Click4Biology: 7.4 Translation

 

Translation

7.4.1 Activation tRNA.

7.4.2 Ribosome structure.

7.4.3 Stages of translation.

7.4.4 Translation direction.

7.4.5 Peptide bonds between amino acids.

7.4.6 Translation process.

7.4.7 Free and membrane bound ribosomes.

Central Dogma of molecular biology: Information does not flow out of the protein. In other words translation cannot be reversed.

The CD is often mistakenly associated with the sequencing from DNA to the polypeptide (an information flow from DNA to the polpeptide). There is a significant difference that you should care about and who better to guide you than Francis Crick. There is actually another version of the central dogma by James Watson, its wrong!

7.4.1 Activation tRNA.

a) Amino acid which is specific to each tRNA.

(b) CCA base sequence to which the amino acid is attached by the 'Activating Enzyme'.

(c) Complementary base pairing sequence. Helical in shape.

(d) 8 free bases non-pairing giving one loop of RNA.

(e) 7 free bases non-pairing giving second loop of RNA.

(f) Small open loop of RNA which is variable in shape between different tRNA.

(g) Anti-codon (3 bases) which binds to the mRNA codon (3 bases) this is specific to the amino acids being carried. The anti-codon is complementary to the sense DNA.

 

 

 

Activation specificity:how does the tRNA attach to the correct amino acid.

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7.4.2 Ribosome structure.

 

 

Ribosome Function:

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7.4.3 Stages of translation.

There are three stages in translation ( just as in transcription)

Initiation:

Elongation:

Termination:

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7.4.4 Translation direction.

 

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7.4.5 Peptide bonds between amino acids.

 

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7.4.6 Translation process.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Both units of the ribosome are now located over the second and third codons

 

 

 

 

 

 

 

 

 

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7.4.7 Free and membrane bound ribosomes

Free ribosomes:

 

 

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