Communicable disease Flashcards
What is a vector?
carry pathogens from one organism to another, but do not have the disease themselves
What type of cell is bacteria?
prokaryotes
What is the average diameter of viruses?
0.02-0.3 nanometers
What are viruses that attack bacteria are known as?
bacteriophages
Protoctista affect what types of organisms?
plants and animals
What are the four types of communicable disease?
virus
fungi
bacteria
protista
What is ring rot and what is the effect on plants?
bacterial disease that affects the fields, and damages leaves
What is TMV and what is the effect on plants?
tobacco mosaic virus, causes loss in cholorphyll, which stunts growth of plants
What is tuberculosis?
a bacterial disease in mammals which destroys lung tissue and suppresses the immune system
What is Bacterial Meningitis and how does it work?
a bacterial infection, of the brain which can spread to the rest of the body
What is HIV and how does it work?
human immunodeficiency virus
targets T helper cells
- contains RNA as its genetic material
- Contains the enzyme reverse transcriptase
- which produces a single strand of DNA in the host cell
What are the three types of direct transmission?
- direct contact
- inoculation (through the skin)
- ingestion
What are the three different types of indirect transmission?
- fomites (inanimate objects)
- droplet infection (inhilation)
- vectors
What is a communicable disease?
pass from an infected person to an unaffected person
diseases caused by pathogens
How do viruses attack an individual?
- attachment of virus to the host cell
- insertion of viral nucleic acid DNA or RNA
- DNA replication of the virus
- synthesis of viral protein
- assembly of virus particles
- lysis of host cell
How does the plant disease of fungus work?
(like protist)
hyphae penetrate the host cell, destroy leaves and there is no cure
How can you control the spread of fungal disease?
using fungicides
What is a virus and what are some examples?
e.g. influenza/bird flu
smaller than bacteria and invade host cells
What are some of the factors affecting transmission of disease in animals?
- lack of sanitation
- overcrowding
- diet
- ventilation
How does direct transmission work in plants?
entering through roots
leaves touching etc.
What are the factors affecting transmission of disease in plants?
more susceptible because they are clones of each other = monoculture
overcrowding
damp
lack of nutrient availability
climate change
How does indirect transmission work in plants?
airborne transmission
How does a plant detect pathogen?
the pathogen will attach to a receptor in the cell surface membrane
some defensive molecules directly attach
polysaccharides made to strengthen cell wall
What are the two polysaccharides that are produced to by the plant to strengthen the cell wall?
chitin and lignin
How does the mechanical defense of the plants work?
produce a high level of callose
Callose is synthesised and deposited between the cell wall and membrane to prevent spread
What do callose papillae do?
act as barriers, preventing the pathogens entering other cells around infection
What does callose do to the phloem?
blocks the sieve plates, sealing off the infectious part, preventing the spread
Where is callose deposited?
in the plasmodesmata between the infected and non infected cells
How do chemical defenses in plants work?
produce chemicals such as insect repellents
What do insecticides do and where are they found?
e.g. pyrethrins = made in chrysanthemums, act as toxins towards insects
What is an example of an antibacterial produced by plants?
gossypol produced by cotton
What are some examples of antifungal compounds produced by plants?
e.g. = phenols
= chitinase = enzyme that break down fungal cell walls
What is the first line of defence?
a non specific response to keep pathogens out
natural barriers that prevent their entry
both chemical and physical
How are mucous membranes an example of a non specific response?
trap the pathogen and then expel themselves out or in the stomach
goblet cells = produce mucus
ciliated cells = move mucus
e.g. respiratory tract
How is blood clotting an example of a non specific response?
1st reaction = co factor joins to enzyme
2nd reaction = the enzyme turns the blood from soluble to insoluble so that its able to clot
How do inflammatory responses happen and how can they be dealt with?
histamine = dilate blood vessels, causes area to look red, plasma leaks from capillaries taking WBC with it
antihistamines = release mast cells
