Biochemistry 7: RNA and the Genetic Code

Question 1

stop codons

Answer 1

UAA - U Are Annoying

UGA - U Go Away

UAG - U Are Gone

Question 2

missense mutation

Answer 2

a mutation where one amino acid substitutes for another

Question 3

nonsense mutation

Answer 3

a mutation where the codon now encodes for a premature stop codon

a truncation mutation

Question 4

eukaryotic RNA Polymerase I

Answer 4

located in the nucleolus and synthesizes rRNA

Question 5

eukaryotic RNA Polymerase II

Answer 5

located in the nucleus and makes hnRNA (pre-processed mRNA) and some snRNA (small nuclear RNA)

Question 6

heterogeneous nuclear RNA

Answer 6

hnRNA

primary mRNA transcript formed during transcription by RNA Pol II

Question 7

eukaryotic RNA polymerase III

Answer 7

located in the nucleus

synthesizes tRNA and some rRNA

Question 8

strands of rRNA in eukaryotic ribosomes

Answer 8

28S 18S 5.8S 5S

28, 18, 5.8 transcribed by RNA Pol I as a single unit

5S transcribed by RNA Pol III

18S - small subunit (40S)

28S, 5.8S, and 5S- large subunit (60S)

complete ribosome is 80S

Question 9

strands of rRNA in prokaryotic ribosomes

Answer 9

5S 23S 16S

16S - small subunit (30S)

5S and 23S - large subunit (50S)

complete ribosome is 70S

Question 10

phosphorylation

Answer 10

posttranslational modification by protein kinases to activate or deactivate proteins

most commonly seen with serine, threonine, tyrosine in eukaryotes

Question 11

carboxylation

Answer 11

posttranslational modification

addition of carboxylic acid groups, usually to be Ca2+ binding sites

Question 12

glycosylation

Answer 12

posttranslational modification

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

Question 13

prenylation

Answer 13

posttranslational modification

addition of lipid groups to certain membrane-bound enzymes