Microbiology Part 3
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Microbiology Part 3
During cellular respiration, how many ATP are made total? Where do those come from?
38 ATP per glucose - 2 from glycolysis, 2 from krebs cycle, 34 from oxidative phosphorylation
How many ATP are made during oxidative phosphorylation? How many from NADH? How many from FADH?
NADH - 3
FADH - 2
What do aerobic and anaerobic respiration have in common?
they both use glycolysis, the Krebs cycle, and oxidative phosphorylation
What is the final electron acceptor in anaerobic respiration?
an inorganic molecule, like nitrate, sulfate, or carbonate
Why would some species use both aerobic and anaerobic respiration?
Lack or excess of oxygen
If a species can't use any form of respiration, what do they use?
molds use what form of respiration?
What species can do all three types of respiration?
what does fermentation use?
glycolysis - but not the krebs cycle or oxidative phosphorylation
Fermentation does not require...? Making it what form of respiration?
oxygen - anaerobic
Why is ATP production limited in fermentation?
only 2 ATP are made from the glycolysis
During lactic fermentation... the pyruvate produced...?
is converted back to lactic acid (NADH converted to NAD+ to accept more electrons)
What is an example of lactic acid fermentation?
What does lactobacillus make?
yogurt and cheese
During alcoholic fermentation... the pyruvate...?
is converted to carbon dioxide and ethanol
What is an example of a bacteria that uses alcoholic fermentation? What does it make?
Saccharomyces cervisiae - bread, wine, beer
What are some other useful fermentative organisms?
Propionibacterium freundenreichii - swiss cheese
How many ATP are produced during aerobic respiration?
How many ATP are produced during anaerobic respiration?
How many ATP are produced during fermentation?
Where does photosynthesis occur in bacteria?
folds of the cell membrane (thylakoids of the cyanobacteria)
Where does photosynthesis occur in plants and algae?
What are the two major groups of photosynthetic bacteria?
cyanobacteria & purple and green bacteria
Where are cyanobacteria found?
wherever sunlight is available, where it's moist - waters, soils, plants
Where are purple and green bacteria found?
they are senstive to oxygen, so they're found in bodies of water at a deep depth where they is light but no oxygen
The photosynthesis of cyanobacteria is similar to what?
photosynthesis in eukaryotes
What two stages do photosynthesis occur in?
light reactions & the Krebs cycle
What do light reactions do in photosyntheiss?
convert energy in light to chemical energy (ATP, NADPH) and produce oxygen as a waste product - light is captured by pigments
What is the electron carrier during photosynthesis?
When is oxygen produced during light reactions?
When water is broken down to provide electrons
What does the Calvin Cycle use? To produce what?
Carbon dioxide and energy - glucose
What is the major pigment in plants, algae, and cyanobacteria?
What is the major pigment in green and purple bacteria?
Oxygenic means what?
use or produce oxygen
Plants, algae, and cyanobacteria are oxygenic or anoxygenic?
Green and purple bacteria are oxygenic or anoxygenic?
anoxygenic - they break down other compounds for electrons like H2S (hydrogen sulfide)- which produces sulfur
What does the Calvin Cycle fix?
How can organisms be divided when it comes to their metabolism?
by their primary source of energy and their primary source of carbon
What are the choices of energy for organisms?
light (phototrophs), or chemicals absorbed from the environment (chemotrophs)
Where can the sources of an organisms carbon be found?
carbon dioxide (autotrophs "self feeders") or organic molecules in the environment (heterotrophs "other eaters... carbohydrates, lipids)
photoautotrophs are...? what do these include?
photosynthetic and fix CO2 for carbon -- classic photosynthetic organisms like plants, algae, and cyanobacteria
Photoheterotrophs are...? these include?
photosynthetic, but they don't fix carbon (run light reactions, but not calvin cycle) they consume organic compounds (like fats) as carbon sources -- green and purple bacteria
chemoautotrophs do what?
they fix carbon dioxide for their carbon, but do not have light reactions, they oxidize inorganic compounds (iron or sulfur) to release energy
Where are chemoautotrophs capable of living and why?
Nutritionally extreme environments like volcanic deep sea vents or walls of caves -- they get their nutrients from the air
Chemoautotrophs are also called what?
Chemoheterotrophs include...? where do they get their energy?
all animals, algae, fungi, protozoa, and most bacteria --other organisms, they depend on the things produced by other organisms
Chemoheterotrophs are called what? This includes mostly what?
"organic eaters" -- all pathogenic bacteria (food spoilage organisms)
Chemoheterotrophs that get their organic molecules from living tissues are...? Those that get theirs from dead and decaying material are...?
Bacteria and Fungi on Earth are what?
How can bacteria be seperated into categories?
The temperature range each grow in. Since each grows in a different range, their growth can be controlled by altering temps (heating, cooling)
What temp range do most microbes grow in? What does the optimum growth depend on?
30 degrees celsius -- the optimum temp for its enzymes
Psychrophiles are known as? What is their optimum temperature range? Where are they found usually?
cold lovers -- 10 degrees celsius -- cold or icy places like ocean depths
Where do psychrophiles grow?
Regrigeration/Freezer -- but don't really cause food spoilage or disease because they don't live in environments that humans live near
Psychrotrophs are known as what? Grow best at what temperature range? Are usually what?
