RECAP questions - Final

Question 1

• what is a hydrogenosome?
• secondary endosymbiosis example
• cyst?
• example of parabacelid?
• example of diplomonad?
• euglenids

Answer 1

• found in eukaryotes who only do fermentation
• euglenids get their chloroplasts that way –> chloroplast is actually a green algae
• some eukaryotes differentiate into a cyst (a bit like a spore)
• parabacelid: pathogen in humans
  -diplomonad: agent of beaver fever
• euglenids: nonpathogenic and photophic. a type of euglenozoan. will lost chloroplast if incubated in dark for a long time

*maybe add more details for the answers!

Question 2

• What is a guild?
• what is a niche?
• what is a microenvironment?
• compare richness and abundance

Answer 2

GUILD: set of populations that are doing the same thing from metabolic/catabolic perspectives

NICHE: place where you will find a guild bc characteristics that fit with metabolic/catabolic functions

MICROENVIRONMENT: the immediate environmental surroundings of a microbial cell or group of cells

RICHNESS: how much variety
ABUNDANCE: how much of each

Question 3

1) example of bacteria that can do Nitrogen fixation?
2) what is rhizobium?
3) what is photic zone?
4) oligotrophic vs eutrophic?
5) what is a xenophyophore?

Answer 3

1) some cyanobacteria! (heterocysts), rhizobium, aztobacter (aerobic respiration), clostridium
2) bacteria that have symbiotic relationship with legumes (soybean) –> plants supply organic acids + lagemoglobin to limit O2
3) water column/depth that receives photons! max depth: 300m. lots of primary productivity
4) OLIGO: nutrient limiting, lots of O2 in water
VS EUTROPHIC: lots of nutrients, low O2 –> can become anoxic –> anaerobic/fermentation –> can produce H2S = bad
5) massive protoplasts/protists that exist deep down on sea bed (5000m deep)

Question 4

1) what is BOD?
2) give examples of waterborne pathogens
3) difference btw coliforms and fecal coliforms?
4) biofilm definition?

Answer 4

1) biochemical O2 demand –> measurement of how much O2 is consumed by microorgs + indirectly how much organic material there is
2) G. lamblia –> protozoa, forms cyst –> removed at filtration stage
VS cryptosporium: passes through filtration: need ozone to get rid of cysts
3) both can ferment lactose. coliforms grow at 37°C vs fecal coliforms grow at 44.5° -> can use same media to detect, just incubate at dif temps
4) community of orgs growing together + attached to surface + inside ECM

Question 5

1) describe rumnicoccus’ characteristics ish. what is special about them?
2) in rumen: main fermentation product that powers the cow?
3) bugtail squid: what bacteria makes light?
4) bacteria that causes tooth decay?
5) bacteria on human skin does what type of metabolism?

Answer 5

1) have cellulosome (enzymes + scaffoldin) –> degrade cellulose outside their body bc they’re smaller than the actual cellulose molecule
*main bacteria in cow rumen that does cellulose degradation. also use soluble glucose to produce volatile FA
2) volatile fatty acids: acetate, butyrate, propionate
3) Aliivibrio fischeri
4) streptococcus mutans –> synthesizes extracellular polysaccharides (dextran) that aid its attachment to tooth surface + ferment sucrose and produce lactic acid that demineralizes tooth enamel
5) aerobes or facultative aerobes or aerotolerant

Question 6

1) what is a pathogen?
2) what are the steps of invasion?
3) name virulence factors
4) name intracellular pathogens
5) name extracellular matrix enzymes that degrade ECM

Answer 6

1) microbial parasites that are able to cause infection = cause damage!
2) exposure, adherence, invasion, colonization of tissues and growth
3) adhesins, capsules, enzymes that destroy host tissue, invasins, T3SS, T4SS, toxins
4) legionella pneumophila, chlamydia, salmonella, mycobacterium…
5) collagenase, lecithinase, hemolysin, phospholipase, hyaluronidase

Question 7

1) what is the complement system?
2) what are 2 ways to activate the complement system?
3) what triggers inflammation?
4) which cytokine hormone is important for inflammation?

Answer 7

1) set of protein in blood (known as complement bc complement action of antibodies) –> makes pores in membrane of bacterial cells
2) classical pathway: antibodies
alternative: microbial cell wall components (like LPS)
3) damage, endotoxins, LPS
4) Interleukin-1!

Question 8

1) which 2 cells are phagocytic?
2) what are the 2 mechanisms by which macrophage can kill phagocytic bacteria?

Answer 8

1) macrophage + neutrophils (PMNs: polymorphonuclear leycocytes)
2) - fusion of lysosome with phagosome to form phagolysosome –> granules containing hydrolytic enzymes fuse with phagosome!
- oxidative burst –> ROS molecules! (leaky! can destroy your own cells and create damage)

Question 9

1) name the microorg to ripen brie cheese
2) name the microorg to make yogurt
3) why don’t we use wild yeast to make wine?
4) what is mashing in beer making?
5) who produces amylase needed to make beer?

Answer 9

1) mixture of mold (penicilium) and bacteria (brevibacterium) that are spread on the surface of the curd
2) streptococcus thermophilus (more heterofermentatve) and lactobacillus bulgaris (more homofermentative)
3) bc hard to control + cannot tolerate high levels of alcohol
4) MASHING: malt (dried and crushed grains) is soacked in warm water (65°C) for 1-2h –> amylase degrades starch into fermentable sugars (glucose and maltose)
5) grains (ie barley) produces amylase when allowed to germinate