Question

QUESTION 3 Crossing over refers to the pairing of homologous chromosomes during melosis a mutation that makes all alleles in homologous chromosomes identical an exchange of segments between the two members of a homologous chromosome pair during meiosis the loss of one or more chromosomes during melosis QUESTION 4 Place the following events of Meiosis I and Meiosis ll in the correct order: Duplicated chromosomes are separated Duplication of chromosomes Crossing over occurs Homologous chromosomes pair up - Homologous chromosomes are separated

Answer 1

Sol. 3

Crossing over is the exchange of genetic material between two homologous chromosomes.

So, crossing over refers to an exchange of segments between the two members of homologous chromosome pair during meiosis.

So, third option is correct.

The pairing of homologous chromosomes during meiosis is called synapsis.

So, first option is incorrect.

Second and fourth option are also irrelevant,so these options are incorrect.

Hence, third option is the correct answer for this question.

Sol. 4

The correct order of the events given in the question of Meiosis I and Meiosis II are as follows

1. Duplication of chromosomes.
2. Homologous chromosomes pair up.
3. Crossing over occurs.
4. Homologous chromosomes are separated.
5. Duplicated chromosomes are separated.

The above events can be easily understood with the help of the following diagrams.

Metaphase I Anaphase I Prophase I Telophase I

Fig. 1 Stages of Meiosis I

Metaphase II Anaphase II Telophase I Prophase II

Fig. 2 Stages of Meiosis II