Biology- Communicable diseases

Questions!

Define 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