Biology 1115 chapter 9
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. What would you like to do?
What do living cells require from the outside source?
Energy flows into a ecosystem as _______ and leaves as __________.
Cells use chemical energy stored in organic molecules to _____________.
regenerate ATP, which powers work
What would "denotation" of our food molecules be?
highly destructive and highly wasteful
What's the point of cellular respiration? (2)
- allows for the controlled, gradual release of energyallows for energy to be harnessed to perform work
what does the multi- step nature of cellular respiration allow?
allows the diversion of molecules into other pathways when the cell has sufficient energy.
Is cellular respiration a catabolic or anabolic pathway?
Is cellular respiration endergonic or exergonic?
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
Chemical reactions that transfer electrons between reactants are called?
What is oxidation?
A substance loses electrons, or is oxidized.
What is reduction?
A substance gains electrons, or is reduced. (the amount of positive charge is reduced)
The electron donor in a redox reaction is?
The electron acceptor in a redox reaction is?
What is generally oxidized and reduced in cellular respiration?
- the fuel (such as glucose) is oxidized
- oxygen is reduced
Electrons from organic compounds are first transferred to?
NAD+ which is a coenzyme.
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+
What is NAD+?
- is an electron acceptor
- functions as an oxidizing agent during cellular respiration
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
How does the electron transport chain work?
it passes electrons in a series of steps instead of one explosive reaction.
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
What is the process that generates most of the ATP in cellular respiration called? Why?
- Oxidative Phosphorylation
- because is it powered by redox reactions
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
What are the three stages of cellular respiration in order? Describe them briefly.
- Glycolysis: breaks down glucose into two molecules of pyruvate
- Citric Acid Cycle: completes the breakdown of glucose into CO2
- Oxidative Phosphorylation: accounts for most of the ATP synthesis
In glycolysis, what happens to the glucose?
It's broken down into two molecules of pyruvate, which has 3 carbons
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
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
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.
What does glycolysis NOT produce?
- produces very little energy
Glycolysis is technically anaerobic, which means?
doesn't require energy
What is the net energy yield from glycolysis?
In the presence of ________, pyruvate enters the mitochondria
Before the citric acid cycle can begin, pyruvate must be converted to ___________, which links the cycle to glycolysis.
acetyl co A
Where does the transition step take place?
between cytoplasm and mitochondria
What happened to the carbons of pyruvate in the transition step?
got converted to acetyl Co A and CO2
What happened to the electrons of pyruvate in the transition step?
release in energy of NAD+ to form NADH
What was the net energy yield from the transition step? (per glucose molecule)
What would you like to do?
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