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Biology Paper 1 revision - Coggle Diagram

- - - - adult stem cells can be found in various places around the body
        
        brain, eyes, blood, heart, liver, bone marrow, skin, muscles
        
        adult stem cells can differentiate into related cell types only, for example, bone marrow cells can differentiate into blood cells and cells of the immune system but not other cell types.
    - - Cells of the meristem can differentiate to produce all types of plant cells at any time during the life of the plant.
      - The main meristems are close to the tip of the shoot, and the tip of the root.
      - In a growing shoot, new cells are being produced continuously near the tip. As the cells become older, further away from the tip, they become differentiated – they enlarge and develop vacuoles.
- - - - The atria (plural of atrium) are where the blood collects when it enters the heart.
      - The ventricles pump the blood out of the heart to the lungs or around the body.
      - The septum separates the right-hand and left-hand side of the heart.
      - The tricuspid valve is located between the right atrium and right ventricle and opens due to a build-up of pressure in the right atrium.
      - The bicuspid valve is located between the left atrium and left ventricle and likewise opens due to a build-up of pressure, this time in the left atrium.
      - The semilunar valves stop the back flow of blood into the heart. There is a semilunar valve where the aorta leaves the left ventricle and another where the pulmonary artery leaves the right ventricle.
  - - - The systemic circulation transports:
      - oxygen and nutrients to the body
      - carbon dioxide and other wastes away from cells
      - The systemic circulation is under high pressure - it has to deliver blood to the extremities of the body.
      - The pulmonary circulation is under lower pressure, because:
      - blood is delivered to the lungs only, which are very close to the heart
      - in a healthy person, this lower pressure is optimum for the diffusion of gases
  - - - Arteries Veins
      - Always carry blood away from the heart Always carry blood to the heart
      - Carry oxygenated blood, except for the pulmonary artery Always carry deoxygenated blood, except for the pulmonary vein
      - Carry blood under high pressure Carry blood under low or negative pressure
      - Have thick muscular and elastic walls to pump and accommodate blood Have thin walls - have less muscular tissue than arteries
      - A type of supporting tissue called connective tissue provides strength Have less connective tissue than arteries
      - The channel in the blood vessel that carries blood - the lumen - is narrow Have a wide lumen
- - - - Statins
      - Statins are drugs that help to lower cholesterol in the blood. They do this by lowering its production in the liver.
      - Statins are prescribed for people with heart disease or who have a high risk of developing it. They need to be taken long-term. Cholesterol levels will rise again if a person stops taking them.
      - Some studies have raised concerns regarding the side effects of statin use, while others believe they can bring additional positive benefits.
      - Statins are not suitable for everyone - they should not be prescribed for people with liver disease, or pregnant or breast feeding women.
      - Some patients taking statins often experience side-effects such as headaches and memory loss. There have been reports of statins being linked with type 2 diabetes and liver damage.
      - Other people argue that statins should be used more widely. They may protect against other conditions such as Alzheimer's disease, but further research is needed.
      - Stents
      - Coronary arteries that are blocked or have become narrow can be stretched open and a stent inserted to restore and maintain blood flow.
      - Treatment Advantages Disadvantages
        
        Drugs - statins Reduce the risk of heart attack. Studies have shown a decrease in 'bad cholesterol' and an increase on 'good cholesterol.' Used to reduce high cholesterol levels that have genetic causes. May have beneficial effects on other conditions. Not suitable for people with liver disease. Some side effects. Must be taken for life. Should not be taken if pregnant or breastfeeding.
        
        Heart transplant Improve quality of life. Few donor hearts are available. Recovery time is long. There is a risk of rejection by the body's immune system.
        
        Replacement heart valves Restore blood flow through the heart. Biological valves may wear out. Blood clots may stick to mechanical valves - anti-blood clotting drugs need to be taken.
        
        Stents Widen coronary arteries that have not responded to drug treatment. The recovery time is short following insertion of the stent. In a minority of cases, further treatment is required.
- - - - increased rate
        
        temperature
        
        water
        
        light intensity
        
        chlorophyll
- - - - proteins - biurets
        
        starch - iodine purple/black
        
        fats ethonal red layer cloudy
      - sugars - Benedict warm red