Human chromosomes undergo structural changes during the cell cycle. Chromosomal structure can be best
visualized if a chromosome is isolated from a cell at –
(A) G1 phase (B) S phase (C) G2 phase (D) M phase
A ripe mango, kept with unripe mangoes causes their ripening. This is due to the release of a gaseous plant
hormone–
(A) auxin (B) gibberlin (C) cytokinine (D) ethylene
Some animals excrete uric acid in urine (uricotelic) as it requires very little water. This is an adaptation to conserve
water loss. Which animals among the following are most likely to be uricotelic ?
(A) fishes (B) amphibians (C) birds (D) mammals
The disorders that arise when the immune system destroys self cells are called autoimmune disorders. Which of the
following would be classified under this?
(A) rheumatoid arthritis (B) asthma (C) rhinitis (D) eczema
Diabetes insipidus is due to –
(A) hypersecretion of vasopressin (B) hyposecretion of insulin
(C) hypersecretion of insulin (D) hyposecretion of vasopressin
Peptic ulcers are caused by –
(A) a fungus, Candida albicans (B) a virus, cytomegalovirus
(C) a parasite, Trypanosoma brucei (D) a bacterium, Helicobacter pylori
Transfer RNA (tRNA) –
(A) is present in the ribosomes and provides structural integrity
(B) usually has clover leaf-like structure
(C) carries genetic information form DNA to ribosomes
(D) codes for proteins
In evolutionary terms, an Indian school boys is more closely related to
(A) an Indian frog (B) an American snake
(C) a Chinese horse (D) an African shark