Download Lab Respiration

Name_____________________________________________Roll # ________ Date ____________Score_______
Biology Lab: Does an Oxygen Supply Affect the Rate of Growth and Reproduction of Cell
Reference: Chapter 9 pages 222-226; 229; & 232
Background: Oxygen is very important in the release of energy from food. Most organisms, including humans,
cannot live without a constant supply of Oxygen. Some organisms, however, can get energy from food without
Oxygen. There are a few kinds of microorganisms that will use oxygen if it is available, but if it is not available they
can still get energy from food. In other words, some types of microorganisms are both AEROBIC and
ANAEROBIC. A type of bacterium called Aerobacter aerogenes is such an organism and can be either aerobic or
anaerobic. In this lab you will be given data from an experiment with Aerobacter aerogenes. The bacteria were
allowed to grow in test tubes containing distilled waster to which only a few salts and various concentrations of
glucose were added. Some of the tubes were sealed so that no air was available to the bacteria. Other tubes have
a stream of air (containing O2) bubbling through the growth solution.
Purpose:
Pre-lab Discussion Questions
1. Production of Oxygen gas by Photosynthesis made possible a new, efficient way of obtaining energy from
organic compounds. By using Oxygen, organisms could obtain more energy from the same amount of food.
Define RESPIRATION (pg 222)
______________________________________________________________________________________
______________________________________________________________________________________
2. How many total molecules of ATP are produced
from one molecule of glucose during
FERMENTATION?_____
How many total molecules of ATP are produced per
molecule of glucose when OXYGEN is present during
RESPIRATION? (see page 229, Figure 9-8)______
3. “Organisms who get energy from food in the absence of Oxygen” are called: _________________________
“Organisms who get energy from food by using Oxygen when it is present” are called: __________________
4. What is the equation for cellular respiration, using chemical formulas?
6____________ + _____________
6 _____________ + 6______________
5. What would be the problem if cellular respiration took place in just one step?__________________________
______________________________________________________________________________________
______________________________________________________________________________________
Procedures
1. On the attached graph paper construct two graph lines on the same graph.
2. Position your graph paper so the long axis is in the upright (vertical) position.
3. VERTICAL AXIS
Label: “Millions of cells per Milliliter”
Let every block represent 100 mill/mL
Begin at 000 mill/mL
End at 5000 mill/mL
HORIZONTAL AXIS
Label: “Concentration of Glucose” (mg/100mL)
Let every 4th block represent one of the nine glucose
concentrations
Begin with 18 mg/100mL
End with 540 mg/100mL
Use RED PENCIL plot “concentration of glucose” against “number of bacteria” in Series “A” (tubes without air)
Use BLUE PENCIL plot “concentration of glucose” against the “number of bacteria” in Series “B” (tubes with air)
6. Label ON the first graph line… “Growth without Air” AND Label ON the second graph line… “Growth With Air”
7. IMPORTANT… USING A DOTTED BLUE LINE… EXTEND THE “SERIES B” LINE IN THE DIRECTION YOU
BELIEVE IT WOULD GO IF DATA WERE PROVIDED.
8. (GRAPH TITLE): “EFFECTS OF DIFFERENT GLUCOSE CONCENTRATION ON Aerobic aerogenes
BACTERIA”
4.
5.
Results:
EFFECTS OF DIFFERENT GLUCOSE CONCENTRATIONS ON
THE GROWTH OF AEROBIC AND ANAEROBIC BACTERIA
GLUCOSE CONCENTRATIONS
(Milligram/ 100 mL of water)
18
36
54
72
162
288
360
432
540
NUMBER OF BACTERIA AT MAXIMUM GROWTH (Millions per mL)
TUBE #
TUBES WITHOUT AIR
TUBE
TUBES WITH AIR
(ANAEROBIC)
#
(AEROBIC)
1-A……….……………….50
1-B……….……………….200
2-A……….……………….90
2-B……….……………….500
3-A……….……………….170
3-B……….……………….800
4-A……….……………….220
4-B……….……………….1100
5-A……….……………….450
5-B……….……………….2100
6-A……….……………….650
6-B……….……………….???
7-A……….……………….675
7-B……….……………….???
8-A……….……………….675
8-B……….……………….???
9-A……….……………….670
9-B……….……………….???
Discussion Questions
1.
List the two (2) most obvious differences between the two graph curves
A.____________________________________________________________________________________
B.____________________________________________________________________________________
2.
Compare the growth of bacteria in anaerobic
Series “A” to aerobic Series “B” tubes. How
many times greater is the growth of bacteria in
tubes….
3.
Based upon your projected data (i.e. Dotted line) for Series “B” tubes, approximately how many bacteria
would be found in………. Tube 6-B __________ Tube 7-B ________
4.
Why are there so many more bacteria per milligram of glucose in Series “B” tubes than in Series “A” tubes?
______________________________________________________________________________________
5.
Each milligram of glucose has an equal amount of energy available to do work. The Series “B” tubes
produced more cells per milligram of glucose then did the Series “A” tubes. Assuming that each cell produced
requires an equal amount of energy, which tube should contain some “UNUSED” energy (“A” or “B”) ______
6.
In additional tests it was determined that ethyl alcohol accumulates in Series ‘A” tubes. What energyreleasing process must be occurring in these tubes? ____________________________________________
Is there much “unused” energy still tied up in the ethyl alcohol molecules (yes or no?) ___________
7.
Respiration is occurring in the Series _____ tubes, where glucose is broken down into ________ &________.
1-B than 1-A?
2-B than 2-A?
3-B than 3-A?
4-B than 4-A?
5-B than 5-A?
________Xs
________Xs
________Xs
________Xs
________Xs
Conclusion
Respiration is much more efficient than ________________________ in releasing energy from food (glucose). For
example: the yield of ATP obtained from equal amounts of glucose is ____x (times) greater in Respiration
than Fermentation. Therefore, more bacteria can be supported in an aerobic/anaerobic (circle) than an
aerobic/anaerobic (circle) assuming the same amount of glucose is provided.