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Biology revision AP2 - Coggle Diagram

- - - - movement of water particles from an area of high concentration to an area of low concentration across a partially permeable membrane.
      - required practical: Investigate the effect of a range of concentrations of or sugar solutions on the mass of plant tissue
        
        variables
        
        independent (what's changed): concentration of sugar solution.
        
        dependent (what's measured): change in the mass of the potato cylinders.
        
        control (what's the same): the temperature, the length of time the cylinders were left in the solution and the volume of the solution
        
        Evaluation
        
        Before the mass of the cylinders is measured again, they should be rolled on tissue paper to remove any excess solution
        
        Cylinders need to be left in the solution long enough for a significant change in mass to occur.
        
        If the cylinders change in mass, they have gained or lost water by osmosis
        
        Method:
        
        1) Cut some cylinders of potato tissue and measure their mass.
        
        Place the cylinders in different concentrations of sugar solution
        
        After about 30 mins remove the cylinders and measure their mass again.
    - - net movement of particles from an area of high concentration to an area of low concentration
      - example of diffusion
        
        Some of the substances transported in and out of cells by diffusion are oxygen and carbon dioxide in gas exchange, and of the waste product urea from cells into the blood plasma for excretion in the kidney.
      - factors affecting rate of diffusion
        
        difference in concentration gradient
        
        greater the concentration gradient, higher the rate of diffusion.
        
        temperature
        
        higher the temperature, greater the rate of diffusion because particle gain more kinetic energy.
        
        Surface area
        
        larger the SA, greater the rate of diffusion, because more particles will be able to diffuse at a time.
    - - movement of particles from an area of low concentration to an area of high concentration against the concentration gradient. process requires energy.
      - In plants
        
        allows mineral ions to be absorbed from the soil into the plant roots. this is because there is a low concentration of mineral ions in the soil and a high concentration inside the plant, active transport occurs which allows the plant (roots) t draw out more and more mineral ions from the soil.
        
        Root hair cells have a lot of mitochondria which releases energy for active transport.
      - In animals/humans
        
        there is a lower concentration of sugar molecules in the gut, and high concentration in the blood, and therefore active transport allows sugar molecules to be absorbed from the gut into the blood. These sugar molecules are then used for cell respiration
  - - - Single layer of surface cells.
      - very good blood supply for quicker absorption
      - villi increases the surface area so that digested food is absorbed much more quickly into the blood.
    - - water goes in through the fish's mouth and then O2 diffuses from the water into the blood in the gills where CO2 diffuses from the blood into the water.
      - gill filaments-provide a large surface area which increases the rate of diffusion more gas exchange can happen at once.
      - lamellae-tiny structures which increases the surface area even more. these structures are covered with many blood capillaries to speed up diffusion.
      - thin layer of surface cells-reduces the distance that the gas have to diffuse.
      - blood flows through in one direction and water in the opposite direction which maintains a large concentration gradient. concentration of oxygen in water is always higher than that in the blood, so as much oxygen as possible diffuses from the water into the blood.
    - - lungs transfer oxygen into the blood and remove waste CO2 from it.
      - Large SA
      - surrounded with blood capillaries-a good blood supply
      - moist lining for dissolving gases
      - very thin walls-decreases the diffusion pathway
- - - - inject preferred lab animal with a specific pathogen which will result in an immune response and the production of a specific antibody.
      - immune response leads to the production of antibodies by lymphocytes. these will be collected from the animal
      - obtain a melanoma cell ( cancerous cell) an fuse it with the antibodies that were collected. a hybridoma cell is created
      - hybridoma cells are cloned to produce multiple copies of the antibodies required.
      - isolate/collect the monoclonal antibodies for use.
    - - cancer treatment.
        
        Cancerous cells have antigens on their surface. Monoclonal antibodies can be designed to bind specifically with these antigens. When injected into a person's body, the monoclonal antibodies will bind with these cancer cells and clump them together. this makes it easier to identify a cancerous tumor, which can then be treated or removed. A radioactive substance may be attached to these antibodies so that it is easier to detect the tumor e.g., using a PET scan.
      - pregnancy tests
        
        pregnancy test kits also use monoclonal antibodies. these have been designed to bind with a hormone called HCG, which is found in the urine of pregnant women. Monoclonal antibodies are attached to the end of a pregnancy test stick onto which a woman urinates. is she is pregnant, HCG will be present in her urine and will bind to the monoclonal antibody on the pregnancy stick. This will cause a change in colour or pattern which will indicate pregnancy
    - - cheaper to develop that other drugs.
        side effects on humans are reduced due to animal testing and produces human hybrid cells
      - Monoclonal antibodies create more side effects than expected. They are not yet as widely used as everyone hoped when they were first developed. it can have many side effects. it can be difficult to produce the correct antibody.
  - - - 1) Drug discovery: identification of a possible drug. testing on isolated cells-many drugs fail here.
      - 2) Preclinical trials: Animal testing (might cause ethical issues)- to see effects on a living organism.
      - 3) phase 1-clinical trials: healthy volunteers and patients. low dose only to check side effects.
      - 4) phase 2-physical clinical trials: normal dose given to a small number of people.
      - 5) phase 3-clinical trials: if safe and effective, bigger clinical trials begin. aim to find optimal dose.
      - 6) phase 4-clinical trials and beyond: medicine undergoes legal testing. if passed, can be prescribed by doctors. safety monitored for as long as in use.
    - - placebos
        
        placebos are drugs that do not contain the actual chemical ingredient that will be found in the real drug.
        
        they ensure that any effects seen are due to the medication and not because of something else. It is a control.
      - double-blind trials
        
        neither the doctor nor the patient knows who has the placebo and who has the medication. this reduces bias. only the drug trailer knows.
- - - - uses of glucose.
        
        Releases energy in respiration -Store as starch - glucose converted back when needed e.g. in winter or at night. Starch is insoluble
        
        -Produce cellulose- so strong cells walls (strengthens cells wall)
        
        -Stored as oils or fat- for energy
        
        used to produce amino acids-used for protein synthesis. to produce proteins, glucose is combined with nitrate ions (absorbed from the soil).
    - - Stop photosynthesis from happening faster. Slows/affects the rate of photosynthesis
      - factors affecting rate of photosynthesis
        
        Light intensity, concentration of CO2, temperature and amount of chlorophyll
  - - - Number of bubbles too fast to count accurately -Bubbles are not always the same size