micro exam two

why do organic compound provide more energy than inorganic compounds

why do organic compound provide more energy than inorganic compounds

organic compounds have a more negative reduction potential and more electrons than inorganic compounds

how is the process of generating energy from inorganic compounds similar to generating energy with organic compounds

electrons from the inorganic compound are passed to transmembrane proteins in the electron transport chain, proton motive force is generated, and ATP is generated by chemiosmosis.

how is the process of generating energy from inorganic compounds different to generating energy with organic compounds

glycolysis and the citric acid cycle are bypassed because fewer steps are needed because there is less energy from the inorganic compound

why is hydrogen a good electron source

it has a very negative reduction potential

why is hydrogen a bad electron source

it only has a single electron

why are bacteria that use hydrogen oxidation anaerobic

because H2 levels are unstable in oxygenated environments

what is acetogenesis

the process of anerobic respiration when hydrogen is used as the electron donor and CO2 is used as the electron acceptor

what are the two groups of bacteria that use acetogenesis

homoacetogens and methanogens

homoacetogens

convert CO2 into acetate

marshland mud and ruminants stomachs

methanogens

convert CO2 into methane

found in marshland and ruminants stocmachs

lithotrophs

use inorganic compounds for energy

why is sulfur a good electron source

hydrogen sulfide and elemental sulfur are the most common electron donors because they have the most negative reduction potentials

why do bacteria that use sulfur oxidation live in acidic environments

hydrogen ions are produced from sulfur oxidation which lowers the pH of the surrounding environment

reverse electron flow

the proton motive force provides electrons with enough energy to reduce NAD to NADH for carbon fixation because CO2 does not have a more negative reduction potential than NAD. Also used in sulfur oxidation because some sulfur compounds have a more positive reduction potential than NAD.

what are the disadvantages to using sulfur as an electron source

some compounds of sulfur have a more positive reduction potential than NAD so reverse electron flow is used

what bacteria need to use reverse electron flow

autotrophs because they get there carbon from carbon dioxide which has a more positive reduction potential than NAD

what are the advantages of using iron as an electron source

Fe2+ is one of the most common environmental sources of iron for bacterial metabolism and is has one of the most negative reduction potentials of all iron compounds

what are the disadvantages of using iron as an electron source

iron compounds have a more positive reduction potential than sulfur meaning even shorter electron transport chains so even less total energy generated and a requirement for reverse electron flow.

how do bacteria that use iron oxidation participate in bioremdiation

iron compounds are generated from mining waste so bacteria that use iron as an energy source are found at these sites

what are the advantages of using nitrogen compounds as an energy source

there is little competition for nitrogen as a electron source

what are the disadvantages of using nitrogen compounds as an energy source

nitrogen compounds have quite positive reduction potentials so very little energy is being produced do to the short electron transport chain and the reverse electron flow. This makes them slow growers

why are bacteria that use nitrogen as an electron source bad news for farmers

Often one group of bacteria oxidize ammonia to nitrite and then another group of bacteria oxidize nitrite to nitrate. Plants prefer their nitrogen in the form of ammonia so the nitrification is a harmful process to crops.

do all microbes produces oxygen from photosynthesis

no there is oxygenic photosynthesis and anoxygenic photosynthesis

what types of microbes are phototrophs

bacteria, archaea, and algae

without chloroplasts where do bacteria store their photosynthetic pigments

chlorosomes

chlorosomes

small membrane compartments just inside the cell membrane that contain photosynthetic pigments and components to carry out photosynthesis

if you are an autotrophic phototroph in addition to ATP what do you use the energy from photosynthesis to do?

