b5 communicable diseases Flashcards
What is health?
A state of physical mental, and social well-being, not just the absence of disease.
What are communicable diseases?
Diseases caused by pathogens that can spread between organisms (e.g.
What are non-communicable diseases?
Diseases that cannot spread between organisms (e.g.
How can diseases interact?
One disease can increase the risk of another (e.g.
What are pathogens?
Microorganisms that cause infectious diseases (e.g.
How do bacteria cause disease?
They produce toxins that damage cells and tissues.
How do viruses cause disease?
They invade and replicate inside cells
What are examples of diseases caused by bacteria?
Salmonella (food poisoning)
What are examples of diseases caused by viruses?
HIV (AIDS)
What are examples of diseases caused by fungi?
Athlete’s foot
What are examples of diseases caused by protists?
Malaria (spread by mosquitoes).
How are pathogens spread?
Through air
Why are cultures of microorganisms grown in labs?
To study pathogens and test antibiotics.
What is a culture medium?
A substance with nutrients for microorganisms to grow (e.g.
What is aseptic technique?
A method to prevent contamination when growing microorganisms (e.g.
Why are cultures incubated at 25°C in schools?
To reduce the risk of growing harmful pathogens.
What is the purpose of sterilising inoculating loops?
To kill microorganisms and prevent contamination.
What is the aim of the microbiology practical?
To test the effect of antibiotics or antiseptics on bacterial growth.
How do you set up the practical?
1) Sterilise equipment. 2) Spread bacteria on agar. 3) Add antibiotic discs. 4) Incubate at 25°C.
What do clear areas around antibiotic discs indicate?
Bacteria have been killed
Why must petri dishes be sealed with tape?
To prevent contamination but allow oxygen in.
What are examples of plant diseases caused by pathogens?
Rose black spot (fungus)
What are symptoms of rose black spot?
Purple/black spots on leaves
What are symptoms of tobacco mosaic virus?
Mosaic discolouration on leaves
How do plants defend themselves against pathogens?
Physical barriers (e.g.
What are mechanical defences in plants?
Thorns
What are the three main lines of defence in the human body?
1) Physical barriers (e.g.
How does the skin protect against pathogens?
Acts as a barrier and produces antimicrobial secretions.
How does mucus protect against pathogens?
Traps pathogens in the respiratory and digestive tracts.
What is the role of white blood cells?
They engulf pathogens
What are antibodies?
Proteins that bind to specific antigens on pathogens
What is immunity?
The ability to resist infection
What is vaccination?
Introducing a harmless dose of a pathogen to stimulate immunity.
How do antibiotics work?
Kill or inhibit bacteria (but not viruses).
Why is antibiotic resistance a problem?
Overuse leads to resistant bacteria
What is herd immunity?
When most of a population is immune
How does herd immunity work?
Immune people stop the pathogen spreading
Why is herd immunity important?
It protects vulnerable people who can’t be vaccinated (e.g.
What percentage of the population needs to be immune for herd immunity?
Usually 80-95% for highly infectious diseases like measles.
