7-translation

Question 1

Where does ribosome bind to in prokaryotes?

Answer 1

Shine Dalgarno sequences

Question 2

Where does SSU of ribosome bind in eukaryotes?

Answer 2

5’cap

Question 3

What is the difference between the 5’ cap and Kozac sequence?

Answer 3

the 5’ cap is the ribosomal binding site whereas the Kozac sequence is recognised by the ribosome as translational start site

Question 4

what is a ribosome and what activity does it have?

Answer 4

a ribonucleoprotein with ribozymal activity

Question 5

what is the difference between the tRNA in prokayotes and eukaryotes?

Answer 5

in eukaryotes it is tRNA methionine whereas in prokaryotes it is tRNA formylmethionine

Question 6

what kind of activity takes place at ribosome?

Answer 6

peptidyl transferase activity

Question 7

what to prokaryote IF 1 and 3 do?

Answer 7

stop LSU binding before initiation is complete

Question 8

what does prokaryotic IF2 do?

Answer 8

bring tRNA formylmet to initiation complex

Question 9

what doe eIF1 do?

Answer 9

blocks A site

Question 10

what does eIF2 do?

Answer 10

brings tRNA to P site

Question 11

what does eIF3 do?

Answer 11

stops LSU binding before initiation is complete

Question 12

what occupies P site?

Answer 12

tRNA

Question 13

What is GTP needed for?

Answer 13

the transfer of peptidyl on P site tRNA to A site tRNA aminocyl

Question 14

what is bound to GTP?

Answer 14

eIF2

Question 15

what does peptidyl transferase help form?

Answer 15

a peptide bond between the 2 amino acids

Question 16

what does tRNA deacylase do?

Answer 16

breaks bond berween methionine and it tRNA

Question 17

what does EF1 do?

Answer 17

helps entry of tRNA to A site

Question 18

what does EF2 do?

Answer 18

translocates ribosome (shunts it along)

Question 19

what happens in the LSU?

Answer 19

catalysis of peptide bond formation

Question 20

what happens when termination codon enters a site?

Answer 20

termination

Question 21

how many sites are there and what are they in ribosomes?

Answer 21

3: E,P,A

Question 22

how many release factors are there in e.coli?

Answer 22

3 RF:1,2,3

Question 23

what do release factors cause?

Answer 23

termination

Question 24

how many release factors do eukaryotes have?

Answer 24

1 (eRF)

Question 25

What are release factors?

Answer 25

tRNA peptidyl hydrolases

Question 26

what happens at termination to the ribosome and mRNA?

Answer 26

ribosome dissociates and the mRNA is released.

Question 27

what is cystic fibrosis due to?

Answer 27

misfolding of transmembrane regulator

Question 28

what disease is caused by the misfolding of fibrillin?

Answer 28

Marfan syndrome

Question 29

what disease is caused by a change to a prion protein and what change is it?

Answer 29

Creutzfeld Jakob disease caused by prion extra-cellular aggreggation

Question 30

Why is extra cellular aggregation of beta amyloid bad?

Answer 30

causes alzheimers disease

Question 31

what happens at barrel of GRoel/GroES chaperon?

Answer 31

folding aided (Heat shock protein)

Question 32

where does folding take place in chaperones?

Answer 32

in barrel of GroEL/GroEs

Question 33

what is the 5' ubiquitin tail added to in degradation of proteins process?

Answer 33

lysine of waste protein

Question 34

outline the steps of protein degradation (3)

Answer 34

5' ubiquitin tail added to lysin of waste protein. regulatory subunit recognises this and protein is deubiquinated and unfolded. Finally proteolytic enzymes degrade the protein

Question 35

What 2 things do regulatory subunits do in protein degradation?

Answer 35

de ubiquinate 5'ubiquitin tail and unfold waste protein

Question 36

what is protein folding primarily determined by?

Answer 36

primary structure

Question 37

what does EIF4 do?

Answer 37

untangles mRNA

Question 38

what do we mean by the genetic code is degenerate?

Answer 38

more than one codon codes for same amino acid

Question 39

how many tRNAs are there in comparison to possible codons?

Answer 39

around 40 tRNAs but 64 codons

Question 40

what does wobble mean and 3' base degeneracy mean?

Answer 40

tRNAs can recognise more that one codon as anticodon can bind to alternative bases at 3rd position. This decreases amount of tRNAs required.

Question 41

What can inosine base pair with?

Answer 41

C,A,U

Question 42

what is inosine?

Answer 42

deaminated form of guanine

Question 43

what can g pase pair with when it is at 3rd position in anticodon?

Answer 43

U and C

Question 44

why can variation of anticodon be tolerated (wobble) ?

Answer 44

anticodon loop is not linear and when anticodon binds to codon does not form a perfect RNA double helix.

Question 45

what does polycistronic mean?

Answer 45

a single mRNA encoding several different polypeptide chains

Question 46

do eukaryotes have polycistronic mRNA?

Answer 46

No they have monocistronic

Question 47

what are isoacceptors?

Answer 47

tRNAs that bind the same amino acid

Question 48

what is aminoacy-tRNA? and what does it deliver to the ribosome?

Answer 48

Aminoacyl-tRNA is tRNA to which its cognated amino acid is chemically bonded. The aa-tRNA with elongation factors, deliver the amino acid to the ribosome for incorporation into the polypeptide chain.

Question 49

what processes need GTP?

Answer 49

ribosome movement and binding of accessory factors

Question 50

what processes need ATP?

Answer 50

charging of tRNAs and removal of secondary structure from mRNA