2.4 compare the structures of plant and animal cells.

Differences
Plant cells have a vacuole
Plant cells have chloroplasts
Plant cells have a cell wall

Similarities
They have a nucleus
They have cytoplasm
They have a cell membrane

2.2 describe cell structures, including the nucleus, cytoplasm, cell membrane, cell wall, chloroplast and vacuole

What you need to know for this is the layout of the cell, this is easiest done by diagram, but here are explanations:

Animal cell
A nucleus is in the centre of the cell; it is surrounded by cytoplasm; around the outside edge is the cell membrane.

Plant cell
A vacuole in the centre is surrounded by cytoplasm; with in this is the nucleus and chloroplasts; surrounding this is the cell membrane; and around that is the cell wall.

There are diagrams at the bottom of this page: http://www.bbc.co.uk/schools/gcsebitesize/science/add_edexcel/cells/cells2.shtml

2.3 describe the functions of the nucleus, cytoplasm, cell membrane, cell wall, chloroplast and vacuole

Within a cell there are different organelles, the above are as such.

The nucleus, often thought as as the centre of a cell, contains all the genetic 

information of a cell (the cells chromosomes), it controls the activities of the cell.

Cytoplasm surrounds the nucleus within the cell walls. It is where reactions take place in the cell.

The cell membrane controls the movement of chemicals in and out of the cell.

The cell wall, which is made up of cellulose, strengthens the cell.

Chloroplast contain chlorophyll, and are used in photosynthesis.

Vacuole keeps the cell turgid (basically keeps the cell  filled with water.)