B2 - organisation

• and organ system is a group of organs that work together to preform a particular function
• a tissue is a group of calls that work together to preform a function
• An organ is a group of different tissues that work together to preformed a certain function
• The digestive system breaks down and absorbs food
• Enzymes increase the rate of reaction (they act as biological catalysys)
• Temperature and PH affect the rate of an enzyme controlled reaction as each enzyme has a optimum PH and temperature that they work best at
• Proteins are brocken down in to amino acids
• glycerol and fatty acids are products of lipid digestion
• Proteases are produced in the stomach, pancreas and the small intestine
• The liver produces bile and it’s stored in the gall bladder
• The products of digestion can be used to build new carbohydrate, proteins and lipids, and some of the glucose produced is used in respiration
• Bowl neutralises hydrochloric acid, making conditions in the small intestine alkaline. Enzymes in the small intestine work best in alkaline conditions. Bile also emulsifies fats which means it brakes fats down into tiny droplets, which gives lipase enzymes a much bigger surface area to work on during digestion. These two effects of bile both increase the rate of digestion
• The Benedict’s test is the test for sugars
• The iodine test is for starch
• The biuret test is used to test for proteins.
• Alveoli is where gas exchange occurs in the lungs.
• Breathing rate = number of breaths ÷ time
• Alveoli


  • Surrounded by a network of blood capillaries
  • Blood returning from the rest of the body has low oxygen and high carbon dioxide
  • Alveoli have high oxygen and low carbon dioxide
  • Oxygen diffuses out of alveoli into blood, carbon dioxide diffuses out of blood into alveoli
• Alveoli adaptations for gas exchange

  • Large surface area
  • Thin walls
  • Moist lining for dissolving gases
  • Good blood supply
• Oxygenated blood enters the left atrium through the pulmonary veins it’s then pushed through the bicuspid valve to the left ventricle and leaves the heart via the aorta to the rest of the body
• guard calls open the stomata when turgid and close stomata when flaccid
• Photosynthesis can’t happen in the dark so stomata doesn't need to be open to let carbon dioxide inside the leaf. this means stomata begins to close as it gets darker, which reduces the amount of water able to escape from leaves
• Translation is the movement of food molecules through phloem tissue
• Xylem tubes carry water and minerals ions from the roots to the stem and the leaves
• evaporation and diffusion of water from the leaves create a slight shortage of water in the leaf this means that more water is drawn up from the rest of the plant through the xylem vessels to replace it this causes more water to be drawn up from the roots
• The stomata is a structure in the lower epidermis of a leaf that allows carbon dioxide to diffuse directly into the leaf
• The large spaces of spongy mesophyll tissue allows gas to diffuse in and out of cells
• Godsell is a found in the lower epidermis around the stomata they control the opening and closing of the stomata in response to environmental conditions to control gas exchange and water loss
• White blood cells defend the body against infection
• Plasma is a liquid that carries everything in the blood
• Platelets help clot blood to cause scabs to form and help the body to heal
• Red blood cells help to carry oxygen around the body gas exchange also happens here
• Capillarys walls are only one cell thick which means the distance over which materials are exchanged is very small which increases the rate at which nutrients, oxygen and waste products can be diffused across
• Rate of blood flow = volume blood ÷ time
• Arteries carry blood that has been pumped from the heart at high-pressure so the walls have thick layers of muscle and elastic fibres to make them strong and elastic
• Beans which carry blood back to the heart in a low pressure so the walls don’t need to be as thick they also have a valve which stops the backflow of blood
• Red blood have haemoglobin which oxygen binds to when the blood flows through the lungs
• A stent is a tube that is inserted inside an artery. Stents keep coronary arteries open to oxygenated blood flow through the heart muscles.
• When someone has developed a coronary heart disease, the coronary arteries that supply blood to the heart muscles have been blocked by layers of fatty material building up. This has narrowed the arteries restricting the blood flow which reduces the amount of oxygen that reaches the heart muscle (for respiration)
• Healthy state of physical and mental well-being