organisms that cause disease Flashcards
define communicable disease
a disease that can spread between organisms
define pathogen
an organisms that causes a disease
where do pathogens live in and what are they ?
a host
- HB creates a good habitat in which microorganisms can live in or on the body of another organism
how do pathogens live ?
by taking nutrition from their host but also causing damage in the process
what are the 4 main types of pathogens ?
bacteria , fungi , viruses , protoctista
which kingdom does bacteria belong to ?
prokaryote
what are bacteria smaller than ?
eukaryotic cells
what is the function of a bacteria cell ?
- reproduce rapidly in right conditions
- cause disease by damaging cells , and/or releasing toxins that harm the host
what can some types of bacteria do ?
reproduce every 20 mins
where do bacteria live in plants and they cause ?
in vascular tissue
- cause blackening and death of these tissues
where are common fungal infections and result in ?
- can live in the skin of animals
hyphae form mycelium and grow under the skin surface
what can the fungus send out and resulting redness and .. ?
can send out specialised reproductive hyphae
–> can grow to the surface of the sin to release spores
CAUSES redness and irritation
where does the fungus live in plants and why ?
in the vascular tissue where it can gain nutrients
what causes decay within the tissue of plants ?
the hyphae releases extracellular enzymes
–> such as cellulases which digest the surrounding tissue
what is the function of viruses ?
- invade cells and take over the genetic machinery and other organelles of the cell
- instruct the cell to manufacture more copies of the virus
- the host cell eventually bursts
which releases many new viruses
which will infect healthy cells
what do viruses cause ?
many well-known diseases in both plants and animals
what is the function of protoctista ?
- usually cause harm by entering host cells and feeding on the contents as they grow
what is a number of diseases caused by ?
animal-like protoctists
what are examples of diseases caused by bacteria ?
- tuberculosis
- bacterial meningitis
- ring rot (in plants)
what are the characteristics of tuberculosis
- a disease that affects many parts of the body
- killing the cells and tissues
- lungs are most affected
characteristics of bacterial meningitis
- infections of the meninges
- the membranes that surround the brain and spinal cord
- the membranes become swollen –> may cause damage to the brain and nerves
characteristics of ring rot
- ring of decay in the vascular tissue of a potato tuber
OR
tomato - accompanied by leaf wilting
what are examples of virus ?
HIV/aids , influenza , tobacco mosaic virus
characteristics of HIV/AIDS
- attacks cells in the immune system
- comprmises the immune response
