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Organisation (Cardiovascular diseases (Coronary heart disease (Statins are…

- - - - This means they are not infectious
  - - - This causes the coronary arteries to narrow
        
        This reduces the flow of blood in the artery and results in a lack of oxygen supplied to the heart muscles
    - - This slows down the rate that fatty materials build up in the arteries
      - They have been proven to reduce the risk of CHD
      - They do have some unwanted side effects eg liver problems
    - - To address this a stent (a tube) can inserted into the coronary artery to keep it open
        
        The advantage of this is that the blood can flow normally through the artery
        
        However the stent cannot stop other region of the coronary arteries from narrowing
        
        It does not treat the underlying causes of the disease-
  - - - These patients are sometimes given a donated heart or a donated heart and lungs
        
        They are not enough hearts to treat every patient
        
        The patient must take drugs to stop the donated heart from being rejected by the body's immune system
        
        Sometimes a artificial heart can be used a temporary solution to wait for a heart transplant or to allow the damaged heart to rest
        
        Artifical hearts increase the risk of blood clotting. they are not a long term solution to heart failure
- - - - Digestion turns large molecules into small molecules into small one
  - - - The churning action in the stomach turns the food into a fluid increasing the surface area for enzymes to digest
        
        The fluid then passes into the intestines
        
        Chemicals are released from the liver and pancreas
        
        The pancreas releases enzymes which continues the digestion of starch and protein. They also start the digestion of lipids
        
        The walls of the small intestines release enzymes to continue digestion of protein and lipids
        
        The small food molecules produced by digestion are absorbed into the bloodstream either by diffusion or by active transport
        
        1 more item...
        
        The liver releases bile which helps to speed up the digestion of lipids. The bile also neutralizes the acid released from the stomach
      - The stomach contains hydrochloric acid which helps the enzymes to digest proteins
- - - - The substrate fits perfectly into the active site
        
        Enzymes are specific. The enzyme fits perfectly into the active site
      - If the substrate does not fit into the active site. The enzyme will not break down the substance
  - - - When protein is digested the protein back to the individual amino acids, which are absorbed into the bloodstream
        
        Once the amino acids are absorbed by the body they are joined together in a different order to make human proteins
  - - - These are broken down by amylase
        
        When they are digested, they produce simple sugars
        
        Amylase is found in the saliva and pancreatic fluid
  - - - Bile helps speed up digestion of lipids but bile is not an enzyme
        
        Bile converts large lipids into smaller droplets (emulsifies the liquid)
        
        This increases the surface area of the lipid and increases the rate of breakdown by lipase
      - Bile is also alkaline allowing to neutralise stomach acid
        
        This increases the rate of lipid digestion by lipase
- - - - Tranports soluble digestion products
      - Transports carbon dioxide from the organs to the lungs
      - Transport waste product urea from the liver to the kid
  - - - Contain a nucleus which contains dna which encodes the instructions that the white blood cells need to do their job
  - - - Contain oxygen carrying molecule haemoglobin
        
        Haemoglobin combines with oxygen to make oxyhaemoglobin they can then release the oxygen in the organs
      - Red blood cells have no nucleus, which means that they have more room for haemoglobin
      - Are a biconcave disk which gives them are larger surface area increasing diffusion
  - - - Otherwise the immune system will reject the blood and patient could die
      - Diseases can be transmitted via blood
        
        So donors are screened for diseases prior
- - - - The millions of alveoli mean that the lung have a huge surface area
      - The alveoli have a very thin walls so the diffusion path is very short
      - Alveoli have a good blood supply
        
        Once the oxygen diffuses into the blood, it is rapidly removed, This ensures that the concentration gradient is as steep as possible
- - - - A diet high and low in vegetables increases the levels of certain types of cholesterol in the blood
        
