Cellular Respiration Flashcards
where is energy stored in molecules?
their bonds
what kind of molecule will have more energy
complex one with more bonds
what is the key molecule for cellular respiration
O2
cellular respiration is a ______ reaction
exergonic
cellular respiration is
catabolic
what has less energy in cellular respiration
products
what determines if a reaction is endergonic or exergonic
the delta G
what allows the capture of energy to be greater
if the process is split into steps
catabolic pathways yield
energy by oxidizing organic fuels
glycolysis harvests
chemical energy by oxidizing glucose to pryvuate
what happens to pyruvate after it is oxidized
the citric acid cycle completes the energy-yielding oxidation of organic molecules
what happens during oxidative phosphorylation
chemiosmosis couples electron transport to ATP synthesis
fermentation and anaerobic respiration enbales
cells to produce ATP without the use of oxygen
glycolysis and the citric acid cycle connect
to many other metabolic pathways
_______ requires transfusion of energy from ______ sources
living cells and ouutside
energy flows into an ecosystem in the form of ____ and leaves as ____
sunlight and heat
photosynthesis generates
organic molecules and O2
cells use ______ energy stored in organic molecules to generate ATP
chemical
what powers cellular work
ATO
what types of work does phosphate-group transfer do
- transport work
- mechanical work
- chemical work
how does Cellular Respiration release stored energy
by breaking down complex organic molecules to simpler products
rearranging chemical bonds to ______ energy involves _____
release and electron transfer
_______ of organic molecules is
breakdown and exergonic
aerobic respiration
consumes organic molecules and O2 and yields ATP
anaerobic respiration
consumes compounds other than Oxygen
fermentation
partial degradation of sugars that occurs WITHOUT oxygen
the term cellular respiration refers to what
both aerobic AND anaerobic respiration
what is cellular respiration usually traced with
sugar as glucose
what energy is used to synthesize ATP
the release of energy from the transfer of electrons during chemical reactions
redox reaction
chemical reactions that transfer electrons between reactants
oxidation
substance LOSES electrons
a substance that LOSES electrons becomes
oxidized
reduction
a substance that gains electrons
a substance that GAINS electrons is
reduced
what is the most prevalent and efficient catabolic pathway
exergonic process
oxidation is the ______ or _____ of electrons
partial or complete LOSS
reduction is the _____ or ______ of electrons
partial or complete GAIN
electron transfer requires BOTH
a doner and acceptor
what must happen for a reaction to be a redox reaction
one atom must be REDUCED and another must be OXIDIZED
what acts as a recuing agent
substance being oxidized
what acts as an oxidizing agent
substance being reduced
electron donor
reducing agent
electron acceptor
oxidizing agent
what happens to the fuel in Cellular Respiration
it is oxidized
what is reduced in Cellular Respiration
oxygen
what are electrons from organic compounds usually FIRST transferred to
NAD+
an electron shuttle
NAD+
NAD+ is an _______ and functions as an ______ during cellular respiration
electron acceptor and oxidizing agent
Each NADH contains
stored energy that is used for ATP synthesis
what is the enzyme that reduces and oxidizes NADPH
Dehydrogenase
where does NADPH pass the high-energy electrons
to the ETC
what is the last and strongest agent of the ETC
Oxygen
what is the energy released during the ETC steps used as
to generate ATP
NAD+ is mainly associated with
keeping molecules young
what does an increase in NAD in the body do
reversal of the sings of age
what happens in an uncontrolled reaction
energy would be released at once as light and heat
what does the ETC ensure about the release of energy
it is controlled by passing electrons down a series of steps
the ETC converts
chemical energy extracted from food to a form that can be used to make ATP
where is the ETC found
bound into the inner mitochondrial membrane
what do the increased amount of protrusions of the inner membrane allow
increase of surface area
what are the reduced coenzymes that give the ETC the energy-rich electrons
NADH and FADH2`
