3.7: Mitosis Flashcards
1
Q
Cell division can take place either by what?
A
Cell division can take place either by:
- Mitosis
Or,
- Meiosis
2
Q
Cell division can take place either by mitosis or meiosis.
What does mitosis produce?
A
Mitosis produces 2 daughter cells
3
Q
Cell division can take place either by mitosis or meiosis.
Mitosis produces 2 daughter cells that have what?
A
Mitosis produces 2 daughter cells that have the same number of chromosomes as:
- Each other
- The parent cell
4
Q
Cell division can take place either by mitosis or meiosis.
Meiosis produces what?
A
Meiosis produces 4 daughter cells
5
Q
Cell division can take place either by mitosis or meiosis.
Meiosis produces 4 daughter cells, each with what?
A
Meiosis produces 4 daughter cells, each with half the number of chromosomes of the parent cell
6
Q
Mitosis
A
Mitosis is division of a cell that results in each of the daughter cells having an exact copy of the DNA of the parent cell
7
Q
Mitosis:
Mitosis is division of a cell that results in each of the daughter cells having an exact copy of the DNA of the parent cell.
Except in the rare event of what, the genetic make-up of the 2 daughter nuclei is also identical to what?
A
Except in the rare event of a mutation, the genetic make-up of the 2 daughter nuclei is also identical to that of the parent nucleus
8
Q
Mitosis:
Mitosis is division of a cell that results in each of the daughter cells having an exact copy of the DNA of the parent cell.
Except in the rare event of a mutation, the genetic make-up of the 2 daughter nuclei is also identical to that of the parent nucleus.
Mitosis is always preceded by what?
A
Mitosis is always preceded by a period during which the cell is not dividing
9
Q
Mitosis:
Mitosis is division of a cell that results in each of the daughter cells having an exact copy of the DNA of the parent cell.
Except in the rare event of a mutation, the genetic make-up of the 2 daughter nuclei is also identical to that of the parent nucleus.
Mitosis is always preceded by a period during which the cell is not dividing.
This period is called what?
A
This period is called interphase
10
Q
Interphase
A
Interphase is a period of considerable cellular activity
11
Q
Interphase:
Interphase is a period of considerable cellular activity that includes what?
A
Interphase is a period of considerable cellular activity that includes a very important event
12
Q
Interphase:
Interphase is a period of considerable cellular activity that includes a very important event, what?
A
Interphase is a period of considerable cellular activity that includes a very important event, the replication of DNA
13
Q
Mitosis:
Mitosis is division of a cell that results in each of the daughter cells having an exact copy of the DNA of the parent cell.
Except in the rare event of a mutation, the genetic make-up of the 2 daughter nuclei is also identical to that of the parent nucleus.
Mitosis is always preceded by a period during which the cell is not dividing.
This period is called interphase.
Interphase is a period of considerable cellular activity that includes a very important event, the replication of DNA.
The how many copies of DNA after replication remain how?
A
The 2 copies of DNA after replication remain joined at a place called the centromere
14
Q
Mitosis:
Mitosis is division of a cell that results in each of the daughter cells having an exact copy of the DNA of the parent cell.
Except in the rare event of a mutation, the genetic make-up of the 2 daughter nuclei is also identical to that of the parent nucleus.
Mitosis is always preceded by a period during which the cell is not dividing.
This period is called interphase.
Interphase is a period of considerable cellular activity that includes a very important event, the replication of DNA.
The 2 copies of DNA after replication remain joined at a place called the centromere.
Although mitosis is a what process, it can be divided into how many stages for convenience?
A
Although mitosis is a continuous process, it can be divided into 4 stages for convenience:
- Prophase (early and late)
- Metaphase
- Anaphase
- Telophase and cytokinesis
15
Q
Early prophase:
In early prophase, what first become visible?
A
In early prophase, the chromosomes first become visible
16
Q
Early prophase:
In early prophase, the chromosomes first become visible, initially as what?
A
In early prophase, the chromosomes first become visible, initially as:
- Long
- Thin
threads
17
Q
Early prophase:
In early prophase, the chromosomes first become visible, initially as long, thin threads.
