Biology B7

HideShow resource information
View mindmap
  • B7
    • Exercise
      • BMI
    • The Body
      • Negative Feedback
        • Vasodilation - when the blood is too hot, the capillaries in the skin dilate so blood flow increases and more heat is lost.
          • Blood
            • Capillary fluid contains all the nutrients and oxygen needed by the cells. Capillary walls are only one cell thick so when the blood enters at high pressure, the plasma is forced out of the blood vessel. Gases like oxygen diffuse out so the cells can use it for energy. Waste products such as carbon dioxide diffuse into the capillary while urea is absorbed in. Extra capillary fluid that has been used up is not absorbed back into the capillary, it travels through the lymph vessels, which lead it back to the circulatory system.
        • Vasoconstriction - when the blood is too cold, the capillaries in the skin constrict so blood flow decreases and less heat is lost.
          • Blood
            • Capillary fluid contains all the nutrients and oxygen needed by the cells. Capillary walls are only one cell thick so when the blood enters at high pressure, the plasma is forced out of the blood vessel. Gases like oxygen diffuse out so the cells can use it for energy. Waste products such as carbon dioxide diffuse into the capillary while urea is absorbed in. Extra capillary fluid that has been used up is not absorbed back into the capillary, it travels through the lymph vessels, which lead it back to the circulatory system.
        • Receptor detects a change in the environment (stimuli) and sends the information to the CNS (hypothalamus), which co-ordinates a response and sends this through the motor neuron to the effector (e.g. muscle or gland) that produces the final response.
          • When you are cold, you shiver and your hairs rise.
          • When you are hot, you sweat and your hairs lie flat.
      • Diabetes
        • Type 1- 10% of all cases, mainly caused by genetic links. The body cannot produce insulin
          • High Glucose levels = insulin production increased. Low glucose levels = insulin production decreased.
            • Insulin causes the cells around the body to take glucose from the blood.
            • Exercise can cause glucose levels to fall
            • Food can increase blood glucose levels
        • Type 2- 90% of all cases, mainly found in people over 40 due to a bad diet. Body cannot produce enough insulin and it is rejected by most of the cells in the body.
          • High Glucose levels = insulin production increased. Low glucose levels = insulin production decreased.
            • Insulin causes the cells around the body to take glucose from the blood.
            • Exercise can cause glucose levels to fall
            • Food can increase blood glucose levels
    • Ecosystems
      • Closed loop systems - waste from one part of the system is used as raw materials for the next part - it is a continuous cycle
        • e.g. photosysntheis, paper manufacture
      • Open loop systems - waste from one part of a process cannot be used again
        • e.g. products made from crude oil
      • Many species overproduce their offspring to ensure that many live because not all will germinate due to being eaten by animals or fungi and not living long enough.
      • Eutrophication takes place when farmers use excess fertiliser on their crops, which is carried away by surface run-off into near by water. This causes algal bloom on the top of the water. This blocks light so plants cannot photosynthesise and die. Dead algae are decomposed by bacteria, which use all the oxygen causing the fish to die.
      • Bio-accumulation is when a chemical builds up in a food chain. It starts with lots of primary consumers getting contaminated by the chemical. Then their predator eat lots of them causing the chemical concentration to build up in them. Now their predator eats lots of the secondary consumer. The chemical builds up to such a high concentration that it ends up killing the organism. This can heavily affect the food chain because most animals are interdependent on each-other.
      • Biodiversity is the concept of having lots of species with high populations - high variety means more sustainable.
        • Monoculture - only one species of crop is grown. Low biodiversity. If there is a problem with one plant, all of them have problems and can die. The species could go extinct
      • Fishing - unsustainable because of overfishing and use of pesticides. Can be made sustainable by fishing quotas, restrictions (e.g. fish size, shape, colour), time for fishing
    • Genetic Modification
      • To grow certain genes: the wanted gene from a human cell is isolated and duplicated. It is then inserted into a plasmid (bacteria's circular DNA), which duplicate using enzymes. The plasmid is inserted into an empty bacteria and the bacteria reproduces / duplicates. Wanted gene has been produced.
      • Genetic testing: the gene (unhealthy) must be identified. Then a DNA probe with the matching bases to the gene will need to be made. A florescent marker will be added to the probe so it lights up if it sticks to the gene (this would mean that the gene was present and the patient has what they are testing for). A UV light is shone to detect where the DNA probe is.
    • Farming microbes
      • Microbes reproduce at a fast rate, can form complex molecules easily and are not attached to many ethical concerns. Quorn is an example of food produced from microbes.
      • During fermentation, the conditions need to be controlled because the enzymes in the reactions are very sensitive to pH and temperatures. They have an optimum condition and can become denatured (the shape of their active site changes). Therefore there are temperature and pH monitors, only sterile air allowed in the prevent any outer chemicals from entering the reaction (closed system) and there is a motor / stirrer which makes sure that all the bacteria are reacting.

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all B7 resources »