Animal + plant pathogens Flashcards
What are communicable diseases caused by?
Infective organisms (pathogens), including bacteria, fungi, viruses, + protoctista
Can be passed from 1 organism to another
What are animal + plant pathogens spread by?
Vectors that carry the pathogen between individuals
What are the structural details of pathogens?
Prokaryotic - no membrane bound organelles or nucleus, 10um
How are bacteria classified by shape?
May be rod shaped (bacilli), spherical (cocci), comma shaped (vibrios), spiralled (spirilla), + corkscrew (spirochaetes)
How is bacteria classified by cell wall?
Have diff structures + react differently with gram staining
Gram positive bacteria = Purple-blue under microscope, lots of peptidoglycan
Gram negative bacteria = Red under microscope, less peptidoglycan
How is classifying bacteria by their cell walls useful?
Because cell wall type affects how bacteria reacts to different antibodies
What are some examples of bacteria?
MRSA, E.coli
What is the structure of viruses?
Non living, 0.02-0.3um in size, genetic material (DNA or RNA) surrounded by protein
Examples are plague
Why do viruses need a host cell?
So when they invade living cells, their genetic material can take over the biochemistry of host cells to make more viruses
What type of viruses affect bacteria?
Bacteriophages - take over bacterial cells + use them to replicate, destroying bacteria at same time
What type of cell is a protoctista?
Single-celled, grouped into colonies
E.g. malaria
What are the protists that cause disease called?
Parasitic,
They use animals + plants as host organism, may need vector to transfer them to host
What type of cell is fungi?
Eukaryotic, multicellular organism
Mainly affect plants - crop plants
Single celled = yeast, multicellular = hyphae
What are saprophytic and parasitic fungi?
Saprophytic fungi = feed on dead + decaying matter
Parasitic = feed on living plants + animals
What are the 2 ways pathogens can damage the host cells?
- Damage host tissues directly
- Produce toxins which damage host tissue
How do pathogens damage host tissues directly?
- Viruses take over cell metabolism- viral genetic material gets into host cell + inserted in host DNA
- Some protoctista take over cells + break them open, but dont take over genetic material. Digest + use cell contents as they reproduce
- Fungi digest living cells + destroy them
How do pathogens produce toxins?
- Most bacteria produce toxins that poison/damage host cells
- Some fungi produce toxins which damage host cells + cause disease
