Chapter 15 Cell Division

Front 1

The Eukaryotic Cell Cycle: Humans have how many pairs of Chromosomes? How many total chromosomes?

Back 1

23 pairs and 46 total chromosomes

Front 2

Autosomes : how many pairs in humans?

Back 2

22 pairs

Front 3

Sex chromosomes : how many pairs in humans?

Back 3

1 pair in humans

Front 4

Sex Chromosomes : Sex chromosome pair will be one of 2 choices.

Back 4

XX or XY

Front 5

Ploidy are what?

Back 5

Diploid or Haploid

Front 6

What is a Diploid?

Back 6

humans have 23 pairs of chromosomes. Also called 2n

Front 7

What is a Haploid

Back 7

Gametes have 1 member of each pair of chromosomes or 23 total chromosomes. Also called n.

Front 8

In diploid species, members of a pair of chromosomes are called what?

Back 8

Homologues

Front 9

Homologus Chromosomes: Homologues relate to each other in terms of size and genetic composition how?

Back 9

They are nearly identical in size and genetic composition

Front 10

Homologus Chromosomes: Sex chromosomes are very different from each other how?

Back 10

X and Y differ in size and composition so they are not homologus

Front 11

Cell Cycle: This is what?

Back 11

A sequence of growth, DNA replication and division producing new cells.

Front 12

Phases of the Cell Cycle: (4)

Back 12

G1, S, G2, M

Front 13

Phases of the Cell Cycle: What phases are inside of Interphase?

Back 13

G1, S, and G2

Front 14

Special Case : what is G0 for?

Back 14

substitute for G1 for cells postponing cell division or never dividing again (leaving cell cycle)

Front 15

What is the first Phase of the cell cycle?

Back 15

G1 Phase (Start of interphase)

Front 16

What happens in G1

Back 16

Cell growth phase

Front 17

How do cells grow in G1

Back 17

Cells accumulate molecular changes that cause progression through the cell cycle.

Front 18

What happens at the end of the G1 Phase?

Back 18

The cell passes restriction point where the cells committed to enter S phase.

Front 19

What is the 2nd phase of the cell cycle?

Back 19

S phase. Middle of interphasee

Front 20

What happens in the S Phase

Back 20

Chromosomes replicate

Front 21

In the S phase what happens after replication?

Back 21

2 copies stay joined to each other and are called sister chromatids

Front 22

human cells in G1 have how many chromosomes?

Back 22

46 chromosomes

Front 23

Human cells in G2 have how many chromosomes?

Back 23

46 chromosomes

Front 24

How many chromatids are in 46 chromosomes?

Back 24

92 chromatids and paired up they make 46 sister chromatid pairs

Front 25

What is the 3rd phase of the cell cycle?

Back 25

G2 phase. The end of interphase.

Front 26

What happens in G2 phase?

Back 26

Cells synthesize proteins needed for chromosome sorting and cell division

Front 27

What also can happen in G2 phase? This is an added thing that can also happen aside from the main function.

Back 27

Some cell growth may occur

Front 28

What is the 4th phase of the Cell cycle?

Back 28

M phase (mitosis)

Front 29

What happens in the M phase (mitosis)

Back 29

Division of one cell nucleus into two

Front 30

In the M phase (mitosis) what happens to the sister chromatids?

Back 30

The align and separate.

Front 31

In the M phase (mitosis) what is ensured of the daughter cells?

Back 31

The daughter cells get each get a full set of chromosomes

Front 32

In the M Phase (mitosis) what is the ending part?

Back 32

Cytokinesis

Front 33

In the M phase (mitosis) what happens in Cytokinesis?

Back 33

Division of the cytoplasm into two distinct daughter cells

Front 34

Why do cells decided to divide? External factors (2)

Back 34

Environmental conditions. Signaling molecules.

Front 35

Why do cells decided to divide? Internal factors (2)

Back 35

Cell cycle control molecules. Checkpoints.

Front 36

What are checkpoints?

Back 36

3 critical regulatory points or checkpoints in eukaryotes.

Front 37

What are the 3 checkpoints?

Back 37

G1 checkpoint (restriction point). G2 checkpoint. Metaphase checkpoint.

Front 38

What do checkpoint proteins do?

Back 38

They act as sensors to determine if the cell is in proper condition to divide

Front 39

What happens if the checkpoint finds something wrong?

Back 39

The Cell cycle will be delayed until problem is fixed or the division halts entirely.

Front 40

Loss of checkpoint function can lead to what?

Back 40

mutations and cancer.

Front 41

Checkpoint proteins are made of what?

Back 41

Cyclins and cyclin-dependent kinases (cdks)

Front 42

Checkpoint proteins: what is the cdks responsible for?

Back 42

advancing a cell through the phases of the cell cycle.

Front 43

The amount of cyclins change through the cycle how?

Back 43

The vary throughout the cycle.

Front 44

Kinases controlling cell cycle must do what to activate?

Back 44

bind to a cyclin

Front 45

Mitotic Cell Division : what is it?

Back 45

A cell divides to produce 2 new genetically identical cells

Front 46

Original cell is called what?

