Topic 3-Infection and Response

• How is malaria spread?

  it is spread from animal to animal by mosquitoes as they feed on the animals
• How does isolation (or quarantine) reduce the spread of pathogens?

  if an infected person is isolated, they can’t spread that disease to others because they don’t come into contact with other people
• What are the different stages of drug development?

  1)Test the drug on human cells and tissues

  2)Test the drug on live animals

  3)Test the drug on healthy volunteers to find the maximum dosage before side effects occur

  4)Test the drug on patients that suffer from the relevant disease to find the optimum dosage
• Who discovered penicillin?

  Alexander Fleming
• What do antibodies bind to?

  Antibodies bind to antigens that have a complementary shape
• Briefly outline what has to happen to new drugs before they can be prescribed to patients.

  New medical drugs have to be tested and trialled before being used to check that they are safe and effective

  Specifically they are tested for toxicity, efficacy and dose
• What is a microorganism?

  Microorganisms are very small organisms. They include:

  1)Bacteria

  2)Fungi

  3)Protists(protoctists)

  4)Viruses(viruses aren’t really ’organisms’ but we still refer to them as microorganisms
• Which organism did penicillin originate from?

  A type of fungus- specifically a mould known as penicillium
• What are the main symptoms of ebola?

  Symptoms include fever, bleeding, severe headache and muscle pain
• In the context of pathogens and disease, what is a ‘vector’?

  A vector is a living organism that transmits a pathogen from an infected organism to another organism
• Why is it important for medical trials to be double-blind?

  1)It helps to avoid any bias by the patients or researchers.

  2)If patients know they received the drug, they may be more likely to report side effects

  3)If researchers know who has been given the real drug, they may pay closer attention to those patients and document their symptoms more carefully.

  4)The results are more likely to be valid if there is no bias. 
• What are the symptoms of gonorrhoea?

  1)A thick yellow or green discharge from the vagina or penis

  2)Pain when urinating
• What is a virus?

  They are infectious agents that can only replicate inside the living cells of an organism

  Viruses are not living, are not made of cells and are not considered organisms
• With the reference to drug testing what does the term efficacy mean?

  How well a drug produces the desired effect

  For example if it is a painkiller it’s efficacy is how well it reduces pain
• How does the stomach act as a defence system against pathogens?

  It produces stomach acid (hydrochloride acid) which creates a very low pH that destroys pathogens
• What are the symptoms of measles?

  1)Fever(feeling hot and cold)

  2)Red skin rash
• How can measles be spread between people?

  Via droplets in air when an infected person coughs or sneezes
• What does HIV stand for?

  Human Immunodeficiency Virus

  This is because it affects humans, it weakens the immune system (immunodeficiency) and it is a virus
• Which two ways can HIV be speared between people?

  Sexual contact

  Exchange of bodily fluids
• What is the treatment for HIV/AIDS?

  Antiretroviral drugs
• What type of organism does Tobacco Mosaic Virus (TMV) infect?

  Plants
• what is the main symptom of tobacco mosaic virus?

  patches the of leaves gets discoloured
• Tobacco Mosaic Virus (TMV) reduces the amount of photosynthesis that a plant can do.

  What are the consequences of this?

  The plant won’t be able to produce as many sugars

  The plant won’t be able to grow as well
• Salmonella is a bacterial disease spread by consuming contaminated food.

  Chickens and eggs are the foods most commonly infected with salmonella but in the UK most chickens are vaccinated against salmonella so can transmit the bacteria

  symptoms include fever, stomach cramps, vomiting, and diarrhoea

  The symptoms normally pass within a week if the person stays well hydrated
• Gonorrhoea is an STD transmitted by sexual contact (such as unproductive sex).

  What are the symptoms of gonorrhoea?

  Pain when urinating

  Yellow/green discharge from the vagina or penis
• How can you prevent the spread of gonorrhea?

  Avoid unsafe sex

  Use condom
• What is the treatment for gonorrhoea?

  Antibiotics such as penicillin
• Rose black spot is a fungal disease that causes purple or black spots to develop on leaves, which then often turn yellow and drop off.

  This reduces photosynthesis and so also reduces the growth of the plant.

  It can be spread by water or the wind.

  Treatment involves spraying the infected plants with fungicides or destroying the affected leaves.
• Protists are considered parasites. This means that they live on, or in, a host organism and get their food at the expense of their host
• Protists are often transported between hosts by other organisms. What do we call these other organisms?

  Vectors
• Malaria

  1)The organisms that cause malaria are a type of protist

  2)They are transported between hosts by mosquitoes

  3)The symptoms include recurrent fevers and headaches and in extreme cases it can be fatal
• Suggest three ways that we might try to reduce the spread of malaria


  1)Destroy the mosquito breeding sites

  2)Kill the mosquito with insecticides

  3)Use mosquito nets
• What is an antigen?

  An antigen is any substance that your body sees as foreign, which then causes your immune system to produce antibodies against it. For example, the toxins and cell walls of pathogens would be considered antigens.
• What is an antibody?

  An antibody is a protein produced by a white blood cells that binds to specific antigens. This acts as a signal to our immune system to destroy the antigen (or the pathogen it is part of).
• How does skin help to defend against disease?

  It secretes oils and antimicrobial substances that kill pathogens

  It covers the body physically preventing pathogens from entering
• Does skin act as a physical or chemical barrier to pathogens?

  Physical barrier
• The snow has hairs inside it that act as a physical barrier to pathogens. What are the hairs in the nose coated with to catch pathogens?

  Mucus
• The cells that line the trachea, bronchi and bronchioles have tiny hair-like projections that waft the mucus and pathogens away from the lungs. What are these structures called?

  Cilia
• What substance does the stomach produce to kill pathogens?

  Hydrochloric acid
• Does the acid produced by the stomach act as a physical barrier or a chemical barrier to pathogens?

  Chemical barrier