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What do living cells require from the outside source?
energy
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Energy flows into a ecosystem as _______ and leaves as __________.
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Cells use chemical energy stored in organic molecules to _____________.
regenerate ATP, which powers work
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What would "denotation" of our food molecules be?
highly destructive and highly wasteful
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What's the point of cellular respiration? (2)
- allows for the controlled, gradual release of energyallows for energy to be harnessed to perform work
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what does the multi- step nature of cellular respiration allow?
allows the diversion of molecules into other pathways when the cell has sufficient energy.
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Is cellular respiration a catabolic or anabolic pathway?
catabolic pathway
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Is cellular respiration endergonic or exergonic?
exergonic
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The __________ during chemical reactions releases energy stored in organic molecules. What is this released energy mainly used for?
- transfer of electronsthis released energy is ultimately used to synthesize ATP
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Chemical reactions that transfer electrons between reactants are called?
Redox reactions
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What is oxidation?
A substance loses electrons, or is oxidized.
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What is reduction?
A substance gains electrons, or is reduced. (the amount of positive charge is reduced)
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The electron donor in a redox reaction is?
reducing agent
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The electron acceptor in a redox reaction is?
oxidizing agent
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What is generally oxidized and reduced in cellular respiration?
- the fuel (such as glucose) is oxidized
- oxygen is reduced
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Electrons from organic compounds are first transferred to?
NAD+ which is a coenzyme.
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What is the function of dehydrogenase?
It removes a pair of hydrogen atoms (2 electrons and 2 protons) from the substance and transfer them to NAD+
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What is NAD+?
- is an electron acceptor
- functions as an oxidizing agent during cellular respiration
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What is NADH? (3)
- Reduced form of NAD+
- represents stored energy(potential energy) that is taped to synthesize ATP
- function is to pass the electrons to the electron transport chain
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How does the electron transport chain work?
it passes electrons in a series of steps instead of one explosive reaction.
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What is at the end of the electron transport chain? what does it do?
- oxygen is at the end
- it pulls electrons down the chain in an energy-yielding tumble
- the energy yielded is used to regenerate ATP
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What is the process that generates most of the ATP in cellular respiration called? Why?
- Oxidative Phosphorylation
- because is it powered by redox reactions
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What are the other two minor processes that forms small amounts of ATP?
is formed in glycolysis and the citric acid cycle by substrate-level phosphorylation
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What are the three stages of cellular respiration in order? Describe them briefly.
- Glycolysis: breaks down glucose into two molecules of pyruvate
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In glycolysis, what happens to the glucose?
It's broken down into two molecules of pyruvate, which has 3 carbons
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Where does glycolysis occur and what are the two major phases?
- glycolysis occurs in the cytoplasm
- two major phases: energy investment phase, energy payoff phase
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What is the function of phosphofructokinase PFK? (2)
- is an enzyme that adds phosphate groups in the third step
- controls the rate of glycolysis and is regulated by AMP and ATP
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What is the fourth step in glycolysis?
- glycolytic step
- molecule is broken down into two pieces at this step and everything is multiplied by 2.
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What does glycolysis NOT produce?
- CO2
- produces very little energy
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Glycolysis is technically anaerobic, which means?
doesn't require energy
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What is the net energy yield from glycolysis?
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In the presence of ________, pyruvate enters the mitochondria
oxygen
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Before the citric acid cycle can begin, pyruvate must be converted to ___________, which links the cycle to glycolysis.
acetyl co A
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Where does the transition step take place?
between cytoplasm and mitochondria
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What happened to the carbons of pyruvate in the transition step?
got converted to acetyl Co A and CO2
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What happened to the electrons of pyruvate in the transition step?
release in energy of NAD+ to form NADH
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What was the net energy yield from the transition step? (per glucose molecule)
2 NADH
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