(a) If a Rhwoman is married with a Rh+ man , she
becomes sterilised easily by carrying a Rh+ child
within her body.Though during development,
some cells from the embryo might get mixed
into her blood stream. Therefore, the first child
of the parents with such genetic history is almost
normal always and will survive.
(b)
(d) Microbodies are single membrane covered
small cell organelles which take part in oxidation
reactions other than those of respiration. They
are of different kinds that include Peroxisomes,
Glyoxysomes and Melanosomes.
(b) Predation is not a factor in which productivity
of an ecosystem depends. Predation is an
interaction where one animal which acts as a
predator will kill and consume another animal.
(prey)
(d) Meselson and Stahl in 1958 supported the
hypothesis that DNA replication was semi-
conservative. They proved this by using cultured
in E.coli in a cultural medium containing^15 N
isotopes of heavy nitrogen. After the DNA
replication of E.coli for some generations in^15 N
medium, it was found that both strands of DNA
had^15 N as constituent of purines and pyrimidines.
Therefore, such DNA formed was found to be
hybrid as one strand which was made up of^15 N
(old) and the other was made up of^14 N (new).
(b) Taq Polymerase has thermostable property
as the bacteria from which it is extracted also
contains such property.
(d) Palisade tissue are elongated columnar cells
without intercellular spaces. These cells have
large number of chloroplasts. They take part in
photosynthesis.
(d) During cellulose fermentation by anaerobic
bacteria in rumen and reticulum, Cellulose is
mainly changed into Volatile fatty acid.
(c) Since Calvin cycle is a dark reaction and
oxygen is released during the light reaction.
10. (a) As the Earth is covered by 75% water hence
aquatic ecosystem is found to occur in the largest
surface area.
11. (d) 12. (b)
13. (b) Necrosis is the death of cells and tissues that
causes brown spots.
14. (c) Complete darkness shows etiolation.
15. (a) Gemma cups are found in Marchantia, a
bryophyte, it is cup-shaped structure specially
meant for vegetative propogation.
16. (d) Exine is made up of sporopollenin which is
derived from carotenoids.
17. (b) In Klienefelter’s syndrome (or 47, XXY),
there are some special symptoms which include
weaker muscles, greater height, poor coordination,
less body hair, smaller genitals, breast growth,
and less interest in sex. Such symptoms are
noticed only at puberty. The special feature of
this condition is the increase in size of male breast
tissue (like female breast development) and this is
termed as Gynecomastia which is a common
endocrine system disorder.
18. (d) Perennials survive for more than two years
and produce flowers and fruits during specific
seasons.
19. (a) Cristae are folded structures of the inner
membrane of mitochondria that create more space
to allow for a faster energy production.
20. (b) Statement D is wrong, Hydrosere is a biotic
succession that occurs in an aquatic habitat.
21. (b) A synthesised RNA transcript undergoes many
levels of processing called post transcriptional
modification in Eukaryotes. Taking an example
of mRNA, modification is important to convert
pre-mRNA into a mature mRNA which is ready
for protein translation. Splicing is one such
modification.
