Cellular Respiration Flashcards
Light energy converted to chemical energy via
photosynthesis and cellular respiration
Chemical reactions that transfers electrons between reactants are
called oxidation-reduction reactions or redox reactions
In Oxidation
a substance loses electrons, or is oxidized
- loses a hydrogen
In reduction
a substance gains electrons or is reduced (amount of positive charge is reduced
- gains a hydrogen
Stages of Cellular respiration
glycolysis, Oxidation of Pyruvate, the Citric Acid Cycle, Oxidation of phosphorylation
glycolysis (overview)
breaks down glucoses into two molecules of pyruvate
Oxidation of Pyruvate (overview)
2 pyruvate molecules get oxidized
The Citric Acid Cycle (overview)
Complete the break down of glucose
AKA: TCA cycle, Krebs cycle
Oxidative Phosphorylation (overview)
accounts for 90% of ATP synthesis
Catabolic pathways yeild energy by
oxidizing organic fuels
Energy enters the ecosystem as
light and exist as heat
Photosynthesis uses CO2 and H2O to
make organic molecules and O2
Cellular respiration uses O2 and organic molecules to
make ATP; CO2 and H2O are produced as waste
The breakdown of organic molecules is
exergonic
Fermentation is a
partial dehydration of sugars that occurs without oxygen
Aerobic respiration consumes
organic molecules and oxygen and yields ATP
anaerobic respiration is similar to aerobic respiration
but consumes compounds other than oxygen
Cellular respiration redox readction
C6H12O6 + 6O2 –> 6CO2 + 6H2O + Energy
C6H12O6 becomes
oxidized to 6CO2
6O2 becomes
reduced to 6H2O
The oxidation of glucose transfers electrons from
a higher energy state (in glucose) to a lower energy state with Oxygen Atoms. Which releases energy that is to be used to synthesize ATP
In cellular respiration
glucose and other organic molecules are oxidized in a seris of steps
Hydrogen atoms are usually first passed to
electron carriers, rather than directly to O2
NAD+ is a
coenzyme that functions as an electron carrier
As an electron acceptor NAD+ functions as
an oxidizing agent
Each NADH (reduced form of NAD+) represents
stored energy that is tapped to synthesize ATP
Enzymes called dehydrogenases remove
a pair of hydrogen atoms (2 electrons and protons) from the substrate.
The 2 electrons and 1 proton is transferred
to NAD+ from NADH and the other proton is released as a hydrogen ion (H+) into the surrounding solution
Cellular respiration uses an
electron transport chain to break the fall of electrons to O2 into several energy releasing steps
An electron transport chain consist of
a series of molecules built into the inner membrane of the mitochondria
NADH passes electrons to
the electron transport chain where they are transferred in a series of redox reactions, each releasing a small amount of energy
O2 is the final
electron receptor, it captures the electrons and the hydrogen nuclei forming H2O; the energy yielded is used to regenerate ATP
Reactants of glycolysis
Glucose + NAD+ + 2 ADP + 2 inorganic Phosphate
Products of glycolysis
2 pyruvate + 2 NADH + 2 ATP
The end carbohydrate product of glycolysis is
2 pyruvate
Pyruvate enters the mitochondria for
oxidation to acetyl CoA via transport protein
NAD+ is a
reactant being reduced to NADH
For every 2 glucose
2 pyruvate oxidize to 2 acetyl CoA with a by-product of 2 NADH
Citric Acid cycle (Krebs cycle)
completes the energy yielding oxidation of organic molecules and takes place in the mitochondria
The CoA enters the cycle then
carbon dioxide is released (4), NADH is released (6), ATP is released (2), FADH2 is released (2)
The primary purpose of the citric acid cycle is
to produce electron carriers for oxidation phosphorylation (NADH, FADH2)
The ETC occurs in
the cristae of the mitochondria , and there are proteins embedded in the cristea
The final electron acceptor of the ETC is
O2
as you go down the ETC energy is
decreasing
the energy from the ETC is not to produce ATP, it is used to
pump hydrogen ions from the matrix to the intermembrane space to create a concentration gradient of hydrogen ions; that is used to generate ATP
Chemiosmosis
H+ then moves back across the membrane, passing through channels in ATP synthase (F1 ATPase). ATP synthase uses the exergonic flow of H+ to drive phosphorylation of ATP
Glycolysis probably evolved in
ancient prokaryotes before there was oxygen in the atmosphere
The body uses
small molecules to build other substances. These small molecules may come from food, from glycolysis or from the citric acid cycle.
