The genetic code and protein synthesis Flashcards Preview

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Flashcards in The genetic code and protein synthesis Deck (43):
1

the coded mRNA dependent synthesis of protein

translation

2

scientists who cracked the genetic code

Nirenberg and matthael

3

base pairing at third position is not as constrained as the other two bases
permits flexibility in codon/anticodon recognition, allowing mRNA translation with less than 64 tRNAS

wobble hypothesis

4

formation of aminoacyl-tRNAs

aminoacyl tRNA synthetase binds amino acid to tRNA using ATP

5

in prokaryotes what are the sizes of the ribosomal subunits

50S and 30S

6

what energy is used during translation

GTP

7

protein synthesis occurs in three stages

initiation
elongation
termination

8

binding of mRNA, ribosomal subunits and first aminoacyl-tRNA

initiation

9

sequential formation of all peptide bonds

elongation

10

stop codon recognition, release of polypeptide and dissociation of ribosome subunits

termination

11

three sites in the ribosome

A site
P site
E site

12

four steps in the formation of the prokaryotic initiation complex

IF-1 and IF-3 bind to the 30S subunit
30S subunit bind to mRNA shine-dalgarno sequence just upstream of AUG
30S slides AUG into the P site to insure that first AUG is located
IF-2 and GTP bind to the 30S subunit
IF-1 falls away
GTP is hydrolyzed
IF-2 and IF-3 fall away
50S subunit attaches to 30S subunit

13

blocks A site until ready for first aa-tRNA

IF-1

14

prevents premature binding to 50S subunit

IF-3

15

a purine rich mRNA sequence just upstream from the AUG start codon

shine dalgarno sequence

16

prokaryotes initiate translation with

N-formyl-met-tRNA

17

what enzyme forms peptide bonds

peptidyltransferase

18

how is peptide bond formed

A site amino acid amino group acts as the nucleophile and attacks the carbonyl site of P site amino acid

19

EF-G-GTP hydrolysis promotes

ribosome movement 5 prime to 3 prime allowing next codon into A site

20

what are the five things you need to complete PCR

1. small amount of DNA
2. dNTPS to make complementary strand
3. DNA polymerase
4. buffer with ATP
5. DNA primers

21

where is the DNA polymerase from

hot springs bacteria Taq

22

what replaces the job of helicase

heating the DNA to 90 degrees celcius

23

what is the process for one run of PCR

heat to 90 degrees to break DNA strands
cool to 40 degrees to allow primers to attache
heat to 70 degrees to allow polymerase to build strands

24

what is the equation to tell how many molecules have been produced per so many cycles of PCR

2^n where n is the number of cycles

25

what is the job of EF-G

using GTP to cause a conformational change resulting in peptide translocation

26

what is the job of EF-Tu

delivering the next aa-tRNA to the A site

27

when a stop codon reaches the A site...

a release factor binds to the A site and all members of the assembly dissociate

28

what is different about transcription and translation in prokaryotes vs eukaryotes

in prokaryotes transcription and translation happen in the same place since there is no nucleus and translation of a protein can be occurring while transcription is still taking place

29

the complex formed when transcription and translation are occurring at the same time

polysome

30

what are the ribosomal subunits in eukaryotics

40S and 60S

31

acts only in prokaryotes to block binding of aminoacyl tRNA to A site in ribosome

tetracycline

32

acts only on prokaryotes to block the peptidyl transferase reaction on ribosome

chloramphenicol

33

acts only in prokaryotes to block the translocation reaction on ribosomes

erythromycin

34

acts only on eukaryotes to block mRNA synthesis by binding preferentially to RNA polymerase II

alpha-amanitin

35

the modification of a newly formed protein that is often required to finish a protein or convert it from its inactive form to its active form

post translational modification of proteins

36

the removal of N-terminal methionine, signal peptides; activation of precursor proteins

proteolytic cleavage

37

the attachment of various sugar residues to proteins

glycosylation

38

acylation and prenylation; allows membrane attachment/interaction; activation of Ras proteins

lipophilic modifications

39

activation cascades, tagging for repair/destruction, collagen

phosphorylation, methylation, hydroxylation

40

between cys residues to promote tertiary structure

disulfide formation

41

excision of peptide segments and joining flanking segments

protein splicing

42

a short peptide chain that directs the post translational transport of a protein to its final destination in the cell

signal peptide and protein targeting

43

giant protein complexes that bind protein molecules with ubiquitin tags and degrades them

proteasomes