1. Active Transport Used to move substances from low to high concentration (against a concentration gradient) it requires energy so cells involved often have a lot of mitochondria E.g. in the gut nutrients are moved from gut (low conc) to blood (high conc). Insects spiracles (opening in body) allow gases to diffuse in. Oxygen is delivered direct to tissues via tracheoles. The tubes, are thin and moist and air is pumped through by the insect to maintain a concentration gradient. Keywords: Active Transport, Haemoglobin, Anaerobic, Glycogen, Oxygen Debt. Dialysis Keywords: Fermentation, Lactic Acid, Transpiration, Capillaries, Biofuels, Alveoli, Surface Area, Diffusion, Aseptic Leaves Waxy cuticle-keeps water in Palisade layer-cells contain lots of chloroplasts to capture light Stomata on lower surface to allow gases in/out, they can be closed by guard cells to conserve water Spongy mesophyll layer has air spaces to allow gases to move between cells Thin and flat so there is a short distance over which diffusion occurs Alveoli Large surface area to maximise diffusion Moist so that gases can dissolve and diffuse. Thin walls =short distance for diffusion Good blood supply via capillaries this maintains a steep concentration gradient. Breathing InBreathing Out What do ribs do?Move up & outMove down & in What does diaphragm do Move downMoves up Space inside chestGets biggerGets smaller PressureDecreaseIncreases LungsInflateDeflate Ventilation how air enters and leaves the body Villi- projections in gut to increase surface area Arteries- carry blood away from heart. Veins-carry blood towards heart and contain valves to prevent back flow Capillaries-walls are a single cell thick to allow exchange via diffusion Blood Plasma-liquid carries blood cells and other substances e.g. glucose and CO 2. Red blood cells contain haemoglobin this binds to oxygen creating oxyhaemoglobin, the oxygen can then be released to cells. White blood cells make antibodies Platelets help clotting Exercise and the body Muscles use aerobic respiration to release energy Glucose +oxygen  carbon dioxide +water. Glycogen in muscle cells is also converted to glucose More exercise means more muscle activity so more glucose and oxygen must be supplied and more carbon dioxide must be removed to enable this… 1)Breathing rate increase and breathe deeper to meet the extra oxygen demand 2)Heart pumps faster 3)Arteries supplying the muscles dilate

2. Double Circulation System The right side pumps deoxygenated blood to the lungs to collect oxygen and remove carbon dioxide. The left side pumps oxygenated blood around body. Anaerobic Respiration Glucose broken down without oxygen, occurs during vigorous exercise when enough oxygen can’t be supplied to the muscles. Glucose  energy +lactic acid Allows muscles to keep working but does not release as much energy as aerobic respiration and build up of lactic acid is painful. Leads to oxygen debt, oxygen is needed after exercise to break down lactic acid in to CO 2 and water. 1 2 3 Kidneys (made up of nephrons) 1)A high pressure forces water, urea, ions and sugar out of the blood and into the Bowmans capsule. Large molecules like proteins and blood cells can not fit through. 2)Useful substances are reabsorbed; all sugar is but the amount of ions and water reabsorbed will vary. (the reabsorption is via active transport) 3)Remaining substances including urea continue down nephron and down to bladder via collecting duct. TransplantsDialysis GoodLive more normal life e.g eat what you want Allows to survive don’t need operation and no risk of rejection BadLong waiting list Take drugs that suppress immune system so risk of infection Expensive to run Not pleasant and several sessions a week needed Yeast-a single celled microbe it can respire with or without oxygen Making bread- the yeast respires making CO 2 which gets trapped causing the bread to rise Alcohol - barley grains are soaked in water. Germination begins and enzymes break down the starch in the grains into a sugary solution (malting). This solution is used as an energy source for the yeast. The yeast and sugar mixture is fermented to produce alcohol, when hops are often added to give the drink its flavour. When making wine sugars in grapes are used by the yeast cells as an energy source. Making Cheese Bacteria are added to milk, solid curds are formed. The curds are separated from the liquid whey and left to mature. Making Yoghurt Milk is heated to kill any bacteria, a starter bacteria culture is then added. Bacteria ferment lactose sugar into lactic acid. The lactic acid causes the milk to clot and solidify. Fermenters Used to grow microbes on a large scale, the following are required; -food in nutrient medium -air to provide oxygen -water cooled jacket as microbes make heat by respiration -pH probe -stirrer to keep microbes in suspension and maintain even temperature Biogas This can be made by anaerobic fermentation of waste material in a generator Batch generator-gas is made in small batches the generator is filled with waste and cleared at the end of each session Continuous- gas is made all the time as waste material is continually fed in and digested material removed. Biofuels Ethanol is made from sugar cane juice or from glucose obtained from maize starch. Advantages- doesn’t contribute to acid rain, is carbon neutral as any CO 2 released was taken in by plants, uses cheap and readily available materials, digested material can be used as a fertiliser.