Some viruses infect human cells. A virus can only infect a cell if it attaches to a receptor molecule in the cell membrane.
Virus X infects cells in the lungs. It does not infect cells in the skin.
Explain why virus X infects lung cells but not skin cells.
The cell membrane is described as a selective barrier.
State what is meant by a selective barrier.
A scientist makes a new drug. The drug attaches to the receptor molecules on lung cells.
Suggest how this drug could stop virus X infecting lung cells.
130 exam-style questions on OCR GCSE Biology 1.1 Cell structures, covering 1.1.1 Viewing cells with light microscopes, 1.1.2 Sub-cellular structures and functions, and 1.1.3 Electron microscopy and resolution. Each one has a worked solution and a mark scheme showing where the marks go.