Respiration Lab

CHO+60, →6 C0, +6 H2O + 686 kilocalories of energy/mole of glucose oxidized By studying the equation above, you will notice there are three ways cellular respiration could be measured. 1 2 3

1. Consumption of O, (How many moles of 0, are consumed in cellular respiration?) 2. Production of CO, (How many moles of CO, are produced in cellular respiration?) 3. Release of energy during cellular respiration In this experiment the relative volume of O, consumed by germinating and nongerminating (dry) peas at two different temperatures will be measured. 

In this lab you will: 1 2 3

1. measure oxygen consumption during germination, 2. measure the change in gas volume in respirometers containing either germinating or nongerminating pea seeds, and 3. measure the rate of respiration of these peas at two different temperatures.

How does respirometer work?

As O2 is used up, the pressure of gases inside the respirometer decreases. This causes water to enter the pipette.

The equation below shows the complete oxidation of glucose. Oxygen is required for this energy-releasing process to occur.

CHO+60, →6 C0, +6 H2O + 686 kilocalories of energy/mole of glucose oxidized

It is also important to remember that

gases and fluids flow from regions of high pressure to regions of low pressure.

In this experiment you will work with seeds that are living but dormant. A seed contains an embryo plant and a food supply surrounded by a seed coat. When the necessary conditions are met...

germination occurs and the rate of cellular respiration greatly increases.

Dormancy

is a period in an organism's life cycle when growth, development, and (in animals) physical activity are temporarily stopped. This minimizes metabolic activity and therefore helps an organism to conserve energy. Dormancy tends to be closely associated with environmental conditions.

Aerobic cellular respiration

is the release of energy from organic compounds by metabolic chemical oxidation in the mitochondria within each cell. Cellular respiration involves a series of enzyme-mediated reactions.

In this experiment the CO, produced during cellular respiration will be removed by potassium hydroxide (KOH) and will form

solid potassium carbonate (K,CO,) according to the following reaction: 92 + 2 KOH → K,C0+H2O Since the CO, is being removed, the change in the volume of gas in the respirometer will be directly related to the amount of oxygen consumed.

4. If the temperature changes and the number of gas molecules is kept constant

then either the pressure or volume (or both) will change in direct proportion to the temperature.

3. If the number of gas molecules and the temperature remain constant

then the pressure is inversely proportional to the volume.

2. If the temperature and volume remain constant

then the pressure of the gas changes in direct proportion to the number of molecules of gas present.

1. If the temperature and pressure are kept constant

then the volume of the gas is directly proportional to the number of molecules of the gas.

PV = nRT

where P is the pressure of the gas, V is the volume of the gas, n is the number of molecules of gas, R is the gas constant (its value is fixed), and T is the temperature of the gas (in °K).

Germination in plants is the process by....

which a dormant seed begins to sprout and grow into a seedling under the right growing conditions.