April 17, 2006

Chapter 22 Nucleic Acids and Protein Synthesis

Central Dogma of Molecular Biology

DNA -----> mRNA -----> Protein

22.6 Types of RNA

mRNA: contains codons (triplets of bases)

rRNA: site of protein synthesis (Ribosomes are 65% rRNA and 35 % protein)

tRNA: contains anticodons

22.7 Transcription: Synthesis of mRNA

Induction- turning a gene "on"

Repression - gene turned off

22.8 The Genetic Code

1) universal

2) degenerate

3) precise

4) initiation (AUG)

5) termination (UAG,UGA,UAA)

22.9 Protein Synthesis: Translation

1) activation amino acid reacts with ATP and then attaches to tRNA

2) initiation tRNA carrying met binds to 40S, 60S binds

3) elongation peptide chain forms at P site, new amino acids arrive at A site, translocation

4) termination stop codon encountered; protein and mRNA detach from ribosome

Homework:
22.5, 22.6, 22.11, 22.15, 22.17, 22.19, 22.21, 22.23, 22.25, 22.27, 22.29, 22.31, 22.33, 22.35, 22.37, 22.39, 22.43, 22.45, 22.49, 22.51, 22.53, 22.55, 22.57, 22.59, 22.61, 22.71, 22.73, 22.91, 22.97, 22.101, 22.103, 22.109