meiosis

Question 1

Interphase I

(3)

Answer 1

• Chromosomes replicate
• Chromosome consists of 2 identical sister chromatids held together by a centromere
• Centrioles move towards opposite poles of the cell

Question 2

Prophase I

(4)

Answer 2

• Chromosomes condense & come together in homologous pairs (synapsis)
• Each pair is composed of 4 chromatids, they form a tetrad
• Crossing over occurs & permits the exchange of genetic material between homologous pairs
• Nuclear membrane disintegrates

Question 3

Metaphase I

(2)

Answer 3

• Pairs of homologous chromosomes (homologues) line up at the equator by independent assortment
• Spindle fibres attach to centromere

Question 4

Anaphase I

(2)

Answer 4

• Homologues separate, one of each pair going to each pole of the cell
• Sister chromatids do not separate; they are still attached by a centromere

Question 5

Telophase I & Cytokinesis

(3)

Answer 5

• Two clusters of chromosomes have formed, each containing one member of each pair homologues
• Cytokinesis occurs
• There is little or no interphase between meiosis I and meiosis II

Question 6

Prophase II

(2)

Answer 6

• Chromosomes have relaxed after telophase. They recondese
• Spindle fibers reform

Question 7

Metaphase II

(2)

Answer 7

• Sister cromatids line up along the metaphase plate
• Spindle fibres attach at the centromere

Question 8

Anaphase II

(2)

Answer 8

• Spindle fibres shorten and sister chromatids separate and are now individual chromotids
• Move towards opposite poles

Question 9

Telophase II & Cytokinesis

(2)

Answer 9

• Spindle fibres disappear; the nuclear membrane and nucleus reform
• After cytokinesis, 4 unique daughter cells have formed, each with a haploid number (n) of chromosomes

Question 10

what do you get after meiosis

(4)

Answer 10

• 4 haploid gamete cells
• 1 copy of each chromosomes
• 1 allele of each gene
• Different combinations of alleles for different genes