mitosis and the cell cycle Flashcards
what is mitosis?
a type of asexual cell division which ends in the production of 2 identical daughter cells
give 3 reasons that mitosis is important
- growth
- repair of cells
- reproduction
why is mitosis important for growth?
mitosis helps to ensure that all new cells contain the same genetic information
why is mitosis important for repair of cells?
if cells are damaged or dead, it is important that we have new, identical cells ready to take over
why is mitosis important for reproduction?
some single celled organisms ca reproduce via mitosis
what are the four stages of mitosi?
- prophase
- metaphase
- anaphase
- telophase
what is the stage that happens before mitosis?
interphase
what is the formula for calculating mitotic index?
mitotic
index = number of cells with
condensed chromosomes
——————————————–
total number of cells
x100
what is mitotic index?
the proportion of cells undergoing mitosis at a given point
what happens in prophase?
- chromosomes become visible as long, thin threadlike structures, which later shorten and thicken
- nucleolus breaks down leaving chromosomes free in cytoplasm
what happens in metaphase?
- chromosomes appear as 2 chromatids joined by centromere
- chromatids pulled by spindle fibres
- arrange along the equator of the cell
what happens in anaphase?
- centromere divides
- spindle fibres pull 2 chromatids apart and to opposite sides of the cell (poles)
what happens in telophase?
- chromosomes reach poles
- become long and thin, and disappear again
- nuclear envelope and nucleolus begin to reform
what is interphase? and what does it consist of?
- the steps and process that cells go through before mitosis
- G1, S phase, G2
what is the G1 phase of the cell cycle?
- a part of interphase
- where the cell swells/grows
what is the S phase part of the cell cycle?
- a part of interphase
- where the DNA replicates
what is the G2 phase of the cell cycle?
- a part of interphase
- where the cell is prepared for mitosis
what is metastases?
the process by which cancer spreads through the body, via blood and lymph vessels, and forms secondary tumours/cancers
what is cytokinesis?
the process by which the cell splits into two identical daughter cells after mitosis has occurred
