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Question 1

Describe DNA replication

Answer 1

DNA helicase (unzips) binds to DNA, which breaks the H bonds
DNA helix unwinds and the two strands separate
Primers are made on each strand
Free-floating nucleotides form hydrogen bonds with the complementary bases
(Each strand is used as aa template for the complementary strand)
DNA polymerase forms phosphodiester bonds between the nucleotides
Two new DNA strands are formed

Question 2

What does topoisomerase do?

Answer 2

Stops the DNA from supercoiling

Question 3

What direction is DNA replicated?

Answer 3

5’ to 3’

Question 4

What does ligase do?

Answer 4

Seals the gap between adjacent okazaki fragments

Question 5

How is DNA replication semi-conservative?

Answer 5

DNA replication is considered semi-conservative because each new DNA molecule is composed of one original strand (from the parent DNA) and one newly synthesized strand. This means that half of the original DNA molecule is conserved in each of the two new DNA molecules

Question 6

What is the least and most specialised types of stem cells?

Answer 6

Totipotent - least
pluripotent
multipotent
unipotent - most