Ch 1-8 Test essays:
1.
Suppose
that you have isolated an extract from a tissue and you have found that
the extract speeds up the rate of a
particular reaction. What kind of information would
you need to demonstrate that the
substance responsible for increasing the rate of
this reaction is an enzyme?
Explain how this information would indicate that
the catalytic effect is due to an enzyme.
2. Witnesses in a court of law are asked to "swear to tell the truth, the whole truth and nothing but the truth" What are the problems inherent in this statement? How do laws in science differ from legal laws? What factors lead to "junk science"?
3. After
an enzyme is mixed with its substrate, the amount of product formed is
determined at 10-second intervals for 1
minute. Data from this experiment
are shown below:
|
Time (sec) |
0 |
10 |
20 |
30 |
40 |
50 |
60 |
|
Product formed (mg) |
0.00 |
0.25 |
0.50 |
0.70 |
0.80 |
0.85 |
0.85 |
Draw
a graph of these data and answer the following questions.
a. What
is the initial rate of this enzymatic reaction?
b. What
is the rate after 50 seconds? Why is it different from the
initial rate?
c. What
would be the effect on product formation if the enzyme were
heated to a temperature of 100 oC for 10 minutes before
repeating
the experiment? Why?
d. How
might altering the substrate concentration affect the rate of
the reaction? Why?
e. How
might altering the pH affect the rate of reaction? Why?
4. The unique properties of water make life possible on earth. Select three (3) properties of water and:
a)
for each property,
identify/define the
property and explain it in terms of the physical/ chemical nature of
water.
b) for each property, describe one
(1) example of how the property affects the functioning of living
organisms.
5.
Membranes
are important structural features of cells.
(b)
Describe the
role of membranes in the synthesis of ATP in either
cellular respiration or
photosynthesis.
6.
A laboratory assistant prepared solutions of 0.8 M, 0.6 M, 0.4 M, and
0.2 M sucrose, but forgot to label them. After
realizing the error, the
assistant
randomly labeled the flasks
containing these four unknown solutions as flask A, flask B, flask C,
and flask D.
Design
an experiment, based on the principles of diffusion and osmosis,
that the
assistant could use to determine which
of the flasks contains each of the four unknown solutions.
Include in your
answer
(a) a description of
how you would set up and perform the experiment;
(b) the results you
would expect from your experiment;and
(c) an explanation
of those results based on the principles involved.
(Be sure to clearly
state the principles addressed in your discussion.)