Download How Do Cells Communicate with Each Other?

ANSWERS
Process of Science
How Do Cells Communicate with Each Other?
Lab Notebook
Aggregation Test
Temperature
Change
Number of Plates
with Aggregation
4
Number of Plates
% Aggregation
without Aggregation
4
50%
Food Depletion
7
1
88%
Water Depletion
6
2
75%
Molecule Identification Tests
Aggregation Test
Number of Plates
with Aggregation
Treated with
7
Protease
Not Treated with
7
Protease
Treated with
0
Solvent
Not Treated with
Solvent
Colorimetric Tests
Carbohydrate Test
Nucleotide Test
7
Number of Flasks
with Positive Test
0
7
cAMP Confirmation Number of Plates
Test
with Aggregation
cAMP Treatment
7
Number of Plates
% Aggregation
without Aggregation
1
88%
1
88%
8
0%
1
88%
Number of Flasks
with Negative Test
8
1
% Positive
0%
88%
Number of Plates
% Aggregation
without Aggregation
1
88%
Questions
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Copyright © 2010 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
1. Provide two reasons why communication is essential between cells in multicellular
organisms.
Cell to cell communication in multicellular organisms is needed to: 1) organize the body
for development and growth, and 2) achieve homeostasis by coordinating functions
carried out by different cells.
2. Which environmental factor produced the strongest aggregation response? Explain
why you believe this factor had the strongest effect.
Depleting the food supply had the strongest aggregation effect. The cellular slime mold
enters dormancy during aggregation to avoid unfavorable environmental conditions.
Changes in temperature and water supply may be temporary. Thus, some of the slime
molds keep feeding with the risk of dying if the environmental conditions do not
improve. Probably, the loss of food is a sign of more severe environmental change, and
nutrition is needed to keep the cells active. So, it is beneficial to go dormant and become
active when food becomes abundant again.
3. What can you conclude about the chemical nature of the aggregation molecule?
The aggregation molecule is not a protein or a lipid. It is a carbohydrate, nucleotide, or
another chemical compound.
4. What has this investigation told you about the aggregation molecule and what more do
you need to know about the chemistry of the molecule?
The molecule is a nucleotide. Further investigation is needed to determine the particular
type of nucleotide that is being used for cell communication. The way the nucleotide
signals the target cells must also be investigated.
5. From your data, which nucleotide best matches the aggregation molecule, and what
needs to be done to confirm your answer?
The travel time suggests that the aggregation molecule is cAMP. To confirm this, cAMP
should be tested on slime molds to see if it causes aggregation.
6. What conclusion can you make from the information you gathered from the entire
experiment?
It can be concluded from all the data that cAMP is the molecule that causes aggregation
of slime molds.
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Copyright © 2010 Pearson Education, Inc., publishing as Pearson Benjamin Cummings