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Chapter 7: Cellular Respiration - Coggle Diagram
Chapter 7: Cellular Respiration
metabolic reactions and processes that take place in the cells of all organisms to convert biochemical energy from carbs into ATP and waste products.
Glucose+6O2->6CO2 + 6H2O + ATP
In this reaction, glucose is reduced and oxygen is oxidized.
the most prevalent and efficient catabolic pathway
, regenerates ATP
exergonic reaction
Catabolic pathways
funnel electrons from many kinds of organic molecules into cellular respiration
Redox reactions: catabolic pathways yield energy due to the transfer of electrons. Electrons are transferred to
more
electronegative atoms to form a more stable arrangement. Releases energy
LEO and GER, loss of electrons is oxidation and gain of electrons is reduction
Coenzymes
- non-protein molecules required for some enzymes to function. Act as
electron carriers
NAD+, FAD, and NADP+
becomes reduced (is the oxidized form),
NADH, FADH2, and NADPH
becomes oxidized (is the reduced form)
Citric Acid Cycle
completes energy-yielding oxidation of the organic molecules. The citric acid cycle takes place in the
matrix
of the mitochondrion
Pyruvate must be converted to acetyl CoA, which links to the cycle to glycolysis
If oxygen is present, 2 pyruvate molecules are converted. Input: 2 pyruvate, 2 NAD+ 2 coenzyme A. Output: 2 CO2, 2 NADH, 2 acetyl CoA
The remaining 2 carbon atoms attached to CoA enter the citric acid cycle and are
oxidized to CO2
. Energy from these oxidations is captured by
NADH
and
FADH2
Eukaryotes
perform cellular respiration in the
mitochondria
,
prokaryotes
perform cellular respiration in the
cytoplasm
ATP is generated via
glycolysis, the Citric Acid Cycle, Oxidative Phosphorylation
ATP is generated by an endergonic reaction (substrate-level phosphorylation)
when ADP undergoes phosphorylation. The energy comes from a
coupled reaction
or
chemiosmosis (90%)
occurs in mitochondria, chloroplasts, and plasma membrane of aerobic prokaryotes.
Substrate-level Phosphorylation
- glycolysis and the citric acid cycle.
Glycolysis
occurs in the cytoplasm and glucose is broken down.
Products: 2 ATP, 2 NADH, 2 pyruvic acids
2 major phases of glycolysis: Energy investment phase and energy payoff phase
Energy investment
: kinase (enzymes that transfer phosphates) and isomerase (enzymes that catalyze reactions rearranging structure)
The energy payoff phase yields:
2 NADH, 2 H+, 4 ATP, 2 H20, and 2 pyruvate
NADH move to the electron transport chain in mitochondria
,
ATP can be used in cytoplasm for anabolic process
, and
pyruvate enters the mitochondria, broken down in oxidation and the citric acid cycle
The goal of the
electron transport chain
is to couple energy stored in electron acceptors to a proton gradient that drives ATP synthesis. occurs on the inner membrane of the mitochondria.
In the electron transport chain, electrons from NADH and FADH2 lose energy in several steps. At the end of the chain, electrons are passed to oxygen, forming water
Chemiosmosis
has a
rotor
that spins when H+ flows down the H+ gradient. A
stator
anchored in the membrane holds the knob stationary. A
rod
extending into the knob also spins, activating catalytic sites in the knob.
Three catalytic sites in the knob join ADP and inorganic P
NAD+
accepts electrons from organic compounds,
NADH
passes these electrons through the electron transport chain
Each turn of the citric acid cycle yields
3 NADH, 1 FADH2, ATP, and 2 CO2
NADH
and
FADH2
donate electrons to the electron transport chain, powers ATP synthesis through
oxidative phosphorylation
.
in oxidative phosphorylation
,
chemiosmosis
couples the process of electron transport to ATP synthesis
Cellular respiration is controlled by allosteric enzymes at key points in glycolysis and the citric acid cycle
When there is no
oxygen
, the citric acid cycle cannot occur.
Fermentation occurs, producing lactic acid or ethanol
Fermentation occurs in cytoplasm of all organisms, allows for some cells to produce small amounts of ATP.
Consists of
Glycolysis, NAD+ Regeneration pathway