Lecture 3: Review of Metabolism

you can classify an organism by their ______ of energy AND by how they ______ energy

source; generate

______ is energy produces by breaking down organic, this is a type of ______

chemoorganotrophy; catabolism

______ is energy produced by oxidizing inorganic compounds like H2, NH4+, or H2S

chemolithotrophy

______ is energy produced by harvesting light, this is a type of ______

phototrophy; anabolism

what is NH4+?

ammonium

respiratory is energy generated through an ______ which participates in a series of ______ reactions

ETC; REDOX

in respiration, an electron ______ feeds high energy electrons to the ETC, and a terminal electron ______ is where the electron is ultimately dumped at the end of the ETC

donor; acceptor

Aerobic respiration uses ______, while Anaerobic respiration uses ___(2)___

oxygen; nitrate, sulfate, etc.

fermentative metabolism is the ______ of ______ compounds ______ coupled to energy production

oxidation; organic; DIRECTLY

redox reactions are how biological system general ______

energy

the electron donor goes from ______ to ______

reduced; oxidized

electron acceptor goes from ______ to ______

oxidized; reduced

true or false: Redox reactions ALWAYS release energy

false; depending on thermodynamics, can release or require require

the ______ the distance between the donor and acceptor, the MORE energy generated (or required) by the Redox reaction

GREATER

which of these redox partners will release the MOST energy?

blue

E₀’ (V) = ______

Reduction potential

the more NEGATIVE the E₀’, the greater the electron ______ and the poorer the electron ______

donor; acceptor

the more POSITIVE the E₀’, the greater the electron ______ and the poorer the electron ______

acceptor; donor

are the E0’ values consistent? Or do they change?

values gives are at a pH of 7, as conditions change the values will too and certain reactions may become more or less favorable

what are the 2 main important electron accusers in biological systems?

NADH and FAD

NADH carriers two or three times as much energy as ______

ATP

NADH is the ______ form, while NAD+ is the ______ form

reduced; oxidized

overall reduction of NAD+ consumes ______ hydrogen atoms to make NADH

two

because there is a limited amount of NADH in the cell, this requires a redox ______

balance

what electron carrier is this?

NADH

What electron carrier is this?

FADH2

FADH2 is ______ related to NADH that can ______ electrons

coenzyme; transfer

FADH2 is the ______ form, while FAD is the ______ form

reduced; oxidized

unlocked NAD+, FAD is reduced by ______ electrons and ______ protons

2; 2

which electron carrier is weaker? (NADH or FADH2)

FADH2

when FADH2 is combined with a strong electron acceptor such as ______, electrons are transferred and significant ______ is released

oxygen; energy

what is the redox active portion of FADH2?

isoalloxazine ring

what 3 things does respiratory metabolism require

ETC, e- donor, terminal e- acceptor

respiratory metabolism generates a ______ gradient called the ______

proton; proton motive force

in respiratory metabolism, the break down of ______ compounds produces ______; these carriers then donate electrons to the ______. This is an example of ______

NADH/FADH; ETC; chemoorganotrophy

some organisms use high energy ______ compounds that directly feed electrons into the ______; this is an example of ______

inorganic; ETC; chemolithotrophy

an ETC involves a series of ______ reactions that ______ energy

REDOX; energy

the ETC is located in the ______ (prokaryotes) and is used to generate a ______

cell membrane; proton motive force

what is the first step of the ETC?

electron donor donates their e- to the first carrier in the membrane

with each reaction in the ETC, electrons are ______ the membrane

pumped across

at the end of the ETC, the electrons are transferred to a ______

terminal electron acceptor

what are the 4 main REDOX carriers in the ETC?

flavoproteins, cytochromes, Fe/S proteins, quinones

flavoproteins contain a ______ ring

FMN

cytochromes have a ______ ring that is covalently linked to ______ of cytochrome proteins; typically ______ is coordinated at the center

prophyrin; cysteine; iron

quinones are non-______

proteinaceous

what does non-proteinaceous mean?

non-protein (not made from peptides)

quinones are ______ molecules that are integrated into the ______; some can act as ______ carriers too!

hydrophobic; membrane; hydrogen atom

in prokaryotes, the ETC is ______, which allows for the organism to ______ to its changing environment

flexible; adapt

how is the ETC flexible?

cells can change the types of proteins

what is one example of how the ETC can be modified in highly acidic conditions?

complex 1 modified to NDH-2 (a different NADH dehydrogenase) which no doesn't pump protons

what is one example of how the ETC can be modified in low oxygen conditions?

complex 4 converted to Cyt BD which is better at scavenging oxygen

if Cyt BD is better at scavenging low oxygen, why doesn’t the cell use it all the time?

doesn't pump electrons out like complex 4

what is an example of how the ETC can be modified for anaerobic respiration?

uses nitrate reductase complex which can use nitrate instead of O2 as a TEA

what protein converts the PMF to biochemical energy?

