Principles of Inheritance and Variation
- How many base pairs are found in one genome of man?
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The number of base pairs (bp) found in one genome of man is 3 × 109.
Correct Option: C
The number of base pairs (bp) found in one genome of man is 3 × 109.
- Crossing over in diploid organism is responsible for
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Crossing over involves physical exchange of genetic material between non-sister chromatids of homologous chromosomes, which leads to recombination.
Correct Option: D
Crossing over involves physical exchange of genetic material between non-sister chromatids of homologous chromosomes, which leads to recombination.
- Radioactive thymidine when added to the medium surrounding living mammalian cells gets incorporated into the newly synthesized DNA. Which of the following types of chromatin is expected to become radioactive if cells are exposed to radioactive thymidine as soon as they enter the S-phase?
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Heterochromatin is a specialized chromosome material which remains tightly coiled and stains darkly in interphase. Euchromatin is that portion of the chromosome that stains with low intensity and uncoils during interphase. In the beginning of S-sphase, DNA replication occurs. DNA replication can occur in diffuse/ less tightly coiled euchromatin.
Correct Option: B
Heterochromatin is a specialized chromosome material which remains tightly coiled and stains darkly in interphase. Euchromatin is that portion of the chromosome that stains with low intensity and uncoils during interphase. In the beginning of S-sphase, DNA replication occurs. DNA replication can occur in diffuse/ less tightly coiled euchromatin.
- After crossing between two plants, the progenies are found to be male-sterile. This phenomenon is found to be maternally inherited and is due to some genes which are present in
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Male sterlity occur due to cytoplasmic or cytoplasmic- genenic inheritance, i.e., due to DNA present in mitochondrion or chloroplast under the i.e. control of extra-nuclear gene.
Correct Option: D
Male sterlity occur due to cytoplasmic or cytoplasmic- genenic inheritance, i.e., due to DNA present in mitochondrion or chloroplast under the i.e. control of extra-nuclear gene.
- A fruit fly is heterozygous for sex-linked genes. When mated with a normal female fruit fly, the male-specific chromosome will enter egg cells in the proportion of
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In sex determination, the male specific chromosome will have half as much chance as the other to enter the egg cell. Hence the proportion will be 1: 1.
Correct Option: A
In sex determination, the male specific chromosome will have half as much chance as the other to enter the egg cell. Hence the proportion will be 1: 1.
