Chapter 3.2 Gametogenesis Flashcards Preview

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Flashcards in Chapter 3.2 Gametogenesis Deck (82):
1

Gametogenesis is necessary for what phase of development

Reproductive phase

2

Hereditary information is carried on

Chromosomes

3

Human somatic cells contain how many pairs of chromosomes

23 pairs of chromosomes, 22 pairs of autosomes and one pair of sex chromosomes for a total of 46 chromosomes

4

Autosomes contain

Genetic information for most human characteristics, such as eye color, hair color, height, and skin pigmentation

5

A pair of similar autosomes are called

Homologous chromosomes

6

The pair of sex chromosomes primarily determines

Whether an individual is female (she will have two X chromosomes) or male (he will have one X chromosome and one Y chromosome)

7

If a cell contains 23 pairs of chromosomes it is said to be

Diploid

8

Sex cells are

Haploid because they contain 23 chromosomes only and not 23 pairs of chromosomes

9

The process of gametogenesis begins with cell division, called

Meiosis

10

The sex cells produced in the female are

Secondary oocytes

11

The sex cells produced in the male are

Sperm

12

A type of sex cell division that starts off with a diploid parent cell and produces haploid daughter cells

Meiosis

13

Mitosis produces

Two daughter cells that are genetically identical to the parent cell

14

Meiosis produces

4 daughter cells that are genetically different from the parent cell

15

Produces daughter cells that are diploid

Mitosis

16

Produces daughter cells that are haploid

Meiosis

17

Crossing over does NOT occur in

Mitosis

18

In meiosis a process called crossing over occurs, whereby

Genetic material is exchanged between homologous chromosomes. Crossing over helps shuffle the genetic deck of cards. It is a means of combining different genes from both parents on one of the homologous chromosomes

19

Meiosis begins with a

Diploid parent cell located in the gonad (testes or ovary)

20

The parent cell that is responsible for the production of gametes contains

23 pairs of chromosomes

21

For an organism to produce its own sex cells, the parent cell must divide by the process of

Meiosis

22

Prior to meiosis is a cell phase known as

Interphases

23

During interphase the DNA in each chromosome is

Replicated in the parent cell, resulting in identical or replicated chromosomes

24

Replicated chromosomes are double stranded chromosomes, composed of two identical structures called

Sister chromatids

25

Each sister chromatid in a double stranded chromosome contains an

Identical copy of DNA

26

The sister chromatids are attached at a specialized region termed

Centromere

27

A double stranded chromosome resembles a written letter X and is composed of

Two identical sister chromatids

28

A homologous pair of chromosomes is composed of a maternal chromosome and a

Paternal chromosome of the same number

29

After interphase there are how many pairs of double stranded chromosomes

23

30

Once the DNA is replicated in interphase, the phases of what begin

Meiosis

31

Homologous, double stranded chromosomes in the parent cell form

Pairs

32

The process by which homologous chromosomes pair up is called

Synapsis

33

The actual pair of homologous chromosomes is called

Tetrad

34

When does crossing over occur?

As the maternal and paternal chromosomes come close together

35

When the crossing over occurs what happens

The homologous chromosomes exchange genetic material

36

A tiny portion of the genetic material in a sister chromatid of a maternal chromosome is exchanged with the

Same portion of genetic material transferred in a sister chromatid of a paternal chromosome

37

The shuffling of the genetic material ensures

Continued genetic diversity in new organisms

38

The homologous pairs of double-stranded chromosomes line up above and below the equator of the cell, forming a double line of chromosomes. This alignment of paired, double-stranded chromosomes is random with respect of whether the original maternal or paternal chromosome of a pair is on one side of the equator or the other.

First meiotic metaphase (Metaphase I)

39

Pairs of homologous chromosomes separate and are pulled to the opposite ends of a cell. The pairs of chromosomes are no longer together, because the members of each pair are being pulled to opposite ends of a cell. However, each chromosome is still double-stranded

First Meiotic Anaphase (Anaphase I)

40

The chromosomes arrive at opposite ends of the cell, and a nuclear membrane re-forms around the chromosomes at each end of the cell. Then cleavage furrow forms in the cell, and the cell cytoplasm divides (cytokinesis) to produce two new cells. Each daughter cell contains 23 chromosomes only, but each of these chromosomes is double stranded, meaning it is composed of two sister chromatids. These two cells must undergo further cell division so that the new cells will be composed of single-stranded chromosomes only.

First meiotic telophase (telophase I) and cytokinesis

41

A single-stranded chromosome contains how many chromatids?

