Mitosis Flashcards
Why is cell division important
each new cell must receive a copy of the genetic information stored in the DNA, so dna must be replicated before it divides
What changes when cells divide
number of chromosomes stays the same - the amount of DNA is doubled before division
what are the 6 phases of mitosis
Interphase Prophase Metaphase ANaphase Telophase Cytokinesis
Explain what happens in interphase
growth and synthesis of new ogranelles genetic information (DNA) is replicated (doubles)
Explain what happens in early prophase
chromatin fibres become more tightly coiled and visible
explains what happens in late prophase
nucleoulus and nuclear membrane disapear
chromosomes move into the cytoplasm where microtubules appear as spindle fibres.
Centrioles move towards the poles of the cell and centrioles send out spindle fibres to attach to centromeres.
explain what happens in metaphase
spindle fibres radiate from the poles of the centriole into the centromere of the chromosomes that have aligned along the cells equator
explain what happens in anaphase
centromeres are pulled apart pulling sister chromatids away from each other. These daughter chromosomes are pulled to opposite ends of the cell by spindle fibres
explain what happens in telophase
daughter nuclei begin to form as nucleoli reappear and chromosomes uncoil to form chromatin
explain what happens in cytokinesis
cell membrane constricts and two identical daughter cells are formed
what is non disjunction and what does it result in
one or more pairs of homologous chromosomes are unable to separate evenly/normally.
an abnormal distribution of chromosomes as all chromsomes go to one side which leads to cell death or disformity
What are stem cells
cells that can divide into any type of cells (able to differentiate)
they are capable of repeated mitosis
unlimited sources of cells for repair
