Section 4 DNA, Genes And Protein Synthesis Flashcards
What is a Gene?
A section of DNA that contains coded information for making Polypeptides and RNA
What is a genes locus?
The fixed position on DNA molecule where you find that gene
What 2 two things are responsible for an organisms development and activities?
Their genes and the environment
How did scientists Discover That an amino acid was coded for by 3 bases?
Since each amino acid must have its own code, then 2 bases wouldn’t be enough to code for them all but 3 bases provide a sufficient number of combinations to code for 20 amino acids.
Why are some amino acids coded for by more than one triplet code?
Because 3 bases in a triplet code will provide a total of 64 combinations (4 cubed) and therefore some amino acids have more than one code.
Why is the genetic code called a degenerate code?
Because most amino acids are coded for by more than one amino acid
Are some amino acids coded for by one triplet code?
Yes
What is the maximum number of triplet codes that can code for one amino acid?
6
Can the DNA sequence be read in two direction?
No
What do the three triplets that don’t Code for anything used for?
They are stop codons, they mark the end of a polypeptide chain.
Name three key words used to describe the genetic code.
Universal, degenerate and non-overlapping
What does it mean to say that the genetic code in non-overlapping?
no base is read more than once
What does it mean to say that the genetic code is universal?
with a few exceptions each triplet codes for the same amino acid in all organisms
What are exons?
coding sequence of DNA
What are introns?
non-sequences of DNA
