Unit 1 Topic 2- DNA And The Genome Flashcards
Explain the basic process of DNA replication
• the parent DNA molecule unwinds
•weak hydrogen bonds between the base pairs break causing the strands to separate
• DNA nucleotides present in the nucleus pair with the original strands of DNA in line with complementary base pairing
• DNA ligase joins the nucleotides together to form a new DNA strand
• two daughter DNA strands are created
What does semi- conservative mean?
One strand of the DNA is new and one strand is the original/parental strand
What is DNA polymerase and what is its function?
It is an enzyme which adds nucleotides according to complementary base pairing to the deoxyribose (3’) end of the template DNA strand
What is DNA ligase and what is it’s function?
An enzyme which joins the new and original DNA fragments together
What is a primer and what is its function?
A primer is a short strand of nucleotides which binds to the 3’ end of the parent DNA strand allowing polymerase to add DNA nucleotides
What is the function of ATP?
To provide energy for this process
Why does DNA need to replicate?
So that a complete set of genetic information is passed onto new cells
What is a leading strand?
The strand that the polymerase joins the new nucleotides to
What is a replication fork?
When replicating a long chromosome many replication forks are created which operate simultaneously to speed up the process of replication
what is the lagging strand?
the strand that runs in the opposite direction to the leading strand
what is the first advanced stage of DNA replication?
the double heix of the DNA is unwound and the hydrogen bonds between the complimentary bases are broken and 2 template strands are formed
what is the second advanced stage of DNA replication?
a primer binds to the 3’ end of the leading template strand and the DNA polymerase adds complimentary DNA nucleotides from the nucleus continuously to create a complimentary strand
what is the 3rd advanced stage of DNA replication?
primers bind to the 3’ end of the lagging strand template and as the strand widens the DNA polymerase adds DNA nucleotides from the nucleus that are complimentary to the template strand creating Okazaki fragments
what is the 4th advanced stage of DNA replication?
the fragments of the new, complimentary, DNA sequence are joined to the parent strand by DNA ligase to form a complete DNA strand
which side of the DNA strand can DNA polymerase read from?
the 3’ end
