1. So we can replace cells that get damaged or grow old and die. Skin cells multiply fast enough to cover small cuts by themselves... … and with our help they can cover large burns quite quickly. 22 red blood cells 300,000/second skin cells 1,000,000/second heart muscle cells never replaced brain nerve cells Cell replacement Engage Explore Explain Elaborate Extend Evaluate Elicit

3. Bad news for Mr Patel I’m afraid. Just look at his cheek cells compared to yours. What’s the same and what’s different? I’ve magnified the normal cells so you can compare them with his. Student Sheet 4 30 Normal cells Mr Patel’s cells Engage Explore Explain Elaborate Extend Evaluate Elicit

5. nucleus cytoplasm chloroplasts cell wall vacuole Plant cell Animal cell It’s easy to tell which is which from textbook diagrams. They simplify the images and use colour for parts you can’t see clearly. mitochondria cell membrane 42 Engage Explore Explain Elaborate Extend Evaluate Elicit