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BIO 111 > Chapter 10- How cells divide: Mitosis > Flashcards

Chapter 10- How cells divide: Mitosis Flashcards

1
Q

Bacteria divide by…

A

Binary fission; no sexual life cycle, reproduction clonal

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2
Q

Bacteria cell divison

A

Single, circular bacterial chromosome replicated. Has 4.6 millon nucleotides

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3
Q

Replication in bacteria

A

Begins at origin of replication and proceeds bidirectonally to site of termination

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4
Q

New chromosomes in bacteria

A

Partitioned by opposite ends of cell by unknown mechanisms

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5
Q

Division in bacteria

A

Septum formed to divide cell into 2

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6
Q

FtZ Protein

A

Septation; formation of septum seperates cells other components

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7
Q

FtsZ protein found in…

A

Most prokaryotes

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8
Q

Septum does…

A

Contracts radically to pinch cell in 2

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9
Q

Septation begins with…

A

Formation of ring of FtsZ proteins; Accumulation of other proteins follow

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10
Q

Eukaryotic Chromosomes

A

Every species has different number of chromosomes

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11
Q

Human chromosomes

A

Humans have 46 in 23 nearly identical pairs

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12
Q

Chromosomes composed of…

A

Chromatin; complex of DNA (40%) and protein (60%)

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13
Q

Chromosomes are site of…

A

RNA synthesis

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14
Q

DNA of a single chromosome

A

One long continuous double-stranded fiber

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15
Q

Chromosomes in the…

A

Nondividing nucleus

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16
Q

Heterochromatin

A

Not expressed

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17
Q

Euchromatin

A

Expressed

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18
Q

Each typical human chromosome is _____ long

A

140 million nucleotides

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19
Q

Walter Flemming

A

Discovered chromosomes in 1879 when he discovered Mitosis

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20
Q

Nucleosome

A

Complex of DNA and histone proteins

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21
Q

Histone proteins purpose

A

Promote and guide coiling of DNA

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22
Q

DNA Duplex coiled by

A

8 histone proteins every 147 base pairs

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23
Q

Charge of Histones

A

Pos. charged and strongly attracted to neg. charged phosphate groups of DNA

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24
Q

Solenoids

A

Nucleosomes wrapped into higher order coils
- Fiber 30 nm in diameter
- Usual state in interphase chromatin

