Multiple Choice QuestionsEmbryo sac is
microgametophyte
microsporangium
megagametophyte
megasporangium
D.
megasporangium
Meibomian glands are also called tarsal glands and are modified sebaceous gland on the edges of eyelids, these keep a thin film of oil over the cornea which acts as lubricant.
9: 3: 3: 1 ratio is modified to 9 : 7 ratio due to
complementary gene
epistatic gene
hypostatic gene
supplementary gene
A.
complementary gene
Complementary genes are the genes which are present on different genetic loci but interact with each other to express a single character in combination. That is they both together produce a particular phenotypic trait in an individual. Supplementary genes are the genes which include two pairs of non-allelic genes.
Lichens are important in the studies on atmospheric pollution because they
can grow in polluted atmosphere
can readily multiply in polluted atmosphere
efficiently purify the atmosphere
are very sensitive to pollutants like sulphur dioxide
D.
are very sensitive to pollutants like sulphur dioxide
Lichens are extremely sensitive to SO2 an could be regarded as indicator of SO2 pollution.
sprouting of potato can be prevented in storage by
maleic hydrazide
gibberellins
indole acetic acid
cytokinins
A.
maleic hydrazide
alpha chloronaphthalene, methyl ester of alpha naphthalene-acetic acid (MENA) and maleic hydrazide (MH) applied in wax or water in inhibiting sprouting or potatoes during the latter part of the late-crop shipping season.
The pyramid of energy-in a forest ecosystem is
always upright
always inverted
both (a) and (b)
none of the above
A.
always upright
In a forest ecosystem, the producers are large size trees which make the base of Pyramid. The herbivores such as fruit eating birds, deer, elephants etc. make the primary consumers and are less than primary producers. After that, the number goes down at each successive level.
In the lactose operon of Escherichia coli what is the function of promoter
Binding of Gyrase enzyme
Binding of RNA polymerase
Codes for RNA polymerase
Processing of messenger RNA
B.
Binding of RNA polymerase
Promoters contain specific DNA sequences such as response elements that provide a secure initial binding site for RNA polymerase and for proteins called transcription factors that recruit RNA polymerase.
One of the following is sex-influenced character
Appearance of beard
Baldness in male
Docile behaviour of female
Low BMR in female
B.
Baldness in male
D.
Low BMR in female
Inheritance of pattern baldness in man is an example of sex-influenced trait which is dominant in males and recessive in females.
The map distance between the genes A and B is 3 units, between B and C is 10 units and between C and A is 7 units. The order of the genes in a linkage map constructed on the above data would perhaps be
A, B, C
A, C, B
B, C, A
B, A, C
D.
B, A, C
From the recombination frequencies between different genes A, B and C, it is clear that distance between A and B genes is 3 units between B and C is 10 units and C and A is 7 units. Hence, linear order of genes on chromosomes is
Polymerase chain reaction is most useful in
DNA synthesis
DNA amplification
protein synthesis
amino acid synthesis
A.
DNA synthesis
Polymerase chain reaction (PCR) is a method widely used in molecular biology to make many copies of a specific DNA segment. Using PCR, a single copy (or more) of a DNA sequence is exponentially amplified to generate thousands to millions of more copies of that particular DNA segment
Sex factor in bacteria is
F-replicon
chromosomal replicon
RNA
sex pillies
A.
F-replicon
In bacteria, besides nuclear DNA, there is some extrachromosomal or extranuclear DNA which is known as plasmid. Term plasmid was given by Lederberg (1952). On the basis of their function, the plasmids are of 3 types :
(i) F or fertility factor : Responsible for transfer of genetic material
(ii) R or resistance factor Provides resistance against drugs.
(iii) Colicinogenic factor : Provides colicines which kill other bacteria (other than which produce these colicines).
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