Animal cells contain what?
A
Animal cells contain 2 cylindrical organelles called centrioles
18
Q
Early prophase:
In early prophase, the chromosomes first become visible, initially as long, thin threads.
Animal cells contain 2 cylindrical organelles called centrioles, each of which do what?
A
Animal cells contain 2 cylindrical organelles called centrioles, each of which move to opposite ends (poles) of the cell
19
Q
Early prophase:
In early prophase, the chromosomes first become visible, initially as long, thin threads.
Animal cells contain 2 cylindrical organelles called centrioles, each of which move to opposite ends (poles) of the cell.
From each of the centrioles, what happens?
A
From each of the centrioles, spindle fibres develop
20
Q
Early prophase:
In early prophase, the chromosomes first become visible, initially as long, thin threads.
Animal cells contain 2 cylindrical organelles called centrioles, each of which move to opposite ends (poles) of the cell.
From each of the centrioles, spindle fibres develop, which span how long?
A
From each of the centrioles, spindle fibres develop, which span the cell from pole to pole
21
Q
Early prophase:
In early prophase, the chromosomes first become visible, initially as long, thin threads.
Animal cells contain 2 cylindrical organelles called centrioles, each of which move to opposite ends (poles) of the cell.
From each of the centrioles, spindle fibres develop, which span the cell from pole to pole.
Collectively, these spindle fibres are called what?
A
Collectively, these spindle fibres are called the spindle apparatus
22
Q
Early prophase:
In early prophase, the chromosomes first become visible, initially as long, thin threads.
Animal cells contain 2 cylindrical organelles called centrioles, each of which move to opposite ends (poles) of the cell.
From each of the centrioles, spindle fibres develop, which span the cell from pole to pole.
Collectively, these spindle fibres are called the spindle apparatus.
Plant cells lack centrioles, but do develop what?
A
Plant cells lack centrioles, but do develop a spindle apparatus
23
Q
Early prophase:
In early prophase, the chromosomes first become visible, initially as long, thin threads.
Animal cells contain 2 cylindrical organelles called centrioles, each of which move to opposite ends (poles) of the cell.
From each of the centrioles, spindle fibres develop, which span the cell from pole to pole.
Collectively, these spindle fibres are called the spindle apparatus.
Because plant cells lack centrioles, but do develop a spindle apparatus, centrioles are clearly not essential to what?
A
Because plant cells lack centrioles, but do develop a spindle apparatus, centrioles are clearly not essential to spindle fibre formation
24
Q
Late prophase:
In late prophase, what disappears?
A
In late prophase, the nucleolus disappears
25
Late prophase:
In late prophase, the nucleolus disappears and what breaks down?
In late prophase, the:
1. Nucleolus disappears
2. Nuclear envelope breaks down
26
Late prophase:
In late prophase, the nucleolus disappears and the nuclear envelope breaks down, leaving what?
The:
1. Nucleolus disappears
2. Nuclear envelope breaks down
,leaving the chromosomes free in the cytoplasm of the cell
27
Late prophase:
In late prophase, the nucleolus disappears and the nuclear envelope breaks down, leaving the chromosomes free in the cytoplasm of the cell.
These chromosomes are what?
These chromosomes are drawn towards the equator of the cell
28
Late prophase:
In late prophase, the nucleolus disappears and the nuclear envelope breaks down, leaving the chromosomes free in the cytoplasm of the cell.
These chromosomes are drawn towards the equator of the cell by what?
These chromosomes are drawn towards the equator of the cell by the spindle fibres attached to the centromere
29
Metaphase:
By metaphase, the chromosomes are seen to be what?
By metaphase, the chromosomes are seen to be made up of 2 chromatids
30
Metaphase:
By metaphase, the chromosomes are seen to be made up of 2 chromatids.
What is each chromatid?
Each chromatid is an identical copy of DNA from the parent cell
31
Metaphase:
By metaphase, the chromosomes are seen to be made up of 2 chromatids.
Each chromatid is an identical copy of DNA from the parent cell.
