Microbio Exam 2

what are the 6 macronutrients?

C, H, N, O, P, S

What defines a micronutrient?

what microbes need in smaller quantities to grow

What defines a growth factor?

what microbes need for growth but cannot be synthesized

what distinguishes solid vs liquid media?

solid is a liquid w/a solidifying agent

Media types

synthetic/defined media, complex media, selective media, enrichment media, and differential media

what is synthetic/defined media?

we know exact composition of the media

what is complex media?

we do NOT know exact composition of the media

what is selective media?

when you add something that selects against certain microbes so they don’t grow

what is enrichment media?

add something to enrich target organism growth

what is differential media?

something in the media leads to a visual differentiation of microbes

several critical proteins involved in cell division?

FTS proteins and autolysins

what do autolysins do?

break covalent bonds in PG layer of bacteria

what do Fts I proteins do?

attach amino acid tails of NAMs together

what is another name for Fts I proteins?

transpeptidases

what do Fts Z proteins do?

form ring in the middle of growing cell which tightens to divide the cell

2 types of cell division

budding and binary fission

S-curve 4 stages

1. LAG phase

2. LOG phase

3. Stationary phase

4. Decline

when is the LAG phase?

right after inoculation

What happens in LAG phase?

low growth adjusting to new conditions

what happens during the LOG phase?

growing optimally at the conditions provided

when is doubling time the shortest on the S-curve?

LOG phase

what happens during the stationary phase?

pop size levels off at carrying capacity (death rate = new cell rate)

what happens during the decline?

cell death > new cell growth

batch culture

limited nutrients determines the carrying capacity (classic s-curve)

continuous culture

provide constant input + output into the culture vessel

example of batch culture

secondary metabolites (antibiotics)

example of continuous culture

primary metabolites (amino acids)

ways to quantify bacteria?

Plate Count, Direct Microscopic Count, & Turbidity

what are the factors that can impact bacterial growth?

Temperature, pH, oxygen, salt/sugar, and pressure

what are the extremes for temperature?

psychrophiles = freezing (0-20 C)

hyperthermophiles (>70 C)

what are the extremes of pH?

acidophiles (pH 1-5)

alkaphiles (pH 8+)

what are the extremes of oxygen?

aerobes = need O2

anerobes = do not need O2

term for bacteria that like high pressure?

barophiles

what are the extremes of salt concentration?

halophiles = like high conc.

halotolerant = don’t like high conc.

what happens to a membrane if its environment is too cold or too hot?

cold = less fluid

hot= more fluid

what does low pH mean for an organism (acidic)?

high H+

what does high pH mean for an organism (basic)?

low H+ which can lead to denaturation

what's the role of oxygen in us humans?

humans use oxygen as the final electron acceptor in aerobic respiration to produce ATP

what are 2 ways bacteria deal with radical oxygen form?

catalase enzyme and superoxide dismutase

what does catalase enzyme do to oxygen toxicity?

works against hydrogen peroxcide (H2O2) and makes 2H20 and 1 O2

what does superoxide dismutase do to oxygen toxicity?

works against super oxcides (O2-) and makes 1 H2O2 and 1 O2

what does Mre B do?

determinate of cell shape which makes matrix to guide cell shape

what do transglycolases do?

attach NAG + NAM of adjacent PG molecuels

what is generation time?

the average time it takes for a population to double or for one generation to be replaced by the next

what is a chemostat?

a continuous-culture bioreactor that maintains a steady-state microbial population by continuously adding fresh nutrient medium while removing spent culture liquid at the exact same rate

more sterols means what kind of membrane?

more fluid membrane

less sterols means what kind of membrane?

less fluid membrane

what determines the level of protein structure in terms of features and bonds that hold it together?

specific physical features and chemical bonds (primary, secondary, tertiary, quaternary)

acidic solution means what?

more H+ than OH-

basic solution means what?

more OH- than H+

temperature and pH effect what in the bacteria?

the shape and bonds

How do temperature and pH affect an enzyme's activity?

by changing its kinetic energy or disrupting the delicate 3D structure of its active site

oxidation vs reduction

oxidation = loss of e-s

reduction = gain of e-s

how does water flow through a membrane?

osmosis

isotonic solution

solute conc. is equal to inside the cell

hypotonic solution

higher solute conc. outside the cell

hypertonic

higher solute conc. inside the cell

alternate (from oxygen) e- acceptors

Fe3+, CO2, SO4, NO3

how do plastids relate to the Endosymbiotic Theory?

