B3 Flashcards
What is a pathogen
Microorganism which causes infectious disease
What are the 4 types of pathogens
Fungi, virus, bacteria, protist
How does bacteria make you feel ill
Bacteria enters body and reproduces rapidly. They release harmful chemicals called toxins. These attack your cells making us feel ill
How does a virus make you feel ill
Pathogen enters host cell. Pathogen multiplies. Cell bursts when virus leaves cell. Virus then moves to other cells
What pathogen are antibiotics prescribes for
Bacteria
How are pathogens spread
. Air droplets- travel through air as speak or sneeze or cough etc
. Water- drinking contaminated water
. Direct contact- for example sharing needles
How do we reduce the spread of pathogens
Hygiene eg washing hands, provide ppl with clean drinking water, use protection during intercourse, isolation, vaccination
What is health
A state of physical and mental wellbeing
What is a communicable disease
Disease caused by pathogen. Can spread from person to person
What is non communicable disease? Give example
Not caused by a pathogen. Can’t spread from person to person. Eg: cancer
What pathogen causes salmonella? What are the symptoms? How is it spread? How do we reduce spread?
Cause by bacteria. Treated with antibiotics but usually goes away on its own. Syptoms: fever, abdominal cramps, vomiting, diarrhoea. Occurs when eating poultry like chicken which has bacteria. To prevent, vaccinate all chickens from salmonella
What pathogen causes gonorrhoea? What are the symptoms? How is it spread? How do we reduce spread?
. Caused by bacteria
. Syptoms: thick yellow/green discharge, pain when urinating
.is an STD
. How to prevent- use protection during intercourse
What pathogen causes measles? What are the symptoms? How is it spread? How do we reduce spread?
. Caused by virus.
. Syptoms: high fever, red skin rash, damage breathing system + brain
. Spread through air droplets
. Prevent- vaccinate
What pathogen causes HIV? What are the symptoms? How is it spread? How do we reduce spread?
. Cause by virus
. Symptoms: flue like illness attacks immune system so it becomes hard for body to fight infections or diseases.
. Spread through intercourse and when people shair needles. Need to take anti retro viral drugs
. Prevent- don’t intercourse or shair needle
What kind of disease is malaria
Communicable disease
What pathogen causes malaria
Protist
How is malaria spread
. Infected person bitten by mosquito
. Mosquito carries pathogen. It then bites someone else, infecting them
. Mosquito is a vector- someyhi g that carries pathogen from one person to another
How do we stop the spread of malaria
Drain areas of still water since mosquitos breed in them
Spray water with insecticide
Sleep under mosquito net sprayed with insecticide
Explain tobacco mosiac virus
. It is a wide spread plant infection
. Affects number of different plants including tomato
. Discolouration of leaf occurs causing a mosiac pattern. This means plant lacks chlorophyll so a lack of photosynthesis will occur which will stunt plant growth
Explain rose black spots
. Wide spread plant infection
. Affects number of different plants
. Purple black spots on leaves. Leaves turn yellow and fall off. This reduces rate of photosynthesis which will stunt plant growth
. Spread though water and wind
. Treatment- spray fungicide to kill fungus. Remove and destroy infected leaves
What is the job of a non specific defence system
Prevent pathogens from entering human body
How does the skin protect from pathogens
. Tough dry dead outer layer
. Skin acts as a barrier
. Sebum/oil repels pathogens
. Scabs firm over cuts acting as a barrier
How does the eyes protect from pathogens
Produce tears containing enzymes which kill bacteria. Tears are antiseptic
How does the breathing system protect from pathogens
Trachea/brochi/nose Produce mucus which is sticky so it traps bacteria. It is carried away by the cilia
How does the stomach protect from pathogens
Contains hydrochloric acid which kills bacteria in food
Explain what occurs in phagocytosis
. White blood cells detect pathogens
. Blood cell moves to the pathogen and engulfs it and destroys it with enzymes it made
How do antibodies destroy pathogens
Have a complimentary shape to the antigens on the pathogen. It laches onto the antigens and destroys the bacteria
How do antitoxins work
They neutralise toxins produced by the pathogen.
