Unit 1 KA2 - Structure and Replication of DNA
Wach of the strands is made up of repeating units called...
Nucleotides
What are the 3 parts of a nucleotide?
Deoxyribose Sugar, Organic base and Phosphate
2 strands of DNA are joined together by...
Weak hydrogen bonds
What are the complimentary base pairs?
Adenine->Thymine Guanine->Cytosine
What are the end of the DNA strands called?
3' and 5' end
What end is the 3' at?
Deoxyribose end
What end is the 5' end at?
Phosphate end
The base of DNA forms the...
Genetic code
Replication is necessary so that the... during cell division
chromosone complement is maintained
What must the nucleus contain for DNA replication to occur?
DNA to act as a template
Primer
A supply of the 4 types of nucleotide
Enzymes (DNA polymerase and ligase)
Supply of ATP for energy
What must happen fod DNA to be replicated?
The DNA must be unwound
What happens to the weak hyrdogen bonds between the bases?
They are broken to form 2 template strands
Prior to cell division, DNA is replicated by the enzyme...
DNA Polymerase
For DNA Polymerase to function...
A primer must be present
What is a primer?
A primer is a short strand of nucleotide that binds to the 3' end of the template DNA strand allowing polymerase to add DNA nucleotides
What does DNA polymerase do during DNA replication, and which end of the new DNA strand does it add nucleotides?
DNA Polymerase adds DNA nucleotides using complimentary base pairing to the deoxyribose end (3') of the new DNA strand that is forming.
DNA polymerase can only add DNA nucleotides...
In one direction
The leading strand replicates...
Continuously
The lagging strand replicates...
In fragments (discontinuously)
The fragments are joined together by the enzyme...
Ligase