organisation

• Small intestines - Villi


  • Increase surface area, good blood supply to maintain concentration gradient, short diffusion distance
• Lungs - Alveoli


  • Increase surface area, good blood supply to maintain concentration gradient, thin membranes - short diffusion distance
• Gills in Fish


  • Gill filaments and lamellae - increase surface area, good blood supply to maintain concentration gradient, thin membranes - short diffusion distance
• Roots - Root hair cells


  • Increase surface area
• Leaves


  • Large surface area, thin leaves for short diffusion path, stomata on the lower surface to let O2 and CO2 in and out
• Transpiration


  Water is lost from the leaves of the plant, the transpiration stream is the column of water moving through the roots, stem and leaves, a potometer is used to measure the amount of water lost over time, temperature, humidity, air movement and light intensity affect the rate of transpiration
• Movement of dissolved sugar and minerals


  From the leaves to the rest of the plant through the phloem, moves dissolved sugars made in the leaves during photosynthesis to other parts of the plant for respiration, growth and glucose storage
• Epidermal tissues


  • Waxy cuticle (top layer of leaf) reduces water loss, guard cells and stomata control water loss and gas exchange
• Palisade cells


  • Cells near the top surface that are packed with chloroplasts and contain chlorophyll
• Spongy mesophyll


  • Air spaces in the leaf between cells, increases surface area for gas exchange
• Xylem


  • Hollow tubes strengthened by lignin, transport of water and mineral ions
• Phloem


  • Transports dissolved sugars
• Meristem tissue


  • New cells made including root hair cells, increased surface area for water uptake
• Digestion in the mouth


  Food is broken down by teeth, mixed with saliva, amylase secreted
• Digestion in the stomach


  Food travels down the oesophagus and into the stomach where it is churned with stomach acid to kill germs
• Digestion in the small intestine


  Food is broken down and nutrients are absorbed into the blood
• Digestion in the large intestine


  Water is absorbed into the blood, indigestible food is stored in the anus
• Circulatory system


  • Transports oxygen and nutrients to the body and carbon dioxide and other waste products away
• The circulatory system is under a lot of pressure to deliver blood to the extremities of the body
• Flattened shape of structures


  • Increases surface area, e.g. leaves, alveoli, villi
• Short distance for diffusion


  • Membranes of cells, flattened shape of structures like leaves, capillaries are one cell thick, epithelial and villi are one cell thick
• Carbohydrates


  Source of energy, glucose is the main respiratory substrate, broken down by amylase into simple sugars
• Proteins


  For growth and repair, broken down into amino acids by proteases
• Lipids


  Source of energy, make up part of cell membranes, broken down by lipase into fatty acids and glycerol
• Organelle


  A specialised structure within a cell which performs a specific function
• Cell


  The basic building block of all living organisms
• Tissue


  A group of cells working together to perform a shared function, often with similar structure
• Organ


  A structure made up of groups of different tissues, working together to perform specific functions
• Organ system


  A group of organs with related functions, working together to perform certain functions within the body
• Investigating amylase activity at different pHs

  Pipette iodine solution into depressions of a tile 2) Use a syringe to place amylase solution into a test tube 3) Add pH solution 4) Add starch solution 5) Put in water bath at 30°C 6) After 20 seconds, take a drop and place in iodine, record time for iodine to stay yellow 7) Repeat with different pH
• Bile


  Produced by the liver, stored in the gall bladder, emulsifies lipids by breaking them into smaller droplets, contains sodium hydrogencarbonate to neutralise stomach acid and produce the optimum pH for pancreatic enzymes
• Enzyme active site


  Where the specific reaction occurs, only one substrate can fit into the active site
• Enzyme denaturation


  When the enzyme's active site is disrupted, preventing it from catalysing the reaction
• Circulatory system components


  • Pulmonary artery, vena cava, right atrium, right ventricle, left ventricle, left atrium, pulmonary vein, aorta
• Blood components


  Plasma, red blood cells, white blood cells, platelets
• Biuret test for proteins

  Add biuret solution A to food solution 2) Add biuret solution B, a purple colour indicates protein is present
• Sudan III test for lipids


  Add equal amounts of food and water to a test tube 2) Add drops of Sudan III, a red-stained layer forms if lipids are present
• Test for starch


  Add iodine solution to the food, foods containing starch will turn blue-black
• Benedict's test for sugars


  Add Benedict's solution to food 2) Heat in water bath, colour change indicates amount of glucose present
• Breathing in and out


  Diaphragm and rib cage move to create lower air pressure in the lungs, air rushes in, intercostal muscles contract, diaphragm contracts, volume increases, pressure decreases. Breathing out, muscles relax, volume decreases, pressure increases, air leaves the lungs, diaphragm relaxes