Chapter 13- Meiosis Flashcards

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1
Q

Meiosis reduces the number of

A

chromosomes

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2
Q

A process where a single cell divides twice to produce four cells containing half the original amount of genetic information. These cells are our sex cells – sperm in males, eggs in females.

A

meiosis

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3
Q

Sexual reproduction requires

A

meiosis

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4
Q

Cell division that reduces chromosome number by half

A

meiosis

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5
Q

A haploid reproductive cell.

A

Gametes (eggs and sperm) each contained two chromosomes

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6
Q

Any of the cells of a multicellular organism except those that are destined to form gametes (germ-line cells).

A

Somatic cells (non reproductive cells)

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7
Q

Normal mitotic cell: ___________

Cell after completion of meiosis: _________

A

2n (diploid)

n (haploid)

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8
Q

reproductive cells (n) _______________

nonreproductive cells (2n) _____________

A

Gametes

Somatic cells

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9
Q

An egg and a sperm (gametes), each containing half the complement of chromosomes found in other cells, fuse to produce a single cell called a

A

zygote

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10
Q

_________ can fuse and form a zygote (2n) in a process called_________

A

gametes

fertilization

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11
Q

The diploid (2n) cell resulting from the fusion of male and female gametes (fertilization).

A

zygote

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12
Q

The fusion of gametes to form a new cell is called

A

fertilization

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13
Q

Special reduction division, occurs during gamete formation, producing cells with half the normal number of chromosomes.

A

meiosis

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14
Q

Meiosis and fertilization together constitute a

A

cycle of reproduction

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15
Q

Two sets of chromosomes are present in the somatic cells of adult individuals, making them _______ cells, but only one set is present in the gametes, which are thus ________

A

diploid

haploid

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16
Q

Alternation of 2n and n via meiosis, fusion, and mitosis

A

sexual reproduction

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17
Q

Reproduction that involves alternation of meiosis and fertilization is called

A

sexual reproduction

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18
Q

Offspring inherit chromosomes from____________, You, for example, inherited ___ chromosomes from your mother (maternal homologue), and ___ from your father (paternal homologue).

A

two parents

23

23

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19
Q

In animals, the single diploid zygote undergoes________ to give rise to all of the cells in the adult body

A

mitosis

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20
Q

Somatic cells undergo mitosis to form genetically identical,_________________

A

diploid daughter cells

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21
Q

Both somatic cells and germline cells are __________

A

diploid

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22
Q

Germ-line cells can undergo _______ to produce ____________

A

meiosis

haploid gametes

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23
Q

The life cycles of all sexually reproducing organisms follow a pattern of alternation between

A

diploid and haploid chromosome numbers,

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24
Q

1) Single zygote cell will undergo _________ and eventually give rise to __________________
2) Cells that will eventually undergo meiosis to produce gametes are set aside from somatic cells early in the course of development

A

mitosis
all the cells of the body

germ-line cells

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25
Q

In animals, the zygote first undergoes mitosis to produce _______ cells. Then later in the life cycle, some of these ______ cells undergo meiosis to produce _______ gametes

A

diploid
diploid
haploid

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26
Q

Many types of algae, spend the majority of their life cycle in a _________ state.

A

haploid

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27
Q

in algae, the zygote undergoing meiosis produces ________ cells that then undergo mitosis.

A

haploid

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28
Q

During zygote development, cells that are set aside from the somatic cells and that will eventually undergo meiosis to produce gametes.

A

germ-line cells

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29
Q

Meiosis in a diploid organism consists of two rounds of division, called

A

Meiosis 1 and meiosis 2

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30
Q

The first round of cell division in meiosis; it is referred to as a “reduction division” because homologous chromosomes separate, and the daughter cells have only the haploid number of chromosomes.

A

meiosis I

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31
Q

The second round of division in meiosis, during which the two haploid cells from meiosis I undergo a mitosis-like division without DNA replication to produce four haploid daughter cells.