Back 46

mother cell

Front 47

new cells are called what?

Back 47

daughters

Front 48

Miotic cell division: This process involves what?

Back 48

mitosis and cytokinesis

Front 49

The mitotic cell division process is good for what?

Back 49

asexual reproduction or for production and maintence of multicellularity

Front 50

How many times happen in the preparation for cell division?

Back 50

four things

Front 51

preparation for cell division: (1)

Back 51

DNA is replicated

Front 52

preparation for cell division: (2) What happens to the sister chromatids?

Back 52

2 identical copies with associated proteins

Front 53

preparation for cell division: (3)

Back 53

Tightly associates at cenetromere

Front 54

preparation for cell division: (4)

Back 54

serves as attachment site for kinetochore used in sorting chromosomes

Front 55

Mitotic spindle: is what?

Back 55

sorting process that ensures that each daughter cell will obtain the correct number and types of chromosomes

Front 56

Mitotic spindle: what is it responsible for after attachment?

Back 56

organizing and sorting the chromosomes during mitosis

Front 57

Mitotic spindle: is composed of what?

Back 57

microtubules

Front 58

Animal cell mitotic spindle: What is the centrosomes?

Back 58

microtubules organising enter (MTOCs)

Front 59

Animal cell mitotic spindle: The single centrosome duplicates at the beginning of what phase?

Back 59

M phase

Front 60

Animal cell mitotic spindle: centrosomes define what?

Back 60

The poles that the spindles connect to

Front 61

Animal cell mitotic spindle: What is special about the animal cell?

Back 61

The animal cell has centrioles, but not many other eukaryotes have them.

Front 62

What happens during Interphase?

Back 62

phase of the cell cycle during which the chromosomes are uncondensed and found in the nucleus. G1, S, and G2.

Front 63

Mitosis has what happening in it? (5 parts)

Back 63

Prophase, Prometaphase, Metaphase, Anaphase, Telophase. (PPMAT)

Front 64

What is the first part of Mitosis?

Back 64

Prophase

Front 65

What happens to the chromosomes in Prophase?

Back 65

Replicated chromosomes produce 12 chromatids, joined as six pairs of sister chromatids

Front 66

What happens to the nuclear membrane in Prophase?

Back 66

Nuclear membrane begins to break apart

Front 67

What happens to the chroatids in Prophase?

Back 67

chromatids condense intto highly compact sructures. Chromosomes.

Front 68

What is the second phase of mitosis

Back 68

Prometaphase

Front 69

What happens to the nuclear envelope in the prometaphase?

Back 69

Nuclear envelope completely fragments

Front 70

What happens to the mitotic spindle in Prometaphase?

Back 70

The mitotic spindle is fully formed

Front 71

What happens to Centrosomes in Prometaphase?

Back 71

Centrosomes move apart to the poles

Front 72

What happens to Spindle fibers in Prometaphase?

Back 72

Spindle fibers interact with sister chromatids

Front 73

What happens to kinetochores in Prometaphase?

Back 73

Kinetochores on each pair of sister chromatids attached to kinetochore microtubules from opposite poles

Front 74

What is the third phase of mitosis?

Back 74

Metaphase

Front 75

What happens to the sister chromatids in Metaphase?

Back 75

Pairs of sister chromatids are aligned along a plane halfway between the poles called the metaphase plate

Front 76

How are the sister chromatids organized in Metaphase?

Back 76

Organized into a single row

Front 77

What happens when the alignment is complete?

Back 77

The cell is in metaphase

Front 78

What is the fourth stage of mitosis?

Back 78

Anaphase

Front 79

What happens to the connections between the pairs of sister chromatids in Anaphase?

Back 79

the connections are broken

Front 80

What happens to the chromatids in relation to the microtubules in Anaphase?

Back 80

each chromatid is linked to one of the two poles by kinetochore microtubules.

Front 81

What happens to the kinetochore microtubules in Anaphase?

Back 81

Kinetochore microtubules shorten pulling the chromosomes toward the poles.

Front 82

What is the fifth phase of mitosis?

Back 82

Telophase

Front 83

What happens to the chromosomes in Telophase?

Back 83

Chromosomes have reached their respective poles and de-condense

Front 84

What happens to the nuclear membrane in Telophase?

Back 84

nuclear membrane now starts to re forms to produce two separate nuclei

Front 85

What happens in Cyokinesis?

Back 85

Two nuclei are segregated into separate daughter cells.

Front 86

The process of cytokinesis is ___ in animal and plant cells.

Back 86

Different

Front 87

Cytokinesis in Animal cells.

Back 87

Cleavage furrow constricts like a drawstring to separate the cells

Front 88

Cytokinesis in Plant cells.

Back 88

Cell plate forms a cell wall between the two daughter cells

Front 89

Sexual Reproduction requires what?

Back 89

A fertilization event in which two haploid gametes unite to create a diploid cell called zygote.

Front 90

Meiosis: what is it?

Back 90

The process by which haploid cells are produced from a cell that was originally diploid

Front 91

Meiosis has how many stages?

