DNA Structure and Replication

Question 1

Difference between Eukaryotes and Prokaryotes?

Answer 1

Prokaryotes:
- unbound circular DNA in the cytosol
- single celled

Eukaryotes:
- bound DNA in the nucleus
- multi-celled

Question 2

What is the function of DNA

Answer 2

• the long-term storage of genetic information
• helps make other cells and other organisms

Question 3

What is the function of RNA

Answer 3

• used to transfer the genetic code from the nucleus to the ribosomes to make proteins

Question 4

What is DNA replication

Answer 4

• through DNA helicase, the parent DNA molecule unwinds and unzips to form a replication fork
• the DNA is then copied with complementary nucleotide bases attatching to parent strands through the help of DNA polymerase
• the replication creates two identical strands with one being the template strand and the other a newly synthesised strand

Question 5

In which direction does DNA polymerase build nucleotides?

Answer 5

• from the 5’ to 3’ end
• it can only add nucleotides onto the 3’ end

Question 6

What is the role of DNA helicase?

Answer 6

• it is an enzyme that unwinds and then unzips the parent DNA by breaking the hydrogen bonds between the complementary base pairs
• it results in a replication fork

Question 7

What is the process of nucleotide generation onto the lagging strand?

Answer 7

• DNA primase places sections of RNA primer on the strand
• DNA polymerase builds off the 3’ end in the opposing directions to the movement of the replication fork –> creates Okazaki fragments
• DNA ligase joins these Okazaki fragments and then changes the U in the RNA primer to T so that it is now one full DNA polynucleotide