Topic 1.6: Cell Division Flashcards
Define cell cycle
an ordered set of events which culminates in the division of a cell into two daughter cells
What is an ordered set of events which culminates in the division of a cell into two daughter cells?
cell cycle
Define interphase
The stage in the development of a cell between two successive divisions
What is The stage in the development of a cell between two successive divisions?
interphase
What are the 3 stages of interphase?
G1, S, G2
What happens during G1 of interphase?
First intermediate gap stage in which the cell grows and prepares for DNA replication
What happens during S of interphase?
Synthesis stage in which DNA is replicated
What happens during G2 of interphase?
Second intermediate gap stage in which the cell finishes growing and prepares for cell division
What stage of interphase is the First intermediate gap stage in which the cell grows and prepares for DNA replication?
G1
What stage of interphase is the Synthesis stage in which DNA is replicated?
S
What stage of interphase is the Second intermediate gap stage in which the cell finishes growing and prepares for cell division
?
G2
Define M phase
The period of the cell cycle in which the cell and contents divide to create two genetically identical daughter cells
What is The period of the cell cycle in which the cell and contents divide to create two genetically identical daughter cells?
M phase
What are the two stages of M phase?
mitosis and cytokinesis
What happens during mitosis?
Nuclear division, whereby DNA (as condensed chromosomes) is separated into two identical nuclei
What happens during cytokinesis of M phase?
Cytoplasmic division, whereby cellular contents are segregated and the cell splits into two
What stage of M phase does Nuclear division, whereby DNA (as condensed chromosomes) is separated into two identical nuclei?
mitosis
What stage of M phase does Cytoplasmic division, whereby cellular contents are segregated and the cell splits into two?
cytokinesis
What happens during interphase of mitosis? (4)
DNA is present as uncondensed chromatin (not visible under microscope)
DNA is contained within a clearly defined nucleus
Centrosomes and other organelles have been duplicated
Cell is enlarged in preparation for division
What happens during prophase of mitosis? (4)
DNA supercoils and chromosomes condense (becoming visible under microscope)
Chromosomes are comprised of genetically identical sister chromatids (joined at a centromere)
Paired centrosomes move to the opposite poles of the cell and form microtubule spindle fibres
The nuclear membrane breaks down and the nucleus dissolves
What happens during metaphase of mitosis? (3)
Microtubule spindle fibres from both centrosomes connect to the centromere of each chromosome
Microtubule depolymerisation causes spindle fibres to shorten in length and contract
This causes chromosomes to align along the centre of the cell (equatorial plane or metaphase plate)
What happens during anaphase of mitosis? (3)
Continued contraction of the spindle fibres causes genetically identical sister chromatids to separate
Once the chromatids separate, they are each considered an individual chromosome in their own right
The genetically identical chromosomes move to the opposite poles of the cell
What happens during telophase of mitosis? (4)
Once the two chromosome sets arrive at the poles, spindle fibres dissolve
Chromosomes decondense (no longer visible under light microscope)
Nuclear membranes reform around each chromosome set
Cytokinesis occurs concurrently, splitting the cell into two
During what stage of mitosis is DNA is present as uncondensed chromatin (not visible under microscope)?
interphase
During what stage of mitosis is DNA is contained within a clearly defined nucleus?
interphase
During what stage of mitosis is Centrosomes and other organelles have been duplicated?
interphase
During what stage of mitosis is Cell is enlarged in preparation for division?
interphase