        Increases the rate that fatty materials build up in the arteries
      - A diet high in salt can increase blood pressure, increasing the risk of developing cardiovascular diseases
    - - The risk of developing cardiovascular diseases is increased in people who smoke
      - The risk is decreased in people who exercise regularly
  - - - Cigarette smoke contains a number of chemicals which can trigger cancer called carcinogens
      - Also increases risk of other lung diseases eg emphysema
  - - - Also leads to the baby being born with a low body-mass
    - - Children born with this syndrome can be born with fetal alcohol can have learning difficulties or physical problems
- - - - Protects the surface of the leaf
      - Upper epidermis
        
        Its transparent which allows light to pass through to the photosynthetic cells
        
        Covered with thin layer called waxy cuticle
        
        Reduces evaporation of water from the surface of the leaf
        
        Helps to prevent the leaf from drying out
      - Lower epidermis
        
        Has tiny pores called stomata
        
        Stomata allow CO2 to enter the leaf and O2 to leave
        
        Also helps to control the amount of water vapour that can pass out of the leaf
        
        On either side of the stomata are guard cells
  - - - Allow carbon dioxide to diffuse from the stomata through the spongy mesophyll to the palisade cells
      - Oxygen diffuses from the palisade cells through the spongy mesophyll to the stomata
  - - - Including magnesium which is used to make chlorophyl
- - - - The water vapour then diffuses through the air spaces in the spongy mesophyll and out of the leaf through the stomata
        
        Now water passes from the xylem into the leaf to replace the water that has been lost
        
        Finally water is drawn into the root hair cells and up the xylem vessels to the leaf
        
        Scientists call this whole process the transpiration stream
    - - The transpiration stream transports dissolved mineral ions such as mangesium
        
        The evaporation of water cools the water down
  - - - That is because evaporation is faster when temperatures are higher
    - - This is because the concentration gradient is greater when their is less water vapour in the air
    - - This is because wind removes any water vapour, allowing more water to evaporate
    - - This is because high light intensity increases the rate of photosynthesis
        
        meaning that the stomata will now open to allow CO2 to enter
        
        Once the stomata have opened, water vapour can now pass out of the leaf
  - - - When the light intensity is high for example during the day, the guard cells swell and they change their shape
        
        This causes the stomata to open
        
        Now carbon dioxide can diffuse into the leaf and be used in photosynthesis
        
        Under hot conditions, the plant closes its stomata to reduce water loss by transpiration meaning the plant cannot photosynthesise
- - - - In the first add 2cm³ of starch solution
      - In the second add 2cm³ of amylase solution
      - In the third add 2cm³ of a pH buffer solution
      - Place all three test tubes in water bath at 30°C for 10 minutes to allow the solutions to reach the correct temperature
        
        Put all solutions in the same test tube and mix with a stirring rod. Immediately afterwards place the test tube in the water bath and start a stopwatch
        
        After every 30 seconds place a drop of the solution into a well with iodine in it and see if starch is still present
        
        Once starch is no longer there (We know this if the iodine remains orange) record the amount of time it took and repeat the experiment using different pH buffers for example 6,7,8
  - - - Address this by taking samples every 10 seconds
    - - Address this by having multiple people check the iodine's color
- - - - The oxygenated blood goes to the organs and diffuses into the cells and then goes back to the heart
  - - - The heart then pumps the oxygenated blood to the organs and transfers it's oxygen to the organs and goes back to the heart to get oxygenated again
  - - - These are separated by valves
    - - The deoxygenated passes through the pulmonary artery to go to the lungs to get oxygenated
        
        Oxygenated blood passes from the lungs to the heart using the pulmonary vein
        
        Oxygenated blood is pumped from the heart to the in the aorta
    - - The atria then contract and blood is forced into the ventricles
        
        The ventricles now contract and force the blood out of the heart
        
        The valves stop the blood flowing back into the atria
    - - They provide oxygen to the muscle cells in the heart
    - - Sometimes the pacemaker stops working so doctors can implant an artificial pacemaker
        
