Paper 1 and Paper 2
CB1 K ey Biological Concepts The bone-eating snot-flower worm (Osedax mucofloris) has no digestive system but still manages to feed on one of the hardest substances produced by vertebrate animals – their bones. These worms are a type of zombie worm, so-called because they have no eyes or mouth, and were discovered in the North Sea in 2005 feeding on a whale skeleton. Enzymes in the ‘foot’ of the worm cause the production of an acid, which attacks bone and releases lipids and proteins from inside the bone. Enzymes in bacteria on the foot of the worm then digest these large organic molecules into smaller molecules that the worms absorb (using processes such as diffusion). In this unit you will learn about some of the central ideas in biology, including ideas about cells, microscopy, enzymes, nutrition, diffusion, osmosis and active transport.
The learning journey Previously you will have learnt at KS3: •• how to use a microscope •• about the differences between cells from different organisms •• how some cells are specialised and adapted to their functions •• how enzymes help to digest food in the digestive system •• how substances can move by diffusion. In this unit you will learn: •• how developments in microscopy have allowed us to find out more about the sub-cellular structures found in plant, animal and bacterial cells The ‘foot’ of the worm is buried in the whale bone and contains many bacteria.
•• about the importance of enzymes in nutrition, growth and development •• how enzymes are affected by pH and temperature and why each enzyme only works on a certain type of molecule •• how substances are carried by diffusion, osmosis and active transport.