6.1-2 Cell cycle & mitosis Flashcards
1
Q
What is the role of mitosis and the cell cycle?
A
- to produce identical daughter cells for growth and asexual reproduction of cells
2
Q
What are all the cells produced by mitosis have in common?
A
- genetically identical
3
Q
What does mitosis have no involvement in?
A
- does not give rise to genetic variation
- DNA replication
4
Q
What is a simplistic version of the cell cycle?
A
- a cell forms
- it grows
- divides to form daughter cells
5
Q
What are the three phases of the cell cycle?
A
- mitosis
- cytokinesis
- interphase
6
Q
Mitosis is …
A
- a form of cell division that produces identical cells
- contains four phases
7
Q
What are the four phases of mitosis?
A
- prophase
- metaphase
- anaphase
- telophase
8
Q
Cytokinesis is when …
A
- new cell surface membrane forms down the centre of cell
- cleavage furrow starts to form, where the cell membrane constricts inwards to begin dividing the cytoplasm
- two new diploid genetically identical daughter cells produced
9
Q
Interphase is when …
A
- the mitochondria/ chloroplasts grows and prepares to divide to increase numbers
- DNA is replicated and checked for errors in the nucleus
- protein synthesis occurs in the cytoplasm
- chromosomes also begin to condense
- normal metabolic processes occur within the cell
10
Q
Prophase is when …
A
- the nuclear envelope disintergrates
-DNA condenses to form chromosomes - spindle fibres attach onto centromeres to begin moving the chromosomes to the centre of the cell
- centrioles move to opposite poles of the cell for the purpose of spindle formation
11
Q
Metaphase is when …
A
- chromosomes move to the equator
- attach to spindle fibres via centromeres
- ‘metaphase plate’
12
Q
Anaphase is when …
A
- the sister chromatids are separated as centromeres divide
- spindle fibres shorten
- chromatids attached to spindle fibres form little V shaped
13
Q
Telophase is when …
A
- nuclear envelope/ nucleolus reforms around each set of chromosomes
- spindle is broken down and disappears
- chromosomes become less condense
- chromatids reach the poles now called chromosomes
14
Q
What are the three roles of mitosis?
A
- growth and repair
- asexual reproduction
- binary fission (prokaryotes)
15
Q
What are the three stages of interphase?
A
- G1 (first growth phase)
- S (synthesis)
- G2 (second growth phase)
16
Q
G1 is when…
A
- protein synthesis
- new organelles are made (mitochondria and chloroplasts)
- cell grows in size
17
Q
Synthesis is when…
A
- DNA is replicated in the nucleus
18
Q
G2 is when …
A
- cell continues to grow in size
- energy stores are increased
- replicated DNA is checked for errors
19
Q
G1 checkpoint checks …
A
- cell size, enough nutrients, DNA damaged in phase
- if something is wrong cell enters G0 phase
- happens at end of G1 phase
20
Q
G2 checkpoint checks …
A
- happens at end of G2 phase
- checks that all DNA is replicated with no error
- if something is wrong cell enters G0 phase
21
Q
Spindle assembly (metaphase) checkpoint checks …
A
- checks that chromosomes are attached to spindles and aligned in the middle
- if something is wrong then the error is corrected at the next phase
- purpose of this checkpoint is to avoid aneuploidy
22
Q
Aneuploidy is …
A
- abnormal number of chromosomes in a cell
