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1. Genetic code used in translation Translation occurs in a very precise manner, with each triplet of nucleotides corresponding to one specific amino acid.

Figure 6. Map of codons to amino acids.

Note that since there are 64 different codons (43), but only 20 different amino acids, sometimes as many as 4 different codons code for the same amino acid. However, on the other hand, some amino acids (such as tryptophan) still have only one codon representation.

Also, there are 4 special codons, highlighted in yellow and orange on the diagram above, which do not code for amino acids. UAA, UAG and UGA are stop codons, signaling the ribosome to stop translation. AUG, on the other hand, is a start codon, or the place where translation begins.

2. Key steps in transcription But before translation of RNA takes place, DNA must be transcribed into RNA. There are three basic steps in transcription.

Figure 7. Basic steps of transcription of DNA into RNA

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