The chromatids are what?
The chromatids are joined by the centromere
32
Metaphase:
By metaphase, the chromosomes are seen to be made up of 2 chromatids.
Each chromatid is an identical copy of DNA from the parent cell.
The chromatids are joined by the centromere.
It is to this centromere that what?
It is to this centromere that some microtubules from the poles are attached
33
Metaphase:
By metaphase, the chromosomes are seen to be made up of 2 chromatids.
Each chromatid is an identical copy of DNA from the parent cell.
The chromatids are joined by the centromere.
It is to this centromere that some microtubules from the poles are attached and the chromosomes are what?
It is to this centromere that some microtubules from the poles are attached and the chromosomes are pulled along the spindle apparatus
34
Metaphase:
By metaphase, the chromosomes are seen to be made up of 2 chromatids.
Each chromatid is an identical copy of DNA from the parent cell.
The chromatids are joined by the centromere.
It is to this centromere that some microtubules from the poles are attached and the chromosomes are pulled along the spindle apparatus and do what?
It is to this centromere that some microtubules from the poles are attached and the chromosomes:
1. Are pulled along the spindle apparatus
2. Arrange themselves across the equator of the cell
35
Anaphase:
In anaphase, what divide into 2?
In anaphase, the centromeres divide into 2
36
Anaphase:
In anaphase, the centromeres divide into 2 and the spindle fibres do what?
In anaphase, the:
1. Centromeres divide into 2
2. Spindle fibres pull the individual chromatids making up the chromosome apart
37
Anaphase:
In anaphase, the centromeres divide into 2 and the spindle fibres pull the individual chromatids making up the chromosome apart.
What do the chromatids (daughter chromosomes) do?
The chromatids (daughter chromosomes) move rapidly to their respective, opposite poles of the cell
38
Anaphase:
In anaphase, the centromeres divide into 2 and the spindle fibres pull the individual chromatids making up the chromosome apart.
The chromatids (daughter chromosomes) move rapidly to their respective, opposite poles of the cell and we now refer to them as what?
The chromatids (daughter chromosomes) move rapidly to their respective, opposite poles of the cell and we now refer to them as chromosomes
39
Anaphase:
In anaphase, the centromeres divide into 2 and the spindle fibres pull the individual chromatids making up the chromosome apart.
The chromatids (daughter chromosomes) move rapidly to their respective, opposite poles of the cell and we now refer to them as chromosomes.
The energy for the process is provided by what?
The energy for the process is provided by mitochondria
40
Anaphase:
In anaphase, the centromeres divide into 2 and the spindle fibres pull the individual chromatids making up the chromosome apart.
The chromatids (daughter chromosomes) move rapidly to their respective, opposite poles of the cell and we now refer to them as chromosomes.
The energy for the process is provided by mitochondria, which gather around where?
The energy for the process is provided by mitochondria, which gather around the spindle fibres
41
Anaphase:
In anaphase, the centromeres divide into 2 and the spindle fibres pull the individual chromatids making up the chromosome apart.
The chromatids (daughter chromosomes) move rapidly to their respective, opposite poles of the cell and we now refer to them as chromosomes.
The energy for the process is provided by mitochondria, which gather around the spindle fibres.
If cells are treated with what, the chromosomes remain where?
If cells are treated with chemicals that destroy the spindle, the chromosomes remain at the equator
42
Anaphase:
In anaphase, the centromeres divide into 2 and the spindle fibres pull the individual chromatids making up the chromosome apart.
The chromatids (daughter chromosomes) move rapidly to their respective, opposite poles of the cell and we now refer to them as chromosomes.
The energy for the process is provided by mitochondria, which gather around the spindle fibres.
If cells are treated with chemicals that destroy the spindle, the chromosomes remain at the equator, unable to do what?
If cells are treated with chemicals that destroy the spindle, the chromosomes remain at the equator, unable to reach the poles
43
Telophase and cytokinesis:
In telophase, the chromosomes reach where?
