Cellular Respiration - Intro
Cellular respiration …. An introduction
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Photoautotrophs : An organism, typically a plant, obtaining energy from sunlight as its source
of energy to convert inorganic materials into organic materials for use in cellular functions such
as biosynthesis and respiration. This means that they produce glucose by photosynthesis.
Heterotrophs : is an organism that cannot fix carbon and uses organic carbon for growth. This
means that the obtain energy by ingesting autotrophs or fellow heterotrophs.
REDOX Reactions revisited….
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OIL RIG:
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Cells have developed several different mechanisms to extract the energy they need from available
___________________________. In each case, _______________________reactions are involved.
In one method, the redox reactions result in the transfer of electrons from _____________________ to
_____________________________. Glucose is oxidized to ______________________ and oxygen is
reduced to _______________________________. The overall reaction is as follows:
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Aerobic respiration is accomplished through a series of about 20 reactions in which the product of one
reaction is the reactant of the next, with each step ____________________________ by a specific
______________________________________.
Aerobic means : ______________________________________________________________________
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Cellular Respiration - Intro
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The overall equation for aerobic respiration tells us that ________________ hydrogen atoms break
away from glucose and attach to _________________________atoms from the six
_______________________ molecules to become six _____________________ molecules.
This is called oxidation because ____________________ atoms carry electrons away from
________________ atoms in glucose to oxygen atoms.
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When the hydrogen atoms form covalent bonds with oxygen, the shared electron pairs occupy positions
_______________________ to the oxygen nuclei than they did when they were part of the glucose
molecule.
This happens because oxygen is much more ________________________ than carbon. An electron
occupying an energy level closer to a nucleus is equivalent to a skydiver occupying a position closer to
the ground—both possess __________________________________________________________.
The decrease in potential energy coupled with an increase in entropy causes a decrease in free energy
and an overall _______________________________________ process.
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This change also constitutes an oxidation because, once bound to carbon atoms, the highly
electronegative oxygen atoms draw the shared electron pairs to themselves. This results in a change
that is considered equivalent to _______________________________ losing electrons
In a living cell, the free energy released from the combustion of glucose would also dissipate as
_________________ and ___________________________, but cells have evolved methods to trap
some of the energy (about ________________________% of it). By moving the positions of electrons in
certain molecules to higher free energy states (such as in __________________________).
Activation energy prevents spontaneous combustion and allows living things to control the oxidation
process.
Specific _________________________________ catalyze every step in the ____________________
respiration process. They lower the activation energy and allow the reactions to occur at a rate that is
consistent with the _________________________________ of the cell.
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Oxygen is not the only possible electron acceptor in the oxidation of glucose in a cell.
Some microorganisms use NO2, SO4, CO2, and even Fe3 as final
_______________________________________________. These organisms are known as
___________________ _____________________and include such notable bacteria (and their
associated disorders) as:
Clostridium tetani (tetanus)
Clostridium botulinum (food poisoning)
Clostridium perfringens (gas gangrene).
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Cellular Respiration - Intro
The three overall goals of cellular respiration are:
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Cellular Respiration - Intro
The entire process occurs in four stages :
What is Substrate-level phosphorylation?
What is Oxidative Phosphorylation?
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