Back 91

2 stages

Front 92

Like mitosis, meiosis begins after a cell has progress through what?

Back 92

the G1, S, G2 phases of the cell cycle.

Front 93

What are the 2 key differences in meiosis from mitosis?

Back 93

Homologus pairs form a bivalet or tetrad. Crossing Over.

Front 94

Meiosis: How do the homologus pairs from a bivalet or tetrad?

Back 94

Homologus pairs of sister chromatids associate with each other, lying side by side to form a bivalent or tetrad

Front 95

Meiosis: Homologus pairs form a bivalent or tetrad. What is this process called?

Back 95

Synapsis

Front 96

Meiosis: Crossing Over. What happens in this process?

Back 96

Physical exchange between chromosomes of the crossing bivalent.

Front 97

Meiosis: crossing over. What effect does this have on the genetic variation of a species?

Back 97

It may increase the genetic variation

Front 98

Meiosis: Crossing over. What is Chiasma?

Back 98

arms of the chromosomes that tend to separate but remain adherred at a crossover point.

Front 99

Meiosis: The number of crossovers is controlled by what?

Back 99

Carefully controlled by the cells.

Front 100

Meiosis I does what?

Back 100

Separates Homologus chromosomes

Front 101

Meiosis: What is the first step of Meiosis?

Back 101

Prophase I

Front 102

Meiosis: Prophase I does what?

Back 102

Replicated chromosomes condense and bivalents form as the nuclear membrane breaks down

Front 103

Meiosis: What is the second step of Meiosis?

Back 103

Prometaphase I

Front 104

Meiosis: What happens in Prometaphase I?

Back 104

Spindle apparatus complete, and the chromatids are attached to kinetochore microtubules. Pairs of sister chromatids attached to 1 pole.

Front 105

Meiosis: What is the 3rd phase of meiosis?

Back 105

Metaphase I

Front 106

Meiosis: What happens in metaphase I

Back 106

Bivalents organized along metaphase plate as dobuled row. Mechanism to promote genetic diversity.

Front 107

Meiosis: What is the fourth step of Meiosis?

Back 107

Anaphase I

Front 108

Meiosis: What happens in Anaphase I? (3)

Back 108

Segregation of homologues occur. Connection between bivalents break, but not between sister chromatids. Each pair of chromatids migrates to one pole, Homologus pair moves to the opposite pole.

Front 109

Meiosis: What is the fifth phase of Meiosis?

Back 109

Telophase I

Front 110

Meiosis: What happens in telophase I?

Back 110

Sister chromatids have reached their respective poles and de-condense; nuclear membranes reform.

Front 111

Meiosis: What is the last (6th) phase of Meiosis?

Back 111

Cytokinesis. Same as before. Membrane closes in or cell place expands from center.

Front 112

What happens in Meiosis II?

Back 112

Separation of sister chromatids

Front 113

There is no ____ phase between Meiosis I and Meiosis II.

Back 113

S phase

Front 114

Sorting events of Meiosis II are similar to that of _____

Back 114

mitosis

Front 115

Sister chromatids are separated during _____ as unlike _____

Back 115

separated during anaphase II unlike anaphase I

Front 116

Meiosis vs. Mitosis : Mitosis produces two what?

Back 116

diploid daughter cells that are genetically identical

Front 117

Meiosis vs. Mitosis : Meiosis produces what?

Back 117

four haploid daughter cells. Each daughter has a random mix of 3 chromosomes

Front 118

Changes in chromosome number: What is Euploid?

Back 118

Chromosome number considered normal.

Front 119

Changes in chromosome number: What is polyploid?

Back 119

3 or more sets of chromosomes

Front 120

Changes in chromosome number: What is Aneuploidy?

Back 120

Alteration in number of particular chromosomes. Total number not an exact multiple of a set.

Front 121

Changes in chromosome number: What is trisomic?

Back 121

Normal 2 copies of a chromosome plus a 3rd. 2n + 1

Front 122

Changes in chromosome number: What is monosomic?

Back 122

Missing one of normal copies of a chromosome. 2n -1

Front 123

Nondisjunction: in nondisjunction Chromosomes do not do what during cell division?

Back 123

Sort properly

Front 124

Nondisjunction: in nondisjunction during meiosis what happens to gametes?

Back 124

They can be produced with too many or too few chromosomes

Front 125

Nondisjunction: In nondisjunction Aneuplodiy in all eukaroytic species usually has what?

Back 125

detrimental consequences

Front 126

Nondisjunction: In nondisjunction what happens to trisomic and monosomic individuals?

Back 126

They have an impalance in the level of gene expression interfering with proper cell function

Front 127

Aneuploidy in humans: about _____% of al fertilized human eggs do what?

Back 127

5-10% of all human eggs result in an embryo with an abnormality in chromosome number.

Front 128

Aneuploidy in humans: Approximately ____% of all spontaneous abortions are due to what?

Back 128

50% of all spontaneous abortions are due to alterations in chromosome number.

Front 129

Aneuploidy in humans: We can survive some abnormalities. What are they?

Back 129

Trisomies or abnormalities in sex chromosome number.