B3 Infection and Response

• Suggest one way to reduce the spread of gonorrhea.

  Use a condom during intercourse.
• When testing antibiotics in a petri disc, how can you tell which one is most effective?

  The one with the biggest 'no grow' area has killed the most bacteria.
• Why do bacteria make us feel ill?

  They release toxins.
• What is meant by 'phagocytosis'?

  White blood cells called phagocytes engulf pathogens to destroy them.
• How do viruses make us ill?

  They live and reproduce inside cells and damage them.
• How is salmonella prevented?

  Wash hands thoroughly after handling raw meat, vaccinating poultry, cooking food properly.
• Name the pathogen that causes salmonella and gonorrhea.

  Bacteria.
• How is tobacco mosaic virus (TMV) spread?

  Direct contact.
• Describe the symptoms of tobacco mosaic virus in plants.

  Mottling of leaves, reduced photosynthesis rate.
• How can the spread of plant diseases be prevented?

  Gardeners wear gloves, sterilize equipment after contact with infected plants.
• What is meant by a non-communicable disease?

  A disease not caused by a pathogen so cannot be passed on.
• Give the four stages of a clinical trial.

  1. Testing on human tissues/cells. 2. Animal testing. 3. Tests on healthy volunteers. 4. Tests on patients.
• How does the body respond to infection after a vaccination?

  More antibodies are produced, antibodies are produced more rapidly, and remain in the blood for longer.
• Name the type of drug used to treat HIV.

  Antivirals.
• Name 3 non-specific body defences against disease (1st lines of defence).

  Stomach contains HCl to kill pathogens, skin acts as a physical barrier to pathogens, nose hairs trap pathogens.
• True or false: Paracetamol kills bacterial cells.

  False.
• How do our bodies respond to a vaccine?

  Produce specific antibodies to destroy the weakened pathogen.
• What is a single blind trial?

  When the patient doesn't know if they have been given the drug being tested or a placebo.
• Why can antibiotics not be used to kill a virus?

  Because viruses live inside host cells so a cell would be damaged.
• Why will a measles vaccine not protect against the mumps?

  The antibodies produced are specific for the measles pathogen.
• During drug trials. Who is tested first; healthy volunteers or people suffering with the disease?

  Healthy volunteers.
• State 3 ways to prevent the spread of infection.

  Isolate infected individuals, destroy vectors, sterilize medical equipment.
• Give 3 ways that disease is spread.

  Sexual contact, physical (direct) contact, air (indirect contact).
• Why should independent companies not do research into whether or not a drug is safe?

  To avoid bias.
• Name the pathogen that causes malaria.

  Protist.
• State three ways white blood cells defend against pathogens.

  Makes antibodies, releases antitoxins, engulfs pathogens.
• What is a placebo?


  Something that does not contain the drug being tested.
• What is a double blind trial?

  The patient and the doctor don't know whether the drug or the placebo is being given.
• What is injected into the body during a vaccination?

  Dead/inactive pathogens.
• What happens in the first stage of drug testing?

  The drug is tested on human cells and tissues in a lab.
• How do our bodies defend against bacteria?

  Release antitoxins to neutralise toxins.
• How do bacteria make us ill?

  By releasing toxins.
• What do white blood cells produce to help defend against pathogens?

  Antibodies.
• Which of the following diseases is not spread by sexual contact? HIV, gonorrhoea or measles.

  Measles.
• Which type of pathogen causes rose black spot on leaves?

  Fungus.
• Which type of pathogen causes gonorrhoea?

  Bacteria.
• How does the stomach defend itself against infection?

  It secretes hydrochloric acid to kill pathogens.
• Antibiotics can kill viruses. True or false?

  False.
• Name 4 pathogens.

  Virus, bacteria, fungi & protists.
• What do we call a microorganism that causes disease?

  A pathogen.