Cell Respiration APES 09 by stariya

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Cell Respiration


Driving Questions

In this lab you will compare the respiration rates in dormant and germinating seeds.

 Do both germinating and non-germinating seeds undergo cellular respiration?



Background

The term respiration refers to the exchange of gases between and organism and its environment.
This intake of oxygen gas and exhalation of carbon dioxide gas is closely linked to the production
of ATP at the cellular level, a process called cellular respiration. ATP is generated by
mitochondria within the cell. During cellular respiration, the energy stored within
macromolecules such as glucose is released and harnessed to phosphorylate ADP, producing
ATP. In the presence of oxygen, glucose can be fully oxidized releasing large amounts of energy.

                               C6H12O6 + 6 O2 (g)  6 H2O + 6 CO2 (g) + energy


The process of cellular respiration also produces water and carbon dioxide gas as waste products.

Organisms that utilize oxygen for the breakdown of glucose are called aerobic organisms. Plants
and animals are both examples of aerobic organisms. While it seems obvious that a growing
plant would undergo cellular respiration, the question remains do plant embryos (seeds) undergo
respiration before or after germination? In this lab, you will determine if there is a difference in
respiration rates of dormant and germinating pea seeds. You will also determine the effect of
temperature on respiration rates of both types of peas.



Materials and Equipment
 Electronic data collection and display device           50 germinating pea seeds
 1 Oxygen gas sensor                                     50 dry pea seeds
 1 plastic bottle                                        50 glass beads




Lab Safety

 Keep water away from electrical outlets.




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                                                                                Student Worksheet




Procedure

After you complete a step (or answer a question), place a check mark in the box () next to that step.


Set Up Equipment - Oxygen Gas Consumed

1.  Connect the oxygen gas sensor and the temperature probe to the electronic data
     collection and display device.


2.  Place 50 germinating pea seeds into one of plastic bottles and insert the oxygen gas
     sensor into the top of the bottle. Be sure that the bottle is tightly sealed by firmly
     pressing on the rubber stopper connected to the sensor.


Collect Data - Oxygen Gas Consumed

3.  Determine the temperature of the room and record the measurement in the table.


4.  Begin collecting data. After five minutes, stop data collection.


5.  Select Statistics to determine the average rate of respiration record your results in the
     table.


7.  Place 50 dry pea seeds into a plastic bottle and insert the oxygen gas sensor into the top
     of the bottle.


8.  Begin collecting data. After five minutes, stop data collection.


9.  Select Statistics to determine the average rate of respiration record your results in the
     table.


10.  What is the purpose of testing oxygen consumption in dry seeds?




11.  Place 50 glass beads into a plastic bottle and insert the oxygen gas sensor into the top of
      the bottle.


12.  Begin collecting data. After five minutes, stop data collection.


13.  Select Statistics to determine the average rate of respiration record your results in the
      table.




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14.  What is the purpose of the glass beads?



Data Analysis
Table Rates of respiration for germinating and dormant peas and glass beads.]

Test Subject                                         Rate of Respiration (%O2/min)
Germinating peas, room temperature (    C)
Non-germinating peas, room temperature (    C)

Glass beads, room temperature (     C)


Graph the respiration data from both the germinating and non-germinating peas and the glass
beads at room temperature.

 KEY:
 Germinating peas (       )
 Non-germinating peas (       )

 Glass beads (     )




Analysis Questions

1. How do the respiration rates of germinating and non-germinating peas compare?


2. What is the relationship between oxygen consumption and time in the germinating
peas?


3. What is the effect of germination on pea seed respiration?




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                                                                      Student Worksheet

Synthesis Questions

Use available resources to help you answer the following questions.


1. Would you anticipate that all seeds would show similar rates of respiration?


2. If this experiment were repeated with an exothermic animal what results might
you expect? How would those results differ in an endothermic organism?




Multiple Choice Questions


1. The function of cellular respiration is

       A. reduce CO2
       B. extract CO2 from the atmosphere
       C. extract usable energy from glucose
       D. synthesize macromolecules from monomers
       E. produce carbohydrates

2. In cell respiration, the largest number of ATP molecules is produced during

       A. glycolysis
       B. the Krebs Cycle
       C. oxidative phosphorylation
       D. the Calvin Cycle
       E. the light reactions

3. The function of oxygen in cell respiration is to

       A. absorb and harness light energy
       B. act as a building block for organic molecules consumed in glycolysis
       C. accept electrons and form CO2 in the electron transport chain
       D. accept electrons and form H2O in the electron transport chain
       E. provide electrons to the electron transport chain

4. Most CO2 from cell respiration is released during

       A. glycolysis
       B. the Krebs Cycle
       C. oxidative phosphorylation
       D. lactic acid fermentation
       E. electron transport



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