Question

Unit 3 Study Resource Meiosis • Process by which diploid cells create haploid cells NOT part of the cell cycle > only some cells ever undergo meiosis During meiosis I, homologous chromosomes line up to allow them to be separated into two new cells o They can become "tangled" during this phase, which leads to crossing-over (rearranging the alleles) O Result of meiosis I is two non-identical haploid cells Meiosis Il looks very similar to mitosis, in that sister chromatids separate to form two new nuclei • End result is four non-identical haploid cells Non-disjunction during either phase of meiosis results in some daughter cells having too many chromosomes & some having too few chromosomes 0 Non-disjunction during meiosis I means that homologous chromosomes failed to separate • Produces two daughter cells with an extra chromosome & two daughter cells missing a chromosome (i.e., ZERO normal, haploid daughter cells) o Non-disjunction during meiosis II means that sister chromatids failed to separate - Produces one daughter cell with an extra chromosome, one daughter cell missing a chromosome, and two normal, haploid daughter cells 1. Which of the following is the best description of the process of crossing-over? a. During meiosis I, segments of chromosomes are exchanged b. During mitosis, corresponding segments of homologous chromosomes are exchanged C. During meiosis I, corresponding segments of homologous chromosomes are exchanged d. During meiosis II, segments of chromosomes are exchanged e. During meiosis II, corresponding segments of homologous chromosomes are exchanged 2. Go is the phase in which meiosis occurs. a. True b. False

Answer 1

1. Best description of the process of crossing over is statement C.

During meiosis 1 corresponding segments of homologous chromosome are exchanged.

2. This statement is false.

Meiosis does not occur in G0 phase. G0 is known as resting phase in which the cell cycle machinery comes to a halt, neither mitosis nor meiosis takes place.

3. Process of DNA replication accomplish C)makes exact copies of every chromosome.

DNA replication is the process that takes place in the first stage of mitosis . In this every chromosome make exact copies of themselves.