GCSE Biology - Communicable Diseases, Human defenses

what are pathogens?

microorganisms that enter a body and cause infectious disease

what size are bacteria cells compared to body cells

1/100th

how does bacteria make you feel ill?

produces toxins that damage cells and tissues

are viruses cells?

no

what size are viruses compared to bacteria?

1/100th

what do viruses do inside a human?

live inside cells and replicate

the cell then burst releasing the new viruses

how do viruses make you feel ill?

cell damage

what are protists?

single celled eukaryotes

give an example of protists

parasites

what is the body of fungi made out of ?

hyphae

how do fungi spread?

produce spores

give three ways pathogens spread

water

air

direct contact

name three viral diseases

measles

HIV

TMV

how is measles spread?

inhalation of droplets

give two symptoms of measles

red skin rash

fever

what combats measles?

vaccination

how is HIV contracted? (2)

sexual contact

exchange of bodily fluids

give a symptom of HIV

flu-like

what name is given to late stage HIV?

AIDS

how can early stages of HIV be combatted?

antiretroviral drugs

what does HIV do to the human body?

attacks immune cells

what is TMV?

plant pathogen

give two symptoms of TMV

- mosaic pattern on leaves

- discoloration of leaves causing stunted growth

why does TMV stunt growth ?

discolouration of leaves stops the process of photosynthesis

give an example of a fungal disease

rose black spot

give two symptoms of rose black spot

- purple or black spots on leave

- leaves turn yellow then drop off

what does rose black spot affect and why?

growth as reduces photosynthesis

how is rose black black spot spread ? (2)

wind

water

give two ways gardeners can treat rose black spot

fungicides

stripping the plant of affected leaves

name a disease caused by protists

malaria

name the vector which carries malaria

mosquitoes

name a symptom of malaria

fever

give three ways to reduce the spread of malaria

- stopping mosquitoes from breeding

- insecticides

- mosquito nets

name two bacterial diseases

- salmonella

- gonorrhoea

give four symptoms of salmonella

- fever

- abdominal cramps

- vomiting

- diarrhea

what are the symptoms of salmonella caused by?

toxins

in the UK what is done to prevent salmonella?

poultry given vaccination

how is gonorrhoea transmitted?

sexual contact

give two symptoms of gonorrhoea

pain when urinating

green or yellow discharge

how is gonorrhoea treated ?

antibiotics

how can the spread of gonorrhoea be controlled?

condoms

give four ways that the spread of disease can be prevented or reduced?

being hygienic

destroying vectors

isolating infected individuals

vaccination

give four primary defences which the human body has against disease

skin

hair and mucus in the nose

cilia and mucus in trachea

hydrochloric acid in stomach

what does skin secrete and what does it kill?

antimicrobial substances kills pathogens

what does the mucus in the nose and trachea do to stop diseases?

traps particles that could contain pathogens

what do pathogens have on their surface?

antigens

describe phagocytosis

ingestion of pathogens by phagocytes destroying them so that they cannot make you ill

describe function of antibodies

lymphocytes produce antibodies unique to the pathogen. they target the pathogen and destroy it

describe function of antitoxins

lymphocytes produce antitoxins which counteract the toxins released by the pathogen

what are antibodies made from?

proteins

what do vaccinations involve?

dead or inactive pathogens introduced in the body to stimulate the white blood cells to produce antibodies

what is MMR?

measles

mumps

rubella

what is the function of antibiotics?

kill bacteria

what do antibiotics not kill ?

viral pathogens

function of painkillers

treat symptoms but do not kill pathogens

why is it difficult to treat viral diseases?

hard to develop drugs which kill the virus without damaging the body's tissues

how can bacteria become resistant to antibiotics?

mutations

name two drugs which come from plants

aspirin

digitalis

what does aspirin do?

relieve pain

lower fever

what does digitalis do?

treat heart conditions

what plant does aspirin come from?

willow

what plant does digitalis come from?

foxgloves

give an example of a drug which comes from microorganisms

penicillin