INFECTION AND RESPONSE Flashcards
what is a pathogen?
a microorganism that enters the body and cause disease e.g bacteria, fungi, protists, virus
what type of disease do they cause?
communicable (infectious)
what are bacteria?
small cells that reproduce fast in the body (1/100th the size of cells)
how does bacteria make you feel ill?
release toxins that damage cells and tissues
what are viruses?
not cells - 1/100th the size of bacterium that reproduce fast
how does viruses make you ill?
live inside your cells and replicate then they burst which releases viruses
what are protists?
single celled eukaryotes
how do protists make you ill?
live on/inside other organisms and damages them OR transferred to the organism by a vector
what is a vector?
something that transfers disease without being affected
what is fungi?
single celled eukaryotes - some have a body made up of hyphae
why is hyphae dangerous?
they grow and penetrate human skin and plant surfaces OR produce spores which can be spread
how can pathogens be spread?
water e.g cholera - bacterial infection spread by drinking contaminated water
air - sneezes/coughs e.g influenza
direct contact e.g athletes foot
examples of viral diseases?
measals
HIV
TMV
how is measals spread?
droplets from an infected person’s sneeze/cough
what are the effects of measals?
red skin rash, fever, pneumonia, inflammation of the brain
how is HIV (virus) spread?
sexual contact or exchanging body fluids or sharing needles
what are the effects of HIV?
flu like symptoms
how is HIV treated?
antiretroviral drugs - stop the virus from replicating
what is TMV?
tobacco mosaic virus - affects plants
what are the effects of TMV?
mosaic pattern on leaves, discolouration of leaves - can’t carry out photosynthesis -> affects growth
example of fungal disease?
rose black spot
what is rose black spot?
fungus
what are the effects of rose black spot?
causes purple/black spots on leaves, then turns yellow and falls off -> can’t photosynthesise -> plant can’t grow
how does rose black spot spread?
water and wind
how can rose black spot be treated?
fungicides OR remove the affected leaves then destroy them
example of a disease from a protist?
malaria
how is malaria spread?
everytime a mosquito feeds on an animal, it infects it by inserting the protist into the animals blood vessel
how can malaria be prevented?
insecticides and mosquito nets
examples of bacterial diseases?
salmonella
gonorrhoea
what is salmonella?
type of bacteria that causes food poisoning
what are the effects of salmonella?
fever, cramps, vomiting, diarrhoea
what causes salmonella?
toxins that bacteria produces
how can you get salmonella?
eating foods that have been contaminated with salmonella bacteria
what is gonorrhoea?
sexually transmitted disease (STD) caused by bacteria
how is gonorrhoea spread?
sexual contact
what are the effects of gonorrhoea?
pain during urination
thick yellow/green discharge
how can gonorrhoea be prevented?
antibiotics and barrier methods (condoms etc)
how can the spread of disease be prevented/reduced?
staying hygienic
destroying vectors
isolating infected individuals
vaccines
how does the body fight against disease?
skin - barrier to pathogens, secretes antimicrobial substances
hair and mucus (nose) - traps particles -> trap pathogens
trachea and bronchi - secrete muscus to trap pathogens
stomach - produces hydrochloric acid -> kills pathogens
how does the immunse system attack pathogens?
white blood cells:
1. phagocytosis - engulf foreign cells and digest them
2. produce antibodies - every pathogens have antigens on their surface -> white blood cells detect foreign antigens and produce antibodies (proteins) to lock on the antigen - if this happens too much then it becomes naturally immune
3. produce antitoxins
what are vaccines?
dead/inactive pathogens e.g MMR
how do vaccines work?
they carry antigens which causes your body to produce antibodies
what are the advantages of vaccines?
helps control communicable diseases e.g measals, mumps, tetanus -> smallpox doesn’t exist anymore
epidemics are prevented
what are the disadvantages of vaccines?
don’t always give immunity
bad reaction to vaccine e.g swelling, fever, seizure
what are painkillers?
drugs that relieve pain e.g morphine, asprin but don’t tackle the disease or kill pathogens - just relieve symptom
what do antibiotics do?
kill the bacteria causing the problem without killing your body cells BUT don’t kill viruses
why doesn’t antibiotics kill viruses?
viruses reproduce using your body cells
why can bacteria become resistant to antibiotics?
they can mutate which causes some to be resistant
what are the dangers of resistant strains of bacteria?
cause a serious infection that can’t be treated e.g MRSA is resistant to methicillin
how can resistance be slowed down?
doctors should avoid over-prescribing antibiotics, only prescibe it when it is serious and finish the whole course of antibiotics
where did drugs originally come from?
plants - produce a variety of chemicals to defend themselves against pests/pathogens e.g. asprin (willow) and digitalis (foxgloves)
mircoorganisms - alexander fleming -> penicillin
what are the (3) stages of drug testing?
- tested on human cells/tissues
- test on live animals
- tested on human volunteers
what are statins?
drugs that reduce cholestrol
what is a parasite and examples?
an organism that lives in its host to get food e.g. fungi and protists
give examples of drugs that used to be extracted from plants and organisms.
asprin - willow tree
penicillin - mould
what do white blood cells produce?
antitoxins - to neutralise poisons
what do pathogens produce?
antibodies - stick to an antigen on a pathogen
what is a lymphocyte?
type of immune cell made in the bone marrow
do fungicides treat diseases or infections?
infections
what is aseptic?
prevent contamination
what is antiseptic?
using chemical agents to inhibit the growth of microorganisms
what is culture?
a growth of microorganisms in a specially prepared nutrient medium under supervised conditions
at what degrees is culture incubated?
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