Protein synthesis and processing Flashcards Preview

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Flashcards in Protein synthesis and processing Deck (21):
1

nucleolus

where ribosomes are assembled

2

tRNA

possess unique 3 anti-codons, (cloverleaf structures)

3

three steps to charge a tRNA

- activation of amino acid
- addition of amino acid to tRNA
- proper folding of tRNA ( brings amino acid to ribosome)

4

difference of mRNA in prokaryotes and eukaryotes

monocistronic ( eukar) - one gene codes for one protein
polycistronic ( pro) - one gene codes for more than one protein

5

20 different aminoacyl tRNA synthetase

- recognizes the correct amino acid
- the correct codon on the mRNA

6

Shine-Dalgarmo sequence

mRNA sequence that binds to complementary base pairs in 16S rRNA in prokaryotes

7

Small Ribosomal subunit

binds to 5' m7G cap of the mRNA then slides along mRNA until it finds the start codon

8

Monocistronic dis. and adv.

slower but less prone to accident, less expensive

9

Polycistronic dis. and adv.

faster, more prone to accident, more expensive, more waste

10

Three adjacent tRNA binding sites on ribosome

A (aminoacyl) site : Arrival
P (peptidyl) site: Pause
E (exit) site: Exit

11

A site

where tRNA arrives

12

P site

where polypeptide chain is main and waits for right amino acid to be brought by tRNA

13

E site

where tRNA is punted off the complex and hopefully recycled and charged again.

14

Decoding centre

within small 40s ribosomal subunit that ensures proper aminoacyl tRNA pairs with codon

15

Steps in specificity of amino acid incorporation during translation

- correct amino acid /tRNA (ensured by PABP)
- simple base pairing
- Decoding centre

16

Release factor

-causes structure to come apart
-causes ribosomal subunits and polypeptide to be released

17

Post translational modification

chemical mod of a polypeptide chain after translation

18

Types of post trans mods

Glycolsyation
Lipid addition
Phosphorylation

19

Phosphorylation

Phosphate addition on serine/threonine or tyrosines or tyrosines by specific protein kinases to form phosphoproteins.

20

Glycosylation

carbohydrate addition to form glycoproteins

21

Lipid addition

lipid addition to lipoproteins