Mic 230 – Microbiology Test Questions – Flashcards

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question
first microbes evolved when?
answer
3.8 billion years ago
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what did the evolution of the poryphrin ring allow the development of?
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  • allowed development of cytochrome which allowed respiration to occur
  • Chlorophyll is also a poryphrin ring allowing photosynthesis
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how did the first cell form?
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  1. RNA developed abiotically, then duplicated
  2. RNA enters lipoprotein and used as coding information and catalytic protein.
  3. protein takes over catalytic functions
  4. DNA is formed from RNA and takes over coding
  5. DNA->RNA->protein
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examples of microorganisms having an impact on history? 5
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  1. bubonic plague-yersinia pestis
  2. potato blight- fungus
  3. smallpox-variola virus
  4. Cholera - vibrio cholerae
  5. common flu - influenza
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What was a major killer in the civil war?
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  • staphylococcus aureus
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what was the first antibiotic? year? by?
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penicillin - sir alexander fleming in 1928
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How much did the Romans and Greek society know about disease?
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  • Romans - If you were sick from the plague and recovered, you could treat individuals infected with plague and not get sick again
  • Greeks - thought that animals entered the nose and mouth and caused disease.
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who discovered the first microbes? when? with what?
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  • Antoine van leeuwenhoek in the 1600s with a 300x microscope. lens maker merchant
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what did Louis Pasteur do? time frame?
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  • yeast caused fermentation in wine
  • pasteurization
  • disproved spontaneous generation with swan neck exp.
  • late 1800's
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Ignaz semmelweis discovered? when?
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  • more mothers died after childbirth when the babies were delivered by the doctors than if delivered by midwives.  He thought it was due to not washing hands/utensils.
  • went nuts as he was rediculed (1845)
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Robert Koch did what? when?
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  • 1876 - proved germ theory with koch's postulates with anthrax in cattle.
  • also discovered causative agents of cholera,TB
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Sergei Winogradski did? when?
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  • discovered chemolithotroph
  • father of environmental micro
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who is the father of modern taxonomy?
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  • Carl Woese - saw difference in rRNA and methane producing bacteria (later called archaeabacteria)
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TaxonomyPhylogeny?
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How we classify different organisms
classification due to evolutionary descendants in the past
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difference between prokaryotes and eukaryotes?
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Prokaryotes- no nucleus, 70s ribosomes, 1 circular chromosome, growth above 80C
Eukaryotes - nucleus, membrane bound organelles, linear DNA, introns, 80s ribosomes, sexual reproduction
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Defining Reference for prokaryotes?
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Bergey's Manual
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characteristics of prokaryotes that makes them Adaptable?
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biochemically diverse
growth potential
extremely tolerant
capable of genetic variation
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algal characteristics?
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oxygenic photosynthesis
cell walls
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protozoa characteristics?
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lack cell walls
ingulf food
motile by flagella, cilia, amoeboid movement
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Fungal characteristics?
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cells walls of chitin
produce spores
absorb food by extracellular enzymes
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purpose of cholesterol(eukaryotes) and hapanoids(prokaryotes) in membrane?
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strengthen, more rigidity
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archaeal lipids differences?
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made of isoprenoid alcohols
ether linkages
can be tetraether lipids, lipid tails connected!
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functions of the membrane?A-G
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1. permeability barrier except for water, gases and nonpolar molecules
2. houses proteins
3. transport
4. export of proteins and polysaccharides
5. energy generation
6. motility and chemotaxis
7. biosynthesis
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3 types of transport?
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simple transport(uses proton gradient), group translocation(requires PEP), ATP binding Cassette(ABC)requires ATP
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function of cell wall?
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confer shape and strength
provide elasticity to prevent lysing
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difference between gram +/-?
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+ = no outer membrane, 20-40 layers peptidoglycan, no periplasm
- = outer membrane, few layers of peptidoglycan, periplasm
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peptidoglycan composition?
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N - acetyl glucosamine
N - acetyl muramic acid
4-5 AAs
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molecular arrangement of peptidoglycan?
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N-AM 4 AA cross linked to adjacent strands
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what is the target of penicillin, vanomycin and other antibiotics?
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peptidoglycan synthesis
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teichoic acids?
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polymers of alcohols and phosphates
attach to peptidoglycan or membrane
make envelope of cell negative
antigenic
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what does the outer membrane of a gram negative bacteria do?
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creates periplasmic space
contains porins
linked to peptidoglycan by lipoprotein
contains liposaccharides
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gram negative liposaccaride structure?results in?
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o specific polysaccarride, core polysaccharide, lipid A
negative charge, antigenic, endotoxin, binds cations
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porins in outer membrane result in?
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small molecules can get through
causes membrane to not be a permeability membrane
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S layers? function?
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crystalline protein layers outside the wall of gram +/- bacteria
antigenic, block other antigens, protect against toxins
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cell walls of archaea made of?
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ALL LACK peptidoglycan
s layers
polysaccharides
pseudopeptdoglycan
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glycocalyx? fxns?
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highly hydrated polysaccharide layers
antigenic, mask antigens, antiphagocytic, attachment, trap nutrients, protect(toxins)
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pili? uses?
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protein appendages on cells
gene transfer(sex pilus)
attachment, antigenic
bacteriophage attachment
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types of motility?
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flagella, spirochetes, gliding, gas vesicles, twitching
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flagella structural components?
