4.2.6 Nucleic Acid & Amino Acid Sequence Comparison Flashcards
A triplet is
a sequence of three DNA bases that codes for a specific amino acid
A codon is
a sequence of three mRNA bases that codes for a specific amino acid
A codon is transcribed from
the triplet and is complementary to it
An anticodon is
a sequence of three tRNA bases that are complementary to a codon
When comparing the genetic code to amino acid sequences
mRNA codons are often used
The four bases found in RNA molecules
adenine, uracil, cytosine and guanine
The four bases found in RNA molecules (adenine, uracil, cytosine and guanine) have the ability to form
64 different codons
The genetic code is degenerate, multiple mRNA codons can
encode the same amino acid
Multiple mRNA codons can encode the same amino acid, this means that a change in the genetic code doesn’t necessarily result in
a change in the amino acid sequence
UGU and UGC both code for the amino acid
cysteine
The START codon marks
the start of the protein and therefore initiates the process of translation from the right location (this is always the amino acid methionine in eukaryotic cells, coded for by the codon AUG)
STOP codons cause
translation to terminate at the end of the protein and do not code for any amino acids e.g. UAA
The genetic code is non-overlapping, each base is only read
once in the codon it is part of
The number of amino acids in a protein can be calculated using the number of
coding nucleotides in the mRNA molecule
When given the number of coding mRNA nucleotides
divide by 3 and minus one (for the stop codon – it is best to state this in your answer too)
mRNA Codons and Amino Acids Table