In telophase, the chromosomes reach their respective poles
44
Telophase and cytokinesis:
In telophase, the chromosomes reach their respective poles and they begin to uncoil and become less distinct.
They become what?
The chromosomes become:
1. Longer
2. Thinner
45
Telophase and cytokinesis:
In telophase, the chromosomes reach their respective poles and they begin to uncoil and become less distinct.
They become longer and thinner, finally doing what?
The chromosomes become:
1. Longer
2. Thinner
,finally disappearing altogether
46
Telophase and cytokinesis:
In telophase, the chromosomes reach their respective poles and they begin to uncoil and become less distinct.
They become longer and thinner, finally disappearing altogether, leaving what?
The chromosomes become:
1. Longer
2. Thinner
,finally disappearing altogether, leaving only widely spread chromatin
47
Telophase and cytokinesis:
In telophase, the chromosomes reach their respective poles and they begin to uncoil and become less distinct.
They become longer and thinner, finally disappearing altogether, leaving only widely spread chromatin.
What do the spindle fibres do?
The spindle fibres disintegrate
48
Telophase and cytokinesis:
In telophase, the chromosomes reach their respective poles and they begin to uncoil and become less distinct.
They become longer and thinner, finally disappearing altogether, leaving only widely spread chromatin.
The spindle fibres disintegrate and what re-form?
The spindle fibres disintegrate and the:
1. Nuclear envelope
2. Nucleolus
re-form
49
Telophase and cytokinesis:
In telophase, the chromosomes reach their respective poles and they begin to uncoil and become less distinct.
They become longer and thinner, finally disappearing altogether, leaving only widely spread chromatin.
The spindle fibres disintegrate and the nuclear envelope and the nucleolus re-form.
Finally, what divides in a process called what?
Finally, the cytoplasm divides in a process called cytokinesis
50
The stages of mitosis in an animal cell:
In interphase, the cell is actively doing what?
In interphase, the cell is actively synthesizing proteins
51
The stages of mitosis in an animal cell:
In interphase, the cell is actively synthesizing proteins.
Chromosomes are what?
Chromosomes are invisible
52
The stages of mitosis in an animal cell:
In interphase, the cell is actively synthesizing proteins.
Chromosomes are invisible.
Prior to mitosis, what happens?
Prior to mitosis, DNA replicates
53
The stages of mitosis in an animal cell:
In prophase, what become visible?
In prophase, the chromosomes become visible
54
The stages of mitosis in an animal cell:
In metaphase, what forms?
In metaphase, spindle forms
55
The stages of mitosis in an animal cell:
In metaphase, spindle forms.
Chromosomes line up where?
Chromosomes line up on the centre of the cell
56
The stages of mitosis in an animal cell:
In anaphase, what contract?
In anaphase, spindle fibres attached to chromatids contract
57
The stages of mitosis in an animal cell:
In anaphase, spindle fibres attached to chromatids contract.
What are pulled towards poles?
Chromatids are pulled towards poles
58
The stages of mitosis in an animal cell:
In telophase, chromosomes reach poles and become what?
In telophase, chromosomes:
1. Reach poles
2. Become indistinct
59
Cell division in prokaryotic cells takes place by what?
Cell division in prokaryotic cells takes place by a process called binary fission
60
Cell division in prokaryotic cells takes place by a process called binary fission.
Binary fission:
1. What replicates?
The circular DNA molecule replicates
61
Cell division in prokaryotic cells takes place by a process called binary fission.
Binary fission:
1. The circular DNA molecule replicates and both copies do what?
The circular DNA molecule replicates and both copies attach to the cell membrane
62
Cell division in prokaryotic cells takes place by a process called binary fission.
Binary fission:
1. The circular DNA molecule replicates and both copies attach to the cell membrane.
2. What also replicate?
The plasmids also replicate
63
Cell division in prokaryotic cells takes place by a process called binary fission.
Binary fission:
1. The circular DNA molecule replicates and both copies attach to the cell membrane.
2. The plasmids also replicate.
3. What begins to grow?
The cell membrane begins to grow
64
Cell division in prokaryotic cells takes place by a process called binary fission.