"cold eaters" -- 20 degrees celsius -- environmental bacteria
These are usually responsible for what? What is an example? They are rarely what?
Food spoilage -- Psuedomonas fragi -- human pathogens, bc they dont grow at human body temperature
Mesophiles are known as what? Grow at what optimum temp range? Nearly all of these are what?
"middle lovers" -- 37 degrees celsius -- human pathogens
How can the growth of mesophiles be stopped? What is an example of a mesophile?
Cooling or refrigerating food -- Listeria monocytogenes (causes listeria)
Thermophiles are known as what? Grow at what optimum temp range? and are usually found where?
"hot lovers" -- 60 degrees celsius -- hot springs or warm soils
Thermophiles don't do what?
Cause disease or spoil food -- they can't grow at human body temp or at room temp/cooling temp
Hyperthermophiles are known as what? Grow at what optimum temp? Are found where? They don't do what?
"very hot lovers" -- 90 degrees celsius -- boiling hot springs -- spoil foods or cause disease
What is the "danger zone" for food? What is most likely to happen if food is in this zone? How can it be prevented?
60-130 degrees farenheit/15-50 degrees celsius -- growth of foodborne pathogens -- keep foods really hot or really cold for storage
State law often requires restaurants to keep the temp for foods at what?
135 degrees farenheit
Listeria monocytogenes can grow at what extreme temps? Clostridium perfringens?
<40 deg. faren -- >140 deg. faren.
What bacteria is most commonly associated with soups and gravies?
clostridium perfringens -- endospores survive boiling and germinate when food is cooled down
Since microbes require water to metabolize.. microbial growth can be controlled by...?
decreasing water content of foods
foods with <20% of water...?
don't have microbial growth (crackers, raisins)
what type of organism tolerates reduced water content (20-80%)? like what?
xerophiles -- bread & cheese
What are most xerophiles?
How can microbial growth be controlled with pH?
What is the optimum pH of most bacteria? Marine bacteria?
6.5-7.5 -- 8.5 (pH of the ocean)
What is the optimum pH of fungi?
What are acidophiles called?
Where do acidophiles grow? example?
in acidic environment of pH 4 of less -- Lactobacillus
Lactobacillus is produced by what?
What are the two strategies acidophiles use to resist the effects of acids?
Numerous hydrogen ion pumps to continuously eject H+ and maintain roughly neutral inner pH -- cytoplasm is acidic and all cells enzymes have acidic optima
Depending on osmotic range, how can microbial growth be controlled?
by altering salt/sugar concentrations in foods
Most bacteria we encounter tolerate what level of salt? marine bacteria?
less than 2%/ 3.5% (ocean salt level)
What do high salt or sugar concentrations cause? What is the concentration in/out of cell normally?
plasmolysis (cell shrinkage due to loss of water) -- solute is greater inside cell
How does plasmolysis happen?
when concentration of sugar or salts is high enough, osmotic movement of water reverses and water leaves cell
What foods are protected by osmostic pressure?
honey, syrups, jelly, salted meats
What are halophiles called? What do they tolerate?
"salt lovers" -- high salt concentrations
Where are halophiles found in nature? Like where?
bodies of water with high salt concentrations -- great salt lake, dead sea, evaporation pond
What pathogen has the highest salt tolerence? How much can it tolerate?
Staphylococcus aureus (causes staph infections) -- above 7% salt
Obligate aerobes require what? Example?
oxygen - molds
What three groups can anaerobes be divided into? examples?
Facultative - don't require oxygen but can use it ( yeasts )
aerotolerant - cannot use oxygen but tolerate its presence ( lactobacillus )
obligate anaerobes - cannot use oxygen and are harmed by it (clostridium)
Most bacteria fall under what with oxygen functions?
Oxygen is not usually toxic to cells, but what related compounds produced by oxygen are?
superoxide (O2-) - hydrogen peroxide (h2o2)
How are superoxide and hydrogen peroxide produced? Why are they toxic?
mistaken during metabolism - they are reactive molecules
The damage that ROS cause and pressure put on cells to survive is called what?
How can microbe tolerate the presence of oxygen?
they have enzymes to eliminate superoxide and peroxide
Most bacteria multiply how? Others use what? Example of the second?
binary fission - spores - streptomyces
What happens during binary fission?
single bacterium divides into two cells (there's no nuclues or spindle fibers)
The time it akes to divide into two cells
generation time - doubling time
The generation time of E. Coli in ideal conditions is what?
20 minutes - most bacteria are longer
How are bacteria numbers given?
in exponential notation due to reproducing large numbers so quickly
Growth of cell population refers to what?
cell population, not size
When bacteria is introduced to a new environment it goes thruogh what four stages to growth-death?
lag, log, stationary, death
adjustment time, cells are active but producing deifferent enzymes to fit its new environment - there's no growth
a time of growth - metabolic machinery is dedicated to growth rather than defense so population is growing, but reproduction isn't high - vulnerabe to death by antibiotics
a time of survival - growth stops because conditions are crowded and nutrients are low, so they stop to survive -- strongest against antibiotics
time of death, nutrients has run out
The ability to detect when conditions become crowded is called what?