Metabolism Flashcards
why are there microbes were life is present on earth?
because of metabolic diversity
what is impossible for bacteria to grow?
using CO2 as an energy souce
why is CO2 not used as an energy source?
because energy sources have to be oxidized, and co2 is already fully oxidized
Metabolism
the sum of chemical processes in a living system
what is metabolism the basis for?
Bioremediation
Bioremediation
the ise of microbes to decontaminate the environment
Microbes have huge roles in _____, ______, and ______ cycling on earth
carbon, nitrogen, and phosphorus
Microbes can metabolize ALL or NONE or SOME of naturally occurring organic compounds and many inorganic ones
ALL
_____ bacteria use reduced Inorganic compounds as energy sources
Chemoautotrophic
bacteria near black smokers (volcanos) oxidize ___
H2S for energy
Bacteria in drainage streams from acid mines oxidize ____
Fe for energy
Bacteria living on “desert Varnish” oxidize ____
Mn2+ for energy
how many genes in E.coli are known to encode enzymes?
1/2
What is an E.coli cell mostly made up of ?
Protein, RNA, Phospholipids
Ribozymes
enzymes that are RNA
Denaturation
loss of secondary, tertiary, and /or quaternary structure
Enzymes exhibit great ______ for their ______
specificity for their substrates
Specificity depends on the enzymes _____ and ______
the enzymes shape and the electrical charges at its ACTIVE SITE
Active site
where the substrate binds to the enzyme
Specificity prevents _____
anarchy from happening
Competitive inhibition
A competitive inhibitor competes for binding to the enzymes active site
Example of competitive inhibition
Sulfa drugs
Sulfa drugs
competitive inhibitors of the bacterial enzyme for making folic acid,
what do Sulfa drugs compete with for the active site of the enzyme
PABA
Noncompetitive inhibition
Inactivates an enzyme by binding to an allosteric site
what does binding to an allosteric site result in
results in an alteration in the conformation of the active site
Common electron acceptors
NAD+ and NADP+
Organic source of carbonm and organic source of energy
Chemoheterotrophs
Organic source of carbon and light as the source of energy
Photoheterotrophs
CO2 as C source and inorganic compound as the source of energy
Chemoautotrophs
CO2 as C source and light as source of energy
Photoautotrophs
Which is higher energy?
NADH or NAD+
NADH
Which is higher energy?
Mn3+ or Mn2+
Mn2+
Which is higher energy?
C6H12O6 or CO2
C6H12O6
“het” = ___ source C
Organic source of energy
“auto” = ____ source C
CO2 source energy
Energy in a cell comes from
electrons moving down an energy gradient (in oxidation reactions) to make 2 usable forms of energy
what are the 2 usable forms of energy
1) High energy P bonds
2) transmembrane ion gradients
what are the 2 ways to synthesize ATP
1) substrate-level phosphorylation
2) Harvesting energy from a transmembrane ion gradient using ATP synthase
NAD+/NADH and NADP+/NADPH are ____
coenzymes that are common participants in cellular redox reactions
When microbes are fermenting, they can generate all the ATP they need via ______
substrate level phosphorylation
Fermentation always uses ______
organic molecules as substrates
fermentation does not involve
transmembrane ion gradients
fermentation does not require
oxygen
fermentation has many _____
fermentators that involve pyruvate
Microbes make diverse fermentation products from _____
Pyruvate
Proton gradient across the membrane
Proton motive force
proton gradient represents a form of ______
electrochemical energy
ATP synthase mediates ….
the interconversion of the energy of the gradient with ATP
2 common ways prokaryotes can generate a transmembrane ion gradient
1) respiration (aerobic or anaerobic)
2) Photosynthesis (oxygenic or anoxygenic)
2 rare ways prokaryotes can generate transmembrane ion gradient
1) enzyme ion pumps
2) Scalar reactions
4 ways prokaryotes generate transmembrane ion gradient
1) respiration (aerobic or anaerobic)
2) Photosynthesis (oxygenic or anoxygenic)
3) enzyme ion pumps
4) Scalar reactions
Enzyme ion pumps
membrane proteins not associated with the electron transport chain that can pump protons or other ions across the membrane
Scalar reactions
Reactions that consume or produce protons, rather than move them
Respiration
electrons are passed from an electron donor to a terminal electron acceptor through the ETS in the cell membrane, making a proton gradient
aerobic respiration
O2 is the terminal electron acceptor, reduced to H2O
Anaerobic respiration
An ion or compound other than O2 is the terminal electron acceptor (ex nitrate, nitrite, sulfur)
Microaerophilic
slight growth in air, mostly grows without oxygen
A faculatative anerobe, like E>coli yields more ATP when respirating _______ compared to ______ affecting its growth rate
aerobically, compared to fermentating
Chemoautotrophs generate ATP by
oxidizing inorganic compounds through the ETS
Passive transport
relies on diffusion, requires no energy. import only occurs if solute is at higher concentration than outside of the cell
facilitated diffusion
type of passive transport. It uses channel proteins for specific molecules
active transport
for import of nutrients against a concentration gradient
active transport
for import of nutrients against a concentration gradiention
Ion-coupled transport
type of active transport. uses energy of the transmembrane ion gradient
ATP binding cassette (ABC) transport
type of active transport. uses ATP hydrolysis to pump a nutrient into the cell after it has bound its corresponding periplasmic binding protein
Phosphotransferase system (PTS)
uses a high energy phosphate group to chemically modify the solute after it is imported, so it cannot exit
_______ use calvin cycle to _____ fixation
Autotrophs use the calvin cycle for CO2 fixation
RuBisCO
catalyzes the addition of CO2 to ribose biphosphate
3 common pathways of central metabolism
1) glycolysis
2) pentose phosphate pathway
3) TCA (krebs) cycle
how were biosynthetic pathways discovered?
through analysis of auxotrophs of E.coli and Salmonella
prototrophs
bacteria that have no nutritional requirements for the building blocks
AUxotroph
has blockage in 1 or more steps to make building blocks
feedback inhibition
a type of non competative inhibition, it is a way to control metabolic pathways
