Studied by 2 peopleDefine communicable disease
A disease that can be spread by pathogens
What are the 4 types of pathogen?
Fungi, bacteria, viruses, protists
After a pathogen infects a host what happens?
The pathogens reproduce (replicate if virus)
What is the second stage after infection?
The pathogens spread from their host
What is the final stage of infection?
The pathogens infect a new host and repeat
What method of spread is sneezing?
Airborne/ droplet infection
How is chlamydia spread?
Sexual (direct) contact
What bacterium can be spread via dirty water?
Cholera
What causes food poisoning?
Undercooked or reheated food
What is a vector?
An animal that transmits a disease without being infected itself
How can we avoid droplet infection?
Cover nose/ mouth when sneezing or coughing
What is a vaccine?
A medicine containing an inactive form of a pathogen
What does a vaccine trigger?
A low level immune response so that a second infection can be dealt with effectively
How can we avoid the spread of STDs?
Condoms and other barrier methods
How can we avoid food contamination?
Cleaning and disinfecting surfaces with antiseptics
Why are viruses not considered living?
They do not fulfil all 7 life processes
How do viruses replicate and spread?
They infect individual (host) cells, replicate, cause the cell to burst so the virus spreads
Name an example of a plant virus
Tobacco mosaic virus
What are the symptoms of TMV
Leaf mottling, stunted growth, yellow spots/streaks on leaves
What disease can the HIV virus lead to?
AIDS
How does pathogenic bacteria make us ill?
They produce toxins/poisons that damage tissues
What cell type are bacteria?
Prokaryotes as they have no nucleus
How was gonorhea treated in the past vs now?
With penicillin, but we are now resistant so antibiotics used
What causes food poisoning (salmonella)?
-Unhygienic conditions
-Undercooked/reheated food
How is salmonella prevented?
All UK poultry are vaccinated against salmonella
What cell type are fungi?
Eukaryotic as they have a nucleus
What is their cell wall made of instead of cellulose?
Chitin (polymer made from sugars
Give examples of single and multi-celled fungi
Single- yeast
Multi- mushrooms
What is an example of a fungal disease that effects plants?
Rose black spot
What are the signs of rose black spot?
Leaf turns yellow, purple mottling
What cell type are protists?
Eukaryotic as they have a nucleus
How are protists different to animal, plants and fungi?
They don’t have tissues, organs or organ systems
What is the most common protist caused disease
Malaria
How are mosquitoes vectors?
They spread malaria without being infected themselves
How is malaria spread reduced?
-By preventing mosquito breeding
-Bug spray
-Mosquito nets
What is plasmodium?
The protist causing malaria
Where in the body does plasmodium reproduce? Is it sexual or asexual?
Asexually in the liver
What are these daughter parasites called?
Merozoites
What happens when protists feed on haemoglobin in the blood?
More merozoites are produced which burst out of blood cells
How do merozoites make us ill?
Merozoites release toxins which make us ill
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