1.6 - Cell Division

Question 1

what is the role of mitosis and the cell cycle ?

Answer 1

to produce genetically identical daughter cells for
growth
asexual reproduction

Question 2

state the 3 stages of cell cycle

Answer 2

interphase
mitosis
cytokinesis

Question 3

what happens during interphase ?

Answer 3

in addition to the cell function continues normally, the cell grows and prepares to divide by
- replication of organelles
- DNA replication

Question 4

what are the 4 stages of mitosis?

Answer 4

Prophase
Metaphase
Anaphase
Telophase
(PMAT)

Question 5

what happens during the ‘Prophase’ stage in mitosis?

Answer 5

• chromosomes condense
• centrioles move to opposite poles of cell

Question 6

what happens during the ‘metaphase’ stage of mitosis?

Answer 6

chromosomes line up on the equator of the cell

Question 7

what happens during the ‘anaphase’ stage of mitosis?

Answer 7

• spindle attaches to the centromeres causing them to split apart
• sister chromatids are pulled by spindle to opposite poles

Question 8

what happens during the ‘telophase’ stage of mitosis?

Answer 8

• nuclear membrane begins to reform
• chromosomes decondense
• spindle disappear

Question 9

what happens during cytokinesis ?

Answer 9

• cytoplasm divides
• cell membrane begins to reform splitting the cells

Question 10

state the main role of meiosis

Answer 10

• production of haploid gametes that have half the number of chromosomes
• create genetic variation

Question 11

how does meiosis produce genetically different cells?

Answer 11

• crossing over of chromatids
• independent assortment of chromosomes

Question 12

what is crossing over ?

Answer 12

when bivalents exchange some of their genetic material (genes)

Question 13

what is independent assortment?

Answer 13

when there are various combinations of chromosome arrangement

Question 14

state the differences between meiosis and mitosis

Answer 14

1. mitosis gives genetically IDENTICAL daughter cells, meiosis gives genetically DIFFERENT daughter cells
2. mitosis = diploid, meiosis = haploid
3. mitosis = 2 daughter cells, meiosis = 4 daughter cells

Question 15

what happens in ‘prophase I’ of Meiosis ?

Answer 15

• chromosomes condense and nuclear envelope breaks down
• homologous chromosomes come together to form a Bivalent
• crossing over occurs at the chiasmata (where the bivalent crosses over)

Question 16

what happens in ‘metaphase I’ of Meiosis ?

Answer 16

• bivalents randomly line up on metaphase plate (independent assortment)
• spindle fibers attach to centromere

Question 17

what happens in ‘anaphase I’ of Meiosis ?

Answer 17

• spindle contract and pull bivalent apart to opposite poles
• sister chromatids are still attached by centromere

Question 18

what happens in ‘telophase I’ of Meiosis ?

Answer 18

• chromatids begin to decondense
• spindle dissolve
• nuclear envelope forms around each new nucleus
  (ready for next division)

Question 19

what happens in ‘prophase II’ of Meiosis ?

Answer 19

• sister chromatids condense
• new spindle begins to form
• nuclear envelope begins to break down

Question 20

what happens in ‘metaphase II’ of Meiosis ?

Answer 20

• chromosomes line up on the metaphase plate
• spindle attaches to centromeres of sister chromatids

Question 21

what happens in ‘anaphase II’ of Meiosis ?

Answer 21

• spindle contract and pull sister chromatids to opposite poles splitting the centromere

Question 22

what happens in ‘telophase II’ of Meiosis ?

Answer 22

• chromosomes decondense
• nuclear envelope forms around the four nuclei