cell division

Question 1

stages of cell division

Answer 1

interphase
prophase
metaphase
anaphase
telophase
cytokenisis

Question 2

what stages are in mitosis

Answer 2

prophase
metaphase
anaphase
telophase

Question 3

what happens in interphase?

Answer 3

• everything in the cell is replicated
• dna is replicated
• proteinsynthesis occurs
• subcellular structures double up
• dna in form of chromatin

Question 4

what happens in prophase?

Answer 4

• chromosomes become visible (chromatin condense to form chromosomes)
• nucleus disappears as the nuclear envelope breaks down

Question 5

what happens in metaphase?

Answer 5

• chromosomes line up along the middle of the cell
• spindle fibres attach to the centromeres of the chromosomes

Question 6

what happpens in anaphase?

Answer 6

• spindle fibres contract and pull on the chromosomes
• centromere splits and sister chromatids move to opposite ends of the cell
• half move to each end

Question 7

what happens in telophase?

Answer 7

• chromosomes return to the form of chromatin
• nuclear membrane forms around the dna at each end of the cell
• spindle fibres disintegrate

Question 8

what happens in cytokenisis?

Answer 8

• cytoplasm and cell membrane divide to produce 2 new daughter cells

Question 9

what is the mitotic index?

Answer 9

tells us how fast cells are dividing

Question 10

how do you work out the mitotic index?

Answer 10

number of cells in mitosis / total number of cells

Question 11

how does cancer affect the mitotic index?

Answer 11

cancer increases the mitotic index as cancer causes uncontrolled cell division

Question 12

how do chemotherapy drugs work?

Answer 12

kill cancer cells by targeting rapidly dividing cells

Question 13

what cells replicate using binary fission?

Answer 13

prokaryotic cells

Question 14

what happens in binary fission?

Answer 14

1. circular dna molecule replicates and both copies attach to the cell membrane
2. plasmids replicate
3. cell membrane begins to grow between the two dna molecules adn begins to divide the cytoplasm in two
4. new cell wall forms, dividing the original cell into two daughter cells, each with a single copy of dna and variable numbers of plasmids

Question 15

how do viral cells replicate?

Answer 15

1. virus attaches to host cell
2. virus infects host cell
3. host cell copies genetic material of the cell virus and makes viral proteins
4. new virus particles are assembled inside the host cell
5. new virus particles leave the host cell