1.5 Nucleic Acids Flashcards
What is DNA?
Deoxyribonucleic acid and holds the genetic information
What is RNA?
Ribonucleic acid which translates and transfers the genetic information to the ribosomes.
What is a nucleotide?
A monomer made out of a base, a pentose sugar (deoxyribose or ribose) and a phosphate group
What is a base?
An organic base (contains nitrogen) is either A,G,C,T (T is substituted for U)
What is a pyramidine?
A single ring base- Cytosine and Thymine
What is a purine?
A single ring base- Adenine and Guanine
Which bases are complimentary?
A and T form 2 H Bonds
G and C form 3 H Bonds
What is the backbone and its function?
The backbone is the phosphate sugar molecule and it is rigid and strong whilst protects the inner bases?
What is meant by an antiparralel backbone?
The direction of the backbone flips (imagine one of the sugars as an upside down house) this is because the bonds run 3’ to 5’ on one side and 5’ to 3’ on the other
What replaces Thymine in RNA?
Uracil
What is semiconservative replication?
DNA replicates by using 1 side of the double helix as a template for the new strand.
How is DNA unwound?
DNA Helices breaks the H bonds in between the bases of the 2 strands. This makes 2 single strands.
How is DNA replicated?
Complimentary base pairs of free nucleotides line up alongside one of the original strands
How are the 2 strands formed?
Condensation reactions join the nucleotides of the new strand together, catalysed by DNA polymerase. H Bonds form between the old and new strand and the helix rewinds.
Which direction does DNA polymerase work in?
It works from 3’ to 5’ so there is a leading strand. A lagging strand (5’ to 3’) is built in fragments and require DNA Ligase to ‘glue’ these fragments together.
