Label the parts of two paired nucleotides in the polynucleotide of DNA.

Using the cladogram, identify one diagnostic feature that characterizes the given groups of vertebrates at A, B and C.

A:  .....................................................................
B:  .....................................................................
C:  .....................................................................
 

State the name of the domain to which these organisms belong.

I: nitrogenous base
OR
adenine
OR
purine base

II: deoxyribose

III: phosphate

A: gills or fins or scales or no limbs or external fertilization

B: homeothermic or endothermic or warm-blooded or lungs or tetrapod or four limbs or pentadactyl limbs or internal fertilization

C: hair or fur or mammary glands or milk

Eukaryotes

Most candidates gained two marks, the most common mistake being to label the deoxyribose as ‘sugar’ or ‘ribose’

Again this seems to be an area that escaped some teachers in their reading of the new specification and resulted in a large number of G2 comments, most of which seemed to think that the oversimplification of the cladogram led to confusion. In the end better prepared candidates had no problem with the question, managing to state a fish characteristic for A, something in common between birds and mammals, e.g. homeothermic for B and  a general mammalian feature for C (but not forgetting the monotremes)

If candidates had been taught this section, they knew that the domain was eukaryotes.