LEC 9 PROTEIN SYNTHESIS Flashcards
What’s is protein synthesis?
Making protein from DNA via RNA
The production of protein from specific gene is called?
Gene expression
What are the two stages of protein synthesis?
Transcription & Translation
What happens during ‘transcription’?
Specific code from gene create mRNA
DNA»_space; mRNA
What happens during ‘Translation’?
Ribosomes reads code from mRNA and make protein (polypeptide chain)
mRNA»_space; Protein
Whats the bases of the FIRST codon?
AUG
(Chain always starts with AUG)
What are ‘introns’?
Non-coding region of gene - No amino acids
(Non-specific information)
What are ‘Exons’?
Coding region of gene
(Specific information)
T/F
Exons are taken by mRNA and introns are removed
TRUE
(specific information taken by mRNA - make protein)
Define ‘Genetic code’?
List of ‘Amino acid’ & matching ‘mRNA codons’
Which condon is alway the START codon?
AUG (Methionine)
Chain always start with
List the three (3) STOP codons?
UAA
UAG
UGA
T/F
Stop codons does not encode for amino acid
TRUE
Transcription of the gene occurs in the nucleus with an enzyme called?
RNA polymerase
RNA copy is called?
mRNA
What are the 3 steps to transcription?
Initiation, Elongation & Termination
Explain initiation? (1st step)
- Transcription factors binds to > promoter
- RNA polymerase binds to > promoter >DNA unwind
Explain Elongation? (2nd step)
RNA polymerase builds> mRNA transcript
Double helix formed
Explain Termination?
End of gene > mRNA transcript released
Production stops
If information translation goes wrong, what’s the result?
Abnormal cells produce > Cancer
Is the Statement TRUE or FALSE?
Introns - Remove
Exons - Spliced together
TRUE
Where does Translation occur?
Cytosol (cytoplasm)
(mRNA exit nucleus )
mRNA information/coding is translated into___?
Amino acids
mRNA is translated by____ &____?
Ribosome & tRNA
(mRNA only reads ribosomes)
What’s the function of ribosomes?
Protein synthesis Site
(Reads code from mRNA to make protein)
Name the 2 subunits of Ribosomes
Large subunit- tRNA -anticodon
Small subunit- mRNA-codon
Codon > Anticodon
What are the three (3) binding sites of ribosomes?
A, P & E
What is bonded to the A site, P site and E site?
A site - Binds incoming tRNA
P site - Amino acid added to protein
E site - tRNA exit
What is Transfer RNA?
Link between mRNA and amino acid > produce protein
Note:
tRNA make and release amino acid then return to make more
What is located at the top and bottom ends of tRNA?
- What are anticodons?
T- Amino acid
B- anticodons
- tRNA 3 nucleotides - match mRNA codon
What are three (3) stages of translation?
Initiation, Elongation and Termination
What happens during initiation?
tRNA binds to mRNA
What happens during Elongation?
Amino acid linked - peptide bond
Chain gets longer
(Amino acids joined)
What happens during termination?
-Ribosome reaches STOP CODON
(UAG, UAA or UGA)
-Release factor binds to stop codon
- Translation ENDS
What is the end product of the translation stages?
Polypeptide chain
(Protein chain)
Post translational modification
Polypeptides destined:
Cytocol < Free ribosome
Organelle < Bound ribosome- RER
START AND STOP CODONS
(MEMORIZE)
Start: AUG
Stop: UAA, UAG & UGA
