4. section 7: size and shape of DNA molecules Flashcards
1
Q
what is supercoiling of DNA?
A
when enzymes or proteins (eg toperesomes) bind to DNA which causes a twist in the double strand. This adds tension to the DNA strand and it twists on itself
2
Q
give three resasons why DNA supercoiling is important
A
- packaging DNA in cells - DNA is very long
- helps segregation during replication - DNA is close together so can pass genetic info to close genes nearby
- required for DNA/RNA synthesis - DNA must be unwound for DNA polymerase, therefore supercoiling will help the stress make more DNA unwound
3
Q
how does relaxed supercoiling occur?
A
when the DNA is nicked in a place and the DNA dosent have so much strain on it
