B3 Flashcards
What is a pathogen?
A disease-causing microorganism
How do bacteria causes diseases?
Once inside the body they divide rapidly by binary fission. They kill cells and produce harmful toxins
How do viruses cause disease?
They invade and reproduce inside living body cells, leading to cell damage
Give three ways in which pathogens can be spread?
Air, water, direct contact
Give four ways in which the spread of pathogens can be reduced?
Hygiene
Reducing contact with infected
Removing vectors
Vaccination
Why is it especially important to prevent the spread of viral diseases?
Scientists have not yet developed cures for many viral diseases
What is measles?
Measles is a serious viral disease that can cause blindness and brain damage. The main symptoms are fever and a red skin rash
How’s is measles spread?
Air
What is HIV/AIDS?
HIV is a virus which attacks and damages the immune system until it can no longer function properly. AIDS is the condition resulting from long-term HIV infections. There is no cure or vaccine
How is HIV spread?
Direct contact
How can the spread of HIV be prevented?
Use of condoms
Screening of blood transfusions
Not sharing needles
Bottle-feeding by HIV-positive mothers
Use of antiretroviral drugs to prevent the development of AIDs
What is the tobacco mosaic virus?
A plant pathogen which causes leaf discolouration when cells are damaged. Affected areas cannot photosynthesise, reducing the crop yield. As there is no treatment, farmers grow TMV-resistant crop strains to avoid infection
How is tobacco mosaic virus spread?
Contact between infected and healthy plants. Insects may act as vectors
What is salmonella?
A type of bacteria found in raw meat, poultry and eggs. If they enter the body they can affect natural gut bacteria
What are the symptoms of salmonella food poisoning?
Fever
Abdominal cramping
Vomiting
Diarrhoea
How can the spread of salmonella be limited?
Vaccinating animals intended for consumption
Keep raw meat away from cooked meat
Disinfect hands and surfaces after contact with raw meat
Cook meat thoroughly
What is gonorrhoea?
An STD bacteria infection caused by unprotected sex
What are the symptoms of gonorrhoea?
Yellow/green discharge from genitals and painful urination (can be symptomless)
What is rose black spot?
A fungal disease which causes purple or black spots to develop on rose leaves. It reduces the area of the leaf which is available for photosynthesis and causes leaves to turn yellow and drop prematurely
How is the rose black spot fungus spread?
Fungal spores are spread by the wind and in water
How can rose black spot fungus be treated?
Using fungicides
Destroying infected leaves
What is malaria?
A disease caused by protist pathogens.
It is carries host to host by mosquitoes and the portists enter the human blood stream when they feed
What are the symptoms of malaria?
Fever and shaking