Identify the biochemical structures labelled $A$ and $B_1, B_2$ etc.
State the biochemical processes occurring in stages 1 and 3.
Give the molecular formula of adenine.
Name the three other nitrogenous bases in DNA.
DNA has a double helical structure made up of two linked strands. What kind of bonding occurs between the phosphate and sugar groups within one DNA strand, and between the bases on opposite strands?
The breakdown of adenosine triphosphate, ATP, supplies energy for many cellular reactions. $\text{ATP} + \text{H}_2\text{O} \rightarrow \text{ADP} + P_i$. What type of chemical reaction is this?
X-ray crystallography can be useful for finding out about the structures of large organic molecules such as ATP. Which element in the ATP molecule will interact most strongly with the X-ray beam?
Explain why X-ray crystallography will not detect hydrogen atoms.