preventing and treating disease Flashcards
what are the physical defences your body has against disease? (4)
skin - a barrier to pathogens that secretes antimicrobial substances.
hairs and mucus in the nose - trap particles that could contain pathogens.
cilia - hair like structures that line the trachea and bronchi that waft mucus to the back of the throat to be swallowed. (trachea and bronchi release mucus)
stomach acid - hydrochloric acid that kill pathogens.
how do vaccinations work?
- vaccinations usually involve injecting small amounts of dead or inactive pathogens that carry antigens for your body to produce antibodies to stick to.
- if live pathogens with the same antigens appear after the body already knows how to produce antibodies to defend.
what are the 3 line of attack for white blood cells?
- white blood cells can engulf and digest pathogens. (phagocytosis)
- some white blood cells release proteins called antibodies that travel around the body and grab onto foreign antigens clumping them together so other white blood cells can kill them.
- antitoxins counter toxins produces by bacteria.
what are the pros and cons of vaccinations?
- vaccines have helped control lost of communicable diseases that were once common.
- big outbreaks of disease (epidemics) can be prevented if a large percent of the population is vaccinated. (herd immunity)
- vaccines don’t always work.
- you can have a bad reaction to a vaccine. (side effects)
what are painkillers and antibiotics?
painkillers are drugs that relieve pain by reducing the symptoms.
antibiotics kill the bacteria causing a problem without killing your cells. (the cannot kill viruses as viruses hide in regular body cells)
how can bacteria become resistant to antibiotics?
- bacteria can mutate which can cause them to be resistant to an antibiotic.
- when you treat the infection only the resistant bacteria will remain and reproduce.
how do drugs come from plants?
plants produce lots of chemicals to defend themselves from pests and pathogens that can be used to treat human diseases.
what are the 3 stages of drug testing? (and what happens)
- testing on human cells and tissues in a lab.
- testing on live animals - test for efficacy (if the drug works) and for toxicity (how harmful it is) and for dosage (the amount given) and has to be tested on 2 different animals.
- human volunteers in a clinal trial - first the drug is tested on healthy volunteers to find any side effects when the body is normal at an increasing dosage.
the drug is then tested on people with the illness to find the optimum dosage. (best effect least side effects)
patients are in 2 group one gets a placebo the other gets the drug. (blind trial the patient doesn’t know, double blind the doctor doesn’t know)
the results aren’t published until a peer review.
how are monoclonal antibodies produced?
monoclonal antibodies are produced from lots of clones of a white blood cell.
1. a mouse is injected with an antigen.
2. the b-lymphocytes producing the antibody for the antigen are extracted from the mouse.
3. tumour cells are grown in a lab.
4. the b-lymphocytes and tumour cells are fused to make a hybridoma.
5. the hybridoma divides rapidly and releases monoclonal antibodies.
how are monoclonal antibodies used in a pregnancy test?
a hormone called HCG is only found in pregnant urine.
1. the part of the stick you pee on has antibodies to HCG with blue beads attached.
2. the test strip (that turns blue if you are pregnant) has more antibodies to HCG stuck down.
3. if you’re pregnant HCG binds to the antibodies with the blue beads, the pee moves up the stick carrying the HCG and beads, the beads and HCG bind to more antibodies on the test strip turning it blue.
how can monoclonal antibodies be used to treat cancer?
cancer cells have antigens on their cell membranes that aren’t found on normal body cells called tumour markers.
1. monoclonal antibodies can be made to bind to these markers.
2. an anti cancer drug can be attached to the antibodies.
3. the antibodies are given to a patient with a drip.
4. the antibodies deliver the drugs directly to the cancer cells.
what are 3 things monoclonal antibodies can be used for in a lab?
- binding to hormones and other chemicals in blood to measure their levels.
- test blood samples for specific pathogens.
- locate specific molecules on a cell or in a tissue.
what are the negatives of monoclonal antibodies?
there is more side effects than originally expected. (such as fever vomiting low blood pressure)
they are not as widely used due to this reason than originally expected.
what mineral ions do plants need, what for and what happens if they don’t get them?
nitrates to make proteins for growth - stunted growth.
magnesium ions to make chlorophyll for photosynthesis - chlorosis and yellow leaves.
what are 6 signs a plant has a disease?
- stunted growth.
- spots on leaves.
- patches of decay.
- abnormal growths.
- malformed stems or leaves.
- discolouration.
how can a plant disease be identified? (3)
- look up signs in a gardening manual or website.
- take the plant to a laboratory.
- use testing kits.
what are the physical defences for a plant? (3)
- leaves and stems have a waxy cuticle which provides a barrier to stop pathogens entering.
- plants cells are surrounded by cell walls made of cellulose. (a barrier beyond the waxy cuticle)
- layers of dead cells around the stem to provide a barrier.
what are the chemical defences for a plant? (2)
- some plants produce antibacterial chemicals.
- some plants produce poisons which can deter herbivores.
what are the mechanical defences for a plant? (3)
- thorns and hairs.
- leaves that droop or curl when something touches them.
- some plants can mimic other organisms. (such as butterfly eggs to prevent egg laying)
