Pharm706 Quiz 4

Front 1

Start codon

Back 1

AUG

Front 2

Stop codon

Back 2

UAA
UAG
UGA

Front 3

"Wobble hypothesis"

Back 3

-can occur at the 5' anticon to the 3' condon
-tRNA anticodon can pair with up to 3 differnet codons for the same amino acid
A-U or I
G-C or U
C-G or I
U-A or I or G

Front 4

Silent mutation

Back 4

no change in amino acid sequence

Front 5

Missence mutation

Back 5

changes in amino acid sequence

Front 6

nonsence mutation

Back 6

formation termination codon

Front 7

Frameshift mutation

Back 7

insertion or deletion of a single nucelotide.
-reading frame ultered from pt of mutation till termination codon reached.

Front 8

Point mutation

Back 8

form or destroy terminatio codon resulting in a premature termination or (readthrough" of termination codon.

Front 9

Aminoacylation of tRNA

Back 9

aminoacyl-tRNA transferase

enzyme+aa+ATP
to enzyme-aminoacyl-AMP +PPi(1)

enzyme-aminoacyl-AMP + tRNA to
enzyme + aminoacyl-tRNA + AMP (2)

Front 10

Eukaroyotes

Back 10

monomer size
80s

SMALL SUBUNITS
40s
34 protein
18s RNA

LARGE
60 S
50 protein
28S, 5.8S 5S RNAs

Front 11

Prokaryotes

Back 11

monomer
70s
SMALL UNIT
30s
21 proteins
16s RNA

LARGER subunit
50s
34 protein
23s, 5s RNA

Front 12

eIF2a

Back 12

binds to GTP and met-tRNA^met
formoning a ternary complex
-causes association w/ IF3 and blocks 6o s association (antissociation)

Front 13

EF-1a

Back 13

correct aminoacyl-tRNA is enhanced
-EF-1a, EF-1, first form a tenary complex w/ aminoacyl-tRNA and GTP.
-The EF-1a-aminoacyl-tRNA-GTP complex binds to the ribosomeand if the codon/anticodn are correct, the aminoacyl-tRNA is placed at the A-site, GTP is hydrolized, and EF-1a GDP complex dissociates.

Front 14

EF-2

Back 14

translocase
-move the mRNA and dipeptidyl-tRNA in the anticodon-codon register, from the 40s (A site) to the (P site).
-GTP is hydrolyzed
-A site vacant
-Dipeptidyl-t-RNA moves to the (P site), the deacylated donor (methionine) tRNA also moves to the (E site) on the 60S

Front 15

A-site

Back 15

aminoacyl-tRNA specified by the next codon of the mRNA bond to acceptor, aminoacyl, or A site

Front 16

P site

Back 16

the initiating methionyl-tRNA is placed in position so that its methionyl residue can be transfered (or donated) to the free alpha group of the amino group of the incomming aminoacyl-tRNA.
donar, peptidyl or P site

Front 17

E site

Back 17

anticodon of the deacylated tRNA remains in the 40S P site, and its acceptor end located in the 60s exit or E site.

Front 18

mitochodrial protein syn

Back 18

-circular DNA genome
encodes fro 13 proteins
22 tRNA
12S and 16S rRNA
enzymes-
RNA ploymerase
aminoacyl-tRNA synthetase
tRNA and ribosomes
initiation codon
fmet-tRNA^met
UGA-tryptophan
AUA-methionone
AGA and AGG stop
proteins are endodes in nuclear DNA
-synthesized in the cytosol and imported into organelle.

Front 19

Streptomycin

Back 19

initiation and elogation
30s sudunit

Front 20

neomycins

Back 20

translation
multiple site

Front 21

tetracycin

Back 21

aminoacyl-tRNA binding
30s or 40s

Front 22

puromycin

Back 22

peptide transfer
70s and 80s

Front 23

erthromycin

Back 23

translocation
50s

Front 24

Fusidic acid

Back 24

translocation
EF-G (Euk)

Front 25

Cycloheximide

Back 25

Elongation
80s (Euk)

Front 26

Ricin

Back 26

Multiple
60s (euk)

Front 27

Signal peptide

Back 27

at or near the amino terminus
-positivly charged N-rgion
-serves as a cleavage site for excision of a signal peptide.

Front 28

Carbo's used fro glycosylation

Back 28

mannose
NANA
GlcNAc
galactose
fucose

Front 29

N-linkage

Back 29

amide nitrogen of asparagin
-specific sequence is required AsnXTHr
-glycosylation rxn occurs "contranslationally"
-dolichol phosphate- lipid attached to the ER where oligosaccharides are initially assembled.

Front 30

O-linked

Back 30

hydroxyl serine or theronine
-occurs only on foilded proteins
-no specific sequence necessary
-residues must be on the protein surface

Front 31

target proteins to mitochondria

Back 31

-syn in the cytosol as prepproteins
-N-terminal seq have a (+) charged amphilillic alpha-helix theat is recognized by mitochondria receptor.
-proteins transported across the membrane in the unfolded state w/ the help of chaperones.
- translocation across the membrane requires energy
-protease removes the matrix targeted protein

Front 32

to nucleus

Back 32

nuclear translocation signal includ a cluster of basic aa
-carrier proteins (importins) mediate transport through cylindrial nuclear pore complex

Front 33

target proteins to more an one place

Back 33

-suboptimal location signal can lead to dual location
-gene duplication resultin in similar gene products w/ different targeting sequences.-alternative splicing of mRNAs
-alternative translocation initiation.

Front 34

Posttranscriptional
RNA degradation

Back 34

half-life varry from min. to hrs
-poly-a tail and cap
-PABP-binding protein protects mRNA from degradation.
-deadenylases-progressive removal of poly-A tail
-decapping enzyme removes 5' cap when the tail is < 10 nucleotides long.

Front 35

Posttranscriptional
RNA interferance

Back 35

DsRNA can lead to sequence-specific degradation of homologous mRNA sequence.

Front 36

Posttranscriptional
control of translation initation

Back 36

under control nutrient starvation, heat shock, or viral infection, eIF2a is phosphorylated and binds elF2a tightly making it unavailable fro initation.