Passage 1 A group of scientists discovered that a strain of bacteria,
Bacteria P, grows under previously unconsidered conditions.
The cells of Bacteria P grow colonies when incubated for
48 hours on a growth medium with a pH of 7 in a controlled
environment of 15°C and an o, concentration of 15%. To
determine whether these conditions are optimal, a researcher
а
performed an experiment, varying the pH levels of the growth
medium and the incubation temperatures and O, concentration
of the controlled environment. In every trial, Bacteria P cells
were incubated for 48 hours, and colony growth was measured
by comparing the surface area coverage (SAC) on the growth
material (see the table).
2. How did increasing the incubation temperature of the
controlled environment from 10°C to 15 °C affect the SAC
when Bacteria P cells were exposed to an 0, concentration
of 15% and a pH of 9 ? When the incubation temperature
was increased from 10°C to 15 °C, the SAC:
F. increased; the SAC for Trial 10 was 7% and the SAC
for Trial 4 was 9%.
G. increased; the SAC for Trial 5 was 9% and the SAC for
Trial 11 was 15%.
H. decreased; the SAC for Trial 10 was 9% and the SAC
for Trial 4 was 7%.
J. decreased; the SAC for Trial 5 was 15% and the SAC
for Trial 11 was 9%.
Controlled environment
Growth
material
3. Which of the growth conditions varied among Trials 7-9 ?
A. Incubation temperature only
B. Oxygen concentration only
C. pH only
D. Oxygen concentration and pH only
Trial
SAC
02
concentration
pH
7
yo
1
2
3
4
5
6
7
8
9
Incubation
temperature
(°C)
10
10
10
10
10
10
15
15
15
15
15
15
11
7
9
11
4. One scientist predicted that the SAC for Bacteria P would
be the lowest when the bacteria were incubated at 15°C and
exposed to an 0, concentration of 10% with a pH of 7. Is
her prediction consistent with the results in the table?
F. No; the SAC for Bacteria P was the lowest in Trial 2.
G. No; the SAC for Bacteria P was the lowest in Trial 10
H. Yes, the SAC for Bacteria P was the lowest in Trial 2.
J. Yes; the SAC for Bacteria P was the lowest in Trial 10.
10%
10%
10%
15%
15%
15%
10%
10%
10%
15%
15%
15%
11%
19%
13%
9%
15%
11%
8%
15%
11%
6%
9%
7%
10
11
12
这些
9
11
7
9
11
5. The controlled environments used in Trial 2 and Trial 5
differed in which of the following ways?
A. The pH of Trial 2 was more acidic than the pH of
Trial 5.
B. The pH of Trial 5 was more acidic than the pH of
Trial 2.
C. The O, concentration of Trial 2 was greater than the O,
concentration of Trial 5.
D. The O, concentration of Trial 5 was greater than the 0,
concentration of Trial 2
1. To determine whether decreasing the O, concentration in
the controlled environment decreases the SAC of Bacteria
P, the scientists should compare the results of which of the
following 2 trials?
A. Trial 4 and Trial 1
B. Trial 4 and Trial 3
C. Trial 2 and Trial 3
D. Trial 11 and Trial 9