Biomolecules

Question 1

Glucose- use

Answer 1

• Hexose sugar (Monosaccharide)

- Oxidation of glucose provides energy to the cell

Question 2

Ribose- use

Answer 2

• pentose sugar (Monosaccharide)

- synthesis of RNA nucleic acid

Question 3

Deoxyribose- use

Answer 3

• Pentose sugar (Monosaccharide)

- Synthesis of DNA nucleic acid

Question 4

Maltose

Answer 4

• Disaccharide
• Reducing sugar
• Occurs in plants as a product of starch
• Melting point is 135 degree celsius

Question 5

Lactose

Answer 5

• Disaccharide
• Reducing sugar
• called milk sugar
• animal origin, formed as 5% in milk of mammals

Question 6

Sucrose

Answer 6

• Disaccharide
• Non-reducing sugar
• Called table sugar. Principal disaccharide of higher plants.
• Forms colourless crystals and melting point is 160 degree celsius

Question 7

Glycogen

Answer 7

• Polysaccharide
• Reserve carbohydrate seen in animals
• Stored in liver and muscles

Question 8

Starch

Answer 8

• Polysaccharide
• Major fuel store in plants
• Sugar is converted to starch during photosynthesis
• Found in cereals, rice and wheat

Question 9

Cellulose

Answer 9

• Polysaccharide
• Structural polysaccharide in plants
• Forms the cell wall in plants

Question 10

Inulin

Answer 10

• Polysaccharide
• Muco-polysaccharide seen in plants
• Polymer of fructose and seen in tubers

Question 11

Chitin

Answer 11

• Polysaccharide
• Structural polysaccharide
• Forms the fungal cell wall and exoskeleton of insects and shells of crustaceans

Question 12

Fundamental building blocks of proteins

Answer 12

The fundamental building blocks of proteins are amino acids.

All proteins that exist in living beings are constructed from 20 amino acids

Question 13

Primary structure (Proteins)

Answer 13

• It is the number and sequence of amino acids held together by peptide bonds in a polypeptide chain
• The sequence of amino acids of a protein indicated its biological function
• It is strictly controlled by the sequence of bases in a DNA.

Question 14

Secondary Structure (proteins)

Answer 14

• It indicates the shape of the polypeptide chain
• The bonding of amino acids could lead to pleating or folding of protein chain
• The two main secondary structures exhibited by proteins are:
  1. Alpha-helical structure. Example- Keratin (seen in nails, hair, claws, wool, feathers etc.)
  2. Pleated structure. Example- Silk fibrion (protein used by silkworm to make their cocoon)

Question 15

Tertiary structure (proteins)

Answer 15

• Super-folding of proteins yield intricate spheres and globules
• E.g. Myoglobin- acts as catalytic and carrier molecules

Question 16

Quaternary structure (proteins)

Answer 16

Aggregate of multiple polypeptides to form a single functional protein

E.g. enzymes and haemoglobin

Question 17

Functions of proteins

Answer 17

• Repair and maintenance of body, carries out transportation and storage of molecules
• Major source of energy
• Act as enzymes, antibodies and creates hormones

Question 18

Essential amino acids

Answer 18

• They are not biosynthesized in the body
• They have to be included in the diet

Examples- the 9 essential amino acids are- Valine, Leucine, Isoleucine, Threonine, Tryptophan, Lysine, Methionine, Phenylalanine, and Histidine.
(PVT TIM HaLL)

Adults need to obtain only 8 of them. The 9th amino acid- Histidine is only essential for infants

Question 19

Non-essential amino acids

Answer 19

• They are biosynthesized in the body
• May be included in the diet also

Examples- the 11 non-essential amino acids are ‘Almost Always All Girls Go Crazy After Getting Taken Prom Shopping’ which stands for Alanine, Asparagine, Arginine, Glutamate, Glutamine, Cysteine, Aspartate, Glycine, Tyrosine, Proline and Serine.

Question 20

Lipids

Answer 20

• Lipids (triglycerides) have a glycerol molecule (head) and three fatty acids (tail)
• Seen in butter, vegetable oil, avocado etc.
• The enzyme lipases help in breaking down these fatty acids and energy is released

Question 21

Fats

Answer 21

• Simple lipids
• Esters of fatty acid with glycerol
• Solid at room temperature

Question 22

Oils

Answer 22

• Simple lipids
• Esters of fatty acid with glycerol
• Liquid at room temperature

Question 23

Waxes

Answer 23

• Simple lipids
• Esters of fatty acids other than glycerol
• Solid at room temperature

Question 24

Phospholipids

Answer 24

• Compound lipids
• Lipids with fatty acids, glycerol, A PHOSPHORIC ACID, nitrogen bases and certan substitutes like lecithin, cephalins etc

Question 25

Glycolipids

Answer 25

- Compound lipids - Lipids with fatty acids, glycerol, **carbohydrates**, nitrogen bases and substitutes like gangliosides etc.

Question 26

Steroids

Answer 26

- Derived lipids - Cholesterol is the principal sterol seen in animal tissues (nerve tissues). - It is a precursor of bile salts, Vitamin D3 (write 3 as subscript), and hormones like testosterone and progesterone

Question 27

Carotenoids

Answer 27

- Derived lipids - It is exclusively of plant origin - Due to the presence of conjugated double bonds, they are coloured red or yellow

Question 28

Functions of lipids

Answer 28

- Lipids are very rich in calorific value - Fats are stored as reserve food material in adipose tissues and creates heat insulation - Lipids are structural components of membranes - Some lipids like cholesterol maintains the fluidity of the cell membrane and also helps in the synthesis of hormones and vitamins

Question 29

What are enzymes?

Answer 29

Enzymes: 1. act as biological catalysts. 2. accelerate the rate of a reaction but do not themselves undergo any change. 3. are active in very small quantities 4. are very specific in nature

Question 30

Simple proteins

Answer 30

Proteins with only amino acids

Question 31

Conjugated proteins

Answer 31

Proteins with attached non-protein groups/co-factor 1. Apoenzyme (protein only) 2. Holoenzyme (protein + co-factor) Co- factor: Inorganic- metal ion Organic- Prosthetic group/co-enzyme

Question 32

Oxidoreductases

Answer 32

Reaction catalysed: Transfer of hydrogen and oxygen atoms or electrons from one substrate to another Examples: Dehydrogenases, Oxidases

Question 33

Transferases

Answer 33

Reaction catalysed: Transfer of a specific group (a phosphate or methyl etc.) from one substrate to another Examples: Transaminase, Kinases

Question 34

Hydrolases

Answer 34

Reaction catalysed: Hydrolysis of a substrate Examples: Estrases, Digestive enzymes

Question 35

Isomerases

Answer 35

Reaction catalysed: Change of the molecular form of the substrate Example: Phospho hexo isomerase, Fumarase

Question 36

Lyases

Answer 36

Reaction catalysed: Nonhydrolytic removal of a group or addition of a group to a substrate Example: Decarboxylases, Aldolases

Question 37

Ligases (Synthetases)

Answer 37

Reaction catalysed: Joining of two molecules by the formation of new bonds Examples: Citric acid synthetase

Question 38

Factors affecting enzyme activity

Answer 38

- Temperature (30 degrees celsius to 50 degrees celsius) - Substrate concentration - pH (4 to 9) - Competitive inhibitors

Question 39

Competitive inhibition

Answer 39

The inhibitor molecule is structurally similar to the substrate and blocks the active site of the enzyme, thus inhibiting the formation of E + S complex.