Lecture 14

Question 1

eukaryotic microbes

Answer 1

1. prominent members of ecosystem
2. useful as model systems and in industry
3. important human and plant pathogens
4. two groups: protists and fungi

Question 2

general features of protists

Answer 2

domain eukarya
< 60,000
mostly unicellular
algae (photosynthetic), slime molds, protozoa (chemoorganotrophic)
terrestrial or aquatic (mostly)
some parasitic
motile (cilia, flagella, pseudopodia: extensions of cell)
asexual or sexual reproduction

Question 3

protists

Answer 3

important link in food chain
major part of plankton in aquatic habitats
ex. radiolarians, diatoms, foraminiferans
- silica, calcium carbonate walls, reef formation, beach sand, limestone

Question 4

protist structure

Answer 4

plasmalemma: plasma membrane
ectoplasm: under pm; rigid; cilia and flagella embedded within
endoplasm: fluid “cytoplasm”

Question 5

micronucles vs macronucleus

Answer 5

micronucleus: true nucleus; undergo meiosis and mitosis
macronucleus: genetic info storage

Question 6

contractile vacuole

Answer 6

osmoregulatory

Question 7

encystment vs excystment

Answer 7

encystment: cell becomes more simpler and develops into dormant cyst
- stress resistance
- protection, transmission

excystment: escape from cyst to metabolically active, often motile –> trophozoite

Question 8

metabolism

Answer 8

photosynthesis I and II - oxygenic
chemoorganoheterotrophs
mixotrophs (lithotrophs)… organic and inorganic

Question 9

nutrition

Answer 9

solid nutrition by phagocytosis (holozoic)

facilitated diffusion and active transport of soluble nutrients

Question 10

phagocytosis mechanism

Answer 10

1. pseudopodia surrounds food particle
2. phagosome develops
3. fuses with lysosome to form phagolysosome
4. nutrient diffuses into cytoplasm, waste released

Question 11

chlamydomonas

Answer 11

single-celled green alga
cellulose cell wall
photosynthetic
motile (in response to light)
stigma (eyespot) role in phototaxis
sexual and asexual reproduction

Question 12

Slime molds

Answer 12

dictyostelium
similar to myxococcus in formation of fruiting bodies and spores
“slug”

Question 13

giardia

Answer 13

protozoan parasite
human pathogen
- cysts ingested
- trophozoites attach to intestine (disrupts nutrient, H20 flow)
causes backpacker's diarrhea

Question 14

alveolata

Answer 14

dinoflagellate
major component of marine plankton
causes toxic red tide
produces neurotoxins
free-living also symbionts to zooxanthelle

ciliates
stentor
paramecium

apicomplexans
apical complex (organelles dedicated to secretions to invade other cells)

Question 15

apicomplexans

Answer 15

causes of human diseases
cryptosporidiosis
- caused by cryptosporidium parvum
toxoplasmosis
- toxoplasma gondii
malaria
- plasmoidum falciparum

Question 16

cryptosporidium parvum

Answer 16

oocysts ingested; trophozoite in intestine
- oocysts small chlorine resistant and stable
transmitted from animals in contaminated food and water

Question 17

toxoplasmosis

Answer 17

oocyst from raw or undercooked meat or from cat feces
cats: host required to complete sexual cycle
ingested oocyst develop into tachyzoites (trophozoites) localized in neural and muscle tissue