use energy to reduce NAD to NADH for carbon fixation

why are is carbon fixation important in autotrophic phototrophs

because CO2 is the carbon source in autotrophs and it needs to be fixed into a carbon that can be used as building blocks in macromolecules

what is oxygenic photosynthesis

type of photosynthesis that produces oxygen and uses oxygen

where does the electron come from that gets excited by light in oxygenic photosynthesis

water

where does the electron in oxygenic photosynthesis end up

reducing NAD to NADH for carbon fixation

how many electron transport chain are in oxygenic photosynthesis

2 electron transport chains

how is atp generated in oxygenic photosynthesis

through ETC, PMF, and chemiosmosis

how is NAD reduced to NADH in oxygenic photosynthesis

after gaining energy from photosystem 1 and 2 the electron reduces the NAD

what is noncyclic phosphorylation

the electron has a beginning (coming form the splitting of water) and an end (reducing NAD) therefore does not cycle through again

photosystem 1

the second ETC and the electron reduces NAD

photosystem 2

electron exited from water and the first ETC

the Z scheme

photosystem 1 and 2 make a scheme of photosynthesis that look like a z

what is anoxygenic photosynthesis

photosynthesis that does not produce or use oxygen

where does the electron come from that gets excited from light in anoxygenic photosynthesis

photosynthetic pigments

where does the electron end up in anoxygenic photosynthesis

it ends up back in the photosynthetic pigments

how many electron transport chains are in anoxygenic photosynthesis

1 ETC

how is ATP generated in anoxygenic photosynthesis

ETC, PMF, and chemiosmosis

how is NAD reduced to NADH in autotrophs in anoxygenic photosynthesis

electrons come from inorganic compounds to reduce NAD have more positive reduction potentials than NAD so reverse electron flow must be used to generate energy to reduce NAD to NADH for carbon fixation

what is cyclic phosphorylation

the electron that gets excited by light energy in photosynthetic pigments continues to cycle thorough the electron transport chain making a cycle

what are the similarities in anoxygenic and oxygenic photosynthesis

an electron transport chain, PMF, and chemiosmosis is used, electron is excited by light, NAD is reduced to NADH for carbon fixation,

what are the differences in anoxygenic and oxygenic photosynthesis

two photosystems in oxygenic while one in anoxygenic

oxygen is used and produced in oxygenic while it isn’t in anoxygenic

oxygenic is noncyclic and anoxygenic is cyclic

excited electron comes from water in oxygenic while they come from photosynthetic pigments in anoxygenic

reverse electron flow is used in anoxygenic to reduce NAD while it isn’t in oxygenic

more energy produced in oxygenic than in anoxygenic

why does oxygen make the best electron acceptor

has one of the most positive reduction potential

why do bacteria create less energy by using non-oxygen electron acceptors

because any electron acceptor has a more negative reduction potential than oxygen which limits the amount of ATP that can be produced

why would bacterium use something other than oxygen as an electron acceptor

because there is no other option or there is less competition for a different electron acceptor

what are the two different pathways in bacteria that use alternative electron acceptors to generate ATP

dissimilative metabolism and assimilative metabolism

is carbon dioxide a good electron acceptor

yes because it is a waste product from chemoorganotrophs and is often readily available

what are the special groups that use carbon dioxide as an electron acceptor

bacterium that use acetogenesis

acetogenesis

electrons from hydrogen can be used to reduce carbon dioxide into acetate or methane

what is the difference between assimilative and dissimilative metabolism

is assimilative metabolism bacteria use inorganic compounds as building blocks for macromolecules while in dissimilative metabolism inorganic compounds are used as electron acceptors then discarded

can the same compound be used for assimilative and dissimilative metabolism

yes, when sulfur is used as an electron acceptor in anaerobic respiration it gets reduced into hydrogen sulfide then the bacterium uses that sulfur source for producing amino acids

is nitrate a good electron acceptor

yes because it has a very positive reduction potential

what role do denitrifying bacteria play in soil health

the products of nitrate reduction are gaseous and remove excess nitrogen from the soil, since most soils contain an excess of nitrogen this process helps maintain healthy soil

are sulfur containing compounds good electron acceptors

not really because they do not have a very positive reduction potential but it can be used if nothing else is available

are organic compounds generally better electron donors or acceptors

most organic compounds have a negative reduction potential which makes them good electron donors not acceptors

why is fumarate the most common organic electron acceptor

a majority of organic compounds have a more negative reduction potential than fumarate (0.03) so fumarate can serve as the electron acceptor

what is a way that organic compounds serve as electron acceptors in ATP generation

organic compounds serve as electron acceptors in fermentation pathways that are a part of anaerobic metabolism

