DNA replication

Question 1

Why is semi conservative replication important?

Answer 1

Ensures genetic continuity between cell generations

Question 2

Describe the process of semi conservative DNA replication

Answer 2

1) DNA helicase breaks H bonds between complementary bases, unwinding the double helix
2) Both strands act as template
3) Free nucleotides attracted to exposed bases and join by specific complementary base pairings
4) H bonds form between AT and GC
5) DNA polymerase joins adjacent nucleotides on new strand by condensation reactions
6) Forming phosphodiester bonds

Question 3

What does semi conservative mean?

Answer 3

Each new DNA molecule consists of one original/template strand and one new strand

Question 4

Why does DNA polymerase moves in opposite directions along DNA strands?

Answer 4

DNA has anti parallel strands
So shapes/arrangements of nucleotides on two ends are different
DNA polymerase is an enzyme with a specific shaped active site
So can only bind to substrate with complementary shape

Question 5

Which scientists proposed models of the chemical structure of DNA and of DNA replication?

Answer 5

Watson and Crick