RESPIRATION LAB Instructor Terry Wiseth Click to go to Next Slide

RESPIRATION RESPIRATION LABLAB

Instructor Terry WisethInstructor Terry WisethClick to go to

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Click to go to Next Slide

Most cells consume oxygen and produce carbon dioxide. The higher the rate of metabolism, the more oxygen used by the cells, and by the animal as a whole. One way to determine the basal metabolic rate (BMR), therefore, is to measure the amount of oxygen consumed by the animal. In general, larger animals consume more oxygen than smaller animals. Rubner's Surface Rule maintains that the metabolic rate is affected by the ratio of surface area to volume.According to this theory, cells in smaller animals maintain a higher metabolic rate to compensate for the greater amount of heat lost from their bodies.

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However, the same relationship between size and metabolic rate has been found in cold-blooded animals. These animals have body temperatures similar to the environment and do not compensate for heat loss. Clearly, other factors must be at work here. While you may predict that a larger animal will consume more oxygen than a smaller animal, the situation may be more complex if you compare the BMR (Basic Metabolic Rate) per gram of two animals. In this lab, the BMR’s of white rats of varying weights are determined by measuring their rates of oxygen consumption.


This data is then used to calculate oxygen consumption per gram of body weight, and the results are graphed to allow comparison of oxygen/minute vs. oxygen/hour/gram. Using this information you should be able to draw conclusions about the effect of body mass on the metabolic rate. In this simulation the rate of oxygen consumption is measured from laboratory rats. You will determine the basal metabolic rate for each rat and calculate the rate of oxygen consumed by a gram of tissue. In this way the effect of body mass on oxygen consumption and on oxygen consumption per gram is determined.


In the traditional wet lab a weighed rat is placed in a wire cage which is placed in a chamber containing soda lime. The chamber is sealed using a cork and soap bubbles are placed in the end of the calibrated tube. In this system the rat consumes oxygen and the soda lime absorbs exhaled carbon dioxide. Thus, as oxygen is used, the volume of air in the chamber decreases, and the bubbles move down the tube. The locations of the bubbles in the tube is measured every 15 minutes and the rate of oxygen consumption is calculated.

1) Four 1) Four Table 1 Data Sheets(1 for each Rat)(1 for each Rat)

2) 2) Table 2 Data Sheet3) 3) Bar Graph 14) 4) Bar Graph 25) Questions O5) Questions O22 Consumption Consumption

1-31-3Click to go to

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Click Here to View Instructions on how

to construct the graphs

If you are done with this lab click here

This lab will require that you collect data using provided data sheets and analyze the data by producing bar graphs. (Use the links below to print the tables and graphs)

Click to Start the Experiment

When you are finished with this lab, be sure that you have included in your lab report the following: (Use the Links below to print the tables and graphs)1) Four 1) Four Table 1 Data Sheets (1 for each Rat)2) 2) Table 2 Data Sheet3) 3) Bar Graph 14) 4) Bar Graph 25) Answers to questions 1-35) Answers to questions 1-3If you are done with

this lab click here

Click Here to View Instructions on how

to construct the graphs

:00There are four rats in the rack. Select one of the rats by clicking on it. The rat will be weighed on the scale in grams. Record the weight of the rat in Data Table 1. You will be using all four of the rats in your experiment.

If you have performed the

experiment with all of the rats click here

Mabel

:00There are four rats in the rack. Select one of the rats by clicking on it. The rat will be weighed on the scale in grams. Record the weight of the rat in Data Table 1

You have chosen Mabel 32.42

g


:00After you have recorded the weight, and the name of the subject, click on Mabel to insert her into the wire cage inside the metabolic chamber.

32.42 g


:00Locate the beaker containing the bubble solution and pipette. Click on the blue pipette to inject the bubbles into the end of the tube leading from the respiratory chamber.