Binary fission:
1. The circular DNA molecule replicates and both copies attach to the cell membrane.
2. The plasmids also replicate.
3. The cell membrane begins to grow between where?
The cell membrane begins to grow between the 2 DNA molecules
65
Cell division in prokaryotic cells takes place by a process called binary fission.
Binary fission:
1. The circular DNA molecule replicates and both copies attach to the cell membrane.
2. The plasmids also replicate.
3. The cell membrane begins to grow between the 2 DNA molecules and begins to do what?
The cell membrane begins to:
1. Grow between the 2 DNA molecules
2. Pinch inward
66
Cell division in prokaryotic cells takes place by a process called binary fission.
Binary fission:
1. The circular DNA molecule replicates and both copies attach to the cell membrane.
2. The plasmids also replicate.
3. The cell membrane begins to grow between the 2 DNA molecules and begins to pinch inward, doing what?
The cell membrane begins to:
1. Grow between the 2 DNA molecules
2. Pinch inward
,dividing the cytoplasm into 2
67
Cell division in prokaryotic cells takes place by a process called binary fission.
Binary fission:
1. The circular DNA molecule replicates and both copies attach to the cell membrane.
2. The plasmids also replicate.
3. The cell membrane begins to grow between the 2 DNA molecules and begins to pinch inward, dividing the cytoplasm into 2.
4. What forms between the 2 molecules of DNA?
A new cell wall forms between the 2 molecules of DNA
68
Cell division in prokaryotic cells takes place by a process called binary fission.
Binary fission:
1. The circular DNA molecule replicates and both copies attach to the cell membrane.
2. The plasmids also replicate.
3. The cell membrane begins to grow between the 2 DNA molecules and begins to pinch inward, dividing the cytoplasm into 2.
4. A new cell wall forms between the 2 molecules of DNA, doing what?
A new cell wall forms between the 2 molecules of DNA, dividing the original cell into 2 identical daughter cells
69
Cell division in prokaryotic cells takes place by a process called binary fission.
Binary fission:
1. The circular DNA molecule replicates and both copies attach to the cell membrane.
2. The plasmids also replicate.
3. The cell membrane begins to grow between the 2 DNA molecules and begins to pinch inward, dividing the cytoplasm into 2.
4. A new cell wall forms between the 2 molecules of DNA, dividing the original cell into 2 identical daughter cells, each with what?
A new cell wall forms between the 2 molecules of DNA, dividing the original cell into 2 identical daughter cells, each with a:
1. Single copy of the circular DNA
2. Variable number of copies of the plasmids
70
Replication of viruses:
Viruses are what?
Viruses are non-living
71
Replication of viruses:
Because viruses are non-living, they cannot undergo what?
Because viruses are non-living, they cannot undergo cell division
72
Replication of viruses:
Because viruses are non-living, they cannot undergo cell division.
Instead, they replicate by doing what?
Instead, viruses replicate by attaching to their host cell
73
Replication of viruses:
Because viruses are non-living, they cannot undergo cell division.
Instead, viruses replicate by attaching to their host cell with what?
Instead, viruses replicate by attaching to their host cell with the attachment proteins on their surface
74
Replication of viruses:
Because viruses are non-living, they cannot undergo cell division.
Instead, viruses replicate by attaching to their host cell with the attachment proteins on their surface.
They then do what?
Viruses then inject their nucleic acid into the host cell
75
Replication of viruses:
Because viruses are non-living, they cannot undergo cell division.
Instead, viruses replicate by attaching to their host cell with the attachment proteins on their surface.
Viruses then inject their nucleic acid into the host cell.
The genetic information on the what then provides what?
The genetic information on the injected viral nucleic acid then provides the 'instructions' for the host cell's metabolic processes
76
Replication of viruses:
Because viruses are non-living, they cannot undergo cell division.
Instead, viruses replicate by attaching to their host cell with the attachment proteins on their surface.
Viruses then inject their nucleic acid into the host cell.
The genetic information on the injected viral nucleic acid then provides the 'instructions' for the host cell's metabolic processes to do what?
