14: Mitosis Flashcards

Module 3, Lesson 3

1
Q

List the two main goals of cellular reproduction.

A
  1. Pass on genetic information to daughter cells
  2. Pass on enough cell components for the daughter cells to survive
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2
Q

Prokaryotes reproduce by…

A

Binary fission

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3
Q

List the three main steps of binary fission.

A
  1. Circular chromosome is replicated
  2. The cell elongates
  3. A septum forms at the midline and separates the cell
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4
Q

Which organelles in eukaryotes also reproduce by binary fission?

A

Mitochondria and chloroplasts

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5
Q

Eukaryotes reproduce by…

A

Mitosis and cytokinesis

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6
Q

Eukaryotic reproduction relies on temporary…

A

Cytoskeletal machines

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7
Q

____ is a form of nuclear division in which the cell’s genome is passed on to two daughter cells.

A

Mitosis

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8
Q

The ____ is a protein machine made from microtubules that is integral to mitosis.

A

Mitotic spindle

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9
Q

What is the function of the mitotic spindle?

A

Aligns and separates chromosomes into the daughter cells

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10
Q

The division of a cell’s cytoplasm is called…

A

Cytokinesis

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11
Q

True or false:

The process of mitosis is similar in all eukaryotic cells.

A

True

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12
Q

True or false:

The process of cytokinesis is similar in all eukaryotic cells.

A

False

The biggest differences are between animal and plant cells.

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13
Q

In animal cells, the cytoplasm is split using an actin-based structure called a…

A

Contractile ring

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14
Q

In plant cells, the cytoplasm is separated by the formation of a…

A

Cell plate

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15
Q

In eukaryotes, DNA is packaged into linear, discrete molecules called…

A

Chromosomes

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16
Q

True or false:

The number of chromsomes in an organism is correlated to the organism’s complexity.

A

False

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17
Q

Because a single chromosome can contain a large number of genes, gaining or losing a chromosome…

A

Is usually fatal to the cell

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18
Q

The array of chromosomes in a species or individual is called the…

A

Karyotype

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19
Q

A cell containing the complete set of chromosomes needed to define its species is called…

A

Haploid
(denoted n or 1n)

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20
Q

A cell that contains two complete sets of chromosomes is considered…

A

Diploid
(denoted 2n)

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21
Q

In humans, a haploid set is ____ chromsomes, and a diploid set is ____.

A

23 ; 46

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22
Q

True or false:

Most human cells are diploids.

A

True

a major exception being the gametes (egg and sperm cells)

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23
Q

The two copies of each chromosome in a diploid cell are called…

A

Homologues

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24
Q

Each chromosome in a pair is called a…

A

Homolog

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25
Q

Prior to replication, each homologous chromosome is made of…

A

A single DNA molecule

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26
Q

The “point of constriction” in a chromosome is called the…

A

Centromere

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27
Q

A complex of proteins that enables the chromosome to attach to the mitotic spindle is called the…

A

Kinetochore

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28
Q

After replication, each chromosome is made of 2 identical DNA molecules called…

A

Sister chromatids

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29
Q

Each sister chromatid has its own ____ and ____.

A

Centromere and kinetochore

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30
Q

Sister chromatids are held together by…

A

Cohesin proteins

(yes I spelled that right)

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31
Q

Eukaryotic chromosomes are made of a complex of DNA and protein called…

A

Chromatin

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32
Q

True or false:

Each chromosome is a single, continuous DNA molecule.

A

True

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33
Q

If the DNA from all chromosomes in a single human were stretched out, it would be ____ long.

A

6 feet

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34
Q

List the two main types of DNA (chromatin) found in the nucleus.

A
  1. Heterochromatin
  2. Euchromatin
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35
Q

The DNA in heterochromatin is…

A

Tightly packaged and cannot be expressed.

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36
Q

The DNA in euchromatin is…

A

Loosely packaged and able to be expressed

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37
Q

Genes are located in the…

A

Euchromatin

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38
Q

Proteins that interact with DNA to form chromatin are critical to…

A

DNA packaging

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39
Q

The first level of DNA packaging is the formation of the…

A

Nucleosome

40
Q

Histone proteins interact with DNA via…

A

Electrical interactions

41
Q

Histone proteins contain many positively-charged…

A

Amino acids

42
Q

During the first level of DNA packaging, DNA coils around the histone protein to make a…

A

Nucleosome

43
Q

A strand of nucleosomes is usually about ____ in diameter.

A

10 nm

44
Q

A strand of nucleosomes looks similar to…

A

“Beads on a string”

45
Q

During the second level of DNA packaging…

A

The 10 nm fiber condenses into a more compact 30 nm fiber.

46
Q

The second level of DNA packaging results in the formation of a…

A

Solenoid

47
Q

DNA in interphase nuclei is usually packaged into…

A

Solenoids

48
Q

The third level of DNA packaging results in the formation of a…

A

Mitotic chromosome

49
Q

During the third level of DNA packaging…

A

30 nm fibers condense about 10,000-fold to form an X-shaped mitotic chromosome.

50
Q

List the four phases of the eukaryotic cell cycle.

