B2 Reducing And Preventing The Spread Of Disease

Question 1

How can we reduce or prevent the spread of disease in animals? 7

Answer 1

Being hygienic (hand washing)
Sterilising wounds
Live in sanitary conditions (clean water, effect sewage system)
Destroy infected animals
Isolate infected individuals (prevent travel)
Vaccination (diseases can’t develop and then can’t be passed on)
Contraception (to prevent STI)

Question 2

How can we reduce the spread of disease in plants? 7

Answer 2

Regulating movement of plant material
Destroy infected plants
Only use healthy sources of seeds and plants
Crop rotation
Polyculture (growing different types of plants in a single area at the same time)
Chemical control (fungicides)
Biological control (another organism used to control the pest)

Question 3

Why reduce or prevent the spread of disease in animals?

Answer 3

If a disease spreads uncontrollably it can result in huge loss of life and affect food sources (if in animals reared for food)

Question 4

Why prevent or reduce the spread of disease in plants?

Answer 4

Plant diseases can reduce food sources and damage habitats in an ecosystem

Question 5

How does use of contraception prevent the spread of disease?

Answer 5

Prevents sexually transmitted disease being transmitted during sex

Question 6

How do vaccinations prevent the spread of disease in animals?

Answer 6

Vaccinating people and animals against communicable diseases mean they won’t develop the infection and then pass it on to others

Question 7

How can isolating infected individuals help prevent the spread of disease in animals?

Answer 7

Prevents infected person from passing on disease to anyone else. Preventing travel prevents it from spreading even further.

It benefits society to isolate individuals, but can be difficult for the infected person as they can be with their loved ones.

Question 8

Why would infected animals be destroyed?

Answer 8

To prevent the spread of disease to large numbers of animals within a herd (on a farm)

This is costly and the disease may still spread if the disease is present in other animals who do not have symptoms

Question 9

How can good sanitary conditions prevent the spread of disease in animals?

Answer 9

Having access to clean drinking water and a good system for disposing of sewage can reduce the transmission of waterborne diseases such as cholera, which is transmitted through urine and faeces of infected people.

Initial cost to a society of creating sanitary conditions can be high

Question 10

How can sterilising wounds prevent the spread of disease in animals?

Answer 10

Kills the microorganisms near the wound so stops them entering the blood.

Question 11

How can being hygienic prevent the spread of disease in animals?

Answer 11

Washing hands regularly removes pathogens and is effective in preventing the spread of disease

Question 12

How can regulating the movement of plant material prevent the spread of disease in plants?

Answer 12

Makes sure infected plants don’t come into contact with healthy plants
(eg plant nurseries can’t sell plants which have crown gall disease)

Question 13

How can destroying infected plants help prevent the spread of disease in plants?

Answer 13

This stops plants being sources of infection

can be costly to the farmer

Question 14

How can using sources of healthy seeds and plants prevent the spread of disease in plants?

Answer 14

Stops diseases from being introduced into a population

Question 15

How can crop rotation help prevent the spread of disease in plants?

Answer 15

Changing the types of plants that are grown stops pathogens becoming established in an area, as many pathogens are specific to a particular plant.

This may limit how profitable a farm is if they have to change farming practices for a different crop each year

Question 16

How can chemical controls help prevent the spread of disease in plants?

Answer 16

Fungicides can be used to kill fungal pathogens.

This can lead to the evolution of resistant strains of the pathogen.

Question 17

How can biological controls help prevent the spread of disease in plants?

Answer 17

Another organism is used to control a pest or pathogen.
(Eg ladybirds can be introduce to reduce aphid numbers)

In some cases the control organism may become a pest itself and cause more problems.

Question 18

Give one benefit and one cost to a farmer of using crop rotation system (2 marks)

Answer 18

Benefit: changing the type of plants that are grown stops the pathogen becoming established in an area since many pathogens are specific to a particular plant.

Cost:may limit how profitable a farm is if it has to change farming practices for a different crop each year.

Question 19

How can polyculture help prevent the spread of disease in plants?

Answer 19

Polyculture is growing different types of plant in the same area at the same time.

If a pathogen specific to a single plant enters one plant it is less likely to infect it’s neighbouring plants because they are different species. This limits the spread of a pathogen through the crop.