organisation

• cells are the basic building blocks of life
• cells are the building blocks of all living things and are the basic units of structure and function
• A tissue is a group of cells with a similar structure and function.
• Organs are aggregations of tissues performing specific functions.
• Organs are organised into organ systems, which work together to form organisms.
• muscle cells can contract (get shorter)
• they contain special protein fibres which can change their length
• muscle cells are packed with mitochondria which provide the energy for contraction
• an organ is a group of tissues working together for a specific function eg the stomach
• the stomach contains muscle tissues and glandular tissue (which releases enzymes)
• The nervous system controls all body functions by sending messages around the body using nerve impulses
• organs are grouped into organ systems which work together to form organisms
• organ systems include the digestive, respiratory, circulatory, skeletal, muscular, excretory and reproductive systems
• during digestion, large food molecules are broken down into small molecules by enzymes. The small molecules can then be absorbed into the bloodstream
• stomach contains hydrochloric acid which helps the enzymes to digest proteins
• enzymes break down carbohydrates into glucose, fats into fatty acids and glycerol, and proteins into amino acids
• food passes through the mouth, oesophagus, stomach, liver, pancreas, duodenum, jejunum, ileum, colon and rectum on its way out of the body
• the liver produces bile which is stored in the gall bladder until it is needed to emulsify lipids (fat)
• enzymes are large protein molecules and they have a groove on their surface called the active site
• enzymes catalyse (speed up) chemical reactions
• the active site is where the substrate attaches to
• substrate is the molecule that the enzyme breaks down
• proteins are long chains of chemicals called Amino acids
• bile is made in the liver and is stored in the gall bladder
• bile helps speed the digestion of lipids but bile isn't an enzyme