10

987654321

32.42 g


:00Measure the location of the extreme right side of the bubble in the tube. Record the value in Data Table 1 at TIME 0:00. (The value recorded should be 10)

10

987654321

32.42 g


Start TimerStart Timer

:00Click the Start Timer button for the timer to initiate the experiment. You will need to record where the edge of the bubble is at every 1 minute interval for 6 minutes. Record these values in Data Table 1

:301:001:302:002:303:003:304:004:305:005:306:00

10

987654321

32.42 g


Stop the Timer and return to select a different Rat

The Timer has startedWait for each 1 minute reading on

the clock above to record your data

Josie


You have chosen Josie 12.0 g


:00After you have recorded the weight, and the name of the subject, click on Josie to insert her into the wire cage inside the metabolic chamber.

12.0 g



12.0 g

10

987654321



12.0 g

10

987654321




:301:001:302:002:303:003:304:004:305:005:306:00

12.0 g

10

987654321





Tex


You have chosen Tex42.89 g


:00After you have recorded the weight, and the name of the subject, click on Tex to insert her into the wire cage inside the metabolic chamber.

42.89 g



42.89 g

10

987654321



42.89 g

10

987654321




:301:001:302:002:303:003:304:004:305:005:306:00

42.89 g

10

987654321





Gertie


You have chosen Gertie 22.92

g


:00After you have recorded the weight, and the name of the subject, click on Gertie to insert her into the wire cage inside the metabolic chamber.

22.92 g



22.92 g

10

987654321



10

987654321

22.92 g




:301:001:302:002:303:003:304:004:305:005:306:00



10

987654321

22.92 g



Questions

:00Construct Bar Graphs

From the data you have collected and calculated, construct bar graphs which compare the weights of different sized rats and their oxygen consumption. Use Bar Graph 1 to compare Average Milliliters of Oxygen consumed per Minute vs the Weight of the individual animals. Use Bar Graph 2 to compare the Average Milliliters of Oxygen consumed per Hour per Gram vs the Weight of the individual animals. Formulas for manipulating the data are given in Table 2.


:00Answer the Following Questions

1)Is there any relationship between the values for oxygen consumed / minute for each animal and the weight?

2) Is there any relationship between the values for oxygen consumed / hour / gram for each animal and the weight?

3) Why would a small rat have a different rate of oxygen consumption than a larger animal?Click to go to

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Click Here to View a Printable

Page of the Questions

Data Table and Graphs

DATA TABLE 1RatName

Weight Difference*Preceding value minus

succeeding value. See below for description.TIME

(min)VALUE (ml)

0:00 10 ____ - ____ = ____

1:00 ____ - ____ = ____

2:00 ____ - ____ = ____

3:00 ____ - ____ = ____

4:00 ____ - ____ = ____

5:00 ____ - ____ = ____

6:00Avg DifferenceAvg O2 / Minute

(total difference divided by 6)

*For example if the value for time 0:00 is 10 and the value for time 1:00 is 8.4, you would subtract 8.4 from 10 for a difference of 1.6 (10 - 8.4 = 1.6). For the next value you would subtract the value given for 2:00 from 8.4.

10

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Click to View A Printable Page

DATA TABLE 2Oxygen Consumption Summary

Rat Name Weight Avg O2 / minute

Avg O2 / hour / g

How to calculate Avg O2 / minuteTotal difference divided by 6

How to calculate Avg O2 / hour / g Avg O2 / minute times 60 divided by weight of rat



BAR GRAPH 1

Avg O2 / minute(ml)

Weight (g)

2 -

1.5 -

1 -

0.5 -

0 -12.0 22.92 32.42 42.89



BAR GRAPH 2

Avg O2 / hr / g(ml)

Weight (g)

4 -

3 -

2 -

1 -

0 -12.0 22.92 32.42 42.89



10

987654321

42.89 g

:00

10

987654321

42.89 g

:00

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RESPIRATION LAB Instructor Terry Wiseth Click to go to Next Slide