5122097
Description
Mind Map by Bee Brittain, updated more than 1 year ago
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Created by Bee Brittain
about 8 years ago
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3.8 The Cell Cycle
- The cell cycle has three stages (represented by the small middle ring in the picture below)
- Interphase
- Occupies most of the cell cycle and is sometimes
known as the resting phase because no division
takes place
- Occupies most of the cell cycle and is sometimes
known as the resting phase because no division
takes place
- Nuclear Division
- When the nucleus divides either into two (mitosis) or four (meiosis)
- When the nucleus divides either into two (mitosis) or four (meiosis)
- Cytokinesis
- Follows nuclear division and is the process by which the cytoplasm
divides to produce two new cells (mitosis) or four new cells (meiosis)
- Follows nuclear division and is the process by which the cytoplasm
divides to produce two new cells (mitosis) or four new cells (meiosis)
- Interphase
- Cancer
- Caused by a growth disorder in cells
- The result of damage to the genes that regulate mitosis and the cell cycle
- Leads to uncontrolled growth and division of cells
- As a consequence to this, a group of abnormal cells forms, this is a tumour and it constantly develops and expands in size
- A Tumour becomes cancerous if it becomes from BENIGN, to MALIGNANT
- A Tumour becomes cancerous if it becomes from BENIGN, to MALIGNANT
- As a consequence to this, a group of abnormal cells forms, this is a tumour and it constantly develops and expands in size
- Leads to uncontrolled growth and division of cells
- The result of damage to the genes that regulate mitosis and the cell cycle
- Benign Tumours - Grow more slowly, are more compact
and are less likely to be life-threatening
- Malignant Tumours - Grow rapidly, are less compact and
are more likely to be life-threatening
- Caused by a growth disorder in cells
- Rate of Mitosis
- Most cells divide by mitosis, either to increase the
size of a tissue during development (growth) or to
replace dead and worn out cells (repair)
- The Rate of mitosis
can be affected by the
environment of the
cell and by growth
factors
- It is also controlled by two types of gene
- A mutation in one of these genes = uncontrolled mitosis
- Mutated cell divide = tumour
- Mutated cell divide = tumour
- A mutation in one of these genes = uncontrolled mitosis
- It is also controlled by two types of gene
- The Rate of mitosis
can be affected by the
environment of the
cell and by growth
factors
- Most cells divide by mitosis, either to increase the
size of a tissue during development (growth) or to
replace dead and worn out cells (repair)
- Treatment on Cancer
- Usually involves killing dividing cells by blocking a part of the cell cycle
- Cell cycle disrupted = cell division and cancer growth ceases
- Cell cycle disrupted = cell division and cancer growth ceases
- Drugs used to treat cancer (chemotherapy)
usually disrupt the cell cycle by ...
- ... preventing DNA from replicating
- ... Inhibiting the metaphase
stage of mitosis by interfering
with spindle formation
- Drugs are more effective against rapidly dividing cells
- Cancer cells = fast rate of division = they are damaged to a greater degree than normal cells
- Cancer cells = fast rate of division = they are damaged to a greater degree than normal cells
- ... preventing DNA from replicating
- Problems?
- These drug also effect normal cells
- The drugs are more effective against fast
dividing cells, this means that normal cells such
as hair-producing cells are vulnerable to
damage
- These drug also effect normal cells
- Usually involves killing dividing cells by blocking a part of the cell cycle
- The graph (left) shows the effect of a chemotherapy
drug that kills dividing cells. It was given to a
cancer patient once every three weeks starting
at 0. This graph plots the changes in the
number of healthy cells and cancer cell sin a
tissue over the treatment period of 12 weeks
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