- 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.

Tube # Distance at 10 minutes Distance at 20 minutes
#1 (Glucose)
#2 ( Starch)

Questions:

1. Which tube had the highest rate of respiration?

Tube 1
Tube 2

2. After incubation, what gas displaced the liquid in the neck of the fermentation tubes ?

CO2
O2
H2O
N2