Ch 23 Exam 4 Flashcards
True or false: microbes that obtain nutrients from the dead are considered pathogens
False, since they are not living
What is common about pathogenic bacteria, viruses and eukarya?
They must transmit from host to host to survive
What pathogen is the major cause of malaria?
What does it need to do to complete its life cycle?
Plasmodium falciparum
needs to infect two or more species
definitive host
intermediate host
the host where the pathogen replicates sexually
host where pathogen replicates non-sexually
True or false: Giardia duodenalis does not complete its life cycle entirely within a single species.
False
trophozoites
protozoan parasites that actively feed
What helps trophozoites cover the small intestine?
ventral disk; disruption decreases ability
What is the significance of G. duodenalis
It causes diarrhea
how may eukaryal pathogens cause disease?
opportunistic pathogens becoming pathogenic during certain conditions (like HIV causing infection when CD4 cells are decreased
What eukaryal microorganisms often infect people with AIDS?
“Pneumocystis jirovecii (previously referred to as Pneumocystis carinii) and Toxoplasma gondii” and Candida albicans
True or False? Candida albicans also causes disease quite frequently in immunocompetent people. It is not opportunistic in the mouth and vagina
false. first sentence is right. second is wrong.
What causes the limitation of growth of C. albicans
bacteria in Lactobacillus genus creates an ACIDIC environment
How do organisms that are not opportunistic typically evade a normal/ strong immune response?
Give an example of an organism
antigenic variation
trypanosomes
kinetoplast
a large mass of DNA in the single mitochondrion of trypanosomes
parasitemia
number of parasites present in the blood of an infected person
(affiliated with sleeping sickness, as variation in # of parasites results in recurring seizures.)
phytopathogenic fungi
fungi that cause disease in plants though secretion of enzymes
xylanase
an enzyme eessential for the breakdoen of the plant cell wall (hemicellulose)
What pathogen causes african sleeping sickness
trypanosoma brucei
appresoria
specialized cells (from fungi) that penetrate plant cuticle by force (like Magnapothe grisea) allowing fungus to invade
mitogens
chemicals that influence the effect of appresoria in M. grisea (with MAP kinase pathway)
without this (or a mutation in the pmk1 gene that encodes MAP) appressoria isn’t made and grisea
doesn’t penetrate
HC-toxin
toxin secreted by fungus Cochliobolus carbonum
inhibits histone deacetylases (HDACs), affecting gene expression
a-amanitin (alpha-amanitin)
toxin made by mushrooms
ingestion of this results in intoxication (and disease)
LD50 is .1mg/kg (inhibits RNA pol. II but not I or III
saxitonin
toxin produced by dinoflagellates (algae with two flagella)
functions as sodium channel blocker
a food amount ingested results in flaccid paralysis (limp without contraction)
Briefly explain the life cycle of malaria in a mosquito and in a human
What are eukaryotic organisms known as?
Human parasites
harmful algal blooms/red tides
toxins released by dinoflagellates and algae
How many people are infected with malaria yearly?
How many people die annually?
300-500 million
1 million
What causes the most severe cases of malaria?
Plasmodium falciparum
What does falciparum do?
destroys red blood cells which lead to anemia ( a decrease in the normal number of red blood cells)
What is important for the entrance of blood cells for plasmodium falciparum
Which ones are the most important? (if ya know the previous question)
merozoites having blood-borne surface proteins (MSPs)
MSP7 (most important), MSP1,MSP6
MSP7
merozoite surface protein that is the cause of red blood cell invasion
What strategies are used to prevent falciparum
bug spray
use of nets/screens
ridding areas of stagnant water
how may chloroquine help stop malaria?
blocks formation of hemozoin in plasmodium cells, leads to accumulation of cytotoxic heme
