Infection and Response Flashcards
What is a pathogen?
A microorganism that can cause disease
Are diseases cause by pathogens communicable or non-communicable?
COMMUNICABLE
Are viruses living organisms?
no
Are viruses made of cells?
no
How many times smaller are viruses than animal or plant cells?
10, 000 times smaller
How can measles be spread between people?
Via droplets in air when an infected person coughs or sneezes
What are the symptoms of measles?
Fever (feeling hot and cold)
Red skin rash
What does HIV do?
it weakens the immune system
What type of pathogen is HIV?
virus
Which two ways can HIV be spread between people?
Sexual contact
Exchange of bodily fluids
What can HIV lead to?
AIDS
What does AIDS do?
it weakens the immune system so much that the person can catch unusual infections
What type of organism does Tobacco Mosaic Virus (TMV) infect?
plants
What is the main symptom of Tobacco Mosaic Virus (TMV)?
Patches of the leaves get discoloured
What affect does the TMV have?
reduces the amount of photosynthesis the plant can do, resulting in stunted growth and decrease in sugar production
How much smaller are bacterial cells compared to animal or plant cells?
100 times smaller
What do bacteria release that harm our body?
toxins
What is salmonella?
bacterial disease spread by consuming contaminated food
What are some symptoms of salmonella?
fever, stomach cramps, vomiting, and diarrhoea
What is Gonorrhoea?
an STD transmitted by sexual contact
What are the symptoms of gonorrhoea?
Pain when urinating
Yellow/green discharge from the vagina or penis
How can you prevent the spread of gonorrhoea?
Avoid unsafe sex
Use a condom
What is the treatment for gonorrhoea?
Antibiotics such as penicillin
Are fungi unicellular or multicellular?
Can be either
What is rose black spot?
fungal disease that causes purple or black spots develop on leaves, which then often turn yellow and drop off.
What affect does rose black spot have on the plant?
reduces photosynthesis and so also reduces the growth of the plant.
How does rose black spot spread?
the fungal spores can get blown off the dead leaves or water can transport them to another plant.
What are treatments of rose black spot?
spraying the infected plants with fungicides, or destroying the affected leaves.
What does it mean when we say that protists are parasites?
This means that they live on, or in, a host organism, and get their food at the expense of their host.
What are vectors?
organisms that transport pathogens without being affected
What vector spread malaria?
mosquitoes
What are the symptoms of malaria?
recurrent fevers, headaches and in extreme cases death
What are 3 ways to reduce the spread of malaria?
Stop the mosquito vectors from spreading the protists
Destroy the mosquito breeding sites
Kill the mosquito with insecticides
Use mosquito nets
Use mosquito repellent
What are 3 barriers to reduce the entry of pathogens?
skin
hairs in the nose
enzymes in tears
How does skin help to defend against disease?
It covers the body, physically preventing pathogens from entering
It secretes oils and antimicrobial substances that kill pathogens
Does skin act as a physical or chemical barrier to pathogens?
physical
What are cilia?
tiny hair-like projections that waft the mucus and pathogens away from the lungs in the trachea, bronchi and bronchioles
What are the 2 main types of white blood cells?
phagocytes and lymphocytes
Which of the following are functions of white blood cells?
Produce antitoxins
Producing antibodies
Phagocytosis
How does phagocytosis work?
the phagocyte tracks down the pathogen and binds to it
the phagocytes membrane surrounds the pathogen and engulfs it
the enzymes in the phagocyte break down the pathogen to destroy it
What do antitoxins do?
Bind and neutralise the toxins produced by bacteria
What does a vaccine contain?
Small quantities of dead, weakened, or inactive forms of a pathogen
Can vaccines be made against both bacterial and viral diseases?
yes
How do vaccines work?
They expose us to the antigens of a pathogen so that we can develop immunity to it
What is herd immunity?
there are enough vaccinated individuals in the population to make the spread of disease from one individual to another unlikely. As a result, the whole population becomes protected - not just those who are immune.
