Previous Solved GATE Life Science Questions - Zoology

1. Hemolin is

(a) An antibody produced by sponges

(b) An antibody produced by Annelids

(c) A member of the immunoglobulin superfamily

(d) A cytotoxic molecule produced by nematodes

Ans: Hemolin is a bacteria-inducible hemolymph protein of the giant silk moth Hyalophora cecropia. Hemolin belongs to the immunoglobulin superfamily

2. Most modern taxonomists group living organisms into how many kingdoms?

(a) 2

(b) 4

(c) 3

(d) 5

Ans: 5 kingdom by Whittaker 1969 based on three criteria

complexity of cell structure
complexity of organism body
mode of obtaining nutrition

3. Acrosome present on the sperm head is derived from

(a) Golgi apparatus

(b) Nucleus

(c) Centrosome

(d) Endoplasmic reticulum

Ans: Golgi apparatus

The golgi body is modified to form a sheath called acrosome on the first part of the head

4. Which of the following non-covalent interactions is considered as strongest?

(a) Hydrophobic interactions

(b) Ionic bonds

(c) Hydrogen bonds

(d) Vander waals forces

Ans: Hydrogen bonds

5. Sickle-cell anemia is caused by mutation in

(a) Haemoglobin A

(b) Haemoglobin B

(c) Haemoglobin S

(d) Haemoglobin F

Ans: Haemoglobin A

Molecular basis for this disease: change of glutamic acid residue for a valine (non conservative substitution reaction).
Normal Hb: Hb A (adult)
Sickle cell Hb: Hb S

6. Life appeared on earth

a) 5000 million years ago

b) 3500 million years ago

c) 1000 million years ago

d) 500 million years ago

Ans: b) 3500 million years ago

For more, refer our post: Geological Time Scale

7. The sub cellular organelle not bound by a single membrane is

a) Golgi apparatus

b) Endoplasmic Reticulam (ER)

c) Mitochondria

d) Lysosomes

Ans: Mitochondria

Double membrane organelle (Nucleus, Chloroplast, Mitochondria)

8. The storage carbohydrate in animal is

a) Starch

b) Cellulose

c) Glycogen

d) Glucose

Ans: Glycogen

Starch: storage carbohydrate in plants
Cellulose: structural polysaccharide in the plant cell wall
Glucose: primary energy source

More about: Carbohydrates

9. The hormone testosterone is produced by

a) Leydig cells

b) Spermatocyte

c) Melanocytes

d) β cells of Pancreas

Ans: a) Leydig cells

10. The predominant antibody in saliva is

a) IgG

b) IgM

c) IgA

d) IgD

Ans: c) IgA

IgG: Most abundant immunoglobulin, produce in the late primary response after IgM production, predominant in secondary immune response, the one and only Ig that cross placenta.
IgA: Secretory antibody, Heaviest antibody and second most abundant
IgM: Macroimmunoglobulin, pentamer, does not cross placenta, also known as natural antibody, first produced antibody upon infection.
IgD: Present on surface of B-cells and in serum.
IgE: which is responsible for allergic reactions, mediate hyper sensitivity. These are concentrated in mucous membrane, skin and lungs.
For More Immunology Notes