- Respiration Lab
Cellular respiration is the
general term which describes the metabolic reactions involved in the formation
of usable energy from the breakdown of nutrients. The goal of respiration
is to produce the "universal" source of energy; adenosine triphosphate
(ATP).
The summary reaction for respiration
is shown below:
The first several steps of cellular respiration are called Glycolysis,
the breakdown of glucose (a six-carbon sugar) to form two molecules of
pyruvate (3 Carbons). Glycolysis takes place in the cytoplasm of the cell.
The resulting pyruvate molecule may pass through one of several pathways,
depending on the organism in question. In some organisms, such as yeast,
fermentation occurs. In other organisms, aerobic respiration occurs. After
completing the lab, you should be familiar with the general reactions
and products of aerobic respiration and fermentation.
Alcoholic Ferementation
One of the more familiar fermentations is conversion of glucose to
ethanol to form alcoholic beverages. After the formation of pyruvate,
ethanol is formed by two simple reactions. First, CO2 is removed from
pyruvate to form acetaldehyde. Then acetaldehyde is reduced by NADH to
form Ethanol. Below, we measure the rate of carbohydrate fermentation
by Yeast.