Chapter 10-Meiosis

Question 1

What is karyotyping?

Answer 1

Finding the number,arrangement, and the order of chromosomes in cells

Question 2

What is Euploidy?

Answer 2

Xn Xtimes the number of chromosomes than sex cells (In humans n=2)

Question 3

What are homologous chromosomes?

Answer 3

Pair of chromosomes that are alike (not identical) that come together in synopsis during prophase of the first meiosis division

Question 4

Where do you find the sex chromosomes?

Answer 4

In all body cells!

Question 5

What are autosomes?

Answer 5

Non sex chromosomes (x&y)

Question 6

What is a tetrad?

Answer 6

A region in which 2 chromosomes ; 4 chromatids are held together by Chiasmata

Question 7

What is the longest phase in meiosis?

Answer 7

Prophase I (90% of whole cycle)

Question 8

What happens during Prophase I?

Answer 8

• Chromosomes condense
• Homologous chromosomes pair along their lengths, gene by gene
• Tetrads are formed , which have one or more chiasmata (exchange genetic material) ∴ genetic variability
• Spindles are formed
• Centrosomes start moving to the opposite poles
• Nuclear envelope is broken down
• LATE PROPHASE; kinetochore of each homologous chromosome is formed

Question 9

What happens during interphase before meiosis?

Answer 9

In S phase chromosomes replicate Centrosome replicated towards late G2

Question 10

What happens during Metaphase I?

Answer 10

The pairs of homologous chromosomes, in the form of tetrads are arranged on the metaphase plate, with each chromosome facing a pole Centromere reach the poles

Question 11

What happens during Anaphase I?

Answer 11

Chromosomes are now moved towards the poles, guided by the spindle apparatus (sister chromatide remain attached at the centromere)

Question 12

When in meiosis does genetic variability occur?

Answer 12

during prophase 1, when chiasmata are formed

during Metaphase 1when tetrads allign

Question 13

How many chromosomes (n#) in late telephase I and Prophase II?

Answer 13

1n, however, the chromosomes at this stage occur as 2 sister chromatids, Which is why they need to divide again until they become chromosomes with “1 chromatid”

Question 14

Are the sister chromatids in prophase II genetically identical?

Answer 14

No, because of the formation of tetrads and chiasmata in prophase I with the homologous chromosomes(loci to loci)

Question 15

What is the stage between Telophase I and Prophase II called in meiosis?

Answer 15

interkinesis , no S phase occurs

Question 16

What are the differences between Mitosis and Meiosis?

Answer 16

• Mitosis results in genetically identical cells, meiosis genetically different cells
• Mitosis only requires 1 division, meiosis 2
• meiosis has synapsis and chiasmata, mitosis does not
• end result of mitosis are cells with same number of chromosomes, in meiosis 1n number of chromosomes
• function of mitosis is tissue repair, growth, multicellular adult rising, while meiosis produce gametes for reproduction and genetic variability
• meiosis 4 Daughter cells arise, mitosis 2

Question 17

What are some examples of asexual reproduction methods?

Answer 17

• binary fission
• mitosis
• budding

Question 18

When do cells become haploid in the meiotic cycle?

Answer 18

Late telophase 1- when the nucleus is formed and 2 daughter cells arise, each with n number of chromosomes (with 2 chromatids each)

Question 19

How many daughter cells arise from the end result of meiosis?

Answer 19

4, each with n number of chromosomes