Translation

Question 1

tRNA translates the codon into

Answer 1

the correct amino acid

Question 2

Ribosomes

Answer 2

are the factories where translation occurs

Question 3

3 stages of translation

Answer 3

Initiation
Elongation
Termination

all require GTP

Question 4

Initiation

Answer 4

the first stage of translation

in prokaryotes occurs when the 30S ribosome attaches to the Shine Delgarno sequence and scans for a start codon; it lays down N - formylmethionine in the P site of the ribosome

in eukaryotes occurs when eh 40S ribosome attaches to the 5’ cap and scans for a start codon; it lays down methionine in the P site of the ribosome

Question 5

Elongation

Answer 5

involved the additions of a new ammoniacal - tRNA into the A site of the ribosome and transfer of the growing polypeptide chain from the tRNA in the P site to the tRNA in the A site. The now uncharged tRNA pauses in the E site before exiting the ribosome

Question 6

Termination

Answer 6

occurs when the codon in the A site is a stop codon; release factor places a water molecule of the polypeptide chain and thus releases the protein

Question 7

Posttranslational modifications include:

Answer 7

• folding by chaperones
• formation of quaternary structure
• cleavage of proteins or signal sequences
• covalent addition of other biomolecules

Question 8

Phosphorylation

Answer 8

addition of phosphates by protein kinases to activate or deactivate proteins

Question 9

Carboxylation

Answer 9

addition of carboxylic acid groups, usually to serve as calcium binding sites

Question 10

Glycosylation

Answer 10

addition of oligosaccharides as proteins pass through the ER and Golgi apparatus to determine cellular destination

Question 11

Prenylation

Answer 11

addition of lipid groups to certain membrane - bound enzymes