biology

• Antibiotics


  A group of drugs that can kill bacteria
• Antibiotics


  • Penicillin
• Penicillin was the first antibiotic to be discovered almost 100 years ago
• At first, penicillin was able to kill loads of different types of bacteria
• We've been using antibiotics for so long


  Some types of bacteria have now become resistant to them
• How antibiotic resistance happens

  1. Bacteria develop random mutations in their DNA

  2. Mutations can change their characteristics

  3. Occasionally, these changes result in the bacteria being less affected by the antibiotic

  4. Resistant bacteria survive

  5. Resistant bacteria replicate quickly

  6. Resistant bacteria form a new colony
• Antibiotic resistant strain


  A new type of bacteria that has the gene for antibiotic resistance
• Antibiotics aren't effective anymore

  You're still infected and can pass on the antibiotic resistant bacteria to other people
• Bacteria becoming resistant to multiple antibiotics

  1. Resistant bacteria to one antibiotic

  2. Resistant bacteria to a different antibiotic

  3. Resistant bacteria to loads of different antibiotics
• Superbugs


  Bacteria that are resistant to lots of different types of antibiotics
• Superbug


  • MRSA
• It's super uncommon for a bacteria to develop resistance, and even when they do it's often only partial resistance
• By completing the full course of antibiotics, we can generally still kill all of the bacteria
• We use around 100,000 tons of antibiotics each year
• Over two-thirds of that 100,000 tons is given to animals by farmers to prevent illness and make them grow faster
• Giving antibiotics to healthy animals is a breeding ground for antibiotic resistance
• Scientists are trying to develop new antibiotics that work against resistant strains, but it is proving difficult and slow
• Diffusion


  The net movement of particles from an area of higher concentration to an area of lower concentration
• Diffusion


  1. Molecules move about randomly

  2. Molecules spread out over time

  3. Molecules become evenly distributed
• Diffusion


  • Can happen in gases and liquids
  • Can take place through cell membranes
• Partially permeable membrane


  • Only some molecules can diffuse through, like water, glucose, amino acids
  • Larger molecules like proteins and starch cannot diffuse through
• Passive process


  Diffusion does not require energy from the cell
• Factors affecting rate of diffusion

  • Concentration gradient
  • Temperature
  • Surface area
• Larger concentration gradient


  Higher rate of diffusion
• Higher temperature


  Higher rate of diffusion
• Larger surface area


  Higher rate of diffusion