Mitosis is a nuclear division which produces two identical daughter cells.
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What happens in interphase?
The cell grows and carries out its normal function, but also prepares for division. The cells DNA is unravelled and replicated to double the genetic information. The organelles are also replicated and ATP is increased.
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What are the 3 stages of interphase?
G1, S, G2.
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What happens in the G1 stage?
This is the 1st growth phase. Proteins from which organelles are made are synthesised and are produced and organelles replicate,The cell increases in size.
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What happens in the S phase?
This is the synthesis phase where DNA is replicated in the nucleus.
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What happens in the G2 stage?
This is the 2nd growth phase. The cell continues to grow in size, ATP and energy stores increases and the duplicated DNA is checked for errors.
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What is the G0 stage?
This is when a cell leaves the cycle. This can happen due to differentiation making a cell speicialised in a function so no ,
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Why is mitosis important?
It is required for growth, replacement and repair of tissues in multicellular organisms. It is necessary for asexual reproduction. It also provides genetic stability.
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What is the G1 checkpoint?
Occurs at the end of the GAP phase 1 and checks for cell size, nutrients, growth factor and DNA damage. It cell satisfies requirements it is enetered in S phase, If not it is sent to G0 phase.
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What is the G2 checkpoint?
Takes place at then end of GAP phase 2 before mitotic phase and checks for DNA replication and damage to DNA.
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What is the Metaphase Checkpoint?
Also known as spindle assembly checkpoint where it ensures all the chromosomes are attached to the spindles and have aligned in the spindle equator.
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What is the structure of chromosomes in mitosis?
As mitosis begins, the chromosomes are made of two starnds joined together by a centromere. The seperate starnds are called chromatids. Two strands on the same chromosome are called sister chromatids.
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What are the stages of mitosis?
Prophase, Metaphase, Anaphase and Telophase.
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What happens in prophase?
The chromosomes become shorter and thicker by the action of coiling and condensing. Each chromosome now exists as a pair of chromatids joined together by a centromere. The nuclear envelope disnitegrates and centrioles move to oppsoite poles.
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What do the centrioles do?
They form a trail of protein spindle fibres, called microtubles which link the poles of the cell. These are needed to move chromosomes to required positions by attaching to the centromere.
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What happens in metaphase?
Each chromatid pair becomes attached by their centromeres to the spindle fibres. The stage is completed when all the chromatid pairs are lined up in the middle of the cell (spindle equator).
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What happens at anaphase?
The centromeres holding the chromatids divide, seperating the pair of sister chromatids, They are then pulled to opposite poles by the contracting of the spindle fibres.
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What happens in telophase?
The chromatids reach the poles, uncoil and become long and thin again. They are now called chrosomes. The nuclear envelope forms around each group of chromosomes - 2 nuclei.
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What happens in cytokenisis?
This when the cell itself divides into 2 seperate cells. In animal cells a cleavage furrow forms. The cytoskeleton pulls the cell-surface membrane inwards until it is close enough to fuse and make 2 new cells.
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Card 2
Front
What happens in interphase?
Back
The cell grows and carries out its normal function, but also prepares for division. The cells DNA is unravelled and replicated to double the genetic information. The organelles are also replicated and ATP is increased.
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