dna rep

tadem repeatssjort sequences of non coding dna used in dna profilling

dna rep 5-3 prim direction

• same on both which is why there are okozaki fragments

dna polymerase III adds new nucleotides to the leading strand

lagging strand is anti parrel so is replicated in segments known as okozaki segments(section between 2 primers in discontinous replications

to know where to attach rna primers

dna polymerase III adds nucleotides

dna polymerase I removes rna primer and replaces with DNA nuceltides (therefore only on lagging strand)

dna ligase joins up okozaki fragments

circle end(phosphate) is 5 prime end (upwards facing 5 to 3)

Transcription

complimentary base pairing using rna polymerase. binds at the promoter region until reaches a terminator region

similar to sl knowledge

Translation

ribosome divided into 2 units: small subunit and large

ribosome seperates and mrna attatches to the small subunit

Trna attatches to Start Codon(AUG)

Large sub unit contains 3 binding sites A P E

will attach to the small subunit with the first tRNA in the P site, anticodon of second tRNA will complimentary base pair with the codon in the A site

to amino acids join together via a codensation reaction to form a peptide bond

ribosome then shifts by 1 codon(trna in P site enters E site)+ trna breaks away from the ribsosome+ leaves the amino acids behind

trna from a site enters P site with amino acids and a new trna enters the a site and complimentary

base pairs with the new codon in the a site

continues until a stop codon is repeated on the messenger rna. polypeptide chain is complete and breaks up then normally sent to golgi for folding up. MRNA released, can be broken down into rna nuceotides for use

Dna>Mra> TRNA

post transcription splicing occurs before the mrna exits nucelous