The clue is in the title here: this topic is all about cells. Much of this is a continuation of GCSE but everything is in a lot more detail. There are more organelles to learn about in the structure, lots more to know about the cell membrane and how substances cross it, vastly more to know about the immune system and a lot of stages that that need to be learnt and understood in the cell cycle and mitosis. In addition, there are some techniques used to study cells that you need to know inside out.
The worksheets are all in Google Docs format. Click the link, click 'file' and then select either 'Add to my Drive' (if you're logged into a Google account) or 'Download as Microsoft Word' (if you're not).