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filament, hook, basal body, Mot(ovals outside), Fli (balls inside)
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How is energy supplied for the flagella motor? On/off?
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H+ proton gradient flows through mot proteins allowing them to rotate around ms ring. Fli proteins are motor switch
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chemotaxis?
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how bacteria respond to certain media
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attractants
repellants?
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chemicals that attract bacteria
chemicals taht repel bacteria
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molecular mechs of chemotaxis?
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chemoreceptors detect environment, then transducer proteins send message to flagellar switch (fli proteins)through che proteins which alter tumbling and receptors
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phototaxis
aerotaxis?
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bacteria that move toward light
move toward or away from oxygen
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characteristics of the endospore?resistant to?why?
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synthesized inside the cell when nutrients are no longer available
resistant to heat, chemicals,radiation, freezing
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structure of endospore?
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dehydrated cytoplasm, membrane and typical wall,cortex of moded peptidoglycan, protein spore coat, exosporium
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when do they exit endospores and germinate?
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activation by heat
if environment becomes suitable again
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other resting stages
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fungal and actinomycete spores
bacterial cysts
both dont survive extreme heat
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bacterial inclusions?storage products?
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poly-B-hydroxyalkonate - unique fat-like storage products
glycogen, Volutin(polyphosphate), cyanophycin(N), sulfur (source of e-)
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Inclusions: Magnetosomes? Gas Vesicles?
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Rows of magnets found in the cytoplasm in aquatic bacteria to orient bacteria in earths magnetic field(swim down)
Allow bacteria to float
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stalks and prostecha
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st- acellular extensions on cells for attachment
pro - cellular extensions that increase SA/V ratio to increase survival in dilute environments, maybe attachment
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anabolism? requires?
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metabolic processes that are involved in cell division
requires NRG(ATP), substrates, reducing power (NADPH)
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catabolism? rxns? products?
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make energy in a usable form either high energy chemical bonds or proton gradient
CO2, urea
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what does a microbe require to reproduce?
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carbon and energy source
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types of nutrition classes that use energy source?
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phototrophs - convert sunlight to E
chemoorganotrophs chemicals to organic
molecules
chemolithotrophs - chemicals to inorganic chemicals
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carbon source types?
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heterotrophs - use organic carbon and phototrophy
Autotrophs-use CO2 for C and E from light
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4 types of cell division
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binary fission
budding
fragmentation division
spore formation
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steps of binary fission?
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DNA replication
elongation
septum formation
septum completion, cell separation
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budding common in?
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yeasts
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fragmentation division steps?
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attachment, penetration, elongation, prey lyses, release of progeny
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growth rateexponential growth
generation time?
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increase in numbers over time
logarithmic curve
latent period where cell rests in between divisions
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4 stages of bacterial growth curve?
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lag, log, stationary, death
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secondary metabolism
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geared toward survival, not reproduction = less E (start to make antibiotics)
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How can one make a continuous culture?
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maintain log phase by continually replacing media by using a chemostat
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why does the culture stop growing and begin to die? 3?
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run out of nutrients, overcrowding, accumulate toxic products
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4 ways to measure growth?
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direct count (microscopic grid count)
viable count (plate count)
measure mass (dry weight)
measure turbidity
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how many ATP pre glucose via glycolysis? oxidation step? ATP steps?
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2 ATP at PEP to pyruvate and 1,3 biphosphoglycerate to 3-phosphoglycerate
oxi at glyceraldehyde 3-phosphate to 1,3-biphosphoglycerate
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lactic acid fermentation bacteria? ethanol?
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lactic - lactobacillus
ehtanol - saccharomyces
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applications of fermentations?
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food: beer, wine, cheese, yogurt
probiotics, chemicals, ID
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How many NADH produced in Krebs cycle?steps?
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8 NADH: pyruvate to acetyl CoA
isocitrate to alpha ketoglutarate to succinyl CoA
malate to oxaloacetate
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what else is produced? steps?
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2 ATP Succinyl CoA to succinate
2 FADH succinate to fumarate
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respiration?
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oxidation of an inorganic or organic energy source in which electrons pass down an ETC and are accepted by an external terminal electron acceptor (O2, NO3, SO4)
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other respiration pathways?
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FA oxidation
Alkanes to FA
Aromatic rings to either Acetyl CoA or Succinyl CoA
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electron carriers in ETC?
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flavoproteins, Quinones(both accept 2e- and 2 protons)
Fe-S proteins
Cytochromes
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ATP synthase components? how does it work?
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Fo = IMP F1 = IC PMP
for every 3 H+ protons that go through it down their conc. gradient and ATP is made.
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anaerobic respirations?
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Nitrate Reduction-E. coli reduces NO3 to NO2. Also pseudomonas denitrifies NO3 all the way to N2.
Sulfate Reduction-Desulfovibrio reduce SO4 all the way to H2S, not favorable so gains little E.
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chemolithotrophy
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bacteria can oxidize inorganic chemicals for energy (mostly aerobic)
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3 types?
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Hydrogen oxidation(methanobacterium)
Ammonia ox. nitrosomonas
sulfur ox. thiobacillus, thiomargaritas
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purpose of pentose phosphate shunt and calvin cycle?
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pps-make NADPH and biosynthetic intermeds(5C sugars)
cc - make organic matter out of CO2 and intermediates from CO2
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