Activity
1. Anticipatory
set for this activity is the question: Are chickens susceptible
to anthrax? (The answer is no,
because their body temperature is too high (41 – 45
degrees Celsius) for the anthrax to survive. The body temperature
of humans is 37 degrees Celsius. The students will not
be given the answer until they complete the activity.
2. The class will be divided up into 6 groups of four
and given instructions for how the activity will proceed.
3. Each group will be given an apple and a freshly cut
section of an apple. They will also be supplied with a
1000mL beaker filled with 500mL of water and 10 drops of
food coloring.
4. The first segment of this investigation is for the
students to place the whole apple and the freshly cut section
in the beaker for 10 minutes (while they are waiting they
can set up the other experiment involving the yeast). The
purpose of this activity is to determine how these two
apples will be affected when they are placed in the beaker.
5. The students will be asked to form a hypothesis based
upon prior observations outside the class, write the procedure
and record their observations (the students can use a plastic
knife in order to cut into the apples and make better observations).
6. The students must record their observations and note
whether the whole apple and the cut-up section experiences
any color change. Students should address whether their
initial hypothesis was supported or rejected.
7. The second portion of this activity requires students
to determine the effects that temperature and pH have on
yeast mortality (the students must first have an understanding
of cellular respiration and alcoholic fermentation).
8. Each group will be given 3 zip lock bags with an equal
amount of yeast and sugar in them.
9. They will
be asked to collect 100mL of boiling water from the hot
water bath using a 250mL beaker with the instructor’s
assistance. They will also collect 100mL of lukewarm water
from a water bath that is regulated at 80 degrees Fahrenheit
plus 100mL of vinegar.
10. Each of these beakers will be poured carefully into
one of each of the zip lock bags, and the bags will then
be sealed.
11. After 10 minutes have elapsed; the students will make
observations about the viability of the yeast on these
three bags. Cellular respiration hopefully was covered
earlier in the year, but if not this would be an opportunity
to begin to introduce it.
12. After all of their observations and conclusions have
been recorded, the groups will share their results as a
class.
13. This discussion will be used to develop an understanding
for innate immunity and its four component defenses which
are: anatomic barriers (skin and mucous), physiologic barriers
(temperature, pH, and chemical mediators), phagocytic barriers
(specialized cells), and inflammatory barriers (leakage
of vascular fluids). Guide the discussion to address the
connection between the exercises that the students performed
and the four component defenses of innate immunity.
Closure
The students will be reminded of the question they were
asked at the beginning of the class regarding chickens
and their susceptibility to anthrax. Chickens have evolved
in such a way that they have innate immune protection against
anthrax because their body temperature is too high for
anthrax to survive.
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