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_Cellular Resperation _
By: Tanya Fisher
CELLULAR RESPIRATION Tanya Instructor: Rose Davis 5:30 to 8:10 Biology 101 St.
Louis CC at FP Cellular Respiration is a series of chemical reactions that
frees the energy in fat, protein, and carbohydrate food molecules, making it
available to the cells. Respiration is defined as the oxygen-requiring stage
in these biochemical reactions. However respiration also occurs without any
oxygen, this is called anaerobic respiration. An anaerobic organism must
abstract oxygen from environmental air or water in order to supports its life
functions. The process of obtaining oxygen and releasing the cellular waste
product, carbon dioxide, into the environment is called respiration. A tiny
unicellular organism, with a diameter no bigger than 1 mm can obtain
sufficient oxygen and simultaneously dispose of carbon-dioxide by means of
passive diffusion through its cell membrane. Multi-cellular organisms,
however, had to figure out specialized respiratory systems for supplying
oxygen to their tissues and removing excess carbon dioxide. These systems are
capable of functioning over a wide range of metabolic demands and within
minimum energy expenditure. During respiration and photosynthesis an enzyme
catalyzes each chemical reaction. To break down glucose molecules, which are
the stable end products of photosynthesis, ATP is needed to provide the
activation energy to initiate the chemical process that follow. ATP is one of
the major energy-providing molecules that initiate biochemical reactions
throughout the body. Because ATP, NADH2 and similar molecules are essential to
the maintenance of living systems, organisms need to ensure the constant
supply of such energy sources . Glucose is the first series of chemical
reaction in cellular respiration, in which glucose is converted to pyruvate
(pyruvic acid) and, depending on the organism and the particular conditions
involved, pyruvate is processed further into other critical end products.
Oxidation, chemically defined as the loss of an electron, usually takes place
through the addition of oxygen or the subtraction of hydrogen. The oxidation
of glucose to pyruvate releases energy, most of which would be lost as heat if
it were conserved. To conserve the released energy so it may be harnessed to
run the cell's metabolism, the cell regulates its chemical reaction.
Word Count: 352
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