cell cycle/mitosis Flashcards
does cell division occur in all multicellular organisms?
no because not all multicellular organisms retain the ability to divide
what are the stages of the cell cycle?
- interphase
- prophase
- metaphase
- anaphase
- telophase (cytokinesis)
what are the three growth stages which occur during interphase?
- gap phase 1
- synthesis
- gap phase 2
what happens during gap phase 1?
cell grows and duplicates organelles
what happens synthesis?
DNA replication
what happens during gap phase 2?
cell continues to grow and produces proteins
(ATP content is also increased to produce energy for cell division)
- cell double checks that organelles have been correctly duplicated before moving onto mitosis
what are four stages of mitosis?
- prophase
- metaphase
- anaphase
- telophase
what happens during prophase?
- chromosomes visible (shorten/thicken/ coil)
- nucleolus disappears
- nuclear envelope disappears
- centrioles divide and migrate to opposite poles of cell
what happens during metaphase?
- centrioles produce spindle fibres which attach to centromeres of chromosomes
- contraction of fibres pulls the chromosomes to equator
what happens during anaphase?
- chromosomes are pulled to opposite poles centromere first
what happens during telophase?
- chromosomes reach poles
- begin to uncoil and less distinct
- nuclear envelope develops
what happens during cytokinesis?
division of cytoplasm producing two identical cells
why is mitosis important?
- growth
- repair
- reproduction
what is the advantage of having offspring genetically identical to parents?
- genetic info of parents has enabled it to survive and reproduce
therefore offspring with same genetic makeup are likely to survive and reproduce
what is the disadvantage of having offspring genetically identical to parents?
- variation is limited
what is cancer?
group of diseases caused by uncontrolled mitosis
what can cause uncontrolled mitosis?
mutation - mutant cells are structurally and functionally different from normal cells
- any mutant cells which survive have the ability to divide and form clones leading to formation of tumours
how does chemotherapy work?
use drugs to disrupt cell cycle by preventing DNA replication and inhibiting metaphase (spindle formation)
what are disadvantages of chemo?
- affects normal healthy cells but more effective against rapidly dividing cells
- leads to hair loss because hair-producing cells divide rapidly so vulnerable to damage