where does the ETC pass the electrons to
down the chain until they reach oxygen
how does the oxygen at the end of the ETC make water
by the electrons passed down with a hydrogen
what happens as the electrons shift toward the more electronegative atom
they lose potential energy and release energy
3 steps in the harvesting of energy from glucose
- Glycolysis
- Pyruvate oxidation and the citric acid cycle
- oxidative phosphorylyation
breaks down glucose into two molecules of pyruvate
glycolysis
completes breakdown of glucose
citric acid ccycle
accounts for most of ATP synthesis
oxidative phosporylation
where does glycolysis take place
the cytosol
glycolysis is a
catabolic reaction
glycolysis is the _____ oxidation of glucose
partial
what does glycolysis convert
6 carbon chain of glucose into 2 3-carbon pyruvates
the kerb cycle is a
catabolic pathway
where does the kreb cycle happen
in the mitochondiral matrix
how does the Kreb cycle complete the breakdown of glucose
breaking down a pyruvate (Acetyl CoA) into CO2
what two phases use substrate-level phosphorylation to release ATP
Glycolysis and Kreb Cycle
what does glycolysis and Kreb cycle produce
- small amount of ATP by substrate-level phosphorylation
- NADH
- FADH2
where is the ETC located
inner membrane of the mitochondrion
what does ETC couple
the exergonic slide of electrons TO the ATP synthesis or oxidative phosphorylation
what produces 90% of ATP
ETC and oxidative phosphorylation
what is oxidative phosphorylation powered by
redox reactions
how much ATP do cells make from ONE glucose
32 ATP
during glycolysis, what is each glucose broken down into
2 molecules of pyruvate
what does the pyruvate cross to enter the matrix
the double membrane of the mitochondrion
where is the pyruvate decomposed to carbon dioxide
Kreb cycle
the ETC converts ______ to a form that can be used to _____
chemical energy and oxidative phosphorylation
two steps of glycolysis
- energy investment phase
- energy payoff phase
energy investment phase
2 ATP is used to excite the electrons
payoff phase
4 ATP is formed
Total atoms produced in glycolysis
- 2 molecules of ATP
- 2 molecules of NADPH
- 3 Protons
where is most of the chemical energy residing
in the two pyruvate molecules produced by glycolysis
what happens to pyruvate if oxygen is present
enters the mitochondrion and it becomes completely oxidized by a series of reactions
pyruvate oxidation links
glycolysis and the citric acid cycle
what 3 reactions are involved in pyruvate oxidation
- one carbon is released as CO2
- the remaining 2-C molecule is oxidized to acetate AND NAD+ is reduced
- acetate is linked to coenzyme A to form Acetyl-CoA
what enters the Kreb cycle
Acetyl CoA
how many carbons enter the Kreb cycle
2 carbon not 3
why is there only 2 carbons entering the Kreb Cycle
one is lost as CO2 when Acetyl Coa is formed
what completes the break down of pyruvate to CO2
the entrance of Acetyl-CoA to the Kreb cycle
what is generated by ONE turn of the Kreb cycle
1 ATP
3 NADPH
1 FADH2
how does the 2-C acetyl group with the Acetyl CoA enter the Kreb cycle
being combined with 4-C oxaloacetate to form citrate (6-c)
why is the kreb cycle a cycle
the decomposition of citrate back to oxalocetate
________ carries high energy electrons to the ETC
NADH and FADH2
what do both NADH and FADH2 do
donate electrons to the ETC which powers ATP synthesis by oxidative phosphorylation
where EXACTLY is the ETC located
the cristae
electrons give up _______ as the move through the chain until they reach _____ and form ____
free energy and oxygen and water
what has higher energy NADPH or FADH2
NADPH
cytochromes
electron carriers that accept electrons and pass them down to Oxygen
does the ETC generate ATP
NO
what IS the energy released during the ETC used for
pump hydrogen ions from the mitochondrial matrix to the intermembrane space
how does hydrogen flow down its concentration gradient
flows back across the inner membrane through ATP synthase
ATP synthases uses the _________ to drive phosphorylation of ____ to form ___
exergonic flow of H+ and ADP and ATP
chemiosmosis
the use of energy in H+ gradient to drive cellular work
Chemiosmosis couples the
ETC to ATP synthesis
ETC is a _____ reaction
downhill
what does the energy stored in the H+ gradient couple