A

meiosis II

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32
Q

Stages of meiosis 1

A

Interphase 1,

Prophase 1

Metaphase 1

Anaphase 1

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33
Q

In this stage of meiosis 1 chromosomes duplicate, forming sister chromatids

A

Interphase 1,

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34
Q

In this stage of meiosis 1 sister chromatids are attached by a cohesion complex

A

Interphase 1,

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35
Q

This stage of meiosis 1 like mitosis, has G1, S, and G2 phases

A

Interphase 1,

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36
Q

In this stage of meiosis 1 the nuclear envelope degrades

A

Prophase 1

37
Q

In this stage of meiosis 1 homologous chromosomes group together to form tetrads: called synapsis

A

Prophase 1

38
Q

In this stage of meiosis 1___________holds homologous chromosomes together

A

Synaptonemal complex

39
Q

Homologous chromosomes pair ________in meiosis

A

early

40
Q

During early prophase I of meiosis, homologous chromosomes find each other and become closely associated, a process called ________ or _________

A

pairing, or synapsis

41
Q

Homologous chromosomes pair during ____________

This process is called ___________

A

prophase I of meiosis.

synapsis

42
Q

Produces paired homologues connected by a structure called the synaptonemal complex

A

synapsis

43
Q

Sturcture that joins the paired homologues in early prophase 1

A

The synaptonemal complex

44
Q

Consists of a central element connected by filaments to two sets of lateral elements that interact with the homologues.

A

The synaptonemal complex

45
Q

This process literally allows the homologues to exchange chromosomal material.

A

recombination, or crossing over

46
Q

paired homologous chromosomes will exchange chromosomal material via chiasma(ta)

A

Genetic recombination (crossing over)

47
Q

a point at which paired chromosomes remain in contact during the first metaphase of meiosis, and at which crossing over and exchange of genetic material occur between the strands.

A

chiasma

48
Q

Each chiasma contains _________________, which probably contain enzymes to break and reattach chromatids

A

recombination modules

49
Q

recombination modules contain

A

enzymes to break and reattach chromatids

50
Q

After recombination, the

________________breaks down and is loosely attached via chiasmata

A

synaptonemal complex

51
Q

After ______________, the synaptonemal complex

breaks down and is loosely attached via chiasmata

A

recombination

52
Q

In this stage of meiosis 1 homologous chromosomes line up at the center and spindle complex forms

A

Metaphase 1

53
Q

In this stage of meiosis 1 orientation of sister chromosome + homologous chromosome pair is random

A

Metaphase 1

54
Q

________ is characterized by the pairing of homologous chromosomes during prophase I. In many species, an elaborate structure called the ___________________ forms between homologues. During this pairing, homologues may exchange chromosomal material at sites called __________. In meiosis I, the homologues separate from each other, reducing the chromosome number to the __________ state (thus the reductive division). It is followed by a second division without replication, during which sister chromatids become separated. The result of meiosis I and II is ________________.

A

meiosis

synaptonemal complex

chiasmata

haploid state

four haploid cells

55
Q

The first meiotic division is termed the __________________—it results in ____________ that contain one ___________ from each chromosome pair.

The second meiotic division does not further reduce the _______________; it will merely separate the ______________ for each homologue.

A

reduction division

daughter cell

homologue

number of chromosomes

sister chromatids

56
Q

Involves two successive divisions with no replication of genetic material between them

A

meiosis

57
Q

consists of two divisions with one round of DNA replication

A

meiosis

58
Q

In meiosis DNA replication must be suppressed between the _______________

Because of the behavior of chromosomes during meiosis I, the resulting cells contain _________________ of each chromosome.

________________ acts like mitosis, without DNA replication, converts these cells into ones with a single copy of each chromosome.

A

two meiotic divisions

one replicated copy

2nd meiotic division

59
Q

like mitosis with no chromosome duplication.

A

2nd meiotic division

60
Q

In this stage of meiosis 1 homologous chromosomes are pulled apart to opposite ends

A

Anaphase 1

61
Q

In this stage of meiosis 1, meiosis-specific cohesin complex degrades; sister chromatids only attached at the centromere

A

Anaphase 1

62
Q

This stage of meiosis 1 is the end of meiosis I

A

Telophase I

63
Q

In this stage of meiosis 1, only sister chromatids exist in each daughter cell, and they are no longer identical

A

Telophase I

64
Q

Stages of meiosis 2

A

Prophase II

Metaphase II

Anaphase II

Telophase II

65
Q

Briefly describe meiosis 2

A

Cell division without DNA replication

66
Q

Stages of meiosis 2: what phase?

