Ch 23 Exam 4

Question 1

True or false: microbes that obtain nutrients from the dead are considered pathogens

Answer 1

False, since they are not living

Question 2

What is common about pathogenic bacteria, viruses and eukarya?

Answer 2

They must transmit from host to host to survive

Question 3

What pathogen is the major cause of malaria?
What does it need to do to complete its life cycle?

Answer 3

Plasmodium falciparum
needs to infect two or more species

Question 4

definitive host
intermediate host

Answer 4

the host where the pathogen replicates sexually
host where pathogen replicates non-sexually

Question 5

True or false: Giardia duodenalis does not complete its life cycle entirely within a single species.

Answer 5

False

Question 6

trophozoites

Answer 6

protozoan parasites that actively feed

Question 7

What helps trophozoites cover the small intestine?

Answer 7

ventral disk; disruption decreases ability

Question 8

What is the significance of G. duodenalis

Answer 8

It causes diarrhea

Question 9

how may eukaryal pathogens cause disease?

Answer 9

opportunistic pathogens becoming pathogenic during certain conditions (like HIV causing infection when CD4 cells are decreased

Question 10

What eukaryal microorganisms often infect people with AIDS?

Answer 10

“Pneumocystis jirovecii (previously referred to as Pneumocystis carinii) and Toxoplasma gondii” and Candida albicans

Question 11

True or False? Candida albicans also causes disease quite frequently in immunocompetent people. It is not opportunistic in the mouth and vagina

Answer 11

false. first sentence is right. second is wrong.

Question 12

What causes the limitation of growth of C. albicans

Answer 12

bacteria in Lactobacillus genus creates an ACIDIC environment

Question 13

How do organisms that are not opportunistic typically evade a normal/ strong immune response?

Give an example of an organism

Answer 13

antigenic variation
trypanosomes

Question 14

kinetoplast

Answer 14

a large mass of DNA in the single mitochondrion of trypanosomes

Question 15

parasitemia

Answer 15

number of parasites present in the blood of an infected person

(affiliated with sleeping sickness, as variation in # of parasites results in recurring seizures.)

Question 16

phytopathogenic fungi

Answer 16

fungi that cause disease in plants though secretion of enzymes

Question 17

xylanase

Answer 17

an enzyme eessential for the breakdoen of the plant cell wall (hemicellulose)

Question 18

What pathogen causes african sleeping sickness

Answer 18

trypanosoma brucei

Question 19

appresoria

Answer 19

specialized cells (from fungi) that penetrate plant cuticle by force (like Magnapothe grisea) allowing fungus to invade

Question 20

mitogens

Answer 20

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

Question 21

HC-toxin

Answer 21

toxin secreted by fungus Cochliobolus carbonum

inhibits histone deacetylases (HDACs), affecting gene expression

Question 22

a-amanitin (alpha-amanitin)

Answer 22

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

Question 23

saxitonin

Answer 23

toxin produced by dinoflagellates (algae with two flagella)
functions as sodium channel blocker

a food amount ingested results in flaccid paralysis (limp without contraction)

Question 24

Briefly explain the life cycle of malaria in a mosquito and in a human

Question 25

What are eukaryotic organisms known as?

Answer 25

Human parasites

Question 26

harmful algal blooms/red tides

Answer 26

toxins released by dinoflagellates and algae

Question 27

How many people are infected with malaria yearly? How many people die annually?

Answer 27

300-500 million 1 million

Question 28

What causes the most severe cases of malaria?

Answer 28

Plasmodium falciparum

Question 29

What does falciparum do?

Answer 29

destroys red blood cells which lead to anemia ( a decrease in the normal number of red blood cells)

Question 30

What is important for the entrance of blood cells for plasmodium falciparum Which ones are the most important? (if ya know the previous question)

Answer 30

merozoites having blood-borne surface proteins (MSPs) MSP7 (most important), MSP1,MSP6

Question 31

MSP7

Answer 31

merozoite surface protein that is the cause of red blood cell invasion

Question 32

What strategies are used to prevent falciparum

Answer 32

bug spray use of nets/screens ridding areas of stagnant water

Question 33

how may chloroquine help stop malaria?

Answer 33

blocks formation of hemozoin in plasmodium cells, leads to accumulation of cytotoxic heme