Friday, 28 September 2012 | By Unknown
1. Semi-conservative Replication
- The process in which a double helix replicates and each of the daughter molecules will have one old strand and one newly made strand.
- Unlike the dispersive model, semi-conservative does not induce mutations by breaking old strands to insert new ones.
2. DNA Gyrase
- An enzyme that releases any tension brought about by the unwinding of the DNA during DNA replication.
- Prevents DNA from breaking or being damaged.
3. Pre-mRNA G-Cap
- A modified form of guanine that's added to the 5' cap
- Helps protect mRNA from hydrolytic enzymes as well as functions as an "attach here" signal for ribosomes.
4. Poly(A) tails
- 50 - 250 adenine nucleotides located at the 3' end
- Inhibits hydrolysis, facilitates ribosome attachment and facilitates the export of mRNA from the nucleus.
5. RNA Introns
- Introns are noncoding segments that lie between coding regions.
- Introns lower the chance of mutations on the exons.
6. Wobble Effect
- Protects from mutations by allowing the third base of a codon to be flexible.
- For example, if the third base of what was initially a "CUC" codon were to be changed into an "A", then it would become "CUA" and still code for the same amino acid, preventing any mutations from occurring.
Thursday, 13 September 2012 | By Unknown
