Bio 111 lecture 16

what are the three ribosome tRNA binding sites?

P site (Peptidyl-tRNA)

A site (Aminoacyl-tRNA)

E site (Exit)

what happens at the P binding site?

initiator tRNA binds

what happens at the A binding site?

the next tRNA binds carrying the next amino acid

what happens at the E binding site?

uncharged tRNAs are ejected

what order are the ribosome tRNA binding sites in from left to right?

E P A

what is translocation?

movement of the ribosome down the length of the mRNA(one codon at a time)

what is the first step in translation termination?

no tRNAs bind to the stop codon

what is the second step in translation termination?

release factor binds to stop codon

what is the third step in translation termination?

synthesized protein is released from the ribosome

what is the fourth and final step of translation termination?

ribosome complex falls apart

what are the four main parts of amino acid structure?

alpha carbon

amino group

R group

carboxyl group

what are R groups?

the variable part of amino acids that give them their individual electrochemical characteristics

how many different R groups are there?

20

how many levels are there of protein structure?

four

what does primary structure of a protein consist of?

the sequence of amino acids

what are amino acids held together by?

peptide bonds

are R groups part of the peptide backbone?

no

what does secondary structure consist of?

folding of the protein

what are the two possible structures of a protein in secondary?

alpha helix

b pleated sheet

what causes folding of the protein for secondary structure?

interactions with the backbonew

what type of bonds are between amino H and carboxyl O in secondary structure?

hydrogen

what is super secondary structure?

when alpha helices and b pleated sheets combine to form motifs

what are the two possible motifs in super secondary structure?

b barrel

bab unit