Lab #2

What are two methods for measuring the rate of cellular respiration?

1) measuring changes in temperature 2) measure gas volume changes

How are the three respirometers assembled? What is contained in each respirometer?

2 sets of 3 respirometers are assembled: each set is incubated at a different temperature. In each set, 1 respirometer will be filled with 25 germinated seeds and 20 mL of water. Another respirometer will be filled with 25 dry seeds (non germinated) and glass beads until the volume is the same as the first respirometer. Finally, the 3rd respirometer will be filled with 20 mL of water and glass beads until the volume is the same as respirometer 1 and 2. Each respirometer will be submerged in water, where water will flow into the respirometer via the pipet tip as oxygen is being used up by the seeds.

If you used the same experimental design to compare the rates of respiration of a 25g reptile and a 25g mammal, at 100ºC, what results would you expect? Explain your reasoning.

Although mother are likely to survive at 100ºC at higher temps a 25g mammal would be closer to its optimal temp for respiration and thus shower a higher consumption of oxygen compared to a 25g reptile which has a lower internal body temp and thus would have significantly lower levels of respiration

Cellular respiration

C6H12O6 + 6O2 --> 6CO2 + 6H2O

Equation to produce potassium carbonate

CO2+ 2KOH--> K2CO3 + H2O

Explain the effect of germination (versus non-germination) on peas' seed respiration

Germinated seeds have a higher rate of respiration compared to non-germinated as non germinated seeds are dormant and waiting for conditions to be germinated

When the respirometers are submerged in water, does the water flow from high to low pressure or low to high pressure?

High to low pressure

What is formed when potassium hydroxide (KOH) combines with carbon dioxide?

K2CO3 + 2H2O

What is the purpose of KOH in this experiment?

KOH absorbs CO2 creating the solid precipitated K2CO3 and water allowing us to measure the consumption of gas

During cellular respiration, two gases are changing in volume. State what these two gases are and how they are changing.

Oxygen is consumed and carbon dioxide is produced

What is a respirometer and how can it be used to measure cellular respiration?

Respirometers are devices used to indirectly measure the rate of cellular respiration by measuring gas volume changes during respiration

Is cellular respiration endergonic or exergonic?

exergonic

Cellular respiration

nutrient molecules and oxygen are broken down to generate ATP, which is then used as energy to perform cellular processes

What are the reactants and products of cellular respiration?

reactants: C6H12O6 (glucose) + 6O2 (oxygen) products: 6CO2 (carbon dioxide) +6H20 (water)

what does "R" stand for in the ideal gas law equation?

the gas constant =.082 L•atm/mol•K

what variable is the respirometer measuring?

the rate of oxygen consumption

What was the purpose of KOH?

to absorb CO2 thus allowing for measurement of oxygen only

Why did the vial have to be completely sealed around the stopper?

to ensure the only water getting in to the vial is due to the consumption of oxygen and water moving from a high to a low concentration and prevent gases from leaving

What was the purpose of respirometer?

to measure the rate of respiration by measuring gas volume changes of oxygen consumption and CO2 production