Topic 4 - The genetic code Flashcards
what is translation
the process by which proteins are produced, vie RNA, using the genetic code found in the DNA
where does translation take place
in the ribosomes
what are ribosomes
site of protein synthesis in the cell
what is a triplet code
the code of 3 bases, and is the bases of the genetic information of DNA
what is a gene
a sequence of bases on a DNA molecule coding for a sequence of amino acids in a polypeptide chain, that affect a characteristic in the phenotype of the organism
what is a codon
a sequence of 3 bases in DNA or mRNA
what is a complementary strand
the strand of RNA formed that complements the DNA acting as the coding strand
what is the function of non-coding DNA
they are involved in regulating the protein-coding sequences, turning genes ‘on’ or ‘off’
what is the % of non-coding DNA
98%
what is the other 2% of DNA made up of
made up of DNA that codes for proteins
what are 3 characteristics of genetic code
- triplet code
- non-overlapping
- degenerate
Scientists were trying to find out how code was read.
What is the advantage of overlapping code
relatively short lengths of DNA could carry the instructions for many different proteins
Scientists were trying to find out how code was read.
What is the disadvantage of overlapping code
the amino acids that could be coded side-by-side would be limited
how did scientists find out that code was not overlapping?
If a codon consists of 3 nucleotides and is completely overlapping, and a single nucleotide is altered by a point of mutation, then 3 amino acids will be affected by that single change
when do mutations happen
they happen any time the DNA is copied
