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Chapter 12 Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q 
Which of the following events does not occur during interphase of the cell cycle?
Production of new mitochondria
Separation of the sister chromatids
Protein production
Production of the endoplasmic reticulum
Duplication of the chromosomes
Growth of the cell
A

Separation of the sister chromatids

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2
Q

Checkpoints in the cell cycle control system

A

Regulate the cell cycle through a variety of stop and go signals

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3
Q

The region of a chromosome holding the two double strands of replicated DNA together is called

A

A centromere

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4
Q

The spread of cancer cells to other locations in the body is known as

A

Metastasis

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5
Q

What is the difference between a benign tumor and a malignant tumor?

A

Cells of benign tumors do not metastasize; those of malignant tumors do

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6
Q

Mitotic (M) phase includes

A

Mitosis and cytokinesis

Shortest part of the cell cycle

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7
Q

Interphase is divided into 3 subleases:

A 
G1 phase (first gap) 
S phase (synthesis)
G2 phase (second gap)
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8
Q

During all 3 interphase subphases…

A

A cell grows by producing proteins and cytoplasmic organelles such as mitochondria and endoplasmic reticulum

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9
Q

S phase

A

Duplication of the chromosomes

Continues to grow as it copies its chromosomes

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10
Q

G1 phase

A

Cell grows

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11
Q

G2 phase

A

Grows more as it completes preparations for cell division

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12
Q

Dividing phase

A

M

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13
Q

During interphase, the genetic material of a typical eukaryotic cell is

A

Dispersed in the nucleus as long strands of chromatin

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14
Q

Which of the following events does not occur during prophase of mitosis?
Nucleoli disappear
The centrosomes move away from each other
Each duplicated chromosome appears as two identical sister chromatids
The chromosomes condense
The mitotic spindle breaks down
The mitotic spindle forms

A

The mitotic spindle breaks down

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15
Q

How many chromatids does a human somatic cell contain after interphase and just prior to mitosis?

A

92

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16
Q

You would know a dividing cell was a plant cell rather than an animal cell if you saw

A

It had formed a cell plate

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17
Q

What occurs during metaphase of mitosis?

A

The chromosomes align along the metaphase plate of the cell

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18
Q

What is part of the mitotic spindle?

A

The aster
Nonkinetochore microtubules
Centrosome
Kinteochore microtubules

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19
Q

What happens during telophase of mitosis?

A

Two distinct daughter nuclei form in the cell

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20
Q

One event during prophase is

A

The beginning of the formation of a spindle apparatus

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21
Q

Which of the following phases of mitosis is essentially the opposite of prometaphase in terms of the nuclear envelope?

A

Telophase

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22
Q

How does the process of mitosis differ between most eukaryotes and other eukaryotes such as diatoms and dinoflagellates?

A

The nuclear envelope fragments in most eukaryotes that remains intact in diatoms and dinoflagellates

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23
Q

What happens during anaphase of mitosis?

A

The sister chromatids are pulled apart toward opposite sides of the cell

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24
Q

What is the difference between mitosis and binary fission?

A

Binary fission involves the replication and division of a single chromosome, whereas mitosis involves the division of multiple, replicated chromosomes

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25
Q

In animal cell mitosis, the cleavage furrow forms during which stage of the cell cycle?

A

Cytokinesis

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26
Q

During prophase

A

Chromatin condenses into distinct chromosomes
Nucleolus disappears
Mitotic spindle apparatus begins to form
Centrosomes move away from each other, propelled along the surface of the nucleus by the lengthening bundles of the microtubules between them

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27
Q

During prometaphase

A

Nuclear envelope fragments

Kinetochores attach to microtubules

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28
Q

During metaphase

A

Mitotic spindle aligns the chromosomes at the metaphase plate, a region along the equator of the cell

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29
Q

During anaphase

A

Centrioles are at opposite ends of the cell
The paired centromeres of each chromosome are separated by spindle microtubules
Sister chromatids begin moving towards opposite poles of the cell

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30
Q

During telophase

A

A new nuclear envelope begins to synthesize
Mitotic spindle breaks down
Chromatic uncoils
Cytokinesis begins

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31
Q

During binary fission in bacterium

A

The origins of replication move apart

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32
Q

The complex DNA and protein that makes up a eukaryotic chromosome if called

A

Chromatin

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33
Q

What occurs during anaphase?