The genetic information on the injected viral nucleic acid then provides the 'instructions' for the host cell's metabolic processes to start producing the:
1. Viral components
2. Nucleic acid
3. Enzymes
4. Structural proteins
77
Replication of viruses:
Because viruses are non-living, they cannot undergo cell division.
Instead, viruses replicate by attaching to their host cell with the attachment proteins on their surface.
Viruses then inject their nucleic acid into the host cell.
The genetic information on the injected viral nucleic acid then provides the 'instructions' for the host cell's metabolic processes to start producing the viral components, nucleic acid, enzymes and structural proteins that are then what?
The genetic information on the injected viral nucleic acid then provides the 'instructions' for the host cell's metabolic processes to start producing the:
1. Viral components
2. Nucleic acid
3. Enzymes
4. Structural proteins
that are then assembled into new viruses
78
The importance of mitosis:
Mitosis is important in organisms, because it produces daughter cells that are what to the parent cells?
Mitosis is important in organisms, because it produces daughter cells that are genetically identical to the parent cells
79
The importance of mitosis:
Mitosis is important in organisms, because it produces daughter cells that are genetically identical to the parent cells.
Why is it essential to make exact copies of existing cells?
There are 3 reasons, what?
There are 3 reasons:
1. Growth
2. Repair
3. Reproduction
80
The importance of mitosis:
Mitosis is important in organisms, because it produces daughter cells that are genetically identical to the parent cells.
Why is it essential to make exact copies of existing cells?
There are 3 reasons - Growth, repair and reproduction.
1. Growth:
When 2 haploid cells (for example what) fuse together to form what?
When 2 haploid cells (for example:
1. A sperm
2. An ovum)
fuse together to form a diploid cell
81
The importance of mitosis:
Mitosis is important in organisms, because it produces daughter cells that are genetically identical to the parent cells.
Why is it essential to make exact copies of existing cells?
There are 3 reasons - Growth, repair and reproduction.
1. Growth:
When 2 haploid cells (for example a sperm and an ovum) fuse together to form a diploid cell, it has all the what needed to form the new organism?
When 2 haploid cells (for example a sperm and an ovum) fuse together to form a diploid cell, it has all the genetic information needed to form the new organism
82
The importance of mitosis:
Mitosis is important in organisms, because it produces daughter cells that are genetically identical to the parent cells.
Why is it essential to make exact copies of existing cells?
There are 3 reasons - Growth, repair and reproduction.
1. Growth:
When 2 haploid cells (for example a sperm and an ovum) fuse together to form a diploid cell, it has all the genetic information needed to form the new organism.
If the new organism is to resemble its parents, all the cells that grow from this original cell must be what?
If the new organism is to resemble its parents, all the cells that grow from this original cell must be genetically identical
83
The importance of mitosis:
Mitosis is important in organisms, because it produces daughter cells that are genetically identical to the parent cells.
Why is it essential to make exact copies of existing cells?
There are 3 reasons - Growth, repair and reproduction.
1. Growth:
When 2 haploid cells (for example a sperm and an ovum) fuse together to form a diploid cell, it has all the genetic information needed to form the new organism.
If the new organism is to resemble its parents, all the cells that grow from this original cell must be genetically identical.
Mitosis ensures what?
Mitosis ensures that this happens
84
The importance of mitosis:
Mitosis is important in organisms, because it produces daughter cells that are genetically identical to the parent cells.
Why is it essential to make exact copies of existing cells?
There are 3 reasons - Growth, repair and reproduction.
2. Repair:
If cells are damaged or do what, it is important that new cells produced have what?
If cells are damaged or die, it is important that new cells produced have an identical:
1. Structure
2. Function
to the ones that have been lost
85
The importance of mitosis:
Mitosis is important in organisms, because it produces daughter cells that are genetically identical to the parent cells.
Why is it essential to make exact copies of existing cells?
There are 3 reasons - Growth, repair and reproduction.
3. Reproduction:
What organisms divide by mitosis to give what?
