Biology 12

Checking the Plan

1.What are your dependent and independent

variables? What are your controlled variables?

2.What will be your control?

3.What will you measure and how?

4.How will you record and graph your data?

Data and Observations

Conduct your investigation and make your
measurements. Graph your results and then enter the
data in a summary table.

Analyze

1. (a)Was the variable you investigated affected by
   coffee?
   (b)If so, how was it affected?
   2.Were your results consistent?
   3.What factors of your population may have affected
   your results?

Conclude and Apply

4.What conclusions can you make about one

physiological response to the intake of coffee?

5.Based on your results, predict what other

measurable effects coffee would have on the

human body.

Exploring Further

6.Using the Internet,

find the results of

various research

studies that

have explored

the positive and

negative effects

of coffee. How

might you account

for the conflicting

conclusions?

Chapter 4 Homeostatic Mechanisms • MHR 119

organ donation. One of the major concerns with the use

of animal organs has been the possibility of transmitting

animal viruses into humans. These fears were somewhat

diminished by a report that showed that none of the

160 people who had received heart valves or other

tissue from pigs had become infected. Concern persists,

however, about potential transfer of viruses.

Pigs are good potential candidates for organ donation.

As you will learn in Chapter 9, the next step in using pigs

as organ donors will be to genetically modify the pig

genome to decrease the risk of rejection after organ

donation. The genetic manipulation of animals is ongoing,

and the creation of transgenic animals (animals that have

genes from more than one species) is producing animals

with new characteristics. Some experts predict that

clinical trials using pig organs as donors for humans

could begin in less than two years.

Follow-up

1.Debate with classmates whether Canada should

adopt an “opting out” policy to increase the number

of cadaveric donors. What problems might this create?

2.Consider the following cost comparison of kidney

transplant versus dialysis. The operation costs

$20 000 and requires $6000 per year in follow-up

treatments. Compare this with the $50 000 per year

required to maintain a patient on dialysis (an artificial

kidney). Over a five-year period, the costs are

$50 000 for the transplant and $250 000 for dialysis.

Kidney transplant operations have a 98 percent

success rate using living donors and a 95 percent

success rate with cadaveric donors. Should a

destitute person be allowed to sell one of his or her

kidneys to avoid starvation? Is this different from a

family member donating a kidney?