Practise IB Biology HL 1.2.9 by explaining how base choice, sequence length and mutations create diverse nucleic-acid information.
At all levels of biological organization there is diversity.
Explain the diversity of possible base sequences in nucleic acids.
a. four bases in DNA / bases in DNA are adenine cytosine guanine and thymine
OR
four bases in RNA / bases in RNA are adenine cytosine guanine and uracil;
b. purines and pyrimidines
OR
uracil instead of thymine in RNA;
c. bases/nucleotides can be arranged in any sequence;
d. many/4 n possible permutations/combinations/sequences (of the four bases)
OR
64 possible triplets of bases/codons;
e. nucleic acids/RNA/DNA can have any number of nucleotides / unlimited in length;
f. mutations can change base sequence/increase diversity;
g. many different proteins/proteins so many sequences needed to code for them;
h. three/triplet of bases needed to code for each amino acid
OR
degeneracy of genetic code/more than one codon per amino acid;
Marking guidance:
Award mark point a and mark point b if the answer includes the four bases in both DNA and RNA.
Do not accept letters instead of base names in mark point a.
Mark points d and g are different: mark point d is for the idea that the four bases in any sequence gives many possible base sequences; mark point g is for the idea that the many different proteins necessitate many different base sequences in the genome.
4
max