by Miller & Levine
[complete Table of Contents]
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Synthase (Image from the Nobel
versions of the Krebs Cycle:
Univ of Virginia
chapter, students will read about the process of cellular respiration.
They will read about the major steps in this process and how it differs
from the anaerobic processes of alcoholic and lactic acid fermentation.
The links below lead to additional resources to help you with this chapter.
These include Hot Links to Web sites related to the topics in this
chapter, the Take It to the Net activities referred to in your
textbook, a Self-Test you can use to test your knowledge of this
chapter, and Teaching Links that instructors may find useful for
9-1: Chemical Pathways
is the process that releases energy by breaking down food molecules in
the presence of oxygen.
Glycolysis is the process in which one
molecule of glucose is broken in half, producing two molecules of pyruvic
acid, a 3-carbon compound.
Glycolysis captures two pairs of high-energy
electrons with the carrier NAD+.
Because glycolysis does not require oxygen,
it supplies chemical energy to cells when oxygen is not available.
The two main types of fermentation are
alcoholic fermentation and lactic acid fermentation.
In the absence of oxygen, yeast and a
few other microorganisms use alcoholic fermentation, forming ethyl alcohol
and carbon dioxide as wastes.
Animals cannot perform alcoholic fermentation,
but some cells, such as human muscle cells, can convert glucose into lactic
acid. This is called lactic acid fermentation.
9-2: The Krebs Cycle and Electron Transport
During the Krebs cycle, pyruvic acid
is broken down into carbon dioxide in a series of energy-extracting reactions.
The electron transport chain uses the
high-energy electrons from the Krebs cycle to convert ADP into ATP.
The products of photosynthesis are similar
to the reactants of cellular respiration. The products of cellular respiration
are the reactants of photosynthesis.