Communicable diseases Year 10

Question 1

What are communicable diseases?

Answer 1

diseases that can be passed from one individual to another. these are caused by pathogens

Question 2

What are pathogens?

Answer 2

microorganisims that cause disease

viruses, bacteria, protists or fungi

Question 3

How do pathogens cause people to feel ill?

Answer 3

• cause damage to tissues = we feel ill
• bacteria may make toxins that damage tissues
• bacteria and viruses may spread rapidly throughout the body

Question 4

How are communicable diseases spread?

Answer 4

• direct contact - touching an infected person (both sexual and non sexual)
• water - pathogens entering water supply, drinking contaminated watter or food it is added to
• air - when infected person sneezes or coughs tiny droplets spray out. another person breathes them in or lands on surfaces that other people touch

Question 5

How do you reduce the spread of disease?

Answer 5

• contact - disinfecting surfaces, regular hand washing, avoided risky sexual contact, isolating sick idividuals
• water and food - sterilisation of drinking water using chemicals or UV light, cooking food, boiling water, treatment & safe disposal of sewage
• air - using a tissue when sneezing or coughing/ good ventilation
• all - vaccination for a specific disease so that people cannot pass it on

Question 6

How do viral diseases work?

Answer 6

• viruses have genetic material enclosed in a protein coat
• reproduces using host cells they infect and enter
• viral genetic material used by host cell to replicate virus
• causes damage and death of cells as new viruses burst from infected cells

Question 7

Examples of viral diseases

Answer 7

• HIV
• measles
• tobacco mosaic virus

Question 8

what are the symptoms of HIV and how would it develop if left untreated?

Answer 8

• flu like illness
• early and ongoing treatment with antiretroviral drugs keeps virus under control
• untreated = leads to AIDS
• immune system is damaged so badly that it can not defend against other infections or cancer cells

Question 9

How is HIV spread?

Answer 9

• sexual contact
• exchange of body fluids (eg blood)

Question 10

What are the symptoms of measles?

Answer 10

• fever
• red skin rash
• can kill or cause pernament damage
• young children are vaccinated against it

Question 11

How is mealses spread?

Answer 11

• in droplets when an infected person coughs or sneezes

Question 12

What are the symptoms of tobacco mosaic virus?

Answer 12

• yellow patches in a “mosaic” pattern on leaves
• reduces photosynthesis & growth of plant

Question 13

What are the symptoms of gonorrhoea?

Answer 13

• think green or yellow discharge from vagina or penis
• pain when urinating

Question 14

How is gonorrhoea spread and treated?

Answer 14

• sexually transmitted
• treated with penicillin
• antibiotic resistant strands appeared = more people with disease

Question 15

What are the symptoms of salmonella and what is it caused by?

Answer 15

• fever
• abdominal cramps
• vomiting
• diarrhoea
• bacteria invading tissues and secreting damaging toxins

Question 16

How is salmonella spread?

Answer 16

• when bacteria is in food that is eaten
• source of contamination = infected animal or person’s faeces
• more likely when food is prepared in an unhygenic way

Question 17

What kind of disease is rose black spot?

Answer 17

fungal disease

Question 18

What are the symptoms for rose black spot?

Answer 18

• leaves develope purple or black spots
• leaves turn yellow and drop off early
• less healthy leaf tissue = growth of plant is slowed

Question 19

how can rose black spot be treated?

Answer 19

• with fungicides- chemicals that specifically kill fungi (sprayed onto the leaves)
• removing and destroying the affected leaves

Question 20

how do fungi reproduce?

Answer 20

• using microscopic spores
• small enough to be carried on the wind

Question 21

What is malaria caused by?

Answer 21

• protist called plasmodium

Question 22

How is malaria spread?

Answer 22

• starts in first host mosquito
• bites first person, they get infected
• second mosquito bites infected person and becomes a vector for the disease
• second (now infected) mosquito bites second person and passes on the disease

Question 23

What are the symptoms of malaria?

Answer 23

• episodes of fever
• headache & high temperature
• could be fatal

Question 24

How is the spread of malaria controlled?

Answer 24

• preventing mosquitos from breeding by draining water from ditches and small ponds
• using insecticides to kill the larvae
• using mosquito nets to prevent people being bitten while asleep

Question 25

What are the four non specific human defence systems?

Answer 25

• skin
• trachea and bronchi
• stomach
• nose

Question 26

How does skin act as a non specific defence system?

Answer 26

• physical barrier that pathogens cannot pass through
• glands in skin secretes substances that have antimicrobial properties (kill or stops the growth of pathogens)

Question 27

How does the stomach act as a non specific human defence system?

Answer 27

• cells of stomach produces hydrochloric acid
• kills pathogens in food

Question 28

How does the trachea and bronchi act as a non specfic human defence system?

Answer 28

• cells produce sticky mucus
• traps pathogens in inhaled air
• cilia (hair like projections) in bronchi move backwards and forwards)
• sweeps the mucus and pathogens to the throat to be swallowed
• pathogens die in stomach

Question 29

How does the nose act as a non specific human defence system?

Answer 29

• nose hiars trap pathogenes that are suspended in the air or attached to dust particles
• reduces the risk of infection of the lungs and throat

Question 30

What are antibiotics for?

Answer 30

• kill bacteria
• do not kill viruses
• different types are needed to treat specific bacterial diseases
• new strains of bacteria that are resistant to antibiotics
• race to develop new types of antibiotics to kill resistant strains as they develop

Question 31

What are painkillers for?

Answer 31

• treating the symptoms of the disease
• does not kill the pathogens
• will not cure the disease

Question 32

Where does digitalis originate from?

Answer 32

foxgloves, used to treat heart conditions

Question 33

Where did penicillin originate from?

Answer 33

• discovered by alexander fleming
• from the mould penicillium
• fungus contaminated a plate of agar which killed the bacteria that he was culturing

Question 34

Where did aspirin originate from?

Answer 34

• extracted from willow tree

Question 35

what are the three stages of drug testing?

Answer 35

• preclinical testing
• early clinical testing
• further clinical testing

Question 36

What happens during preclinical testing?

Answer 36

• tests on cells, tissues, and live animals
• tests for toxicity, efficacy and dose
• takes place in a laboratory

Question 37

What happens during early clinical testing?

Answer 37

• carried out on healthy volunteers
• tests for safety and toxicity
• uses very low concentrations of the drug

Question 38

What happens during further clinical testing?

Answer 38

• carried out on patients with the disease
• tests for optimum dosage and efficacy
• includes double blind trials in which some patients are given a placebo

Question 39

What is a double blind trial?

Answer 39

• both doctors don’t know which is the new drug or placebo to remove bias