One

42

In each of the two new cells, the nuclear membrane breaks down, and the chromosomes collect together. However, crossing over does not occur in this phase because homologous chromosomes separated in anaphase I.

Second Meiotic Prophase (Prophase II)

43

Crossing over occurs in what prophase

Crossing over occurs in the first meiotic prophase only

44

The double-stranded chromosomes form a single line along the equator in the middle of the cell. Spindle fibers extend from the centrioles at the poles to the centromere of each double-stranded chromosome

Second meiotic metaphase (metaphase II)

45

The sister chromatids of each double-stranded chromosome are pulled apart at the centromere. Each chromatid, now called a single stranded chromosome, is pulled to the opposite pole of the cell

Second meiotic anaphase (anaphase II)

46

The single-stranded chromosomes arrive at opposite ends of the cell. Nuclear membranes re-form, a cleavage furrow forms, and the cytoplasm in both cells divides, producing a total of four daughter cells. These daughter cells are haploid, because they contain 23 chromosomes only (not 23 pairs). These daughter cells mature into sperm (in males) or secondary oocytes (in females)

Second Meiotic Telophase (Telophase II) and Cytokinesis

47

Meiosis I (the first meiotic division) separates maternal and paternal pairs of chromosomes, while meiosis II (the second meiotic division)

Separates the remaining double-stranded chromosomes into single-stranded chromosomes.

48

Secondary oocyte is

The sex cell produced in females

49

Oogenesis is

The process of oocyte development

50

The secondary oocyte cell will have how many autosomes and how many X chromosomes

22 autosomes and one X chromosome

51

Oogonia is

The parent cells, or stem cells, that produce oocytes, they reside in the ovaries

52

Diploid cells that undergo meiosis

Oogonia

53

In the female fetus, all the oogonia start the process of

Meiosis and form primary oocytes prior to birth

54

Primary oocytes are arrested in

Prophase I and remain this way until the female reaches puberty

55

Each month a number of primary oocytes begin to mature; usually only one becomes

A secondary oocyte

56

When the primary oocyte completes the first meiotic division (prophase I, metaphase I, anaphase I, and telophase I), what happens

Two cells are produced

57

Is the division of cytoplasm equal or unequal?

It is grossly unequal

58

The cell we call the secondary oocyte receives the bulk of the cytoplasm and is the cell that is arrested in

Metaphase II

59

The polar body is

The second cell, which receives only a tiny bit of the cytoplasm

60

What has the potential to be fertilized

Only the secondary oocyte

61

The secondary oocyte is ovulated along with

Two other components surrounding the oocyte-cuboidal cells that form the corona radiate and a thin ring of proteins and glycoproteins called the zona pellucida

62

Form protective layers around the secondary oocyte

The corona radiata and the zone pellucida

63

The further development of the secondary oocyte varies, depending on what

Depending upon whether or not it is fertilized by a sperm

64

If the secondary oocyte is not fertilized what happens?

It degenerates about 24 hours after ovulation, still arrested in metaphase II

65

If the secondary oocyte is fertilized it

First finishes the process of meiosis. Two new cells are produced and the division of cytoplasm is unequal.

66

The cell that receives very little cytoplasm becomes

Another polar body and eventually degenerates

67

The cell that receives the majority of the cytoplasm becomes

Ovum

68

It is the ovum nuclear that combines with the sperm nucleus to produce the

Diploid fertilized cell, or zygote

69

Typically how many secondary oocyte is expelled each month?

Only one secondary oocyte is expelled (ovulated)

70

The left and right ovaries

Take turns

71

In males their bodies produce and release how many gametes (sperm) throughout the entire month?

Millions

72

In males the sex cell produced is called

Sperm (spermatozoon)

73

Spermatogenesis is

The process of sperm development

74

The parent or stem cells that produce sperm are called

Spermatogonia

75

Spermatogonia are diploid cells that reside in the

Male gonads, the testes

76

Each spermatogonium first divides by

Mitosis to make an exact copy of itself, a new cell called primary spermatocyte

77

Primary spermatocytes undergo meiosis and produce haploid cells called

Spermatids

78

Although spermatids contain 23 chromosomes only, they still must undergo what

Further changes to form a sperm

79

The process where spermatids lose much of their cytoplasm and grow a long tail called a flagellum

Spermiogenesis

80

The newly formed sperm are haploid cells that exhibit what

A distinctive head, a mid piece, and a tail

81

What forms from a single spermatocyte

Four new sperm are formed

82

Of the four newly formed sperm from a single spermatocyte have how many autosomes and chromosomes are present?

Two of the sperm have 22 autosomes and one X chromosome and two have 22 autosomes and one Y chromosome