b2

• Cells


  The basic building blocks of all living organisms
• Tissue

  A group of cells with a similar structure and function
• Organs


  Aggregations of tissues performing important functions
• Organ systems


  Organs organised to work together to form an organism
• Catalyst


  A substance which increases the speed of a reaction, without being used up
• Enzymes


  Biological catalysts that are large proteins made up of long chains of amino acids
• Active site


  The unique shape that fits onto the substance involved in the reaction
• Enzyme needs the right temperature and pH


  To work effectively
• Higher temperature


  Increases the rate of reaction at first, but if it gets too hot, some bonds break and the enzyme becomes denatured
• pH too high or too low


  Can cause the enzyme to become denatured
• Amylase


  An example of a carbohydrase that breaks down starch
• Proteases


  Convert proteins into amino acids
• Lipases


  Break down lipids into fatty acids
• Digestive enzymes


  Convert food into small soluble molecules that can be absorbed into the bloodstream
• The products of digestion are used to build up new carbohydrates, lipids and proteins, some of which are used in respiration
• Bile


  Made in the liver and stored in the gall bladder, it is alkaline to neutralise stomach acid and emulsifies fats to form small droplets which increases the surface area for lipase enzymes
• Chemical tests


  • Benedict's solution tests for sugars (turns brick red)
  • Iodine solution tests for starch (turns black or blue-black)
  • Biuret reagent tests for proteins (turns violet/purple)
• Blood


  A tissue consisting of plasma, red blood cells, white blood cells and platelets
• Red blood cells


  • Carry oxygen
  • Have a biconcave shape
  • Contain haemoglobin
• White blood cells


  • Have a nucleus
  • Produce antibodies
• Platelets


  • Small fragments of cells that help stop excessive bleeding
• Coronary heart disease


  Where the arteries supplying the heart muscle get blocked by fatty materials, restricting blood flow and causing a lack of oxygen which can result in a heart attack
• Stents


  Tubes placed in arteries to keep them open, helping blood flow efficiently and reducing heart attack risk
• Statins


  Drugs used to reduce bad cholesterol levels, slowing down the rate of fatty material deposit
• Heart valve problems


  Where valves become faulty, preventing proper blood circulation, requiring replacement with biological or mechanical valves
• Artificial hearts can be used to keep patients alive while waiting for a heart transplant, allowing the heart to rest and recover
• Health


  The state of physical and mental wellbeing
• Communicable diseases

  Diseases that can spread from person to person
• Non-communicable diseases


  Diseases that cannot spread
• Communicable and non-communicable diseases can interact and cause other physical and mental health issues
• Immune system defects

  Make an individual more likely to suffer from infectious diseases
• Viruses living in cells

  Can be a trigger for cancer
• Immune reactions to pathogens

  Can trigger allergies such as skin rashes and asthma
• Severe physical ill health

  Can lead to depression and other mental illnesses
• Other factors including diet, stress and life situations


  May have a profound effect on both physical and mental health
• In more developed countries, non-communicable diseases are more common as people generally have higher incomes and can buy higher-fat foods
• Smoking


  Has been proven to directly cause cardiovascular disease, lung disease and lung cancer by damaging the walls of arteries and cells in the lining of the lungs
• Alcohol

  Links to liver disease by damaging cells in the brain and lowering volume
• Diet and obesity

  Leads to struggles to control glucose levels
• Those that die from non-communicable diseases have a lower life span and are a burden for themselves and their loved ones