A

Centrioles are at opposite poles
Identical chromatids move to opposite poles
Spindle made of microtubules is present
The centromeres divide

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34
Q

150 units of DNA to 300 units of DNA after G2 phase. How is this possible?

A

The DNA was replicated during the S phase of interphase, which occurs between the two G phases

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35
Q

Chromatids are

A

Identical copies of each other if they are part of the same chromosome

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36
Q

Cytokinesis refers to

A

Division of the cytoplasm

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37
Q

A cell has 40 chromatids at the beginning of mitosis. How many chromosomes will it contain at the completion of cytokinesis?

A

20

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38
Q

Observation of cancer cells in culture support the hypothesis that cancer cells

A

Do not exhibit density-dependent inhibition

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39
Q

The function of the mitotic cell cycle is to produce daughter cells that

A

Are genetically identical to the parent cell (assuming no mutation has occurred)

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40
Q

DNA replication occurs in

A

The S phase of interphase in both somatic and reproductive cells

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41
Q

What describes a cell that undergoes mitosis but not cytokinesis?

A

The cell contains more than one nucleus

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42
Q

G2 of Interphase

A

Chromosomes cannot be seen yet because they haven’t condensed
Two centrosomes have formed by duplication of the centrosome
Nuclear envelope encloses the nucleus
Nucleus contains one or more nucleoli (nucleolus)

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43
Q

Each centrosome has

A

Two centrioles

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44
Q

Prophase

A

Chromatin fibers become tightly coiled; can be seen
Nucleoli disappear
Each duplicated chromosome appears as two identical sister chromatids joined at their centromeres
Mitotic spindle begins to form
Centrosomes move away from each other, propelled by the lengthening microtubules between them

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45
Q

Mitotic spindle is made of

A

Centrosomes and microtubules that extend from them

The radial arrays of shorter microtubules that extend from the centrosomes are called asters

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46
Q

Prometaphase

A

Nuclear envelope fragments
Chromosomes have become even more condensed
Each of the two chromatids or each chromosome now has a kinetochore
Some of the microtubules attach to the kinetochores
Nonkinetochore microtubules interact with those from the opposite pole of the spindle

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47
Q

Metaphase

A

The centrosomes are now at opposite poles of the cell
Chromosomes have all arrived at the metaphase plate, a plane that is equidistant between the spindle’s two poles
The chromosomes’ centromeres lie at the metaphase plate
For each chromosome, the kinetochores of the sister chromatids are attached to kinetochore microtubules coming from opposite poles

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48
Q

Anaphase

A

Shortest stage of mitosis, lasts few minutes
Begins when the cohesion proteins are cleaved. This allows the two sister chromatids of each pair to part suddenly
Each chromatids becomes a chromosome
The two daughter chromosomes begin moving toward opposite ends of the cell as their kinetochore microtubules shorten
The cel elongated as the nonkinetochore microtubules lengthen
By the end, the two ends of the cel have equivalent and complete collections of chromosomes

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49
Q

Telophase

A 
Two daughter nuclei form in the cell
Nuclear envelopes arise from the fragments of the parent cell’s nuclear envelope and other portions of the endomembrane system
Nucleoli reappear
Chromosomes become less condensed
Mitotic spindle breaks down
Mitosis is now complete
50
Q

Mitosis

A

Division of one nucleus into two genetically identical nuclei

51
Q

Cytokinesis

A

Division of the cytoplasm is usually well under way by late telophase
Two daughter cells appear shortly after end of mitosis
In animal cells, cytokinesis involves the formation of a cleavage furrow — pinches the cell in two

