mitotic cell cycle. ch5

Question 1

list the stages of the mitotic cell cycle

Answer 1

1. interphase
2. mitotic phase
3. cytokinesis

Question 2

list three things that happens to the cell during interphase

Answer 2

1. the size of the cell increases
2. the number of organelles increases
3. the volume of the cytoplasm increases

Question 3

list the three phases of interphase in order

Answer 3

1. G1 phase
2. S phase
3. G2 phase

Question 4

list three things that occur during the G1 phase

Answer 4

1. the size of the cell increases
2. the number of organelles increases
3. the volume of the cytoplasm increases

Question 5

what happens during the S phase?

Answer 5

DNA replication occurs. This means that the number of chromosomes doubles so that when the cell splits, they both have equal number of chromosomes

Question 6

what happens during the G2 phase?

Answer 6

any error in the gene sequence is corrected to prevent any form of mutation

Question 7

what are sister chromatids

Answer 7

they are two identical chromatids joined together by a centromere

Question 8

what are chromatids

Answer 8

they are chromosomes that have supercoiled themselves to prevent tangling

Question 9

list the stages that occur in the M phase

Answer 9

1. prophase
2. metaphase
   3.anaphase
3. telophase

Question 10

what occurs during prophase

Answer 10

during prophase, the nuclear envelope disappears. the chromosomes supercoil to form sister chromatids to prevent tangling

Question 11

what happens during metaphase

Answer 11

during metaphase, the sister chromatids lie on the equator and the centrioles move to opposite poles.
NB: dont say opposite ‘sides’

Question 12

what occurs during anaphase

Answer 12

during anaphase, the spindle fibres attach themselves to the centromeres of the sister chromatids and they begin to shorten, thus, pulling apart the sister chromatids so that there are identical and the same number of chromatids at each poles

Question 13

what occurs during telophase

Answer 13

this is the last phase of the m phase. the chromatids uncoil back to chromatins and the nuclear envelope reappears again

Question 14

what occurs during cytokinesis

Answer 14

this is the last stage of the cell cycle. the cell begins to split and finally forms two identical cells/ daughter nuclei

Question 15

what are stem cells

Answer 15

they are undifferentiated cells that can continuously divide and give rise to differentiated/ specialised cells

Question 16

how do stem cells continue to divide without cease?

Answer 16

in stem cells, an enzyme called telomerase rebulids the telomeres on the chromatin lost in dna replication

Question 17

why are stem cells so important

Answer 17

they are required to replace old cells
they produce specialized cells when necessary
they repair worn out tissues