13 Translation Learning Intentions To be able to describe the stages involved in translation To be able to explain the following terms codon polypeptide tRNA anti codon attachment site ID: 780350
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Slide1
Higher Biology
Unit 1:
1.3 Translation
Slide2Learning Intentions
To be able to describe the stages involved in translation
To be able to explain the following terms: codon, polypeptide,
tRNA
, anti codon, attachment site
Slide3Success Criteria
I can identify and explain the stages of translation
I can explain the following terms:
codon, polypeptide,
tRNA
, anti codon, attachment site
Slide4Translation
Translation is the formation of a polypeptide (protein) using the mature mRNA transcript
The mRNA code is read in series of 3 bases (triplet of bases) known as
codons
Each codon is complementary to a triplet of bases on the original DNA strand
Slide5tRNA
Another RNA molecule known as
transfer RNA (
tRNA
)
is found in the cytoplasm and is involved in translation
tRNA
is folded into a 3D structure and held together by hydrogen bonds
Slide6Slide7tRNA structure
tRNA
is composed of a single chain of nucleotides, an amino acid attachment site and an anticodon region
The anticodon is a triplet of bases complementary to the mRNA codon
Each anticodon corresponds to a specific amino acid on the attachment site
Slide8tRNA
tRNA
picks up amino acids in the cytoplasm and then carries them to the ribosome to match with the mRNA codons
Slide9Ribosomes
Ribosomes are organelles found in the cytoplasm and attached to other organelles in cells
They contain ribosomal RNA and enzymes required for protein synthesis
Slide10Ribosome Structure
Slide11Site P
– holds the tRNA carrying the growing polypeptide chain.
Site A
– holds the tRNA carrying the next amino acid to be joined to the chain.
Site E
– releases the empty tRNA once it has dropped off its amino acid.
Slide12Ribosome
The function of ribosomes is to bring
tRNA
into contact with mRNA
This allows the complementary codons and anticodons to form bonds
As the codons and anticodons bond, peptide bonds are formed between amino acids on the
tRNA
molecules
This forms a chain of bonded amino acids known as a
polypeptide
Slide13Slide14The translation process
1. The ribosome binds to the 5
’
end of the mRNA so that the
start codon (AUG)
is in site P.
2. Next a tRNA carrying the amino acid
methionine
becomes attached to site P.
Slide153. The mRNA codon at site A bonds complementary anticodon on the appropriate tRNA bearing the correct amino acid.
4. A
peptide bond
then forms between these two amino acids.
5. The ribosome then moves along one codon.
6. The tRNA from Site P is move to Site E and released.
7. Steps 3-6 then repeat until it reaches a
stop codon.
Slide16Professor Dave will explain…
Slide17Success Criteria
I can identify and explain the stages of translation
I can explain the following terms:
codon, polypeptide,
tRNA
, anti codon, attachment site