52
Q

Genome

A

A cell’s endowment of DNA

Genetic information

53
Q

Meosis

A

Eukaryotic cell division

Sperm and eggs

54
Q

Prokaryotic genome is often

A

A single DNA molecule

55
Q

Eukaryotic genomes have

A

Numbers of DNA molecules

56
Q

Chromosomes

A

What DNA molecules are packed into

57
Q

Chromatin

A

Entire complex of DNA and proteins that is the building material in chromosomes

58
Q

Each eukaryotic species has

A

A different number of chromosomes in each cell’s nucleus

59
Q

Human somatic cells

A

Contain 46 chromosomes

60
Q

Gametes (reproductive cells)

A

Have one set or half as many chromosomes as somatic cells

23

61
Q

Each duplicated chromosome has

A

2 sister chromatids, which are joined copies of the original chromosomes

62
Q

When a cell isn’t dividing, and even when replicating, each chromosome is in the form of

A

A long thin chromatin fiber

After replication, they condense

63
Q

The two chromatids each contain

A

An identical DNA molecule

64
Q

Each sister chromatid has a

A

Centromere

A region of the chromosomal DNA where the chromatid is attached most closely to its sister chromatid

65
Q

Mitosis is

A

The division of the genetic material in the nucleus

66
Q

Meosis

A

Yields daughter cells with only one set of chromosomes, half as many chromosomes as the parent cell

67
Q

Interphase accounts for

A

90% of the cell cycle

68
Q

Some cells in multicellular organisms divide

A

Infrequently or not at all

Spend their time in G1

69
Q

5 stages of Mitosis

A 
Prophase
Prometaphase
Metaphase
Anaphase
Telophase
70
Q

Mitotic spindle

A

Many events of mitosis depend on
Forms in the cytoplasm during prophase
Assembles
In animal cells, assembly of the spindle microtubules starts at the centrosome

71
Q

Centrosome

A

Subcellular region containing material that functions throughout the cell cycle to organize the cell’s microtubules
A pair of centrioles are located at the center of the centrosome

72
Q

Aster

A

Radial area of short microtubules, extends from each centrosome

73
Q

No centrioles in

A

Plant cells

74
Q

Spindle includes the

A

Centrosomes
Spindle microtubules
Asters

75
Q

Kinetochore

A

A structure made up of proteins that have assembled on specific sections of DNA at each centromere

76
Q

Each of the two sister chromatids of a duplicated chromosome has a

A

Kinetochore

77
Q

At metaphase, the centromeres

A

Of all the duplicated chromosomes are on a plane midway between the spindle’s two poles
This plane is called the metaphase plate

78
Q

Metaphase plate

A

Imaginary plate

79
Q

At the end of anaphase

A

Duplicate groups of chromosomes are at opposite ends of the elongated parent cell

80
Q

Nonkinetochore microtubules are responsible for

A

Elongating the whole cell during anaphase

81
Q

Nuclei re-form during

A

Telophase

82
Q

Spindle dissembles by

A

Depolymerization of microtubules

83
Q

Cleavage

A

Cytokinesis occurs by this process

84
Q

First sign of cleavage is

A

The appearance of a cleavage furrow, a shallow groove in the cell surface near the old metaphase plate

85
Q

No cleavage furrow in

A

Plant cells

Instead, during telophase, vesicles move along microtubules to the middle of the cell, where they produce a cell plate

86
Q

The cell plate enlarges until

A

It’s surrounding membrane fuses with the plasma membrane along the perimeter of the cell
Two daughter cells result, each with its own plasma membrane
A cell wall arising from the contents of the cell plate has formed between the daughter cells

87
Q

Binary fission

A

Asexual reproduction of single-cells eukaryotes
No mitosis for prokaryotes
Mitosis for single-celled eukaryotes

88
Q

Origin of replication

A

Where the DNA of the bacterial chromosome begins to replicate at a specific place on the chromosome
Producing 2 origins

