Transcription & Translation

Types of RNA
1. mRNA
  1. single strand
  2. Bases - U, G, A ,C
  3. Synthesised from DNA
  4. Made in the nucleus of Eukrayotic cells
2. tRNA
  1. clover leaf shape
  2. amino acid binding site
  3. complementary anticodon to mRNA
3. rRNA
  1. Ribosome - used in protein synthesis
Transcription - mRNA is formed
1. 1. DNA helicase breaks Hydrogen bonds in DNA
2. 2. RNA nucleotides bond (RNA polymerase bonds bases)
3. DNA bases - A = U, T = A. C = G, G = C
4. 3. RNA polymerase moves along DNA strand
5. 4. mRNA is fully formed when stop signal on DNA is reached
Translation - primary sequence is formed
1. 1. mRNA joins to rRNA
2. 2. Anticodon on tRNA bonds to complementary base on mRNA
3. 3. Peptide bond forms between amino acids
4. 4. Polypeptide chain is formed when stop codon is reached
Introns & Exons
1. Introns as non-coding bases
  1. Splicing pre-mRNA removes defects and any introns
2. Exons are coding bases
Universal - same triplet in all organisms
Degenerate - more than 1 code for each amino acid
Non-overlapping - base triplets don't share bases
Mutations
1. substitution - changing a base for another base
  1. may code for same amino acid
2. Deletion - removing a base
  1. new amino acid gets coded for

Resource summary

	Created by humza tahir about 8 years ago