A
  1. G1 phase
  2. S phase
  3. G2 phase
  4. M phase
51
Q

G1 phase is the “primary growth phase”, during which…

A

The cell focuses on duplicating its contents

52
Q

S phase is the “DNA synthesis phase”, during which…

A

The cell replicates its DNA

53
Q

G2 phase is the “further growth phase”, during which…

A

The cell grows larger and begins preparing for M-phase

54
Q

M phase is the “nuclear and cytoplasmic division phase”, during which…

A

The cell completely rearranges its contents to execute the physical processes of mitosis

55
Q

After M phase is complete…

A

The cell has split into 2 daughter cells, each of which enters the G1 phase

56
Q

The G1, S, and G2 phases are collectively called…

A

Interphase

57
Q

During interphase…

A

The cell grows and carries out normal functions

58
Q

The vast majority of the time spent performing the cell cycle is spent in…

A

Interphase

59
Q

List the six stages of M-phase.

A
  1. Prophase
  2. Prometaphase
  3. Metaphase
  4. Anaphase
  5. Telophase
  6. Cytokinesis
60
Q

The most important process to occur during G2 is the…

A

Duplication of the centrosome

61
Q

What occurs during prophase?

(three)

A
  1. The bipolar mitotic spindle assembles
  2. The chromosomes condense
  3. The nuclear envelope is disassembled
62
Q

The disassembly of the nuclear envelope (NEBD) represents the transition from…

A

Prophase to prometaphase

63
Q

What occurs during prometaphase?

(three)

A
  1. The chromosomes are released into the cytosol
  2. The chromosomes attach to the spindle such that one chromatid interacts with each pole
  3. Chromosomes move to the equator (congress)
64
Q

The spindle’s equator is also called the…

A

Metaphase plate

65
Q

What occurs during metaphase?

A

The chromosomes align at the spindle’s equator

66
Q

What occurs during anaphase?

(four)

A
  1. The sister chromatids separate
  2. The connecting microtubules shorten
  3. The chromosomes move to their attached poles
  4. The poles move further from each other
67
Q

What happens during telophase?

(two)

A
  1. The chromosomes de-condense
  2. The nuclear envelope re-forms
68
Q

What occurs during cytokinesis?

A

The cell’s cytoplasm is split into two.

69
Q

In animal cells, the contractile activity of actin and myosin causes a ____ to form during cytokinesis.

A

Cleavage furrow

70
Q

What are the two irreversible points in the cell cycle?

A
  1. Replication of the genetic material
  2. Separation of the sister chromatids
71
Q

The cell cycle can be put on hold at various…

A

Checkpoints

72
Q

Checkpoints allow the cell to…

(two)

A
  1. Halt the cell cycle if problems are detected
  2. Respond to internal or external signals
73
Q

Internal signals usually relate to the…

A

Detection of problems

74
Q

External signals may either…

A

Stimulate or inhibit the cell cycle

75
Q

List the three major cell cycle checkpoints.

A
  1. G1/S checkpoint
  2. G2/M checkpoint
  3. Spindle checkpoint
76
Q

At the G1/S checkpoint, the cell decides whether to commit to S phase based on…

(three)

A
  1. Whether enough nutrients are available
  2. Whether the cell is large enough
  3. Whether growth factors are present (if necessary)
77
Q

In humans and other higher animals, growth factors are…

A

External signals that must be detected for the cell cycle to proceed to S phase.

78
Q

At the G2/M checkpoint, the cell decides whether to commit to M phase based on…

(two)

A
  1. Whether DNA replication is complete
  2. The extent of DNA damage
79
Q

The cell may pause the cell cycle at the G2/M checkpoint to…

A

Allow further replication or repair DNA damage

80
Q

At the spindle checkpoint, the cell decides whether to proceed to anaphase based on…

A

Whether the chromosomes are aligned on the metaphase plate

81
Q

What would happen if the cell began anaphase before all the chromosomes were aligned?

A

Chromosome disjunction would occur - one daughter cell would receive an extra chromosome and the other would be misisng one

82
Q

True or false:

Unlike unicellular eukaryotes, cells in multicellular eukaryotes generally do not reproduce until “told” to do so.

A

True

83
Q

To stimulate cell reproduction, a ____ is released by other cells and recognized by receptor proteins.

A

Growth factor signal

84
Q

Multicellular organisms depend on the ____ of cell numbers and the ____ of many different types of cells.

A

Maintenance ; organization

85
Q

Failure of cell cycle control in animal cells often leads to…

A

Cancer

86
Q

Cancer involves ____ and ____.

A

Uncontrolled cell proliferation and metastasis

87
Q

List the two types of genes that, when mutated, can harm cell cycle control.

A
  1. Proto-oncogenes
  2. Tumor-suppressor genes
88
Q

Normal genes that can become cancer-promoting oncogenes when mutated are called…

A

Proto-oncogenes

89
Q

Oncogenes stimulate cell cycle progression by becoming…

A

Overexpressed or stuck in the “on” state

90
Q

The formation of oncogenes is a ____ mutation.

A

Gain-of-function

91
Q

For an oncogene to form, ____ copy(ies) of the gene must be mutated.

A

One

92
Q

Normal genes that code for proteins that detect problems or stop the cell cycle in response to problems are called…

A

Tumor-suppressor genes

93
Q

When tumor-suppressor genes become ____ or ____, the cell loses a critical safety net.

A

Inactivated or deleted

94
Q

The mutation of tumor-suppressor genes is a ____ mutation.

A

Loss-of-function

95
Q

In order for tumor-suppressor genes to mutate, ____ copy(ies) of the gene must be mutated.

A

Both