What is vaccination
A small quantity of a dead or weak end form of a pathogen is injected into the body
How do vaccinations work
Dead/weakend form of pathogen is injected into the body and is detected my white blood cells. The white blood cells begin to multiply to engulf and destroy any pathogens. These white blood cells stay in body for a long time. Memory cells remember the antibody so if a person is ever reinfected, they are made faster
What is meant by herd immunity
Vaccinating a large amount of people so that less get infected and also to protect hose who ate not vaccinated since some ppl don’t get vaccinated due to missed appointments, new country
What are painkiller used for
Relieve syptoms of illness
How do antibiotics work
They block vital processes in bacteria. They kill bacteria or stop it from spreading which helps the bodies natural imune system to fight it off. This only works for bacteria
Why can’t antibiotics be used to kill a virus
Virus are surrounded by a protective coat of protien. They don’t have cell walls that can be attacked by antibodies
What is meant by antibiotic reistance
When antibiotic don’t work because bacteria or fungi developed the ability to defeat drug that was designed to kill them. This may occur because the antibiotics where stopped being taken before all bacteria was killed so the antibiotic will no longer work to kill the pathogen
What does the drug digitalis do
Treats heart problems. It is comes from fox plants
What does the drug aspirn do
It is a painkiller. It relieves syptoms of illness. It comes from willow tree
What does penecilin do
It is an antibiotic. It comes from mould
Why do all new drugs need to be trialed and tested
. Make sure they art toxic for humans
. So we know if it is effective
. To find the right dosage of drug
Describe the process of drug trial testing
. Tested on animals/cells/tissue to see if it is toxic
. Tested on human volenteers who are healthy to see if it is safe for human. Done in very low doss to see side effect
. Tested on volenteer patient to see if it is effective and to find optimal dose. Double blinded trial is done to prevent bias
What is a placebo
A fake drug that looks like the real drug used in double blinded trial to see if patients get better or if it because they think they are being treated
Why do we use a placebo
to see if patients get better or if it because they think they are being treated
What is a double blinded trial
Group of people either given real drug or placebo. People and doctor both do not know who gets real drug and who gets fake drug
Why is a double blinded trial important
To see if a person is only getting better because they think they are getting better and to see if drug is actually effective
Scientists can trigger lymphocytes to produce monoclonal antibodies. What are these antibodies used in?
Pregnancy tests, cancer treatments
Explain how monoclonal antibodies are produced
. Inject mouse with an antigen. Lymphocytes will produce antibodies that fight against the antigens.
. Collect the lymphocytes from the mouse and combine then with a tumour cell. Tumour cells are very good at dividing by mitosis.
. They combined tumour cell and lymphocytes produce a hybridoma cell.
. The hybridoma cell can produce antibodies and divide by mitosis.
. We then select a single hybridoma cell that produces the antibodies that we want.
. We then allow this hybridoma cell to divide by mitosis to form clone of the identical hybridoma cell.
The antibodies produced by the hybridoma cell are collected. These are all identical. We call these monoclonal antibodies because they all come from a single clone of hybridoma cell.
. A large amount of these monoclonal antibodies are collected and purified
How are monoclonal antibodies use in pregnancy tests?
They are used to detect a specific hormone. This hormone is produced by the placenta of the developing foetus.
Advantages- cheap and easy to use, highly accurate if used correctly
What are some uses of monoclonal antibodies
. Measure level of hormones in the blood- if a person is tired and lacks energy, it’s can be due to low hormone level
. Detect pathogens in blood like viruses
. Locate and identify specific molecules in cells and tissue- monoclonal antibody attached to fluorescent dye. The antibodies stick to certain molecules in the cell, allowing us to see their location
what are some problems with monoclonal antibodies
In certain drug trails using monoclonal antibodies, they have been found to produce very harmful side effects so there are very few in use now
Plants can be effected by insects such as aphids. How do they do this?
Extract nutrients such as sugars from the plant, stunting its growth
How to we defect if a plant has a disease?
. Aphids
. Spots on leaves
. Discolouration
. Stunted growth
. Decay
. Growths
. Malformed stems or leaves
How do we identify plant disease?
We can use a garden manual or website
We can take infected plant to a lab and identify its pathogen
What are the 3 main defence mechanisms plants use
Physical responses, chemical responses, mechanical responses
What are the physical responses plants use
. All plant cells have a cell wall which makes it difficult for microorganisms like bacteria to penetrate
. Leaves covered in thin oily layer called waxi cuticle with makes it difficult for microorganisms to penetrate which prevent attack
. Bark- dead layer around stem
what are the chemical responses pants use
. Release antibacterial chemicals which kills bacteria and prevent them from attacking the plant
. Plants can also release poisons to deter herbivores from grazing on the plant
What are the mechanical responses plants use?
. Sharp thorns directly protect plant from predators
. Hairs which irritate mouth of predator, making it harder to eat
. Special leaves with droop or curl when touched to scare predators
. Mimicry- mimic look of other plants that are more dangerous to avoid predators
