cell cycle

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 do the cell cycle consist of

Answer 3

I + M phase + cytokinesis

Question 4

what is the cell cycle

Answer 4

series of growth and development steps a cell undergoes between its birth and reproduction

Question 5

what happens during Gap 1 of interphase

Answer 5

cell grows and increase in size
transcription of genes to make RNA
organelles duplicate
biosynthesis [protein synthesis, making enzymes needed in the S phase]

Question 6

what happens during the S phase in interphase

Answer 6

cell replicates its DNA, ready to divide by mitosis

Question 7

what happens during Gap 2 of interphase

Answer 7

cell continue to increase in size
energy stores are increased
special chemicals ensure the cell is ready for mitosis

Question 8

what happens at gap 0

Answer 8

resting phase triggered at checkpoints
1. differentiation
2. damaged DNA
3. senescene

Question 9

what happens at G2 checkpoint

Answer 9

cell checks whether all the DNA has been replicated without any damage, if yes then enter mitosis

Question 10

what happens during G1 checkpoint

Answer 10

cell checks that chemical needed for replication are present and for any damage to the DNA before entering S phase

Question 11

outline the cell cycle

Answer 11

interphase - cell grows in size, makes new organelles
mitosis - DNA is divided
cytokinesis - cell spilts into two identical daughter cells