4.3 Infection and Response Flashcards
What are pathogens?
Microoraganisms that cause infectious diseases
What can pathogens infect?
Plants
Animals
How can pathogens be spread?
Direct contact
Water or air
Vectors
What are Vectors?
Organisms that carry and pass on the pathogen without getting the disease
How can the spread of disease be reduced?
Simple hygiene measures e.g. Washing hands
Destroying vectors
Isolating infected individuals
Giving people at risk a vaccination
How did viruses cause damage to cells?
Reproduce rapidly in body cells
Describe measles
- Symptoms are fever and red skin rash
- Measles is spread by breathing in droplets from sneezes and coughs
- fatal complications
- most young people vaccinated
Describe HIV
- spread through sexual contact and sharing body fluids
- first flu like illness
- if untreated virus enters lymph nodes and attacks body’s immune cells
How do bacteria damage cells?
Directly or produce toxins that damage tissues
Describe Salmonella
Type of food poisoning caused by bacteria
Bacteria ingested in food
Secrete toxins which cause fever abdominal cramps vomiting and diarrhoea
Chicken and eggs can contain bacteria
Describe gonorrhea
Sexually transmitted disease
Spread through sexual contact
Thick yellow or green discharge from vagina or penis
Easily hearted with penicillin but resistant trains now appeared
Contraception can act as a barrier and protects
What are Protists?
Single cells organisms that are eukaryotic
Describe malaria
Caused by protists The protists uses mosquito as a vector Passed on by being bitten by mosquito Malaria causes severe fever Kill mosquitos or use nets
Describe rose black spot
Fungal disease
Spread when spores are carried from plant to plant by water or wind
Black spots develop on leaves
Stunted growth due to reducing of photosynthesis
Fungicides can be treatment
Remove affected leaves also is a treatment
Name some non-specific defences of the body that work against all pathogens
Glands in stomach Wall that produce hydrochloric acid that kills bacteria in food
Sebaceous gland in skin that produces sebum-kills bacteria and fungi
The nose traps particles
Enzymes in tears destroy microorganisms
Goblet cells create mucus which traps particles and bacteria
What does the immune system do?
Tries to destroy pathogens that enter the body
What does phagocytosis involve?
Pathogen being surrounded engulfed and digested
How do white blood cells help to defend against pathogens?
Phagocytosis
Production of special protein molecules called antibodies which attach to antigen molecules on the pathogen
Production of antitoxins which are chemicals that neutralise the poisonous effects of the toxins
What happens when someone has a vaccination?
Small quantities of dead or inactive forms of pathogen are injectors into the body
Vaccination stimulates the white blood cells to produce antibodies and to develop immunity
Why does vaccination work?
If a large proportion of the population can be made immune to a pathogen, then the pathogen cannot be spread easily