16.3 The Formation of Gametes

Question 1

What are the two key outcomes of Meiosis?

Answer 1

Reduction Division

Recombination

Question 2

What is Reduction Division?

Answer 2

When cell division produces daughter cells with fewer chromosomes than the parent cells

Question 3

What is recombination?

Answer 3

When the products of meiosis have different combinations of genes that give rise to genetic offspring that are genetically distinct from one another and their parents

Question 4

What are the phases of Meiosis I?

Answer 4

Prophase I
Metaphase I
Anaphase I
Telophase I

Question 5

What are germ cells?

Answer 5

Gamete producing cells

Question 6

What phase do gamete producing cells undergo that is the same of body cells?

Answer 6

The interphase and Prophase, Metaphase, Anaphase, Telophase

Question 7

What is the interphase?

Answer 7

A period of growth and synthesis that occurs before meiosis begins

Question 8

What does a germ cell contain at the start of meiosis?

Answer 8

Duplicated chromosomes

Question 9

What do duplicated chromosomes consist of?

Answer 9

2 sister chromatids that are joined together at the centromere

Question 10

What happens in the Prophase I of Meiosis?

Answer 10

Each pair of homologous chromosomes align side by side

Question 11

What is Synapsis?

Answer 11

The alignment of homologous chromosomes in the Prophase I

Question 12

What are homologous chromosomes?

Answer 12

Chromosomes that are not identical but contain the same genes

Question 13

What is the name for the pairs of chromosomes that align during the Prophase I?

Answer 13

A tetrad

Question 14

What is a Tetrad?

Answer 14

The four chromatids that align with each other during the Prophase I

Question 15

What is a Tetrad made up of?

Answer 15

A pair of sister chromatids synapsed with another pair of sister chromatids

Question 16

What are non-sister chromatids?

Answer 16

Two homologous but non-identical chromatids

Question 17

What happens is the Metaphase I?

Answer 17

A spindle fiber attaches to the centromere of each chromosome. A spindle fibre from each pole attaches to opposite pairs of sister chromatids in the tetrad and guid each tetrad to the equator of the cell

Question 18

What happens after each Tetrad is guided to the equator in the Metaphase I?

Answer 18

The chromosomes line up as homologous pairs so that in each pair one homologous chromosome is positioned on either side of the cell’s equator

Question 19

What happens during Anaphase I?

Answer 19

The spindle fibres shorten which causes the homologous chromosomes to separate from one another to opposite poles. This results in each chromosome (made of 2 sister chromatids) from each homologous pair move to each pole of the cell

Question 20

What happens during Telophase I?

Answer 20

The homologous chromosomes begin to uncoil and the spindle fibres disappear and the cytoplasm is divided and the nuclear membrane forms around each group of homologous chromosomes. Two cells are formed

Question 21

What do the two new cells formed at the beginning of Telophase I contain?

Answer 21

One set of sister chromatids and is known as a haploid cell

Question 22

What happens during Meiosis II?

Answer 22

The cell proceeds through Prophase II, Metaphase II, Anaphase II, and Telophase II

Question 23

What is the result at the end of Meiosis II?

Answer 23

The daughter cells are haploid but contain single unreplicated chromosomes

Question 24

What is the outcome of Meiosis?

Answer 24

The formation of genetically distinct distinct haploid gametes

Question 25

What are the 2 ways that genetic variation is ensured?

Answer 25

By the creation of Gametes that that carry different variations of maternal and paternal chromosomes and by the exchange of genetic material between maternal and paternal chromosomes

Question 26

How does independent assortment take place?

Answer 26

During Metaphase I when chromosomes are arranged in a line next to their homologous pair, some maternal chromosomes are facing one way and some paternal chromosomes are facing the same or opposite way which results in variation

Question 27

What is Crossing over?

Answer 27

When during Prophase I, homologous pairs exchange genetic information from their chromosomes

Question 28

What is Nondisjunction?

Answer 28

When chromosomes or chromatids do not separate as they should during Meiosis?

Question 29

Where does Nondisjunction occur?

Answer 29

At Anaphase I and II of Meiosis

Question 30

How does nondisjunction occur in Anaphase I?

Answer 30

When homologous pairs are not separated to opposite pole and one pair is pulled toward the same pole together

Question 31

How does nondisjunction occur in Anaphase II?

Answer 31

When sister chromatids do not separate to opposite poles and both sister chromatids are pulled toward the same pole together

Question 32

What happens as a result of nondisjunction?

Answer 32

It produces gametes that have either too few or too many chromosomes

Question 33

What is Monosomy?

Answer 33

When a chromosome is lost due to nondisjunction. So a Gamete is missing on chromosome of a homologous pair

Question 34

What is Trisomy?

Answer 34

The gain of an extra chromosome

Question 35

What are the products of meiosis?

Answer 35

Haploid Gametes

Question 36

What is the process of sperm production called?

Answer 36

Spermatogenesis

Question 37

What is the process of egg production called?

Answer 37

Oogenesis

Question 38

What does the process of spermatogenesis begin with?

Answer 38

A diploid germ cell called a spermatagomium

Question 39

What is a spermatogonium?

Answer 39

The diploid cell that spermatogenesis begins with

Question 40

What stimulates the Spermatogonium to divide?

Answer 40

Puperty

Question 41

How does the spermatogonia divide?

Answer 41

First it divide by Mitosis to form 2 daughter cells, one of which becomes a spermatogonium and the other becomes the primary spermatocyte

Question 42

How does the Primary Spermatocytes divide?

Answer 42

It undergoes Meiosis I to form two secondary spermatocytes. The secondary spermatocytes then undergo Meiosis II to form spermtids

Question 43

What are Spermatids?

Answer 43

The end process of Spermtogenesis

Question 44

What happens after a spermatid is produced?

Answer 44

The nucleus and certain enzymes are arranged into a head region and the parts of the sperm develop

Question 45

What does Oogenesis begin with?

Answer 45

A diploid germ cell called oogonium.

Question 46

How does each Oogonium divide?

Answer 46

It undergoes mitosis to form two primary oocytes. This occurs before a baby is born

Question 47

How long do the Primary Oocytes last?

Answer 47

Until puberty

Question 48

What happens every month after puberty?

Answer 48

One primary oocyte undergoes meiosis

Question 49

What is different between Spermatogenesis and Oogenesis?

Answer 49

Oogenesis involves unequal division of the cytoplasm called asymmetrical cytokinesis

Question 50

What happens as a result of asymmetrical cytokinesis?

Answer 50

Because the cytoplasm is not equally divided at the end of Meiosis I, the cell that receives most of the cytoplasm called the secondary oocyte and the other cell is called the first polar body

Question 51

What happens to the first polar body?

Answer 51

The first polar body may or may not go to through a second division but they cells degenerate anyways

Question 52

What happens to the secondary oocyte?

Answer 52

It undergoes meiosis II and the cell that contains the most cytoplasm will become a mature egg. The second polar body degenerates

Question 53

How many gametes are produced from Oogenesis?

Answer 53

1

Question 54

How many years separates Meiosis I and Meiosis II in women?

Answer 54

About 10 years

Question 55

What state is the primary oocytes suspended in?

Answer 55

Prophase I until puberty. Hormones signal one oocyte to continue a month

Question 56

Where is the secondary oocyte suspended at?

Answer 56

Metaphase II until it comes into contact with sperm