Have you tried searching for macronutrients, all I know(think I know) is:
Macronutrients are protein,fats and carbohydrates, so I guess the beans would be protein, pie would be carb, chips starch(carb)etc.
Don't know if that helps at all, I'm planning on doing my Alevel biology soon, but as yet haven't got much of a clue, sorry! I'll have a little look for you though.
OK, the macronutients would be Protein, in the steak and beans, Fats in the meat, the pastry and in the chips, and carbohydrates in the flour in the pie and in the spuds. Protiens are digested to give amino acids, fats are broken down to give fattu acids and glycerol and carbohydrates give sugars, eventualy glucose. Amino acids are used in the manufacture of protiens and cell walls (so growth and repair), fats are used for energy and for cell membranes (so energy and grown and repair) and carbohydrates are used to give energy. I can't give you the structures here but go to
Each of the macro nutients are made up of chemicals stuch together to make the macromolecule compounds (a compound is two or more elements stuck together, eg carbon dioxide = 1 carbon atom and two oxygen atoms stuck together). So each macromolecule is made up of large numbers of individual atoms stuck together in specific ways. What they are asking you is, I think, to describe how the structures of the macromolecules are put together and which atoms they contain. So for carbohydrates you will hace Carbon (C), Hydrogen (H) and oxygen (O), faths hace the same elements but stuck together in different ways. Protiens have the above, with the addition of Nitrogen (N). Remember that protens are made up of chains of amino acids. If you look at the link I gave you, it gives you the detail of the structues. Think of it like a model being made up of individual lego bricks, they are asking you how each model if put together.