genetic codes Flashcards
(12 cards)
what does the term genetic code mean
its the DNA and mRNA base sequence that determines the amino acid sequences in an organisms proteins
what does the term codon mean
its the triplet of bases in mRNA that codes for a particular amino acid
why is it a triplet code
as 3 bases encode each amino acid
why is the code described as degenerate or redundant
as more that one triplet code can encode each amino acid
why can more that 1 triplet code encode each amino acid
as there are 64 possible codes but only 20 amino acids found in proteins
why is the code universal
as it is known in all organisms as the same triplet codes for the same amino acid
why is the code non overlapping
as each base only occurs in 1 triplet
what does the one gene one polypeptide hypothesis state
it states that 1 gene codes for 1 polypeptide.
what example does the one gene one polypeptide hypothesis provide
that the quaternary structure of haemoglobin has 4 different polypeptide chains, therefore 4 genes are needed to code for haemoglobin and collagen has 3 alpha helices but they are identical there for one gene is enough
what is the modification of a polypeptide called
post translation modification
what can polypeptides be chemically modified by
they can be chemically modified by a combination with non proteins
examples of the non proteins polypeptides can be chemically modified by and what they make
carbohydrates - making glycoproteins
lipids - making lipoproteins
-phosphate - making phospho-proteins
