Unit One - Key Area 2 Flashcards
What are nucleotides?
repeating units which make up the genetic
What are nucleotides made up of?
deoxyribose sugar, phosphate and a base.
What does the alternating deoxyribose sugar and phosphate form?
sugar-phosphate backbone of DNA
What are the bonds between the bases called?
weak hydrogen bonds
What is the base pairing rule?
Adenine - Thymine and Guanine - Cytosine
What end contains the deoxyribose sugar?
3’ end
What end contains the phosphate?
5’ end
What is the arrangement of the sugar phosphate backbone running in opposite directions called?
antiparallel
What does DNA replication require?
ATP, template strands, enzymes, DNA nucleotides and primers.
Describe the formation of template strands?
The DNA molecule unwinds, the hydrogen bonds between the bases break, the DNA separates forming two template strands.
Which enzyme is needed to carry out DNA replication?
DNA polymerase
What are primers and what is their role?
A primer is a short chain of nucleotides which binds to the 3’end of the template strand and primers are required to begin replication.
Why are the leading and lagging strand formed?
Because DNA polymerase can only add nucleotides to the 3’ end of the new DNA strand meaning that DNA can only be synthesised in the 5’ to 3’ direction.
What enzyme joins the fragments of DNA together?
ligase
What is PCR?
Technique used to amplify (make many copies of) a piece of DNA.
Describe the process of PCR?
The DNA is first heated to between 92 and 98 degrees to separate the two strands, then it is cooled to between 50 and 65 degrees to allow the primers to bind to target sequences, and then it is heated to between 70 and 80 degrees for heat tolerant DNA polymerase to replicate the region of DNA.
Name some practical applications of PCR?
Forensics, setting paternity suits and diagnosing genetic disorders.