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25
Karyotype
Particular array of chromosomes in an indiviual organism.
26
Karotypes arranged according to...
Size, staining properties, location of centromere
27
Haploid (n)
1 set of chromosomes; 23 in humans
28
Diploid
Humans are diploid; 2 complete sets of chromosomes
29
Pairs of chromosomes in humans are...
Homologous; each one is a homolouge
30
Replication
Prior, each chromosome composed of single DNA. After, each chromosome composed of 2 identical DNA.
31
Cohesion proteins
How chromosomes are held together
32
One chromosome composed of...
2 sister chromatids
33
G1 (gap phase 1)
Primary growth phase, longest phase
34
S (synthesis)
Replication of DNA
35
G2 (gap phase 2)
Chromosomes coil more tightly using motor proteins; centrioles replicate; tubulin synthesis
36
M (Mitosis)
Subdivided into 5 phases
37
C (cytokinesis)
Separation of 2 new cells
38
Duration of cell cycle
Time it takes to complete a cell cycle varies greatly.
39
Mature cells
Take longer to grow. Typical mammalian cell takes 24 hours
40
Growth occurs during...
Interphase; G1, G2, and S phases
41
Phase with most variation in length
G1
42
G0
Resting phase; cells spend more or less time here
43
Interphase
G1, G2, and S phases
44
Centromere
Point of constriction
45
Kinetochore
Attachment site for microtubles
46
Cohesin allows for
Chromatids to stay attached at centromere
47
Order of Mitosis
1. Prophase- pro: "first 2. Prometaphase- pro meta: "before meta" 3. Metaphase- meta: "middle" 4. Anaphase- ana: "seperate" 5. Telophase- telo: "distance"
48
Prophase
Individual chromsomes become visible
49
____ assembles in prophase
Spindle appartus
50
Ribosomal RNA synthesis ____ in prophase
Stops
51
Spindle apparatus assembily
2 centrioles move to opposite poles and form spindle apparatus
52
Asters
Radial array of microtubles in animals (not plants)
53
_____ breaks down during prophase
Nuclear envelope
54
Prometaphase
Chromosomes begin to move to center of cell - Assembly and disassembly of microtubles - Motor proteins at kinetochores
55
As soon as _____ completly disapears, ____ starts
Nuclear envelop, prometaphase
56
Microtubule attachment
2nd group grows from poles and attached to kinetochores, each sister chromatid connected to opposite poles
57
Metaphase
Alignment of chromosomes along plate; one sister chromatin on each side of plate
58
Anaphase begins when...
Centromeres split
59
Key event in anaphase
Removal of cohesion protiens from all chromosomes
60
Sister chromatids pulled to _______ in anaphase
Opposite poles
61
Anaphase A
Moving chromosomes
62
Anaphase B
Moving cell (poles move apart)
63
Telophase
Spindle apparatus disassembles.
64
_____ _____ forms around each set of _____ _____ in telophase
Nuclear envelope, sister chromatids (called chromosomes)
65
Chromosomes begin to ____ in telophase
Uncoil
66
_____ reapperars in each new nucleus during telophase
Nucleolus
67
Cytokinesis
Cleaveage (splitting) of the cell into equal halves
68
Animal cell- Cytokinesis
Constriction of actin filaments produces cleavage furrow
69
Plant cells- Cytokinesis
Cell plate forms between the nuclei
70
Fungi and some protists- Cytokinesis
Nuclear memebrane doesn't dissolve. Mitosis in nucleus. Divison of nucleus during cytokinesis
71
Control of the Cell Cycle- concept 1
Cell cycle has two irreversible points; - Replication of genetic material - Seperation of sister chromatids
72
Control of the Cell Cycle- concept 2
Cell cycle can be put on hold at specific points (checkpoints) - Process checked for accuracy and can be halted if errors -Allows cell to respond to internal and external signals
73
G1/S checkpoint
- Cell "decides" to divide - Primary point for external signal influence
74
G2/M checkpoint
- Cell makes commitment to mitosis - Assesses success of DNA replication
75
Late metaphase (spindle) checkpoint
Cell ensures that all chromosomes are attached to the spindle
76
Growth factors
Act by triggering intracellular signaling systems; Like an injury, if get hurt cells begin to replicate.
77
Cancer
- Unrestrained, uncontrolled growth of cells - Failure of cell cycle control
78
Primary genes that disturb cell cycle when mutated
- Tumor-suppressor genes - Proto-oncogenes
79
p53
Plays a key role in G1 checkpoint
80
p53 protein
Monitors integrity of DNA - If DNA damaged, cell division halted and repair enzymes stimulated - If DNA damage is irreparable, p53 directs cell to kill itself
81
Tumor-suppressor genes
Prevent the development of mutated cells containing mutations
82
p53 absence or damaged
In many cancerous cells
83
In tumor suppressor genes, ___ ___ must lose function for cancer to develop
copies of tumor suppressor gene
84
First tumor-suppressor identified
Rb gene
85
Inheriting a single mutant copy of Rb means the individual has only one ___ copy left
"good"
86
Rb protein integrates ____ from ___ ___
signals, growth factors
87
Proto-oncogenes
Normal cellular genes that become oncogenes when mutated
88
Uncontrolled divison- Proto-oncogens
Only one copy of this gene needs to undergo mutation
89
Cancer treatment
Either remove tumor or interfere with the ability of cancer cells to reproduce
90
As rapidly dividing cells, susceptible to...
Radiation thearpy and chemotherapy
91
Hormone therapy
Designed to prevent cells from recieving signals for continued growth and divison
92
BRCA
Breast cancer
93
BRCA is a...
Tumor suppressor gene
94

BIO 111 (9 decks)

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