mitosis

Question 1

significance of mitosis

Answer 1

growth of multicellular organisms
two daughter cells produced are genetically identical to another one, hv same number of chromosomes as the parent cell –> unicellular zygotes to grow into multicellular organisms

replacement of cells and repair of tissues
cells are constantly dying, need to be continually replaced by genetically identical cells –> repair damaged tissues
human, cell replacement occurs particularly rapidly in the skin and the lining of the gut
some animals can regenerate body parts, e.g. zebrafish

asexual reproduction
the production of new individuals of a species by a single parent organism, offspring are identical to the parent
new individuals grow from parent organism then detach from parent in different ways

Question 2

what is so special about the chromosomes in homogolous pairs

Answer 2

carry same type of genetic information
same genes
same location
different alleles

Question 3

what happens during metaphase

Answer 3

spindle fibres are attached to centromere
chromosomes line up on equator

Question 4

what happens during prophase

Answer 4

chromatin condenses, chromosomes become visible
nucleolus and nuclear envelope breaks down
mitotic spindle fibres begin to form , organised by spindle fibre

Question 5

what happens during anaphase

Answer 5

spindle fibres shorten
chromosomes get pulled apart to opposite poles of the cell
v shape of chromatids

Question 6

what happens during telophase

Answer 6

sister chromatids reached their respective poles, now called chromosomes
nuclear envelope and nucleolus reform
spindle disassembles
chromatin decondense back into chromatin

Question 7

what happens during cytokinesis in animals

Answer 7

cleavage furrow forms around the middle of the cell as cell membrane is pulled in by cytoskeleton until it fuses

Question 8

what happens during cytokineses during plant cell

Answer 8

presence of cell wall prevents a cleavage furrow
vesicles from golgi form along equator where metaphase plate was
vesicles fuse with each other and the cell membrane dividing the cell into two
new sections of cell wall then form along the new sections of cell membrane

Question 9

what happens during interpahse

Answer 9

cell grows
cell makes new organelles
DNA replicates
nucleolus is visible
nuclear envelop intact
microtubules present throughout the cell