Biology Times March 19
19.Sol:Hypersecretion of androgens from the
a d r e n a l c o r t e x c a u s e a c o n d i t i o n c a l l e d
adrenogenital syndrome. In this excess of adrenal
sex hormones are secreted causing secondary
sexual characters to develop early in male children
and female children become masculinised. Thus,
both Assertion and Reason are true and Reason is
the correct explanation of Assertion.
20.Sol:Parathyroid and adrenal glands are only the
endocrine glands. The pancreas and the gonads
(both ovaries and testes) are examples of organs
that have both endocrine and exocrine functions.
Exocrine function of the pancreas is the production
of digestive enzymes which travel down a duct or
tube from the pancreas into the small intestine. The
exocrine function of the gonads is the production of
the gametes (sperm or eggs) which travel through
ducts to the exterior or interior site of use.
21.Sol:The pineal gland is located in the epithalamus,
under corpus callosumnear the center of the brain,
between the cerebral hemispheres.
22.Sol:
A.Parturition- Delivery of baby from uterus
B.Gestation - Duration between pregnancy and
birth
C.Ovulation- Release of egg from Graafian
follicle
D.Implantation- Attachment of zygote to
endometrium
E.Conception- Formation of zygote by fusion
of egg and sperm
23.Sol:The germinal epithelium is an epithelial
tissue lining both the male and female gonads
from which gametes are formed through
gametogenesis.
24.Sol:Due to Low levels or no secretion of LH
there will be no maturation of ovarian follicle
and this will hinder the release of an ovum.
25.Sol: Test tube baby has raised several legal
problems such as right over the child. Inspite of
that many couples are going for the treatments.
26.Sol: Vasectomy is a surgical procedure for
contraception.
27.Sol:The living form is named as protocell or
protobiont which evolved into prokaryotic cell.
These were originated about 3900-3500 million
years ago during Precambrian era.
28.Sol:Rate and survival of organism is different due
to variation is not a concept of Lamarckism.
29.Sol:Gene flow is the transfer of alleles from
one population to another population through
immigration of individuals.
30.Sol:Malaria which is caused by Plasmodium is
a vector-borne disease transmitted by infected
female Anopheles mosquito. The credit of the
working out complicated life cycle of the malarial
parasite goes to Sir Ronald Ross.
31.Sol: Marijuana is obtained from dried
inflorescence and top leaves of Cannabis sativa
used in America to refer cannabis meaning
‘pleasurable feelings’.
32.Sol: In 1987 ,the recombinant vaccine for
Hepatitis B became the first synthetic vaccine
for public use. It was first marketed by trade
names Recombivax and Engerix-B. Hepatitis B
vaccine is safe to use, very effective and produce
no allergic reactions.
36.Sol: Lake has 3 zones, 1. Littoral zone,
2.Limnetic zone and 3.Benthic zone. Littoral
zone is the part of the lake which is close to the
shore, where sunlight penetrates all the way to
the sediment and allows aquatic plants. Limnetic
zone is the open surface area where light does not
penetrates to the bottom. Benthic zone comprises
the lowest region of body of water. Profundal
zone is the deepest part of the open water which
is relevant only in extremely deep lakes.
37.Sol: As green plants are the producers and all the
others including primary , secondary and tertiary
consumers depends on the producers. So if green
plants are destroyed then all animals will be
destroyed
38.Sol:A climax community is formed after reaching
state of equilibrium
43.Sol: Biomagnification is an increase in
concentration of the toxicant at successive trophic
levels
44.Sol: Cutting trees and increasing human
population will not decrease global warming
but will increase it.
45.Sol: Radioactive fallout causes near immediate
effect like killing cells, damaging tissue and
also long-term effect like causing mutations.
Mutated genes are recessive and can occur in
future generations also. This is the reason for
radioactive fallout will be more harmful to future
generation children than the present day children.
