Infection and Response Flashcards
3 ways pathogens can spread
Air
Water
Direct contact
How do bacteria make you ill
Reproduce rapidly and produce toxins and poisons that damage tissues
How do viruses make you ill
Damage or destroy cells
Ways of identifying plant disease
Gardening manuals and websites
Laboratory testing of infected plants
Testing kits containing monoclonal antibodies
3 types of plant defence
Physical
Chemical
Mechanical
Examples of physical plant defences
Cellulose cell walls
Tough waxy cuticle on leaves
Bark on trees
Bark- cellulose- waxy cuticle
Examples of chemical plant defences
Many plants produce antibacterial chemicals
Produce poison to stop animals eating plants
Example of mechanical plant defences
Thorns and hairs (stop animals eating plant)
Leaves that droop/ curl when touched (scare herbivores/ dislodge insects)
Some plants mimic appearance of unhealthy/ poisonous plant (deters insects and herbivores)
Hair- mimic- curl
True or false, some plant diseases can be directly caused by insects
True (e.g by aphids)
Why are aphids bad for plants
Suck sap from plant stems causing reduced growth rate, wilting, discolouration of leaves
What can be used to control aphid infestations on plants
Ladybirds- they eat the aphids
True or false, both bacteria and viruses reproduce rapidly inside body
True
Which is bigger, bacteria or viruses
Bacteria
(Think b- bacteria= bigger)
Which out of bacteria and viruses can be treated with antibiotics
Bacteria
Not viruses
2 key plant diseases
Tobacco mosaic virus
Rose black spot
What type of pathogen is rose black spot caused by
Fungus
How can diseases spread by air
Droplets of pathogen go into air when you cough/ sneeze
(Prevent by covering mouth when sneezing/ coughing, sneezing into elbow, wearing face mask)
2 ways disease can spread by direct contact
Skin
Bodily fluids
(Prevented by wearing condoms/ not sharing needles)
Symptoms of measles (viral disease)
Fever
Red skin rash
Blindness
Brain damage
Effects of HIV
Mild flu
Damage to immune system (more vulnerable to other diseases)
Gonorrhoea symptoms
Pain whilst urinating
Green/ yellow discharge
How can gonorrhoea be treated
Antibiotics
How is rose black spot spread (fungal disease in plants)
Water and wind
How is tobacco mosaic virus spread
Direct contact of plants with infected plants
Animal and plant vectors
Soil (pathogen can remain in soil for very long time)
Symptoms of tobacco mosaic virus on plants
Mosaic pattern (discolouration of leaves where chloroplasts have been destroyed)
Poor growth
Why can tobacco mosaic virus lead to poor plant growth
Destroys chlorophyll (causing discolouration of leaves)
So sunlight cannot be absorbed so reduces plants ability to photosynthesise
Symptoms of plants with rose black spot
Purple/ black spots on leaves which turn yellow and drop early
Poor growth
How rose black spot can be prevented/ treated
Fungicides
Affected leaves removed and destroyed
How farmers help stop spread of tobacco mosaic virus
Grow TMV resistant strains of crops
(Because otherwise TMV can seriously reduce yield of crop)
What is a vaccine
Small amount of dead/ weakened pathogen
What is herd immunity
Large proportion of population are immune to a disease
(Reduces spread of disease and disease can even disappear altogether)
2 types of white blood cell
Lymphocytes
Phagocytes
Which type of white blood cell produces antitoxins and antibodies
Lymphocytes
What do antibodies bind to on the pathogen in order to destroy it
Antigen
What do antitoxins attach to that’s released from the pathogen
Toxins
(The antitoxin then neutralises it)
Describe phagocytosis
When white blood cells (phagocytes) ingest pathogens and destroy them
Describe vaccination process
Vaccination contains dead/ weakened pathogen
Vaccine injected into patient
White blood cells (lymphocytes) make antibodies to fit on the antigens on the surface of the virus and destroy it
Next time the virus enters your body, your white blood cells recognise it and respond quickly (produce correct antibodies)
You destroy the virus quickly and become immune
What do painkillers do to symptoms
Relieve them
2 limitations of antibiotics
Cannot kill viral pathogens
Bacteria are becoming increasingly resistant to antibiotics
How skin helps defend human body from pathogens
Forms outer protective barrier
Produces antimicrobial secretions (chemicals) to destroy bacteria
Microorganisms living on skin prevent pathogens growing
What does the skin produce as part of the human defence response
Antimicrobial secretions
(Can kill pathogens/ prevent them from spreading)
What does the stomach contain for a human defence response
Hydrochloric acid to kill pathogens caught in mucus from airways/ consumed by food or water
(Chemical barrier)
What does the trachea secrete that taps pathogens
Mucus
What do cilia do once mucus has trapped pathogens in the trachea/ bronchi to stop them from entering the lungs
Move the pathogens back up to throat to be swallowed (and then killed by hydrochloric acid in stomach)
What were drugs originally extracted from and give an example
Plants and microorganisms
E.g Digitalis (heart drug) from foxglove plant and aspirin from willow trees
