14: Mitosis Flashcards
Module 3, Lesson 3 (95 cards)
1
Q
List the two main goals of cellular reproduction.
A
- Pass on genetic information to daughter cells
- Pass on enough cell components for the daughter cells to survive
2
Q
Prokaryotes reproduce by…
A
Binary fission
3
Q
List the three main steps of binary fission.
A
- Circular chromosome is replicated
- The cell elongates
- A septum forms at the midline and separates the cell
4
Q
Which organelles in eukaryotes also reproduce by binary fission?
A
Mitochondria and chloroplasts
5
Q
Eukaryotes reproduce by…
A
Mitosis and cytokinesis
6
Q
Eukaryotic reproduction relies on temporary…
A
Cytoskeletal machines
7
Q
____ is a form of nuclear division in which the cell’s genome is passed on to two daughter cells.
A
Mitosis
8
Q
The ____ is a protein machine made from microtubules that is integral to mitosis.
A
Mitotic spindle
9
Q
What is the function of the mitotic spindle?
A
Aligns and separates chromosomes into the daughter cells
10
Q
The division of a cell’s cytoplasm is called…
A
Cytokinesis
11
Q
True or false:
The process of mitosis is similar in all eukaryotic cells.
A
True
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.
13
Q
In animal cells, the cytoplasm is split using an actin-based structure called a…
A
Contractile ring
14
Q
In plant cells, the cytoplasm is separated by the formation of a…
A
Cell plate
15
Q
In eukaryotes, DNA is packaged into linear, discrete molecules called…
A
Chromosomes
16
Q
True or false:
The number of chromsomes in an organism is correlated to the organism’s complexity.
A
False
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
18
Q
The array of chromosomes in a species or individual is called the…
A
Karyotype
19
Q
A cell containing the complete set of chromosomes needed to define its species is called…
A
Haploid
(denoted n or 1n)
20
Q
A cell that contains two complete sets of chromosomes is considered…
A
Diploid
(denoted 2n)
21
Q
In humans, a haploid set is ____ chromsomes, and a diploid set is ____.
A
23 ; 46
22
Q
True or false:
Most human cells are diploids.
A
True
a major exception being the gametes (egg and sperm cells)
23
Q
The two copies of each chromosome in a diploid cell are called…
A
Homologues
24
Q
Each chromosome in a pair is called a…
A
Homolog
25
Prior to replication, each homologous chromosome is made of...
A single DNA molecule
26
The "point of constriction" in a chromosome is called the...
Centromere
27
A complex of proteins that enables the chromosome to attach to the mitotic spindle is called the...
Kinetochore
28
After replication, each chromosome is made of 2 identical DNA molecules called...
Sister chromatids
29
Each sister chromatid has its own ____ and ____.
Centromere and kinetochore
30
Sister chromatids are held together by...
Cohesin proteins
## Footnote
(yes I spelled that right)
31
Eukaryotic chromosomes are made of a complex of DNA and protein called...
Chromatin
32
# True or false:
Each chromosome is a single, continuous DNA molecule.
True
33
If the DNA from all chromosomes in a single human were stretched out, it would be ____ long.
6 feet
34
List the two main types of DNA (chromatin) found in the nucleus.
1. Heterochromatin
2. Euchromatin
35
The DNA in heterochromatin is...
Tightly packaged and cannot be expressed.
36
The DNA in euchromatin is...
Loosely packaged and able to be expressed
37
Genes are located in the...
Euchromatin
38
Proteins that interact with DNA to form chromatin are critical to...
DNA packaging
39
The first level of DNA packaging is the formation of the...
Nucleosome
40
Histone proteins interact with DNA via...
Electrical interactions
41
Histone proteins contain many positively-charged...
Amino acids
42
During the first level of DNA packaging, DNA coils around the histone protein to make a...
Nucleosome
43
A strand of nucleosomes is usually about ____ in diameter.
10 nm
44
A strand of nucleosomes looks similar to...
"Beads on a string"
45
During the second level of DNA packaging...
The 10 nm fiber condenses into a more compact 30 nm fiber.
46
The second level of DNA packaging results in the formation of a...
Solenoid
47
DNA in interphase nuclei is usually packaged into...
Solenoids
48
The third level of DNA packaging results in the formation of a...
Mitotic chromosome
49
During the third level of DNA packaging...
30 nm fibers condense about 10,000-fold to form an X-shaped mitotic chromosome.
50
List the four phases of the eukaryotic cell cycle.
1. G1 phase
2. S phase
3. G2 phase
4. M phase
51
G1 phase is the "primary growth phase", during which...
