Question X. The Genetic Code.
Evidence for Evidence for Evidence for
Question
Achieved Achieved with Merit Achieved with Excellence
Nucleic acids described as
poly nucleotides that store
genetic information
OR
a.
Polynucleotides described as
a polymer of nucleotides (P +
5C sugar + nitrogenous
base).
TGCCATGAACTC all
b.
correct
thr-val-leu-glu all
c.
correct
Degeneracy of the genetic This provides some
code described i.e. there is protection from point
d. more than one codon for mutations when they occur
rd
most amino acids. on the 3 base of any
codon.
2 nucleotide codon would Code needs to provide Code needs to provide
2
provide 4 = 16 different enough codons for 20 amino enough codons for 20 amino
codons acids. acids + a at least 1 stop /
Thus a 3 nucleotide codon termination codon.
3 nucleotide codon would fulfils this requirement. Code has a built in
e. 3
provide 4 = 64 different degeneracy allowing for
codons backup codons for many
amino acids (and some
protection from point
mutations).
tRNA, mRNA, ribosomes Transcription and translation - Correct names of the
(rRNA), DNA and that should be explained in broad enzymes involved should be
enzymes are required. detail. named.
- There should also be some
discussion of the genetic code
and how the sequence of
bases in DNA is transcribed
to mRNA and then translated
f.
into the amino acid sequence
of a protein.
- Transcription explained as a
process that copies the code
to a temporary messenger.
- Translation explained as
changing from a 4 base code
to a 20 amino acid code.
Total 6 3 2