Comprehensive Biology Paper 1 Revision Guide

Key Point: Animal and plant cells are eukaryotic (have a nucleus), whilst bacteria are prokaryotic (no nucleus) and contain plasmids, loops of DNA, and sometimes flagella for movement.

Key Point: Bacteria are prokaryotic cells with plasmids (rings of extra DNA), flagella for movement, and protective slime capsules - no nucleus or mitochondria needed!

Key Point: Differentiation is when a cell becomes specialised and adapts to carry out one specific function - it's how we get different cell types from identical starting cells.

Key Point: Therapeutic cloning creates an embryo with the same genes as the patient, meaning the stem cells won't be rejected and can be safely used for medical treatment.

Key Point: The digestive system's two-step process - break down then absorb - ensures your body gets all the nutrients it needs from the food you eat.

Key Point: These food tests are reliable and easy to perform - just remember the colour changes and you'll ace any practical exam!

Key Point: Enzymes can denature (lose their shape and stop working) if conditions aren't right, which is why bile's role in creating the perfect environment is so important.

Key Point: Each blood vessel type's structure perfectly matches its function - thick walls for high pressure, thin walls for easy diffusion, large lumens for low-pressure flow.

Key Point: The left ventricle has thicker muscle because it needs to pump blood around your entire body, not just to your nearby lungs.

Key Point: Transpiration isn't just water loss - it's a vital transport system that moves water and minerals from soil to every part of the plant where they're needed.