Ch 9: Cellular Respiration and Fermentation Flashcards
How does energy exist and enter an ecosystem?
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energy enters as light and exits as heat
Catabolic Pathways
release stored energy by breaking down complex molecules
Two types of catabolic pathways
Fermentation, and aerobic respirations, anaerobic respiration
What is fermentation?
a partial degradation of sugars that occurs without oxygen
What is aerobic respiration?
consumes organic molecules ans oxygen and yields ATP
How is anaerobic respiration different from aerobic respiratioon?
anerobic respiration consumes compounds other than oxygen
What type of respiration is used in cellular respiration?
both aerobic and anaerobic respiration but its often used to refer to aerobic respiration
Chemical equastion for cellular respiration
C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + Energy (ATP + heat)
ΔG = -686 kcal/mole glucose
What is a redox reaction?
chemical reactions that transfer electrons between reactants
What is oxidation?
the loss of electrons from a substance in a redox reaction
What is reduction?
the addition of electrons to a substance in a redox reaction
What is a reducing agent?
the electron donor, it reduces the electron acceptor
What is a oxidizing agent?
the electron acceptor, it oxidizes the electron donor
Besides transferring electrons, how can a redox reaction occur?
a redox reaction can occur with a change of electron sharing in covalent bonds
How can energy be released?
the transfer of electrons during a chemical reaction releases energy, the movement of electrons closer to electronegative atoms release energy
What is nicotinamide adenine dinucleotide (NAD+)?
a coenzye that functions as an electron carrier, oxidizing agent during cellular respiration
What does NADH represent?
the reduced form of NAD+, represents stored energy that is tapped to synthesize ATP
How is NADH formed?
enzymes called dehydrogenases remove a pair of hydrogen atoms fron the substrate, the 2 electrons and 1 proton is transferred to NAD+ forming NADH
Why is an electron tranpsort chain used in cellular repiration?
its used to break the fall of electrons to O2 into several energy-relaesing steps
Electron transport chain
consisits of a series of molecules built into the inner membrane of the mitochondria (or plasma membrane of prokarotes)
Electron movement during cellular respiration:
glucose—> NADH—> electron transport chain—> oxygen
The three stages of of harvesting energy from glucose by cellular respiration
gylcolysis, citric acid cycle, and oxidative phosphorylation
What is the glycolysis stage?
glycolysis breaks down glucose into two molecules of pyruvate
What is the citric acid cycle stage?
pyruvate oxidation and the citric acid cycle complete the breakdown of glucose to CO2 and form some ATP by substrate-level phosphorylation