F0/F1 ATP synthase

ATP synthase harnesses energy by pumping proteins from ______ to ______ the cell; is this against or along the gradient?

outside; inside; along

As ATP synthase pumps protons, ______ which is used to generate ______

rotates; ATP

Fo subunit is found in the ______, while F1 is found in the ______

membrane; cytoplasm

what is the chemiosmotic theory?

PMF = chemical gradient and the electrical gradient

some organisms can use a ______ gradient to generate ATP (rather than proton)

Na

why would it be useful for ATP synthase to be reversible? (would would you want to use up energy pumping gradients outside?)

PMF used for other things like motility, want to maintain it

ATP synthase utilization of the PMF is known as ______ phosphorylation

oxidative

fundamentally, there are lots of similarities between the PMF and ______ used in engineering

hydroelectric power systems

what part of the ETC would be analogous to storage reservoir in hydroelectric power plants?

H+/protons

what part of the ETC would be analogous to a dam in hydroelectric power plants?

cell membrane

what part of the ETC would be analogous to a turbine in hydroelectric power plants?

F0/F1 ATP synthase

fermentative metabolism is the generation of ATP by ______ phosphorylation, carried out in the ______ of terminal electron acceptors

substrate-level; absence

what is a facultative fermenter?

organisms can do fermentation AND respiration

EXAM: Substrate level phosphorylation ALWAYS = ______

FERMENTATION

why would you want to be an obligate fermenter if it is less efficient?

they fill a specific niche

true or false: obligate fermentors do not have a PMF

FALSE: they still need to generate a PMF in absence of ETC for motility and active transport!

fermentation is a fairy ______ form of metabolism because you need a LOT of ______

inefficient; substrate

why is respiration more efficient?

you can oxidize more completely in respiratory metabolism

fermentative pathways are named by their ______

WASTE products

you can classify organisms by their ______ of carbon for biosynthesis

source

heterotrophs use carbon derived from ______ of ______ organic compounds

catabolism; external

autotrophs use carbon derived from ______

fixing CO2

many chemolithotrophs are phototrophs are ______

autotrophs

how can an organisms be a chemolithotroph and ALSO an autotroph?

chemolithotroph refers to the source of ENERGY, which autotroph is the source of CARBON

what is the willow tree experiment?

grew a willow tree and weighed it, discovered that the biomass cam from something other than soil → CO2

from one molecule of glucose, you receive ______ molecules of ATP (aerobic respiration)

38

how many ATPs are produced in substrate level phosphorylation?

6

how many NADH molecules are used per molecules of glucose?

10

how many FADH molecules are used per molecule of glucose?

2

how many ATPs are made per 10 molecules of NADH?

30

how many ATPs are made per 2 molecules of FADH?

4

how many ATP are needed for predatory reaction? (are are subtracted from net ATP produced)

2

______% of glucose is captures as ATP

38

what part of central metabolism generates the most e- carriers?

TCA cycle

different ______ pathways eventually funnel into central metabolic pathways

catabolic

what are some other metabolic pathways that can funnel into the central metabolism?

polysaccharides, lipids, proteins

chemoorganotrophs can use all kinds of ______ compounds as energy sources

organic

in this image, the blue lines represent ______

peripheral pathways

in this image, the green lines represent ______

central metabolism

central metabolic pathways are the interface between _____ and _____

catabolism; anabolism

what is catabolism?

break down

what is anabolism?

build up (synthesis)

through _____ of organic compounds (by _____), the cell ultimately funnels breakdown products into the _____ pathways

catabolism; chemoorganotrophs; central metabolic

central metabolic pathways produce the key _____ precursor molecules required for _____ reactions

12; biosynthetic

why do chemolithotrophs and phototrophs still the same central metabolic pathways?

these pathways are needed to make the 12 key precursors

what are the 3 main pathways involved in central metabolism?

EMP (glycolysis), TCA, Pantone phosphate cycle (PPC)