Single-celled organisms divide by mitosis to give 2 new organisms
86
The importance of mitosis:
Mitosis is important in organisms, because it produces daughter cells that are genetically identical to the parent cells.
Why is it essential to make exact copies of existing cells?
There are 3 reasons - Growth, repair and reproduction.
3. Reproduction:
Single-celled organisms divide by mitosis to give 2 new organisms.
Each new organism is what to the parent organism?
Each new organism is genetically identical to the parent organism
87
Metaphase:
By metaphase, the chromosomes are seen to be made up of 2 chromatids.
Each chromatid is an identical copy of DNA from the parent cell.
The chromatids are joined by the centromere.
It is to this centromere that some microtubules from the poles are attached and the chromosomes are pulled along the spindle apparatus and arrange themselves across the equator of the cell.
The chromosomes align where?
The chromosomes align in the middle of the nucleus
88
Metaphase:
By metaphase, the chromosomes are seen to be made up of 2 chromatids.
Each chromatid is an identical copy of DNA from the parent cell.
The chromatids are joined by the centromere.
It is to this centromere that some microtubules from the poles are attached and the chromosomes are pulled along the spindle apparatus and arrange themselves across the equator of the cell.
The chromosomes align in the middle of the nucleus.
Spindle fibres attach to what?
Spindle fibres attach to the centromere of the chromosomes
89
Metaphase:
By metaphase, the chromosomes are seen to be made up of 2 chromatids.
Each chromatid is an identical copy of DNA from the parent cell.
The chromatids are joined by the centromere.
It is to this centromere that some microtubules from the poles are attached and the chromosomes are pulled along the spindle apparatus and arrange themselves across the equator of the cell.
The chromosomes align in the middle of the nucleus.
Spindle fibres attach to the centromere of the chromosomes and each centromere is what?
Spindle fibres attach to the centromere of the chromosomes and each centromere is attached to both poles
90
Metaphase:
By metaphase, the chromosomes are seen to be made up of 2 chromatids.
Each chromatid is an identical copy of DNA from the parent cell.
The chromatids are joined by the centromere.
It is to this centromere that some microtubules from the poles are attached and the chromosomes are pulled along the spindle apparatus and arrange themselves across the equator of the cell.
The chromosomes align in the middle of the nucleus.
Spindle fibres attach to the centromere of the chromosomes and each centromere is attached to both poles.
The chromosomes are pulled to what?
The chromosomes are pulled to the poles
91
Anaphase:
In anaphase, the centromeres divide into 2 and the spindle fibres pull the individual chromatids making up the chromosome apart.
The chromatids (daughter chromosomes) move rapidly to their respective, opposite poles of the cell and we now refer to them as chromosomes.
The energy for the process is provided by mitochondria, which gather around the spindle fibres.
If cells are treated with chemicals that destroy the spindle, the chromosomes remain at the equator, unable to reach the poles.
Each half of the cell receives what?
Each half of the cell receives one chromatid from each chromosome
92
Telophase and cytokinesis:
In telophase, the chromosomes reach their respective poles and they begin to do what and become what?
In this stage, the chromosomes reach their respective poles and they:
1. Begin to uncoil
2. Become less distinct
93
Cytokinesis:
In cytokinesis, what does the cell do?
In cytokinesis, the cell divides
94
Cytokinesis:
In cytokinesis, the cell divides.
In animal cells, cytokinesis starts by what?
In animal cells, cytokinesis starts by invagination
95
Cytokinesis:
In cytokinesis, the cell divides.
In animal cells, cytokinesis starts by invagination, which is what?
In animal cells, cytokinesis starts by invagination, which is constriction from the edges of the cell
96
Cytokinesis:
In cytokinesis, the cell divides.
In animal cells, cytokinesis starts by invagination, which is constriction from the edges of the cell.
In plant cells, what is laid down?
In plant cells, a cell wall is laid down
97
Cytokinesis:
In cytokinesis, the cell divides.
In animal cells, cytokinesis starts by invagination, which is constriction from the edges of the cell.
In plant cells, a cell wall is laid down.
Daughter cells have the same what as what?