Nuclear membrane degrades again; formation of new spindle

A

Prophase II

67
Q

Stages of meiosis 2: what phase?

Spindle moves to opposite ends of the cell; chromosomes line up in the center

A

Metaphase II

68
Q

Stages of meiosis 2: what phase?

Spindle fibers bind to kinetochores of sister chromatids on opposite sides

A

Metaphase II

69
Q

Stages of meiosis 2: what phase?

Spindle fibers from opposite poles bind to kinetochores of each sister chromatid, allowing each chromosome to migrate to the metaphase plate as a result of tension on the chromosomes from polar microtubules pulling on sister centromeres

A

Metaphase II

70
Q

Stages of meiosis 2:what phase?

Spindle fibers contract; cohesin complex between sister chromatids completely degraded, sister chromatids then separate to opposite ends

A

Anaphase 2

71
Q

Stages of meiosis 2:what phase?

The spindle fibers contract, and the cohesin complex joining the centromeres of sister chromatids is finally destroyed, allowing sister chromatids to be pulled to opposite poles.

A

Anaphase 2

72
Q

Stages of meiosis 2: what phase?

Cell pinches off into two cells; nuclear envelope reforms

A

Telophase II

73
Q

Stages of meiosis 2: what phase?

The nuclear envelope re-forms around the four sets of daughter chromosomes. Cytokinesis then follows.

A

Telophase II

74
Q

The final result of this division is four cells, each containing a complete haploid set of chromosomes

A

Meiosis 2 division

75
Q

Meiosis vs Mitosis: Features

  1. Homologous pairing of chromosomes _____________
  2. No homologous pairing of chromosomes _____________
  3. Recombination / crossing over during meiosis I _______________
  4. No crossing over_______________
  5. Sister chromatids connected via centromere during anaphase I (while homologous chromosomes separate) __________________
  6. Sister chromatids are pulled apart in anaphase__________
  7. Kinetochores of sister chromatids attached to same pole (microtubule attachment) ______________
  8. Kinetochores attach to opposite poles of sister chromatids _________________
  9. Cell division occurs twice after initial DNA replication______________
  10. DNA replication is repressed during meiosis I and II ______________
  11. Cell division only occurs once after initial DNA replication ___________________
  12. Daughter cells are not identical, random orientation
    of chromosomes, crossing over, results in variations in offspring, allows for evolution _____________
  13. Daughter cells are identical ______________
A
  1. meiosis
  2. mitosis
  3. meiosis
  4. mitosis
  5. meiosis
  6. mitosis
  7. meiosis
  8. mitosis
  9. meiosis
  10. meiosis
  11. mitosis
  12. meiosis
  13. mitosis
76
Q

Characterized by homologue pairing and crossing over; by loss of sister chromatid cohesion in the arms, but not at the centromere at the first division; by the suppression of DNA replication between the two meiotic divisions; and by sister kinetochores attachment to the same pole of the spindle.

A

meiosis

77
Q

No homologous pairing of chromosomes _____________

A

mitosis

78
Q

Daughter cells are not identical, random orientation

of chromosomes, crossing over, results in variations in offspring, allows for evolution _____________

A

meiosis

79
Q

Cell division only occurs once after initial DNA replication ___________________

A

mitosis

80
Q

Daughter cells are identical ______________

A

mitosis

81
Q

DNA replication is repressed during meiosis I and II ______________

A

meiosis

82
Q

Kinetochores attach to opposite poles of sister chromatids _________________

A

mitosis

83
Q

Cell division occurs twice after initial DNA replication______________

A

meiosis

84
Q

No crossing over_______________

A

mitosis

85
Q

Sister chromatids connected via centromere during anaphase I (while homologous chromosomes separate) __________________

A

meiosis

86
Q

Sister chromatids are pulled apart in anaphase__________

A

mitosis

87
Q

Recombination / crossing over during meiosis I _______________

A

meiosis

88
Q

Homologous pairing of chromosomes _____________

A

meiosis