respiration and fermentation Flashcards
in open systems, what do cells require to perform work (chemical, transport, mechanical)
energy
sunlight energy –> heat energy process
Energy flows into ecosystem as Sunlight
Autotrophs transform it into chemical Energy
O2 released as byproduct
Cells use some chemical Energy in organic molecules to make ATP
energy leaves as heat
how do complex organic molecules break down?
complex organic molecules break down through a catabolic pathways. some energy is used to do work and is dissipated as heat. leaves simpler waste products with less energy
is respiration exergonic or endergonic? what does this mean
exergonic (releases energy)
is photosynthesis exergonic or endergonic? what does this mean
endergonic (requires energy)
respiration chemical reaction
C6H12O6 + 6O2 🡪 6H2O + 6CO2 + ATP (+ heat)
photosynthesis chemical reaction
6H2O + 6CO2 + Light 🡪 C6H12O6 + 6O2
does oxidation lose or gain electrons
lose electrons
does reduction lose or gain electrons
gain electrons
energy harvest
Energy is released as electrons “fall” from organic molecules to O2
energy harvest reaction
Food (Glucose) 🡪 NADH 🡪 ETC 🡪 O2
energy harvest steps
Coenzyme NAD+ = electron acceptor
NAD+ picks up 2e- and 2H+ 🡪 NADH (stores E)
NADH carries electrons to the electron transport chain (ETC)
ETC transfers e- to O2 to make H2O ; releases energy
stages of cellular respiration
Glycolysis
Pyruvate Oxidation + Citric Acid Cycle (Krebs Cycle)
Oxidative Phosphorylation (electron transport chain (ETC) & chemiosmosis)
glycolysis is also known as
sugar splitting
how old is glycolysis
Believed to be ancient (early prokaryotes - no O2 available)
where does glycolysis occur
in the cytosol
does glycolysis require oxygen
no
what happens in glycolysis
Partially oxidizes glucose (6C) to 2 pyruvates (3C)
net gain of glycolysis
2 ATP + 2NADH (also 2H20)
stage 1 of glycolysis
Energy Investment Stage
Cell uses ATP to phosphorylate compounds of glucose
stage 2 of glycolysis
Energy Payoff Stage
Two 3-C compounds oxidized
For each glucose molecule:
2 Net ATP produced by substrate-level phosphorylation
2 molecules of NAD+ 🡪 NADH
substrate level phosphorylation generates
small amt of ATP
phosphorylation
enzyme transfers a phosphate to other compounds
substrate-level phosphorylation reaction
ADP + Pi 🡪 ATP
where does the citric acid cycle occur
matrix of the mitochondria
Pyruvate Oxidation reaction
Pyruvate 🡪 Acetyl CoA
pyruvate oxidation is used to make
citrate
Pyruvate Oxidation produces
CO2 and NADH
Citric Acid Cycle (Krebs) basic process
Acetyl CoA 🡪 Citrate 🡪 CO2 released
Citric Acid Cycle (Krebs) net gain
2 ATP, 6 NADH, 2 FADH2 (electron carrier)
how is atp produced in the citric acid cycle
by substrate-level phosphorylation
what happens in the ETC during Oxidative Phosphorylation
Produces 26-28 ATP by oxidative phosphorylation via chemiosmosis
where is the ETC
inner membrane of mitochondria
what happens during chemiosmosis in Oxidative Phosphorylation
H+ ions pumped across inner mitochondrial membrane
H+ diffuse through ATP synthase (ADP 🡪 ATP)
what is the ETC
collection of molecules embedded in inner membrane of mitochondria
what is the ETC made of
Tightly bound protein + non-protein components
what happens in the ETC
Alternate between reduced/oxidized states as accept/donate e-
does the ETC make ATP
no, not directly
ETC chemical reaction
Ease fall of e- from food to O2
2H+ + ½ O2 🡪 H2O
As electrons move through the ETC, proton pumps
move H+ across inner mitochondrial membrane
Chemiosmosis defintion
H+ gradient across membrane drives cellular work
Proton-motive force
use proton (H+) gradient to perform work
ATP synthase
enzyme that makes ATP
Use E from proton (H+) gradient – flow of H+ back across membrane
Chemiosmosis couples the ETC to
ATP synthesis
oxidative phosphorylation uses
chemiosmosis
chemiosmosis generates
atp
chemiosmosis couples with the
proton gradient
the proton gradient is called the
proton motive force
the proton motive force drives _ through
H+, atp synthase
ATP synthase produces
ATP
ATP uses energy of _ _ of _
redox reactions, ETC
ETC passes ____ to
electrons down energy levels, final electron acceptor
what is the final electron acceptor
O2 –> H2O
electrons passed down energy levels are
H+ pumped from matrix to intermembrane space to the proton gradient
Anaerobic Respiration
generate ATP using other electron acceptors besides O2
final electron acceptors of Anaerobic Respiration
sulfate (SO4), nitrate, sulfur (produces H2S)
can Obligate anaerobes survive in oxygen
no
Facultative anaerobes
make ATP by aerobic respiration (with O2 present) or switch to fermentation (no O2 available)
fermentation =
glycolysis + regeneration of NAD+
glycolysis without oxygen is
fermentation
glycolysis with oxygen is
respiration
where does fermentation occur
cytosol
what happens during fermentation
Keep glycolysis going by regenerating NAD+
fermentation creates
ethanol or lactate (+2 ATP from glycolysis)
what happens during respiration
Release E from breakdown of food with O2
where does respiration occur
mitochondria
oxygen in respiration is the
final electron acceptor
what does respiration produce
CO2, H2O and up to 32 ATP
alcohol fermentation reaction
Pyruvate 🡪 Ethanol + CO2
alcohol fermentation is used in
brewing, winemaking, baking
lactic acid fermentation reaction
Pyruvate 🡪 Lactate
LACTIC ACID FERMENTATION is used to make
cheese, yogurt, acetone, methanol
does lactic acid buildup cause muscle fatigue and pain? why or why not
no, increase in K+
what can be used for fuel in cellular respiration
carbs, facts, proteins
do monomers enter glycolysis and the citric acid cycle at the same or different points?
different
Phosphofructokinase
Allosteric enzyme that controls rate of glycolysis and citric acid cycle
what is Phosphofructokinase inhibited by
ATP and citrate
what is Phosphofructokinase stimulated by
AMP
Phosphofructokinase reaction
AMP+ P + P 🡪ATP
