Organisation

• What are he 5 levels of organisation in living organisms

  Cells -> Tissues -> Organs -> Organ systems -> Organisms
• Cells: the basic building blocks
• Tissues: groups of cells with similar structures + functions
• Organs: groups of tissues working together to preform a specific function
• Organ systems: groups of organs working together
• Organisms: organ systems working together
• Pancreas: makes enzymes amylase, lipase, protease
• Liver: makes bile
• Gall bladder: stores bile
• Function of bile: neutralises hydrochloric acid from the stomach, emulsifies fats
• Large intestine: water + minerals absorbed into blood
• Mouth: food is chewed
• Salivary glands: make saliva containing amylase
• Oesophagus: Carries food to stomach
• Stomach: churns food, digests proteins by releasing protease, kills pathogens by releasing hydrochloric acid
• Rectum: stores feces
• Anus: expels feces
• How air goes through lungs

  Mouth/nose -> down trachea -> into bronchi -> through bronchioles -> into alveoli
• What is blood made up of? + their functions

  Red blood cells: carry oxygen

  Plasma: transports substances

  Platelets: form blood clots

  White blood cells: defend against diseases
• Artery function + structure

  Function: carries blood away from the heart at high pressure

  Structure: Thick walls, small lumen
• Vein function + structure

  Function: carries blood to heart at a low pressure

  Structure: Valves, thin wall, large lumen
• Capillary function + structure

  Function: carries blood to tissues

  Structure: One cell thick, narrow lumen
• Right ventricle job

  Pumps blood to lungs where gas exchange takes place
• Left ventricle job

  Pumps blood to body
• Substances in plasma: Hormones, proteins, urea, carbon dioxide. glucose
• Enzymes are large proteins that catalyse (speed up) reactions
• Lock and key theory

  Substrate fits into specific enzyme at its unique active site
• Describe the effect of temperature on enzymes

  Temp increases, rate of reaction increases

  Up until optimum temp, where reaction is fact as possible

  After optimum temp, enzymes denature and stop working
• When can enzymes denature

  At extremes of PH or very high temps
• What happens when an enzyme has been denatured

  Substrate can no longer bind to the active site
• Amylase

  Sites of production: Pancreas, small intestine, salivary glands

  What does it do: Breaks down starch into maltose (a simple sugar)
• Protease

  Sites of production: Pancreas, small intestine, stomach

  What does it do: breaks down proteins into amino acids
• Lipase sites of production + what the reaction does

  Sites of production: Pancreas, small intestine

  What does it do: breaks down lipids into fatty acids and glycerol
• Why do diff digestive enzymes have diff optimum PHs

  Diff parts of digestive system have diff PHs
• Small intestine: where food is absorbed into the blood
• What is a leaf?

  An organ because they contain many tissues that work together to preform photosynthesis
• Tissues in leaves

  Waxy cuticle

  Upper epidermis

  Palisade mesophyll

  Spongy mesophyll

  Lower epidermis

  Guard cells and stomata
• Waxy cuticle

  Makes the leaf waterproof
• Upper epidermis

  Single layer of cells

  Protects against water loss

  Transparent to allow light through
• Palisade mesophyll

  Tightly packed cells

  Lots of chloroplasts