B5/B6 Flashcards
How do pathogens spread?
Through air, water or direct contact
What would you do in order to grow microorganisms in a lab?
-Pour hot, sterile agar gel into a Petri dish- it will harden as it cools
-Inoculate the agar plate- introduce the bacteria on a sterilised loop of wire
-Provide warmth and oxygen
-Keep the dish incubated at a maximum of 25 degrees Celsius in school labs
Why is it not possible to vaccinate plants?
They have no immune system
What are some ways of preventing infection?
-Hygiene
-Isolating infected
-Destroying vectors
-Vaccinations
How can the spread of TMV be prevented?
-Usage of TMV resistant strains of plant
-Good field hygiene/pest control
How can Salmonella infection be prevented?
-Poultry vaccinated against bacteria
-Maintaining good food hygiene
What happens to the leaves of a plant infected by Rose black spot?
-Purple or black spots form on leaves
-Leaves turn yellow and wilt
How does the respiratory system help the body protect itself from pathogens?
-Hair and mucus in the nose trap pathogens
-Trachea/bronchioles secret mucus- traps pathogens, cilia waft mucus up to throat where it is swallowed
How does nitrate deficiency affect plants?
The plant cannot convert sugars into protein, causing its growth to be stunted
Why does a lack of magnesium cause chlorosis?
The plant cannot make chlorophyll, leading to less photosynthesis
Name some symptoms of disease in plants:
-Spots on the leaves
-Areas of rotting or decay
-Growths
-Discolouration
List some physical defences of plants:
-Cellulose cell walls protect against microorganisms
-Tough waxy cuticle layer
-The bark on trees
-Dead cells on stems
Name the two drugs extracted from foxgloves:
-Digitalis
-Digoxin
Explain how medical drugs can be tested before use:
-pre-clinical trials of the new drug on cells/tissues and live animals
-to test toxicity, dosage and efficacy
-clinical trials both on healthy volunteers and patients at very low doses
-so that you can monitor for side effects
-then do trials to find the optimum dosage and test for
efficacy
-double blind trial
-use of placebo, which does not contain the new drug
-peer review of data to help prevent false claims
Why do we incubate bacteria at 25 degrees Celsius in school labs?
To reduce the chance of harmful bacteria growing
When growing bacteria in a lab, how do you ensure that unwanted microorganisms don’t contaminate a pure culture?
-Sterilise equipment- pass inoculating loop through a flame, boil the solutions/agar
-Use a pre-sterilised Petri dish (newly bought or put into an autoclave)
-Inoculate the agar with a sterile loop
-Partially seal the lid of the Petri dish to prevent microorganisms from the air entering
What is the difference between disinfectants and antiseptics?
Disinfectants kill bacteria within the environment, antiseptics kill bacteria on human skin
List some plant defence mechanisms:
-Hair
-Thorns
-Mimicry (mimicking elements of nature/surroundings)
-Leaves that curl/droop
List some uses of monoclonal antibodies:
-Used in pregnancy tests
-Diagnosing disease
-Measuring and monitoring hormone levels
-Delivering drugs to cancer cells
-Binding to receptors on cancer cells to stop them dividing
How does a pregnancy test work to give a positive result?
-Person urinates onto strip
-Urine contains hCG, which binds to free monoclonal antibodies that are complementary to hCG
-hCG binds to a fixed antibody at the test site
-Dye enzyme attached to free antibody binds to substrate on fixed antibody producing a coloured strip
-Remaining free antibodies bind to fixed antibodies at control site producing a colour
What is an antibody?
A protein designed to counteract a specific antigen
How is measles spread?
Through water droplets from the sneeze of an infected person