89
Q

As the chromosome continues to replicate in binary fission,

A

One origin moves rapidly toward the opposite end of the cell

90
Q

Mitosis evolved from

A

Simpler prokaryotic mechanisms of cell reproduction

91
Q

Cell cycle is controlled by

A

Specific signaling molecules

92
Q

Cell cycle control system

A

Cyclically operating set of molecules in the cell that both triggers and coordinates key events in the cell cycle
Direct the events

93
Q

Checkpoint

A

Control point in the cell cycle where stop and go ahead signals can regulate the cycle

94
Q

3 most important checkpoints found in

A

G1
G2
M (mitotic) phase

95
Q

For a kinase to be active

A

It must be attached to a cyclin

Because of this requirement, these kinases are called cyclin-dependent kinases (Cdks)

96
Q

Cyclin

A

Protein that gets its name from its cyclically fluctuating concentration in the cell

97
Q

Activity of CDKs rise and fall with changes

A

In the concentration of its cyclin partner

98
Q

MPF — Maturation Promoting Factor

A

M-phase promoting factor
Triggers the cell’s passage into the M phase, past the G2 checkpoint
Acts directly as kinase and indirectly by activating other kinases

99
Q

G1 checkpoint - “restriction point”

A

If cell receives go ahead signal at G1, it will usually complete G1, S,G2, and M phases and divide
It it doesn’t, it any exit the cycle, switching into a non dividing state called the G0 phase
Most cells in human body are in G0 phase

100
Q

Anaphase doesn’t being until

A

All chromosomes are properly attached to the spindle at the metaphase plate

101
Q

Growth factor

A

Protein released by certain cells that stimulates other cells to divide

102
Q

Density dependent inhibition

A

A phenomenon in which crowded cells stop dividing

103
Q

Anchorage dependence

A

To divide, they must be attached to a substratum

104
Q

Cancer cells do not

A

Heed the normal signals that regulate the cell cycle

105
Q

Cells in culture that acquire the ability to divide are aid to have undergone

A

Transformation, the process that causes them to behave like cancer cells

106
Q

Benign

A

Do not harm and do not metastize

107
Q

Malignant

A

Harm

Metastasize

108
Q

Mestastasis

A

Spread of cancer cells to locations distant from their original site

109
Q

Gametes are produced by

A

A variation of cell division — meiosis

110
Q

Mitotic spindle made of microtubules controls

A

Chromosome movement during mitosis

111
Q

Kinetochores are

A

Protein complexes associated with centromeres

112
Q

Since prokaryotes evolved before eukaryotes…

A

Mitosis probably evolved from binary fission

113
Q

Cancer cells have neither

A

Density dependent inhibition

Anchorage dependence

114
Q

Cancer cells…

A

Don’t respond normally to body’s control mechanisms
May not need growth factors to grow and divide
Make their own growth factor
Have an abnormal cell cycle control system
May convey a growth factor’s signal without the presence of the growth factor
Normal cell is converted to a cancerous cell by transformation

115
Q

If abnormal cells only remain at the original site, the lump is

A

Benign tumor

116
Q

Malignant tumors…

A

Invade surrounding tissues and metastasize, reporting cancer cells to other parts of the body

117
Q

Every chromosome has

A

A centromere

118
Q

When a cell in S phase is fused with a cell in G1

A

DNA synthesis beings immediately in the original G1 nucleus

119
Q

Tissue culture experiments with PDGF demonstrate that without this substance

A

Fibroblasts fail to divide

120
Q

What is a CDK? What does it do?

A

Cyclin dependent kinase
A kinase that has to be attached to a cyclin to be activated, it is dependent on cyclins
CDKs signal the cell that it is ready to pass into the next stage of the cell cycle

121
Q

Example of CDK

A

MPF
Maturation promotion factor
Triggers the cell’s passage into the M phase, past the G2 checkpoint

Biology (16 decks)

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