bio

• How temperature and pH affect the functioning of enzymes and the rate of enzyme controlled reactions

  1. Temperature increases

  2. Rate of reaction increases

  3. Temperature reaches 37 degrees

  4. Rate of reaction starts to drop rapidly

  5. Enzyme becomes denatured

  6. Optimum temperature is at its highest
• Optimum temperature


  The temperature at which the rate of reaction is highest
• Different enzymes have different optimal temperatures
• How pH affects enzymes

  1. pH gets too high or too low

  2. Bonds holding the enzyme together start to break

  3. Active site changes shape

  4. Substrate can't fit

  5. Enzyme becomes denatured
• Optimal pH


  The pH at which the enzyme works best
• Most enzymes in our body work best at neutral pHs of around 7
• Enzymes that work in the stomach have an optimal pH of around 2 to function in the acidic environment
• Risk factor

  Anything that increases the chance that a person will develop a certain disease during a lifetime
• Risk factors don't guarantee that the person will catch the disease, they just increase the chance of it happening
• Types of risk factors

  • Aspects of a person's lifestyle
  • Substances in the person's body
  • Substances in the person's environment
• Risk factors interact to influence one particular disease


  For example, diet, obesity, smoking and lack of exercise all contribute to cardiovascular disease
• Certain risk factors directly cause a disease

  For example, smoking directly causes cardiovascular disease, lung disease and lung cancer
• Drinking too much alcohol

  Can cause liver disease
• Smoking or drinking while pregnant


  Includes a whole range of health problems for the unborn baby
• Obesity


  Can be caused by poor diet and lack of exercise, and can go on to cause type-2 diabetes and cancer
• Exposure to substances like asbestos or radiation

  Can directly cause cancer
• Diseases don't just affect the individual who has the disease, they also impact their family, friends and sometimes their entire country
• When somebody gets ill, they often rely on their friends and family to support them, and if they're really ill they might not be able to work which means that their whole family gets poorer
• On a national scale, if there's more disease, the workforce will be less productive and a bigger share of government spending will have to be spent on health in order to try and reduce the burden of disease
• Scientists need to find out who catches each type of disease and why, and what they found is that certain groups of people are more likely to have certain risk factors than others
• Globally, people in developed countries like the UK with higher incomes are more likely to eat too much unhealthy food and live a sedentary lifestyle, which are risk factors for obesity and associated diseases
• In the UK, people from more deprived areas are more likely to smoke, have a poor diet and not exercise enough, so we see more cases of cardiovascular disease and obesity in those deprived areas
• Many risk factors are out of our control, but lots of them are not, and the choices that we make have a big impact on how healthy we end up being