reactions of D-Glucose which cannot be explained by its
open chain structure.
5. Explain the structure of Sucrose.
6. Classify the following into monosaccharides and disaccharides.Ribose,2-
deoxyribose,maltose,galactose,fructose and lactose.
7. What are the hydrolysis products of (a) Sucrose. (b) Lactose
8. How do you explain the absence of aldehyde group in the pentacetate of D-Glucose?
9. Glucose or sucrose are soluble in water but cyclohexane or benzene are insoluble in water. Explain
10. What are the expected products of hydrolysis of lactose?
11. How do you explain the absence of aldehyde group in the pentaacetate of D-glucose?
12. Write two main functions of carbohydrates in plants.
13. What do you understand by the term glycosidic linkage?
14. What is glycogen? How is it different from starch?
15. ●What is the basic structural difference between starch and cellulose?
16. ●An optically active compound having molecular formula C 6H12O6 is found
in two isomeric forms (A) and (B) in nature. When (A) and (B) are
dissolved in water they show the following equilibrium.
(A) ↔ Equilibrium mixture ↔ (B)
1110 52.20 19.20
(i) What are such isomers called? (ii) Can they be called enantiomers? Justify your answer
(iii) Draw the cyclic structure of isomer (A)
16. ●Despite having an aldehyde group
(a) Glucose does not give 2, 4 - DNP test. What does this indicate?
(b) Draw the Haworth structure of ά-D-(+)-Glucopyranose.
(c) What is the significance of D and (+) here?
17. ●Name the two components of starch. How do they differ from each other structurally?
Questions related to Proteins
1. Draw the structure of Glycine, Alanine, and Phenylalanine.
2. ●What are essential and non essential amino acids? Give two examples of each type.
3. ●Write a note on zwitter ion and isoelectric point.
4. What do you understand by the term Peptide linkage& Peptide linkage?
5. ●Distinguish between the following: (a)Essential &Nonessential amino acids (b) Fibrous &Globular proteins(c)
-helix and -sheet proteins
6. ●Write a note on: (a)Denaturation of proteins (b)Primary structure of proteins
7. What are the common types of secondary structure of proteins?
8. ●What type of bonding helps in stabilizing the -helix structure of proteins
9. ●How do you explain the amphoteric behaviour of amino acids?
10. ●What is the effect of Denaturation on the structure of proteins?
11. The melting point and solubility in water of amino acids are generally higher than that of the corresponding
haloacids.Explian
12. ●Where does the water present in the egg go after boiling the egg?
13. ● What changes occur in the nature of egg proteins on boiling?
14. ●Name the type of bonding which stabilizes -helix structure of proteins.
15. ●An optically active amino acid (A) can exist in three forms depending on the pH of the medium. If the
molecular formula of (A) is C3H7NO2 write
Kalra sir, 09462305605,kalra1977@gmail.com 3
 (i) Structure of compound (A) in aqueous medium. What are such ioncalled?
(ii) In which medium will the cationic form of compound (A) exist?
(iii) In alkaline medium, towards which electrode will the compound (A)
migrate in electric field?
Questions related to Proteins
1. Draw the structure of Glycine, Alanine, and Phenylalanine.
2. ●What are essential and non essential amino acids? Give two examples of each type.
3. ●Write a note on zwitter ion and isoelectric point.
4. What do you understand by the term Peptide linkage& Peptide linkage?
5. ●Distinguish between the following: (a)Essential &Nonessential amino acids (b) Fibrous &Globular proteins(c)
-helix and -sheet proteins
6. ●Write a note on: (a)Denaturation of proteins (b)Primary structure of proteins
7. What are the common types of secondary structure of proteins?
8. ●What type of bonding helps in stabilizing the -helix structure of proteins
9. ●How do you explain the amphoteric behaviour of amino acids?
10. ●What is the effect of Denaturation on the structure of proteins?
11. The melting point and solubility in water of amino acids are generally higher than that of the corresponding
haloacids.Explian
12. ●Where does the water present in the egg go after boiling the egg?
13. ● What changes occur in the nature of egg proteins on boiling?
14. ●Name the type of bonding which stabilizes -helix structure of proteins.
15. ●An optically active amino acid (A) can exist in three forms depending on the pH of the medium. If the
molecular formula of (A) is C3H7NO2 write
(i) Structure of compound (A) in aqueous medium. What are such ioncalled?
(ii) In which medium will the cationic form of compound (A) exist?
(iii) In alkaline medium, towards which electrode will the compound (A)
migrate in electric field?
Question related to Vitamin
1. Define vitamins. How are vitamins classified?
2. ●Name the deficiency diseases caused due to lack of vitamin A, C, E, B1, B2,, B6 , B12 E &K.
3. Give the main sources of vitamin A, C, E, B1, B2,, B6 , B12 E &K.
4. Write the chemical name of vitamin A, C, E, B1, B2,, B6 , B12 E &K.
5. ●Except for vitamin B12, all other vitamins of group B, should be supplied regularly in diet. Why?
6. ●Why cannot Vitamin C be stored in our body?
Questions related to Enzymes & Nucleic acids
1. ●Define Enzymes. Explain the mechanism of Enzyme action
2. Define Nucleic acids. How are they classified? Mention their two important sources.
3. ●Write the important differences between DNA and RNA.
4. What is the difference between a nucleoside and a nucleotide?
5. The two strands in DNA are not identical but are complementary. Explain
6. What are different types of RNA found in the cell?
7. What products would be formed when a nucleotide from DNA containing thymine is hydrolysed?
8. ●Write a note on DNA fingerprinting.
Questions related to Hormones
1. Define Hormones. (d) Oxytocin
2. Give the important functions & Source of (e) Insulin
following Hormones: (f) Angiotensin
(a) Testosterone(androgens) (g) Adrenaline
(b) Estrogens & Progesterone (h) Thyroxine
(c) Cortisone

Kalra sir, 09462305605,kalra1977@gmail.com 4