Paper 1 biology

• the gall bladder stores bile produced by the liver until needed to aid fat digestion.
• the liver is the largest internal organ, it stores glucose as glycogen and converts amino acids into urea.
• bile is stored in the gallbladder
• bile contains enzymes called lipases which break down fats into glycerol and fatty acids.
• the pancreas produces insulin which regulates blood sugar levels
• the large intestine absorbs water from undigested material and forms faeces
• the small intestine absorbs nutrients from food through villi and microvilli
• the small intestine has villi that increase surface area for absorption
• enzymes are specific catalysts that speed up chemical reactions without being used up themselves
• pancreas produces enzymes that break down carbohydrates, proteins and lipids
• the stomach secretes hydrochloric acid to denature proteins
• the mouth breaks food down with saliva containing amylase
• microvilli are tiny finger-like projections on the surface of cells lining the small intestine, they also increase surface area for absorption
• bile emulsifies fats so they can be broken down into fatty acids and glycerol