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Questions:

Multiple Choice Question

10 x 1 = 10

The common instant source of energy for cellular activities is ___________

(a)

Mitochondria

(b)

DNA

(c)

RNA

(d)

ATP

The diameter of DNA molecules of DNA is:

(a)

34 \(\mathring { A } \)

(b)

20 \(\mathring { A } \)

(c)

3.4 \(\mathring { A } \)

(d)

10 \(\mathring { A } \)

What is Guanine?

(a)

Purine

(b)

Hormone

(c)

Enzyme

(d)

Pyrimidine

Which biomolecule fights against infectious organisms?

(a)

Lipid

(b)

Nucleic acid

(c)

Protein

(d)

Enzyme

The structure of protein can be destroyed by which rays?

(a)

Ultra violet rays

(b)

Infra red rays

(c)

Radio waves

(d)

Micro waves

Which of the following is not a disaccharide?

(a)

Maltose

(b)

Starch

(c)

Sucrose

(d)

Lactose

Which one of the following pairs is correctly matched?

(a)

Fats \(\rightarrow\) Long saturated Fatty acids chain.

(b)

Derivatives of Lipid \(\rightarrow\) Vitamins A, D, E.

(c)

Deoxyribose \(\rightarrow\) RNA.

(d)

Glycogen \(\rightarrow\) Forms the plant cell wall

Sanger first sequenced the protein called ____________.

(a)

Inulin

(b)

Glycine

(c)

Insulin

(d)

Peptidase

Proteins perform many physiological functions. For example some functions as enzymes. One of the following represents an additional function that some proteins discharge:

(a)

Antibiotics

(b)

Pigment conferring colour to skin

(c)

Pigments making colours of flowers

(d)

Hormones

10.

The most basic amino acid is

(a)

Arginine

(b)

Histidine

(c)

Glycine

(d)

Glutamine

Generic 2

5 x 2 = 10

11.

Why oil does not get mixed if added with water?

12.

What is Starch?

13.

What are steroids? Explain with an example.

14.

What is a prosthetic group?

15.

Distinguish between nitrogenous base and a base found in inorganic chemistry.

Generic 3

6 x 3 = 18

16.

Which was the first alkaloid discovered? Mentions its uses.

17.

How will you identify the presence of protein in food samples?

18.

Draw the structure of Purine & Pyrimidine.

19.

Give examples of secondary metabolites in plants

20.

Write a short note on Chitin.

21.

Briefly outline the classification of enzymes.

Generic 5

2 x 5 = 10

22.

Compare DNA with RNA.

23.

Explain any two factors affecting the rate of enzyme reaction, with the help of graphical representation.

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Answers Key:

Multiple Choice Question

10 x 1 = 10

(d)
ATP

(b)
20 \(\mathring { A } \)

(a)
Purine

(a)
Ultra violet rays

(b)
Starch

(a)
Fats \(\rightarrow\) Long saturated Fatty acids chain.

(d)
Hormones

10.

(a)
Arginine

Generic 2

5 x 2 = 10

11.

Oil is a lipid. Lipids are long hydrocarbon chains that are non-polar & thus hydrophobic, which avoids the oil to dissolve in water.

12.

Starch is a storage polysaccharides made up of repeated units of amylose and amylopectin. Starch grains are made up of successive layers of amylose and amylopectin, which can be seen as growth rings

13.

These are complex compounds commonly found in cell membrane and animal hormones, ego Cholesterol which reinforces the structure of the cell membrane in animal cells and in an unusual group of cell wall deficient bacteria - Mycoplasma.

14.

Prosthetic groups are organic molecules that assist in catalytic function of an enzyme. Flavin adenine dinucleotide (FAD) contains riboflavin (vit B2), the function of which is to accept hydrogen.

15.

Nitrogenous base	Inorganic base
In nitrogenous base the basic character is because of lone pair electron called lewis base	Inorganic base is because of hydroxyl ion that is Arrhenius base
Eg: Pyridine, Pyrimidine	Eg: NaOH

Generic 3

6 x 3 = 18

16.

Morphine is the first alkaloid to be found. It comes from the plant Opium poppy (Papaver somniferum). It is used as a pain reliever in patients with severe pain levels and cough suppressant.

17.

The biuret test is used as an indicator of the presence of protein because it gives a purple colour in the presence of peptide bonds (-C- N-). To a protein solution an equal quantity of sodium hydroxide solution is added and mixed. Then a few drops of 0.5% copper (II) sulphate is added with gentle mixing. A distinct purple colour develops without heating.

18.

19.

1. Pigments - Carotenoids, anthocyanins
2. Alkaloids - Morphine, codeine
3. Essential oil - Lemon grass oil, rose oil
4. Toxins - Abrin, ricin

20.

1. Chitin is a homo polysaccharide with amino acids added to form mucopolysaccharide.
2. The basic unit is a nitrogen-containing glucose derivative known as N-acetyl glucosamine.
3. It forms the exoskeleton of insects and other arthropods. It is also present in the cell walls of fungi.

21.

Classification of enzymes:
Enzymes are classified into six groups based on their mode of action.

Enzymes	Mode of action	General scheme of reaction	Example
Oxidoreductase	Oxidation and reduction (redox) reactions.	A_red + B_ox \(\longrightarrow\)A_ox + B_red	Dehydrogenase.
Transferase	Transfer a group of atoms from one molecule to another.	A - B + C \(\longrightarrow\) A + C - B	Transaminase, Phosphotransferase.
Hydrolases	Hydrolysis of substrate by addition of water molecule.	A - B + H₂O \(\longrightarrow\) A - H + B - OH	Digestive enzymes.
Isomerase	Control the conversion of one isomer to another by transferring a group of atoms from one molecule to another.	A - B - C \(\longrightarrow\) A - C - B	Isomerase.
Lyase	Break chemical bond without addition of water	A - B \(\longrightarrow\) A + B	Decarboxylase.
Ligase	Formation of new chemical bonds using ATP as a source of energy	A + B + ATP \(\longrightarrow\) A - B + ADP + Pi	DNA ligase

Generic 5

2 x 5 = 10

22.

S.no	DNA	RNA
1	Deoxyribose sugar is present	Ribose sugar is present
2	Thymine is present	Uracil is present
3	More stable	Less stable
4	Double stranded	Single stranded
5	Types: A-DNA, B-DNA, Z-DNA	Type: mRNA, tRNA, rRNA
6	Genetic material for most of living organism except few viruses	Genetic material for few viruses only

23.

Enzyme Reactions: Enzymes are sensitive to environmental condition. It could be affected by temperature, pH, substrate concentration and enzyme concentration. The rate of enzyme reaction is measured by the amount of substrate changed or amount of product formed, during a period of time.
Temperature: Heating increases molecular motion. Thus the molecules of the substrate and enzyme move more quickly resulting in a greater probability of occurrence of the reaction. The temperature that promotes maximum activity is referred to as optimum temperature.

pH: The optimum pH is that at which the maximum rate of reaction occurs. Thus the pH change leads to an alteration of enzyme shape, including the active site; If extremes of pH are encountered by an enzyme, then it will be denatured.

Substrate Concentration: For a given enzyme concentration, the rate of an enzyme reaction increases with increasing substrate concentration.
Enzyme Concentration: The rate of reaction is directly proportional to the enzyme concentration.