Infection and response

pathogens spread through

contaminated water

cough/ sneeze droplets

direct contact

bacteria

small

multiply very quickly thru binary fission

produce toxins that can damage cells

virus

very small

hijacks host cells and makes copies of itself.

cells bursts and the copies are released into the bloodstream

the cell damage makes u ill

protists

use humans and animals as their host

some could be vectors not infected

fungi

produce spores which spread to other organisms

bacterial diseases?

salmonella

gonorrhoea

salmonella

spread by eating raw meat that contain the salmonella bacteria

• symptoms: fever, vomiting, cramps, diarrhoea

gonorrhea

STD

• symptoms: thick yellow discharge and pain while urinating

• treated: penicillin until antibiotic resistance. barrier methods

viral diseases

measles

HIV

TMV

measles

can be fatal

spread by inhaling droplets

• symptoms: fever, red rash

HIV

STD

virus attacks immune cells

initially flu like symptoms

last stage called AIDS

TMV

plant virus: less chlorophyll

no light so causes discolouration in leaves

reduces photo and affects growth

fungal disease

rose black spot

rose black spot

black spots on leaves

turns yellow and drops

reduces photo

spread by wind

treated with fungicides

protist disease

malaria

malaria

vector

repeating fever

could be fatal

reduced by using mosquito nets

phagocytes

detects pathogens

engulfs and digests it

antibodies

detect the antigen and produce specific antibodies for those

antitoxins

produce it to neutralise the toxins released by the pathogens

vaccine

dead/ inactive form of pathogen injected into body

harmless but still carries antigens

WBC recognise the antigens and produce antibodies

some WBC remain in the body as memory cells

next time ur body will remember that pathogen and produce the antibodies quicker

herd immunity

if large amount of population is vaccined

spread of pathogen reduced

fewer people catch on the disease and spread it

helps people who cant be vaccinated

herd immunity: pros and cons

• pros: helped control many diseases and prevents epidemics

• cons: not always a 100% immunity

painkillers vs antibiotics

• painkillers: relive pain but dont kill the pathogens

• antibiotics: kills bacterias not viruses bcz they use ur body cells to reproduce.

antibiotic resistance

random mutation making it resistant to a certain antibiotic

when the antibiotic is used the ones with the resistant allele survive and reproduce

pass on that resistant gene to their offsprings

population of resistant bacterias increases

and the antibiotic is no longer effective for that pathogen

digitalis

foxgloves

aspirin

willow bark

penicillin

penicillium mould

drug testing (5)

• preclinical: for toxicity. on cells, tissues and live animals

• clinical: for effectiveness and optimum dosage. on healthy volunteers

• blind trials: observe effect. Placebo given to patient.

• double blind: avoid bias. patient and doc dont know if its the real drug

• peer review: by other scientists to avoid bias and check for repeatability.