Cellular Respiration Lab
What is the purpose of KOH in this lab?
To absorb carbon dioxide as it is produced so that the pressure change due to oxygen consumption can be measured.
What is the purpose of the glass beads?
To make sure that the volume of both tubes stays constant. Particularly in the germinating vs. non germinating peas, the volume of the same number of germinating peas is much larger than the volume of dry peas.
Write the balanced equation for Cellular Respiration.
C6H12O6 + 6 O2 → 6 CO2+ 6 H2O
State a quantitative hypothesis for the effect of temperature on the respiration rate of germinating peas.
If 25 germinating peas are put into 2 test tubes and one is kept at 10 degrees celcius while the other is kept at 25 degrees celcius, then the change in pressure in the tube of the peas at 25 degrees celcius will be at least 2 times that of the peas at 10 degrees celcius over 20 minutes.
State a quantitative hypothesis for the effect of germination on the respiration rate of peas.
If 25 germinating peas are put into a test tube and 25 non germinating peas are put into a different test tube and both are kept at 25 degrees celcius, then the change in pressure of the non germinating peas will be less than 10% of the respirating peas over 20 minutes.
Other than the way we are using in this lab, how else could the rate of cellular respiration be measured?
Measuring how fast glucose is being used (but this would only be able to be done with single celled organisms), or the amount of CO2 production could be measured.
If the non-germinating peas have a change in pressure, what may be the explanation?
Most likely the peas got wet and are germinating.
If the peas at 10 degrees celcius have a very large decrease in pressure, what may be the explanation?
Most likely, the water bath is warmer than thought.
For what is ATP being used in these seeds?
Moving chromosomes in mitosis, creating macromolecules for cell membranes, cell walls, organelles. More specific answers are okay.
In this lab, why are we using the equation PV=nRT? What does each variable mean? Which do we know already?
P is the pressure as measured in the lab V is the volume of the container n is the number of moles of gas (Oxygen) R is the gas constant T is the temperature
Where are the mitochondria in the pea seeds getting the carbohydrates to do cellular respiration?
The carbohydrates are stored in the pea seeds. Seeds do not do photosynthesis. There is enough energy stored until the baby plant is big enough to do photosynthesis.
How is the rate of cellular respiration being measured in this lab?
The change in pressure is being measured which is due to the amount of Oxygen being used up.
Write a title for this lab: Include the following terms: cellular respiration, oxygen consumption, pressure change, temperature, seed activity, and RATE
The effect of seed activity and temperature of pea seeds on the rate of cellular respiration as measured by the change in pressure due to oxygen consumption
What activity is going on in the pea seeds?
The embryo is growing into a plant
If KOH were not added to the tube, what would happen?
There would be no measureable change in pressure because for every oxygen used, a carbon dioxide would be produced and the KOH wouldn't be present to remove the carbon dioxide.
Sketch the activity positive control group.
The sketch should show test tube with 25 large peas on top of non absorbant cotton on top of absorbant cotton that is soaked with KOH. There is a stopper and sensor in the stopper and it is in a water bath with no ice
Sketch the temperature positive control group.
The sketch should show test tube with 25 large peas on top of non absorbant cotton on top of absorbant cotton that is soaked with KOH. There is a stopper and sensor in the stopper and it is in a water bath with no ice
Sketch the temperature experimental group.
The sketch should show test tube with 25 large peas on top of non absorbant cotton on top of absorbant that is soaked with KOH. There is a stopper and sensor in the stopper and it is in a water bath ice
Sketch the activity experimental group.
The sketch should show test tube with 25 small peas and glass beads on top of non absorbant cotton on top of absorbant cotton that is soaked with KOH. There is a stopper and sensor in the stopper and it is in a water bath with no ice
If your germinating pea container at 25 degrees celcius does not show a change in pressure over 20 minutes, what might be the problem? State several reasons.
The tube is not sealed properly. The computer is not linked to the logger pro equipment properly. The pressure sensor is not working properly. There is no or not enough KOH in the container.
Sketch what you expect the graph to look like for the activity trials. Be sure to label the axes and have 2 lines.
The vertical axis would be pressure and the horizontal axis would be time. The line for the cold would be a straight line or have a very slight decrease while the line for the germinating peas would decrease with a larger slope.
Sketch what you expect the graph to look like for the activity trials. Be sure to label the axes and have 2 lines.
The vertical axis would be pressure and the horizontal axis would be time. The line for the dry peas would be a straight line while the line for the germinating peas would steadily decrease.
