Question

Part 7

Which of the following happens during meiosis II?

• A. homologs separate

• B. sister chromatids separate

• C. homologs cross over

• D. sister chromatids form

Which of these is a unique feature in sexual reproduction?

• A. mitosis

• B. cell division

• C. formation of gametes

• D. formation of clones

In a diploid organism, pairs of chromosomes inherited from father and mother are known as;

• A. homologous chromosomes

• B. condensed chromosomes

• C. sex chromosomes

• D. homozygous alleles

What parts of eukaryotic chromosomes become short at each DNA replication, and stop cell division after a certain number of divisions?

• A. terminators

• B. centromeres

• C. telomeres

• D. genes

• E. promoters

Answer 1

7. B

During anaphase 1 of meiosis 1, homologous chromosome separate from each other and during anaphase 2 of meiosis 2, sister chromatids of chromosomes separate from each other.

Crossing over is the exchange of genetic material between non sister chromatids of homologous chromosomes. It occurs during prophase 1 of meiosis 1.

Sister chromatids are formed during synthesis phase of cell cycle in which they are replicated and condensation occurs during prophase 1.

8. C

Mitosis is a type of cell division in which one diploid parent cell gives rise to to diploid daughter cells. The parent cells and daughter cells are genetically identical to each other. This process can be used for the formation of clones, individuals which are genetically identical to each other. This is a process which is common for sexually and asexually reproducing organisms.

Formation and fusion of gametes is a process which is exclusive to only sexually reproducing organisms.

3. A

One pair of homologous chromosome contains two chromosomes, out of which one of them is paternal chromosome and the other is maternal chromosome. They undergo crossing over during prophase 1 of meiosis 1.

4. C

Telomeres are repetitive sequences which are present at the tips of the chromosomes. They are added by enzyme telomerase after DNA replication is completed. In linear Eukaryotic chromosomes, the ends of the chromosomes are not replicated and therefore after every round of DNA replication, the chromosomes get shortened. Therefore to solve this problem, enzyme comes into play.

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