Plastids descend from cyanobacteria that were engulfed by an ancestral eukaryotic host cell that evolved

evidence for the Endosymbiotic Theory

rRNA of mitochondria amtch seq. in proteobacteria

rRNA of chloroplasts match seq. in cyanobacteria

what is the importance of a proton gradient?

primary energy reservoir that cells use to build ATP (cellular energy) and power vital transport and movement

what is a heterotroph?

something that eats things for carbon

what is an autotroph?

something that fixes their own carbon

where do phototrophs get their energy?

light energy

where do chemotrophs get their energy?

molecular energy

what is a photoheterotroph (give an example)?

mix of a phototroph and a heterotroph (bacteria/archea)

what is a photoautotroph (give an example)?

mix of a phototroph and an autotroph (plants, cyanobacteria)

what is a chemoautotroph (give an example)?

mix of a chemotroph and an autotroph (bacteria/archea)

what is a chemoheterotroph (give an example)?

mix of a heterotroph and a chemotroph (humans, fungi, bacteria)

what is the net total of Embden-Meyeroff glycolysis?

(+4,-2) = net 2 ATP and 2 pyruvate

what is the total of Eatner-Doudoroff glycolysis?

ATP made is 1/glucose and ATP used is 1/glucose

what are the “layers” of the mitochondria?

outer membrane, inter membrane space, inner membrane, & matrix

where does oxidative phosphorylation occur in the mitochondria?

inner membrane

what are the “layers” of G- bacteria?

outermembrane, periplasmic space, cytoplasmic membrane, and cytoplasm

where does oxidative phosphorylation occur in G- bacteria?

the cytoplasmic membrane

what does the Tricarboxylic acid pathway (krebs) do?

oxidizes acetyl-CoA into carbon dioxide to capture chemical energy

what is the Electron transport chain?

protein complexes and organic molecules that transfer electrons to generate a proton gradient

what is nitrate?

NO3

what is nitrite?

NO2

what is nitric oxcide?

NO

what is nitrogen gas?

N2

what is Proton-motive force?

stored energy that results from pumping protons (H+) across a biological membrane

Electron donors vs Electron acceptors

Donors = Fe2+, CO, H2

Acceptors = Fe3+, CO2, SO4

what is Chemiosmosis?

the movement of ions (H⁺ protons) through ATP synthase

what is Fermentation?

microorganisms break down sugars and carbohydrates w/out using oxygen

Substrate-level phosphorylation

transfer of a phosphate group from a high-energy intermediate substrate to ADP (or GDP) to form ATP w/out the ETC

Where is energy stored in the energy molecules ATP, NADH, FADH2?

in specific chemical structures and high-energy bonds

how does chemiosmosis work to power ATP synthase?

energy stored in H⁺ drives the enzyme's physical rotation synthesizing ATP

How does the cell use products of glycolysis to power chemiosmosis? 

proteins transport high energy e-s to the ETC

what form (cyclic/non-cyclic) of phosphorylation creates more energy?

noncyclic

what is noncyclic phosphorylation?

when e-s that enter eventually leave —> ATP, NADPH, and O2

what is cyclic phosphorylation?

when e-s that get excited from PS1 end back up at PS2 —> only ATP

how does glycolysis get altered when oxygen is not available?

breakdown pyruvate to get NADH—> NAD+

what is the anaerobic glycolysis process in humans?

pyruvate —> lactic acid (lactate)

what are the 2 anaerobic glycolysis process (fermentation) in bacteria?

homolatic fermentation = makes just lactic acid

heterolactic fermentation= makes lactic acid + smth

what is the anaerobic glycolysis process in yeast?

pyruvate → acetaldehyde → ethanol

what is the pathway for Embden-Meyeroff glycolysis? (bolded are whats different b/w glycolysis pathways)

glucose → glucose 6-phosphate → fructose 6-phosphate → fructose 1,6-biphosphate → (split) glyceroaldehide 3 phosphate → 1,3-biphosphate → 3-phosphoglycerate → 2-phosphoglycerate → phosphoenol pyruvate → pyruvate

where in the Embden-Meyeroff glycolysis pathway does ADP → ATP?

(only in the 2 branches)

1. 1,3-biphosphohlycerate → 3-phosphoglycerate

2. phosphoenol pyruvate → pyruvate

where in the Embden-Meyeroff glycolysis pathway does ATP → ADP?

(before the split)

1. glucose → glucose 6-phosphate

2. fructose 6-phosphate → fructose 1,6-biphosphate

when is NAD+ → NADH in the Embden-Meyeroff glycolysis pathway?

when there is the addition of inorganic phosphate