Daughter cells have the same:
1. Chromosome number
2. Genetic makeup
as each other and the parent cell
98
Cytokinesis:
In cytokinesis, the cell divides.
In animal cells, cytokinesis starts by invagination, which is constriction from the edges of the cell.
In plant cells, a cell wall is laid down.
Daughter cells have the same chromosome number and genetic makeup as each other and the parent cell.
DNA replication comes before what?
DNA replication comes before mitosis
99
Interphase comes between what?
Interphase comes between successive cell divisions
100
Interphase comes between successive cell divisions.
It is not really a part of mitosis, but mitosis couldn't happen without it.
DNA replication occurs, allowing for what?
DNA replication occurs, allowing for the double stranded chromosome
101
Interphase comes between successive cell divisions.
It is not really a part of mitosis, but mitosis couldn't happen without it.
DNA replication occurs, allowing for the double stranded chromosome, which later does what?
DNA replication occurs, allowing for the double stranded chromosome, which later divides
102
Interphase comes between successive cell divisions.
It is not really a part of mitosis, but mitosis couldn't happen without it.
DNA replication occurs, allowing for the double stranded chromosome, which later divides.
What are made?
Cellular structures are made
103
Interphase comes between successive cell divisions.
It is not really a part of mitosis, but mitosis couldn't happen without it.
DNA replication occurs, allowing for the double stranded chromosome, which later divides.
Cellular structures are made, subsequently divided between what?
Cellular structures are made, subsequently divided between the 2 daughter cells
104
Interphase comes between successive cell divisions.
It is not really a part of mitosis, but mitosis couldn't happen without it.
DNA replication occurs, allowing for the double stranded chromosome, which later divides.
Cellular structures are made, subsequently divided between the 2 daughter cells.
A significant proportion of time in interphase is spent doing what?
A significant proportion of time in interphase is spent checking genetic information
105
Late prophase:
In late prophase, the nucleolus disappears and the nuclear envelope breaks down, leaving the chromosomes free in the cytoplasm of the cell.
These chromosomes are drawn towards the equator of the cell by the spindle fibres attached to the centromere.
The chromosomes are clearly what?
The chromosomes are clearly visible
106
Late prophase:
In late prophase, the nucleolus disappears and the nuclear envelope breaks down, leaving the chromosomes free in the cytoplasm of the cell.
These chromosomes are drawn towards the equator of the cell by the spindle fibres attached to the centromere.
The chromosomes are clearly visible, as what?
The chromosomes are clearly visible, as 2 chromatids are joined at the centromere
107
Early prophase:
In early prophase, the chromosomes first become visible, initially as long, thin threads.
The chromosomes become more distinct, as they do what?
The chromosomes become more distinct, as they:
1. Coil up
2. Shorten
3. Thicken
4. Take up stain more intensely
108
Early prophase:
In early prophase, the chromosomes first become visible, initially as long, thin threads.
The chromosomes become more distinct, as they coil up, shorten, thicken and take up stain more intensely.
What is present?
The nuclear envelope is present
109
Early prophase:
In early prophase, the chromosomes first become visible, initially as long, thin threads.
The chromosomes become more distinct, as they coil up, shorten, thicken and take up stain more intensely.
The nuclear envelope is present and what is evident?
The:
1. Nuclear envelope is present
2. Nucleolus is evident
110
When is DNA copied?
DNA is copied during interphase
111
The importance of mitosis:
Mitosis is important in organisms, because it produces daughter cells that are genetically identical to the parent cells.
This means that mitosis gives what?
This means that mitosis gives genetic stability
112
The importance of mitosis:
Mitosis allows for the what of tissues and the what of dead cells?
Mitosis allows for the:
1. Repair of tissues
2. Replacement of dead cells
113
What does prophase look like?
114
What does interphase look like?
115
What does metaphase look like?
116
What does anaphase look like?
117
What does telophase look like?
118
What is the formula for mitotic index?
The formula for mitotic index is that:
119
Mitotic index
Mitotic index is the ratio of the number of cells undergoing mitosis to the totial number of cells
