Chapter 5

Question 1

What is the process of the semi-conservative method of DNA replication?

Answer 1

• DNA helicase breaks the hydrogen bonds between the 2 strands of DNA = unwinds stands
• original strands act as templates
• free nucleotides in nucleus joint to complementary bases on both stands through condensation reaction (DNA polymerase)
• new DNA molecule contains one original strand and one new strand

Question 2

What does mitosis produce?

Answer 2

2 identical daughter cells (clones)

Question 3

What happens during interphase in the cell cycle?

Answer 3

• DNA replicating

Question 4

What happens during prophase in the cell cycle?

Answer 4

• nuclear envelope disintegrates
• nucleolus disappears
• spindle fibres form
• chromosomes become visible

Question 5

What happens during metaphase in the cell cycle?

Answer 5

• chromosomes line up

- spindle fibres attach to centromere

Question 6

What happens during anaphase in the cell cycle?

Answer 6

• spindle fibres contract pulling chromatids apart

- chromatids pulled towards poles

Question 7

What happens during telophase in the cell cycle?

Answer 7

• cytoplasm splits in 2 = cytokinesis
• nuclear envelope reforms
• nucleolus reforms
• spindle fibres disintegrate
• chromatids reach poles and become chromosomes again
  BACK TO INTERPHASE

Question 8

What is the process of binary fission?

Answer 8

• replication of circular DNA and plasmids

- division of cytoplasm to produce 2 daughter cells each with 1 copy of DNA and variable numbers of plasmids

Question 9

How do viruses replicate?

Answer 9

• inject nucleic acid into host cell which replicates virus particles
• do not undergo cell division

Question 10

What happens when cell division id uncontrolled?

Answer 10

tumours and cancers from

Question 11

How do cancer treatments work?

Answer 11

they aim to control the rate of cell division