Infection and Response Flashcards
Give two ways a person with a mild infection of Salmonella can help prevent the spread of the bacteria to other people.
wash hands before preparing / handling food
disinfect clothes / surfaces
A person with AIDS may take longer than a healthy person to recover from a Salmonella infection. Explain why.
immune system is damaged / weakened
white blood cells cannot kill bacteria / Salmonella (as effectively)
New drugs must be tested before they can be used.
Give one reason why drugs should be tested.
to check they are safe / effective
Vaccination can be used to prevent an illness in a person.
Explain how a vaccination can prevent an illness.
Any from:
dead / inactive pathogen introduced to the body
white blood cells respond and produce antibodies
antibodies are specific to pathogen
antibodies produced quickly when infected again
in larger quantities, killing the pathogen
Explain how different types of organism defend themselves against microorganisms.
Animals:
skin-sebum / oils to kill microbes dead layer difficult to penetrate
nose-hairs keep out dust and microbes
trachea / bronchi-mucus traps microbes cilia moves mucus
stomach-(hydrochloric) acid kills bacteria
white blood cells-produces antibodies, produces antitoxins, engulf microbes / phagocytosis
Plants:
cell wall and waxy cuticle-tough / difficult to penetrate
dead cells / bark-fall off, taking pathogens with them
production of antibacterial chemicals
How to grow some bacteria in the laboratory.
1.Remove the lid of the Petri dish, sterilise (Petri) dish
2. Remove the lid of the bottle containing the bacteria.
3. Use the inoculating loop to remove some of the bacteria from the bottle, pass inoculating loop (through flame).
4. Spread the bacteria over the agar using the inoculating loop.
5. Put the lid back on the Petri dish, secure lid with (adhesive) tape.
6. Put the Petri dish into an incubator at 25 °C for 24 hours.
Describe how monoclonal antibodies are produced.
A mouse is injected with an antigen.
Mouse lymphocytes begin to produce antibodies specific to the antigen.
Lymphocytes are fused with tumour cells to make them divide more rapidly. These are called hybridomas.
Hybridomas divide rapidly and produce lots of cells that create lots of the same antibody.
These antibodies are monoclonal antibodies and are collected and purified before use.
Explain how the pregnancy test strip works to show a positive result.
(as) urine passes through reaction zone
HCG hormone binds to the mobile HCG antibody (in the reaction zone)
(passes up the stick) HCG hormone binds to the immobilised HCG antibodies in the results zone
(the other) antibodies which do not attach to HCG
bind to antibodies in control zone
blue dye appears in both control and results zones (to show positive result)
Give 2 ways that monoclonal antibodies can be used in the diagnosis or treatment of cancer.
Locates cancer cells so they can be treated and removed. Can attach anticancer drugs to target and destroy cancer cells. Can bind to cancer cells and trigger natural immune response. Can block chemicals that cause the cancer to divide.
Magnesium deficiency symptoms include:
* yellow leaves
* stunted growth.
Explain how a deficiency of magnesium could cause these symptoms.
yellow leaves due to lack of chlorophyll
(therefore) less / no light absorbed (by chlorophyll)
(therefore) lower rate of / no photosynthesis
therefore) plant makes less / no sugar / glucose
(therefore) plant converts less / no sugar / glucose into protein (for growth, so growth is stunted)
Explain how the cactus is adapted for defence and protection.
leaves are reduced to spines to reduce water loss
wide and deep roots absorb rainwater on the surface and below
sunken stomata to reduce water loss
large, fleshy stems to store water
Explain why he chose Fertiliser S.
(fertiliser S) has most nitrogen for good growth
has high(est) potassium content for stronger roots
cheaper than fertiliser T
but has less phosphate than fertiliser T
Explain why plants with TMV have stunted growth.
less photosynthesis because of lack of chlorophyll
therefore less glucose made so
less energy released for growth
because glucose is needed for respiration
therefore less amino acids / proteins / cellulose for growth
