Ch. 5.5 Meiosis

Question 1

Why does Meiosis occur?

Answer 1

To produce gametes and gemetes are haploid

Question 2

What cells undergo Meiosis?

Answer 2

Germ cells in testis or ovary (in mammals)

Question 3

What is the resulf of Meiosis in humans?

Answer 3

Sperm and eggs are results; Sperm fetilize egg to produce zygote which is the first stage of eukaryotes)

Question 4

What divisions does Meiosis involve?

Answer 4

Meiosis l and Meiosis ll

Question 5

When does DNA replicate?

Answer 5

Only before Meiosis l

Question 6

What does Meiosis l do?

Answer 6

Meiosis l separates homoglous paris

Question 7

What does Meiosis ll do?

Answer 7

Meiosis ll separates sister chromatids

Question 8

What is the result when Meiosis is complete?

Answer 8

The result is one diploid cell becomes one haploid egg and four haploid sperms

Question 9

When does male begin to produce sperms and how many gemates do males produce?

Answer 9

Males begin to produce sperms during puberty and it continues through life of their time; Males produce milliions gemates per day

Question 10

When does female begin to produce egg and how many gemates do females produce

Answer 10

Females produce egg before birth and meiosis is completed when the egg is fertilized; Females produce one egg per month

Question 11

What is prophase l?

Answer 11

Homologues begin to pair up and exchange segments (Crossing Over)

Question 12

What is metaphase l?

Answer 12

The paired homologues chromosomes align at the equotorial plane

Question 13

What is anaphase l?

Answer 13

Homologues separate from pairing and move to opposite poles

Question 14

What is telophase l?

Answer 14

Individual chromosomes gather at each of two poles

Question 15

What is prophase ll?

Answer 15

After a brief interphase with no DNA replication, new spindle
fibres form

Question 16

What is metaphase ll?

Answer 16

The sister chromatids align at the equatorial plane

Question 17

What is anaphase ll?

Answer 17

Sister chromatids separate from the pairing and move to
opposite poles

Question 18

What is telophase ll?

Answer 18

Individual chromosomes gather at each of the two poles, and a
new nuclear envelope form

Question 19

Where do crossing over occur?

Answer 19

between two non-sister chromatids of
homologous chromosomes

Question 20

How does crossing over occur and what is the result of crossing over?

Answer 20

The chromatids break in the same place and a section of each
chromosome is swapped with the other
The result is a hybrid chromosome

Question 21

How is homologous paired?

Answer 21

The pairing is held together by the cohesin between sister chromatids
and the cross-overs

Question 22

What is independent assortment?

Answer 22

the process where the chromosomes move randomly to separate poles during meiosis as a result in gemate

Question 23

What are two unique features of meiosis that are not found in mitosis?

Answer 23

1. Synapsis 2. Reduction division

Question 24

What is synapsis?

Answer 24

The process of drawing together homologous
chromosomes down their entire lengths so that crossing over
can occur

Question 25

What is reduction division?

Answer 25

Because meiosis involves two nuclear divisions but only one
replication of DNA, the final amount of genetic material passed
to the gametes is halved (2n–>n)

Question 26

What are 3 mechanisms that help genetic variety through sexual reproduction?

Answer 26

1. Independent assortment
2. Crossing over
3. Random fertilization—one of 8 million different sperm can fertilize
   the egg