Give 2 examples of painkillers.
paracetamol and aspirin
What is antibiotic resistance?
when the bacteria mutate to become immune to the antibiotics
What measures could help reduce the spread of antibiotic resistance?
Patients taking antibiotics for the full prescribed course
less antibiotics to farm animals
Doctors only prescribing antibiotics for serious bacterial infections
How do antibiotics help to cure bacterial infections?
They directly kill bacterial cells
From what is aspirin developed?
willow bark
From where is digitalis developed?
foxgloves
What does digitalis do?
treats heart problems
Where was penicillin made from?
a fungus that kills bacteria
What are the 3 main things tested for when testing drugs?
efficacy, toxicity, dosage
What are the 3 main stages of drug testing?
1) testing on human cells and tissues
2) testing on live animals
3) testing on humans
What are the 2 stages of pre-clinical testing?
testing on human cells and tissues
testing on live animals
What are the 2 parts to clinical testing?
1) give the drug to healthy volunteers starting from very low dose and gradually increasing to find the max dosage we can give without side effects
2) Give the drug to the people suffering the particular illness to find the optimum dosage
How do we make clinical testing fair?
use a placebo
trials should be blind or double blind
What is a double blind trial?
a trial in which neither the patient nor the doctors know which is the placebo and which is the real one
What do blind trial prevent?
unconscious bias
What happens after the tests?
peer-review the results by other scientists to make sure its all correct
What are monoclonal antibodies?
Antibodies made from clones of a single type of cell
Where are monoclonal antibodies made?
in a lab
How do you produce monoclonal antibodies?
Inject an animal, like a mouse, with the antigen that we want our antibodies to bind to.
Let the animal develop an immune response, and then isolate some of their B-lymphocytes (which will produce the antibody we want).
Combine those B-lymphocytes with fast-dividing tumour cells to form hybridoma cells.
Let these hybridoma cells divide rapidly in a petri dish.
Collect and purify the monoclonal antibodies they produce
What is a hybridoma cell?
Lymphocytes combined with fast-dividing tumour cells
N
What do antibodies bind to?
Antigens with a complementary shape
What do pregnancy tests detect?
the chemical HCG
What hormone is produced when a woman is pregnant?
HCG
how do pregnancy tests work?
1) there are fixed monoclonal antibodies that are specific to HCG on the right of the strip
2) there are monoclonal antibodies attached to coloured beads on the left and are free to move
3)the urine carries the M.As from the right to the left, if HCG is present the chemical binds the antibodies
4) if the HCG is present and has binded to the M.As, they will go on to bind to the fixed M.As as well, otherwise they will just travel through
5) Since the coloured beads are stuck with the M.As and the HCG, a blue line appears, confirming the pregnancy
Which type of antibodies does the pregnancy test use?
Monoclonal antibodies
What are the benefits of the pregnancy test?
its cheap and quick
What are the 3 main causes of plant diseases?
Infection by microorganisms such as fungi, bacteria, or viruses.
Attack by larger organisms, such as insects.
Lack of essential minerals, such as nitrates, or magnesium ions.
What is the primary mode of transmission for tobacco mosaic virus (TMV)?
Direct contact with infected plants
Why do plants require nitrates?
to make proteins
Which of the following is a symptom of nitrate deficiency (lack of nitrates) in a plant?
stunted growth
Why do plants require magnesium?
To make chlorophyll
What is the main symptom of magnesium deficiency (lack of magnesium) for a plant?
Chlorosis (yellow leaves due to lack of chlorophyll)
List three physical changes that could indicate that a plant has a disease.
Stunted growth
Spots of leaves
Abnormal growths / lumps
Patches of decay
Malformed stems or leaves
Discolouration
N
What do we mean by mechanical defences?
Structures that reduce the chance of being attacked
What are 3 mechanical plant defences?
Hairs and thorns
Leave that curl or droop when insects land on them
Mimicking other organisms to trick animals
