5.6 Diseases Caused By Fungi And Protists

Question 1

give examples of fungal diseases in humans

Answer 1

• athlete’s foot (minor skin condition)
• small number of fungal diseases can be fatal if they attack lungs and brains of already ill people
• damaged heart valves can develop serious fungal infections (rare)

Question 2

How do you treat fungal infections in humans?

Answer 2

• antifungal drugs effective against skin fungi

Question 3

Are fungal diseases common in plants?

Answer 3

• yes
• can be devastating, huge areas of crops lost every year due to fungal infections

Question 4

What is rose black spot?

Answer 4

fungal disease of rose leaves

Question 5

symptoms of rose black spot

Answer 5

• causes black or purple spots to develop on leaves
• leaves often turn yellow and drop early
• this weakens the plant because it reduces area available for photosynthesis
• this means plant does not flower well

Question 6

how is rose black spot spread

Answer 6

• spores of fungus spread in the environment, carried by the wind
• spores stay dormant over winter on dead leaves and stems of rose plants

Question 7

how do you prevent the spread of rose black spot

Answer 7

• removing and burning affected leaves and stems
• using chemical fungicides to treat the disease + prevent it spreading
• horticulturists bred types of roses that are relatively resistant, but disease cannot be prevented or cured

Question 8

what is the best known disease caused by protists

Answer 8

malaria

Question 9

What is a vector?

Answer 9

transfers disease from protist to host (in the case of malaria, mosquitoes are the vectors)

Question 10

why are malaria protist pathogens parasites

Answer 10

they live and feed on other living organisms

Question 11

what type of mosquito is the vector for malaria

Answer 11

the anopheles female mosquito

Question 12

how is malaria transmitted to humans?

Answer 12

• protists passed into the human bloodstream when female feeds on human
• protists travel around human body in circulatory system
• can affect liver and damage red blood cells

Question 13

what are the symptoms of malaria

Answer 13

• can affect liver and RBC
• causes recurrent episodes of fever and shaking when protists burst out of blood cells, can be fatal
• weakens the affected person over time

Question 14

How many malaria cases are there and how many people die every year?

Answer 14

• several hundred million cases of malaria each year
• 660,000 die from disease each year

Question 15

How can malaria be treated?

Answer 15

• if diagnosed quickly, can be treated using a combination of drugs
• not always available in the countries most affected
• protists have become resistant to most commonly used medicines

Question 16

How can the spread of malaria be prevented?

Answer 16

• mosquito nets
• using insecticides to kill mosquitoes
• preventing vectors from breeding by removing standing water
• antimalarial drugs to kill parasites in the blood if bitten by an infected mosquito

Question 17

describe how malaria is spread between people (2 marks)

Answer 17

• mosquitoes bite infected people and become infected
• mosquito bites uninfected person and protist is transferred into bloodstream

Question 18

Explain how spraying insecticides on lakes help to reduce spread of malaria

Answer 18

• lakes and ponds are where mosquitoes reproduce
• insecticides kill female mosquitoes to prevent them from reproducing
• less mosquitoes mean protist is unable to spread

Question 19

suggest problems that may arise from spraying lakes and ponds with insecticides

Answer 19

• other insects will be affected
• this will damage the food web
• some organisms may accumulate the insecticide
• this leads to bioaccumulation