        The artificial pacemaker is a small electrical device that can correct irregularities in the heart rate
- - - - The arteries has elastic fibres stretch when the surge of blood passes through and then recoil in between surges, which keeps the blood moving
  - - - To stop this from happening the veins contain valves that open when the blood is travelling in the correct direction to allow the blood to flow through
        
        When the blood flows backwards the valves shut
- - - - Past the optimum temperature the activity of the enzyme rapidly drops to zero
        
        This due to the heat denaturing it causing the active site to change shape
- - - - Contrained in a membrane
      - Do not invade other parts of the body
      - Benign tumours are growths of abnormal cells which are found in one area
    - - Invade neighbouring tissues and move into the bloodstream
        
        Once in the bloodstream and travel around the body forming new,secondary tumours
      - Classed as a cancer
  - - - Certain types of breast cancer
      - Prostate cancer
      - Cancer of the large intestine
    - - Smoking: lung cancer
      - Ultraviolet light: skin cancer
      - Alcohol: mouth and throat cancer
    - - Radioactive gas which increases the risk of developing lung cancer
      - Radon releases ioning radiation which damages dna in cells
        
        This can cause cells to undergo uncontrolled mitosis
- - - - Tuberculosis (TB) is a lung disease. TB can be fatal
        
        In most people the immune system can fight off TB
        
        Some people with defective immune systems (people with HIV) can not fight off TB
    - - In some people HPV can cause cervical cancer
  - - - The body is infected with a pathogen which the immune system but the person is left with allergy
    - - People with arthritis can find it very difficult to move and lead a normal life
        
        In certain cases, this can make them feel isolated and depressed
- - - - Filter the solution to remove suspended food particles
        
        To test for starch you have to place 2cm³ of food solution into a test tube
        
        Add a few drops of iodine into the test tube
        
        If starch is present then iodine will turn blue-black
        
        If starch is not present then iodine will remain orange
        
        To test for reducing sugars you have to place 2cm³ of food solution into a test tube
        
        Add 10 drops of Benedict's Solution
        
        Place the test tube into a beaker half-filled with hot water from a kettle and leave for 5 minutes
        
        A Green color means that there is a small amount of sugar
        
        A Yellow color means that there is a more amount of sugar
        
        A Blue color means that there is no sugar
        
        A Brick-Red color means that there is a large amount of sugar
        
        To test for proteins you have to place 2cm³ of food solution into a test tube
        
        Add 2cm³ of Biuret Solution
        
        If protein is present then the biuret soluton will turn purple/pink
        
        If protein is not present then the biuret soluton will remain blue
        
        To test for lipids(fats) you have to place 2cm³ of food solution into a test tube however do not filter the paste prior to this test
        
        Add 3 drops of Sudan-3
        
        If lipids are present then a **red stained oil layer will separate out and float on the surface
        
        If lipids are not present then there will be no colour change
- - - - Provides large surface for the absorbing products of digestion
    - - Massively increase surface area for absorption of molecules
        
        Microvilli on the surface of villi increase the surface area even further
      - Villi have a very good blood supply, so the blood stream rapidly removes the products of digestion
        
        Increase the concentration gradient
      - Have a thin membrane
        
        Ensures a short diffusion path
- - - - Scientists noticed that people who smoked cigarettes had a higher chance of developing lung cancer
      - Scientists looked to see if there is correlation a link between lung cancer and smoking
        
        To do this scientists make a scatter graph
        
        For example the risk of developing lung cancer increases number of cigarettes is a positive correlation
        
        A correlation does not prove cause
        
        It simply suggests that they might be linked
      - Causal mechanism is when scientists try to see how a risk factor causes an increased risk of getting a disease
        
        For example scientists discovered the cigarette smoke contains chemicals which damage DNA and increase the risk of cancer
        
        These are called carcinogens
        
        This proves that smoking increases the chance of lung cancer
      - Scientists can't use a census of the entire population instead they sample a group of people and try to draw conclusions about the whole population
        
        Some samples may not represent the entire population and will give a biased conclusion
        
        To do this a random and large sample has to be taken