What drug originates from foxglove plants
Digitalis (heart drug)
What painkiller originates from willow trees
Aspirin
What is meant by a double blind trial
Neither the doctors nor patients know who has been give the real drug and who has been given the placebo
(Reduces biases in trial)
What is a placebo
A dummy drug
What 3 things are drugs tested and trialled for
Toxicity (is it harmful)
Efficacy (does it work)
Dose (amount safe and effective to give)
Process of drug trials
1) pre-clinical: computer stimulation, tested on cells/ tissues, tested on animals
2) clinical trials: drug trialled at very low dose on healthy volunteers
3) if safe, larger number of healthy volunteers+ patients receive drug
4) peer review
How can malaria be treated/ reduce spread
Mosquito nets, mosquito spray, anti malarial medicine, prevent mosquitos breeding
How does malaria spread
Mosquitos
How do the trachea/ bronchi stop pathogens entering body
Trachea secretes mucus which traps pathogens
Cilia move mucus back up throat to be swallowed
What is a vector
Organism (e.g ticks biting insect) that passes a disease/ parasite from plant to plant/ animal to animal
What is an antigen
Marker on pathogen that antibody binds to
What is preclinical testing
Any stage of drug testing before it involves people
Includes computer stimulation, testing on cells/ tissues and live animals
True or false, malaria is a communicable disease
True, it is caused by a pathogen (protist)
What do mosquitos breed in
Still water
Does the protist causing malaria reproduce sexually or asexually in humans
Asexually
(However it reproduces sexually in mosquitos)
Does the protist causing malaria reproduce sexually or asexually in mosquitos
Sexually
(But asexually in humans)
What does the female mosquito need before she can lay her eggs
Meals of human blood (at this stage the protist causing malaria is passed into the human blood)
How is the protist causing malaria carried around the body
Circulatory system
What does the protist causing malaria first infect once inside human body
Liver
What does protist causing malaria infect after the liver once inside human body
Red blood cells
It destroys the red blood cells by bursting out of them causing shaking/ fevers
First symptoms of malaria
Shaking/ fever
(Caused by malaria bursting out of red blood cells and destroying them)
Apart from a weakened immune system, what’s another symptom/ effect of HIV
Mild flu
Main ways to stop diseases from spreading
Hygiene (wash hands, clean surfaces…)
Kill vector
Vaccinations
Isolate (usually as a last resort only for really serious diseases)
How are new strains of pathogens developed which become resistant to antibiotics
When pathogens mutate
3 ways HIV can spread between people
Blood
Sexual intercourse
Contaminated needles
How does a virus spread within the body
1) infects suitable host cell through the blood/ body opening
2) replicates itself many times-copies its genetic material and protein coat
3) causes host cell to burst releasing many copies of the virus
4)other cells can then be affected
True or false, viruses can reach cells through the blood/ body openings
True
What does the virus do once it’s infected a host (original) cell
Replicates itself many times
(Copies genetic material and protein coat)
What happens after the virus has replicated itself many times in the host cell
Causes the cell to burst releasing lots of copies of the virus
What happens after many copies of the virus have been released from the host cell
Other cells can be infected then the viruses replicate, burst and go on to infect even more cells
True or false, vaccines can work for both bacteria and viruses
True
3 Consequences on plant of aphids sucking cell sap out of them
Discolouration of leaves
Wilting
Reduced growth rate
Last stage of drug trial
Peer review
What is magnesium needed for in plants
Production of chlorophyll
2 symptoms of magnesium deficiency in plants
Stunted growth
Yellow leaves
(From lack of chlorophyll being produced)
How does the hybridoma cell divide to make a large number of identical cells (clone)
Mitosis
How is a hybridoma cell formed from the tumour cell and lymphocyte
They’re combined together
What hormone do pregnant women excrete (excreted in their urine)
HCG
Pregnant women produce the hormone HCG which is excreted in their…
Urine
Stages of pregnancy test using antibodies
Urine applied to end of the stick which contains monoclonal antibodies that bind to HCG and are attached to a dye
If HCG is present the monoclonal antibodies bind to the antigens causing a line to appear (pregnancy result is positive)
Second line appears in control zone showing test is valid
Difference in 2 lines formed in pregnancy test using antibodies
First line- test is positive
Second line (in control zone)- test is valid
Describe how monoclonal antibodies can be used for cancer treatment and diagnosis
Monoclonal antibodies that bind to antigens on cancerous cells are injected into the body
Monoclonal antibodies will bind to cancer cells and clump them together
Makes it easier to identify cancerous tumour which can then be removed
How can monoclonal antibodies be used to identify diseases
Monoclonal antibodies attached to fluorescent dye
