B2-Organisation

• large multicellur organisms (humans) are made up of organ systems
• the process in which cells become specialised for a particular job is called differentiation
• differentiation occurs during the development of cells
• specialised cells form tissues which form organs which form organ systems
• muscular tissue contracts to move whatever its attached to
• glandular tissues which makes and secretes chemicals like enzymes and hormones
• epithelial tissue which covers some parts of the body like inside the gut
• muscular tissue moves the stomach wall to churn up food
• glandular tissue makes digestive juices to digest food
• epithelial tissue covers inside and outside the stomach
• glands e.g pancreas and salivary glands produce digestive juices
• stomach and small intestine digest food
• liver produces bile
• small intestine absorbs soluble food molecules
• large intestine absorbs water from undigested food leaving faeces
• enzymes are catalyst produced by living things
• you can make a reaction happen more quickly by raising the temperature but also unwanted ones too however enzymes act as a biological catalyst reducing high temperatures
• a catalyst is a substance that increases the speed of the reaction without being changed or used up in the reaction
• enzymes are large proteins and all proteins are made up of chains of amino acids
• enzymes need the right PH and temperature
• enzymes are the most active at the optimum temp
• lock and key

  A) active site

  B) unchanged

  
• in enzymes if the temp gets to hot some bonds can break
• if PH isn`t correct bonds can break and cause enzymes to change shape
• enzymes have an optimum PH its often 7
• required pratical 1

  A) amylase

  B) iodine solution

  C) browny orange

  D) amylase solution

  E) starch solution

  
• rate = 1000 / time
• digestive molecules break down big molecules
• starch, proteins and fats are too big to pass through the wall of the digestive system
• digestive system breaks down big molecules like fats and starch into small ones like sugars
• small soluble molecules can easily pass through the walls of the digestive system into the blood stream
• carbohydrase converts carbohydrates into into simple sugars
• proteases coverts proteins into amino acids
• lipases covert lipids into glycerol and fatty acids
• bile neutralises the stomach acid and emulsifies fats
• bile is stored in the gall bladder
• bile is alkaline and neutralises hydrochloric acid in the stomach which is acidic
• bile breaks down fats into tiny droplets
• enzymes

  A) salivary glands

  B) pancreas

  C) small intestine

  D) amino acids

  E) glycerol and fatty acids

  
• digestive systsem

  A) stomach

  B) salivary glands

  C) gullet

  D) liver

  E) gall bladder

  F) large intestine

  G) pancrease

  H) small intestine

  I) rectum