1. 7.3 Translation Understanding: -Initiation of translation involves assembly of the components that carry out the process -Synthesis of the polypeptide involves a repeated cycle of events -Disassembly of the components follows termination of translation -Free ribosomes synthesize proteins primarily for secretion or for use in lysosomes -Translation can occur immediately after transcription n prokaryotes -The sequence and number of amino acids in the polypeptide is the primary structure -The secondary structure is the formation of alpha helixes and beta pleated sheets -The tertiary struture is the further folding of the polypeptide -The quarternary structure exists in proteins with more than one polypeptide chain Applications: -tRNA-activating enzymes illustrate enzyme-substrate specificity and the role of phosphorylation Skills: -The use of molecular visualization software to analyse the structure of eukaryotic ribosomes and a tRNA molecule -Identification of polysomes in an electron micrograph Nature of science: -Developments in scientific research follow improvements in computing

2. Structure of the ribosome and tRNA Draw and label Ribosome -Subunits (one large, one small) -Three tRNA binding sites -mRNA binding site tRNA -CCA base sequence at 3’ end (amino acid attaches) -Anticodon loop -T arm -D arm

3. Initiation of translation 1.mRNA binds to small ribosomal subunit at mRNA binding site 2.Initiator tRNA molecule carrying methionine (amino acid) binds at start codon ‘AUG’ at the P site 3.Large ribosomal subunit binds to small one 4.Another tRNA binds at the A site 5.Peptide bond forms between amino acids in P and A site

4. Elongation of translation 1.tRNA moves from P site to E site – frees it 2.Allows next tRNA to bind, and occupy the A site

5. Termination of translation 1.Process continues until a stop codon is reached 2.Polypeptide is released

7. Story board Create a story board to show the steps in: -Initiation -Elongation -Termination In translation. Include: -Description -Key words -Diagrams and labels

8. Ribosomes Type of ribosomeProteins used at: FreeCytoplasm Mitochondria Chloroplasts Bound to EREndoplasmic reticulum Golgi apparatus Lysosomes Plasma membrane Outside of cell

9. Polypeptide structures Create presentations for the following polypeptide structures: 1.Primary structure (Joshua/Jeffrey) 2.Secondary structure (Angel/Megan) 3.Tertiary structure (Arthur/Kelvin) 4.Quaternary structure (Hon/Chun To)