Cell Cycle Flashcards
what is the cell cycle?
- only a some cells in multicellular organisms retain the ability to divide
- those that do not divide continuously but undergo a regular cycle of division spears ted by periods of cell growth
what are the stages of the cell cycle?
- interphase
- nuclear division
- division of the cytoplasm
what is interphase?
-occupies most of the cell cycle and is sometimes known as the resting place because no division takes place
what is nuclear division?
-the nucleus divides either into two (mitosis) or four (meiosis)
what is division of the cytoplasm (cytokinesis)?
-cytokinesis follows nuclear division an is the process by which the cytoplasm divides to produce two new cells (mitosis) or four (meiosis)
how do you control mitosis?
- the rate of mitosis can be affected by the environment of the cell and by growth factors
- it is controlled by two types of genes so any mutation to those genes can result in uncontrolled mitosis
- the mutant cells are usually structurally and functionally different from normal cells
- most mutated cells die but any that survive are able to divide to form clones which form tumours
how do you treat cancer?
- you have to kill dividing cells by blocking a part of the cell cycle
- the cell cycle is disrupted and cell division and cancer growth stop
- drugs used to treat cancer disrupt the elk cycle
how do drugs disrupt the cell cycle?
- preventing DNA from replicating
- inhibiting the metaphase stage f mitosis by interfering with spindle formation
How long does the cell cycle last?
- the length of the complete cell cycle varies greatly amongst organisms
- a mammal takes 24 hours to complete the cell cycle which is 90% interphase
What is the problem with drugs that are used to treat cancer growth?
-they disrupt the cell cycle of normal cells like hair producing cells that also divide rapidly this is why hair loss is frequently seen in cancer patients undergoing treatment