the redox reactions of ETC to the ATP synthesis
what is the H+ gradient referred to
the proton-motive force
what is the sequence that most energy flows in Cellular Respiration
glucose -> NADH or FADH2 -> ETC -> proton-motive force or proton [ ] -> ATP
how much energy in glucose molecule is transferred to ATP by cellular respiration
34% = 30 to 32 ATP
how much ATP does Glycolysis produce
2 ATP
how much NADPH does Glycolysis produce
2 NADPH
how much NADPH does Pyruvate oxidation produce
2 NADPH
how much ATP does Kreb cycle produce
2 ATP
how much NADPH does Kreb Cycle produce
6 NADH and 2 FADH2
how much ATP does Oxidative phosphorylation produce
26 or 28 ATP
what does most cellular respiration need to make ATP
oxygen
what happens to the ECT if there is no oxygen
It will stop working
what happens to glycolysis in the absence of Oxygen
couples with fermentation to produce ATP
Anaerobic respiration
uses an ECT with a final electron acceptor other than oxygen
Fermentation
enables glycolysis to continue making ATP by substrate-level phosphorylation in the absence of oxidative phosphorylation
what does fermentation regenerate
NAD+
two types of fermentation
- alcohol fermentation
- lactic acid fermentation
alcohol fermentation
pyruvate is converted to ethanol in two steps
1. releasing CO2
2. regenerating NAD+
examples of alcohol fermentation
yeast used in brewing, winemaking and baking
lactic acid fermentation
pyruvate is reduced by NADH which yields NAD+ and forms lactate as an end produce
does lactic acid fermentation release CO2
NO
what is made by some bacteria and fungi with lactic acid fermentation
cheese and yogurt
how do human cells use the lactic acid fermentation
generate ATP when O2 i scarce
Fermentation, Anaerobic and Aerobic respiration ALL use
glycolysis to oxidize glycose and harvest chemical energy from food
what is NAD+ in Fermentation, Anaerobic and Aerobic respiration
the oxidizing agent that accepts electrons
Fermentation, Anaerobic and Aerobic respiration all have DIFFERENt
Final electron acceptos
Cellular respiration produces ____ ATP per glucose
32
fermentation produces _____ ATP per glucose
2
Obligate anaerobes
carry out fermentation or anaerobic respiration
CANNOT survive in presence of oxygen
obligate anaerobes
facultative anaerobes
can survive using either fermentation or cellular respiration
yeast is an example of
faculative anaerobes
what do pyruvates act as in facultative anaerobes
a fork in the metabolic pathway with two alternative catabolic routes
what does pyruvate lead to if there is NO oxygen present
ethanol, lactate or other products
what does pyruvate lead to if there IS oxygen present
aerobic cellular respiration
when did O2 levels in the atmosphere begin to increase
2.7 billion years ago
what did early prokaryotes likely use to produce ATP
glycolysis
what is an ancient and universal process
glycolysis
two major intersections to various catabolic and anabolic pathways
glycolysis and citric acid cycle
catabolic pathways funnel electrons
from many kinds of organic molecules into cellular respiration
what does glycolysis accept
a wide range of carbohydrates
what must proteins be first before entering glycolysis or citric acid cycle
broken down into amino acids
what are fats digested to before used in glycolysis
glycerol
what are fatty acids broken down to before used in the citric acid cycle
broken down by beta oxidation to produce acetyl CoA
what produces more than twice the ATP to _____
fat and carbohydrates
where are amino acids used in Cellular Respiration?
- glycolysis
- citric acid cycle
- acetyl CoA
body uses ____ molecules to build other substances
small
where can small molecules come from to build other substances
- directly from food
- from intermediates of glycolysis
- from intermediates of citric acid cycle
most common mechanism for control
feedback inhibition
If ATP [ ] begins to drop
respiration speeds up
when there is plenty of ATP
respiration slows down
how is control achieved in cellular respiration
regulating key enzymes in the pathway
the KEY enzyme in cellular respiration for feedback inhibition
phosphofructokinase
phosphofructokinase is found in the
glycolysis
where is positive inhibition from
AMP entering the phosphofructokinase
where is negative inhibition from
- citric acid cycle
- ATP produced