how is ATP made in anaerobic metabolism

glycolysis generates ATP through substrate level phosphorylation

what is fermentations purpose in anaerobic metabolism

fermentation provides a way for NADH to donate is electron so NAD can return to glycolysis and keep the pathway running

is a lot of ATP produced by anaerobic metabolism

no because only a small amount of ATP is generated through substrate level phosphorylation

what is fermentation

dissimilative metabolism because the electron acceptor is just a waste

what are the products of fermentation

alcohols, acids, and gases

what is lactic acid fermentation

lactic acid is the main product of fermentation

what bacteria use lactic acid fermentation

gram positive bacteria

what do humans use lactic acid for

to flavor yogurt and sauerkraut

what is mixed acid fermentation

the fermentation of glucose produces acetic acid, lactic acid, and succinic acid

what bacteria use mixed acid fermentation

gram negative enteric bacteria

enteric bacteria

bacteria found in the digestive tract of humans and other animals

what do humans use mixed acids for

in diagnostic tests to detect the presence of gram negative enteric bacteria

what is succinate fermentation

fermentation that does not use glycolysis because not enough energy is produced via substrate level phosphorylation to establish a proton motive force so instead sodium ion gradient is establish across the cell membrane

what is binary fission

cell division in prokaryotes

how long does binary fission take

15 minutes to days depending on the bacterium

why is binary fission simpler than meiosis and mitosis

because there is only one chromosome, no nucleus, and there are not organelles that must be replicated and split

what is generation time

the time is takes for once cell to replicate and form two cells

what things affect the length of generation time

size-smaller replicate faster

if organic materials are used replication is faster

aerobic respiration makes faster replication

older bacteria replicate slower

environmental conditions

being inside or outside of a host for pathogens

how do prokaryotes control the steps of binary fission

by using Min proteins, Fts proteins, and MreB protein

whare are the roles of Min proteins

signal to the cell when replication of the solitary chromosome is complete

what does the MinE protein do and how does it work

oscillates from on e end of the cell to other spending more time at the poles of the cell than in the exact center. The cell then knows where to form the septum and split the cell by finding the location where there is the least amount of MinE

what are the roles of the Fts proteins

Min proteins recruits Fts proteins to the exact center of the cell to form a complex called the divisome

function of the divisome

responsible for generating new membrane and cell wall to help elongate the cell

what does the FtsZ protein do and how does it work

FtsZ forms a ring where the septum in and depolymerizes to pinch off the two daughter cells

how do bacillus maintain their shape during binary fission

the MreB protein forms a sort of cytoskeleton underneath the cell membrane that acts as scaffolding. The contact points with the membrane only occur on the long sides of the cell. Theses points are the only places that new cell wall and cell membrane synthesis take place.

do coccus shaped bacteria have the MreB protein

no they lack the protein and are spherical by default

why do prokaryotes need to be carful when making more cell wall during binary fission

because the cell wall maintains the shape, protects and support and the cell would suffer without it

what are autolysins

make very small snips in various locations in the existing peptidoglycan and add new cell wall material across the break which forms a scar called the wall band

what is bactoprenol

is a lipid carrier that transports N-acetylglucosamine and N-acetylmuramic acid across the cell membrane

what is glycoslylases

an enzyme that attach the new sugars to the existing sugar backbone of the peptidoglycan

what are transpeptidases

they link together amino acids that make up the side chains on the peptidoglycan

why are autolysins, bactoprenol, glycosylases, and transpeptidases antibiotic targets

because humans do not have any of these enzymes because we do not have peptidoglycan so we can target theses enzymes without hurting our own cells

what is a bacterial growth curve

tracks the growth of a bacterial population over time in a closed system

what are the four phases of the bacterial growth curve

lag, log, stationary, and death

what happens during the lag phase

the total number of bacteria remain the same but massive amounts of ATP are used to replicate macromolecules and grow the cells

what are factors that effect the timing of the lag phase

what nutrients are in the media

the temperature of the environment

the size and shape of the microbes

they kind of bacteria

what happens during the log phase

the total number of the bacteria increase exponentially

massive amounts of ATP are still being used to replicate macromolecules

generation time is measured during this phase

what are factors that effect the timing of the log phase

how much space there is to grow into

how much nutrients there are to use

how much toxic products are produced

how fast the bacterium reproduce