The cell focuses on duplicating its contents
52
S phase is the "DNA synthesis phase", during which...
The cell replicates its DNA
53
G2 phase is the "further growth phase", during which...
The cell grows larger and begins preparing for M-phase
54
M phase is the "nuclear and cytoplasmic division phase", during which...
The cell completely rearranges its contents to execute the physical processes of mitosis
55
After M phase is complete...
The cell has split into 2 daughter cells, each of which enters the G1 phase
56
The G1, S, and G2 phases are collectively called...
Interphase
57
During interphase...
The cell grows and carries out normal functions
58
The vast majority of the time spent performing the cell cycle is spent in...
Interphase
59
List the six stages of M-phase.
1. Prophase
2. Prometaphase
3. Metaphase
4. Anaphase
5. Telophase
6. Cytokinesis
60
The most important process to occur during G2 is the...
Duplication of the centrosome
61
What occurs during prophase?
| (three)
1. The bipolar mitotic spindle assembles
2. The chromosomes condense
3. The nuclear envelope is disassembled
62
The disassembly of the nuclear envelope (NEBD) represents the transition from...
Prophase to prometaphase
63
What occurs during prometaphase?
| (three)
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
The spindle's equator is also called the...
Metaphase plate
65
What occurs during metaphase?
The chromosomes align at the spindle's equator
66
What occurs during anaphase?
| (four)
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
What happens during telophase?
| (two)
1. The chromosomes de-condense
2. The nuclear envelope re-forms
68
What occurs during cytokinesis?
The cell's cytoplasm is split into two.
69
In animal cells, the contractile activity of actin and myosin causes a ____ to form during cytokinesis.
Cleavage furrow
70
What are the two irreversible points in the cell cycle?
1. Replication of the genetic material
2. Separation of the sister chromatids
71
The cell cycle can be put on hold at various...
Checkpoints
72
Checkpoints allow the cell to...
| (two)
1. Halt the cell cycle if problems are detected
2. Respond to internal or external signals
73
Internal signals usually relate to the...
Detection of problems
74
External signals may either...
Stimulate or inhibit the cell cycle
75
List the three major cell cycle checkpoints.
1. G1/S checkpoint
2. G2/M checkpoint
3. Spindle checkpoint
76
At the G1/S checkpoint, the cell decides whether to commit to S phase based on...
| (three)
1. Whether enough nutrients are available
2. Whether the cell is large enough
3. Whether growth factors are present (if necessary)
77
In humans and other higher animals, growth factors are...
External signals that must be detected for the cell cycle to proceed to S phase.
78
At the G2/M checkpoint, the cell decides whether to commit to M phase based on...
| (two)
1. Whether DNA replication is complete
2. The extent of DNA damage
79
The cell may pause the cell cycle at the G2/M checkpoint to...
Allow further replication or repair DNA damage
80
At the spindle checkpoint, the cell decides whether to proceed to anaphase based on...
Whether the chromosomes are aligned on the metaphase plate
81
What would happen if the cell began anaphase before all the chromosomes were aligned?
Chromosome disjunction would occur - one daughter cell would receive an extra chromosome and the other would be misisng one
82
# True or false:
Unlike unicellular eukaryotes, cells in multicellular eukaryotes generally do not reproduce until "told" to do so.
True
83
To stimulate cell reproduction, a ____ is released by other cells and recognized by receptor proteins.
Growth factor signal
84
Multicellular organisms depend on the ____ of cell numbers and the ____ of many different types of cells.
Maintenance ; organization
85
Failure of cell cycle control in animal cells often leads to...
Cancer
86
Cancer involves ____ and ____.
Uncontrolled cell proliferation and metastasis
87
List the two types of genes that, when mutated, can harm cell cycle control.
1. Proto-oncogenes
2. Tumor-suppressor genes
88
Normal genes that can become cancer-promoting oncogenes when mutated are called...
Proto-oncogenes
89
Oncogenes stimulate cell cycle progression by becoming...
Overexpressed or stuck in the "on" state
90
The formation of oncogenes is a ____ mutation.
Gain-of-function
91
For an oncogene to form, ____ copy(ies) of the gene must be mutated.
One
92
Normal genes that code for proteins that detect problems or stop the cell cycle in response to problems are called...
Tumor-suppressor genes
93
When tumor-suppressor genes become ____ or ____, the cell loses a critical safety net.
Inactivated or deleted
94
The mutation of tumor-suppressor genes is a ____ mutation.
Loss-of-function
95
In order for tumor-suppressor genes to mutate, ____ copy(ies) of the gene must be mutated.
Both
