b5

Question 1

what are communicable diseases?

Answer 1

diseases that can be passed from person to person by a pathogen
virus, bacteria, protist, fungi

Question 2

what are direct transmission ways

Answer 2

direct contact, secual contact, placental transfer

Question 3

indirect transmission ways

Answer 3

vector - organisms transfer pathogen from one host to another
droplet infection
waterbourne and food

Question 4

preventing spreading of communiable diseases

Answer 4

destroying vectors eg killing mosquitos for malaria
simple hygiene methods
isolation and vaccines

Question 5

how do viruses work?

Answer 5

they live and reproduce rapidly by inserting genetic material into host cells, causing cell damage

Question 6

measles

Answer 6

viral disease
symptoms: fever, red skin rash
prevention: young children are vaccinated against it
spread: by inhalation of droplets from sneezes and coughs

Question 7

HIV

Answer 7

viral disease
symptoms: flu-like initially. if not controlled with antiretroviral drugs, virus attacks immune cells.
- can lead to AIDS in long term. this is when body’s immune system is so badly damaged it cannot deal with other infections or cancers
spread: sexual contact or exchange of bodily fluids like when sharing needles

Question 8

tobacco mosaic virus

Answer 8

viral disease, mainly tomato plants
symptoms: gives mosaic pattern of discolouration on leaves which affects the growth of plant due to lack of photosynthesis
prevention: good field hygiene
spread: direct contact with infected plant

Question 9

salmonella

Answer 9

bacterial disease
symptoms: fever, abdominal cramps, vomiting, diarrhoea
spread: bacteria on ingested food, food prepared in unhygenic conditions
prevention: poultry vaccinated against it

Question 10

gonorrhoea

Answer 10

bacterial disease
symptoms: thick yellow/green discharge from vagina or penis, pain when urinating
spread: by sexual contact
treatment: antibiotic - penicillin but resistant strains developed
prevented by barrier contraception eg condoms

Question 11

how do bacteria work?

Answer 11

produce toxins which cause damage to cells and tissues directly

Question 12

rose black spot

Answer 12

fungal disease
symptoms: black/purple spots on leaves. it affects the growth of plant as photosynthesis is reduced
spread: by water or wind
treated: fungicides or removing/destroying affected leaves

Question 13

how do fungi work?

Answer 13

have thread like structures called hyphae which grow and penetrate surfaces of animals and plants. produce spores which can spread the infection

Question 14

malaria

Answer 14

protist disease
vector: mosquito
symptoms: recurrent episodes of fever and can be fatal
prevention: prevent vectors (mosquitos) from breeting and use mosquito nets to avoid being bitten

Question 15

non-specific defence systems in humans and what they do

Answer 15

skin - acts as a physical barrier and also secretes antimicrobial substances which kills pathogens
nose - contains hair and mucus which trap particles containing pathogens
trachea and bronchi - secrete mucus which traps pathogens. lined with cilia which are hair like substances that waft mucus to back of throat so it can be swallowed
stomach - contains hydrochloric acid which kills pathogens that make it that far from mouth

Question 16

white blood cells - phagocytosis

Answer 16

engulf and digest pathogens
- normally helped by antibodies clumping them together.
- phagocyte surrounds pathogen and releases enzymes to digest and break it down to destroy it

Question 17

white blood cells - antibodies

Answer 17

lymphocytes produce antibodies
- antibodies produced have a specific/ complimentary shape to the antigens on the surface of the pathogen
- it clumps the pathogens together

Question 18

antitoxins

Answer 18

bacteria produce toxins. lymphocytes produce antitoxins to neutralise effect of the toxins