Life Science Exam

Front 1

Students in a science class measure the
heights of plant specimens and record
their measurements to the nearest centimeter.
The students then use calculators
to determine the average height of the
plants. The teacher notices that many
students write down averages that extend
to tenths or hundredths of centimeters
and asks them to round the averages only
to the nearest centimeter. Which of the
following statements is the best explanation
of why students should round their
averages to the nearest centimeter?

Back 1

Calculations based on the measurements
of plant height can be only
as precise as the original measurements.

Front 2

As part of a project on the effects of
pollution on ecosystems, students in a
science class measure air, soil, and water
quality in the area surrounding the school.
They also make daily counts of various
animal and plant species in the area.
Which of the following types of computer
software would be most useful for storing
and analyzing the students' data?

Back 2

spreadsheet software

Front 3

A researcher has documented a decline in
the population of wood frogs in an area in
which bullfrogs have been introduced.
According to the researcher's data, the
wood frog population began to decline
soon after the introduction of the bullfrogs,
and the decline has accelerated
since the bullfrog population began
growing more rapidly. The researcher
notes that bullfrogs are much larger and
more aggressive than wood frogs and
concludes that the wood frogs are being
driven from their breeding areas. This
conclusion is questionable because the
researcher:

Back 3

has not shown a causal relationship
between the establishment of the
bullfrog population and the decline
of the wood frog population.

Front 4

Which of the following is one of the most
important principles guiding the ethical
conduct of research with human subjects?

Back 4

Before beginning the study, subjects
must be informed of any known
risks associated with participation.

Front 5

Sucrase is an enzyme that catalyzes only
one particular reaction, the splitting of
sucrose molecules into glucose and fructose.
Sucrase recognizes sucrose as its
substrate, distinguishing it even from
other closely related sugar molecules.
This specificity depends on which
of the following?

Back 5

the fit between the shape of the
sucrase molecule's active site and
the shape of the sucrose molecule

Front 6

Given the experimental results described
above, it is most likely that the holdfast
contains a:

Back 6

chloroplast.

Front 7

Asking students to perform the experiment
with Acetabularia is most likely to be
useful if the students have some prior
knowledge of:

Back 7

the mechanisms of genetic control
of cellular activity.

Front 8

After students complete the experiment,
which of the following questions would
be most likely to stimulate higher-level
thinking about the experimental results?

Back 8

Why does the first cap that
regenerates have characteristics
of both species

Front 9

One difference between aerobic and
anaerobic respiration is that:

Back 9

net energy from aerobic respiration
is higher than net energy from
anaerobic respiration.

Front 10

Which of the following statements best
describes how oxygen moves from the
bloodstream into the cells where it is used
in metabolic processes?

Back 10

Oxygen diffuses passively into the
cells without the expenditure of
energy.

Front 11

Which of the following examples best
illustrates that cellular differentiation is,
in certain instances, a reversible process?

Back 11

In some animals, body parts that are
lost from injury can be regenerated.

Front 12

It has been observed that a prolonged
episode of malnutrition has more severe
and less reversible effects on human brain
development if it occurs during the first
year after birth, compared to an episode
that occurs later in infancy or childhood.
Which of the following is the most likely
explanation for this observation?

Back 12

Brain cells continue to divide
rapidly during the first year after
birth, while active cell division
slows markedly after this time

Front 13

Step 1: X attaches itself to the surface
of a cell.
Step 2: It then injects its own genetic
material into the cell.
Step 3: This destroys the host cell's
genetic material.
Step 4: The genetic material of X
reprograms the host cell's
metabolic activities to make
multiple copies of X.
Step 5: The host cell then breaks
open, releasing

Back 13

virus

Front 14

A team of researchers has isolated a
chemical from a tropical tree that causes
insects to die when they ingest it. The
researchers determine that the chemical
deactivates the enzyme RNA polymerase.
This chemical likely causes the insects to
die by interfering directly with:

Back 14

transcription of RNA from the DNA
template.

Front 15

When red-flowered snapdragons are
crossed with white-flowered snapdragons,
all of the offspring have pink flowers.
When these pink-flowered snapdragons
are crossed, one-fourth of the F2 offspring
will be have red flowers, one-fourth will
have white flowers, and one-half will have
pink flowers. This pattern of inheritance
is most likely due to:

Back 15

incomplete dominance of either the
red or the white allele.

Front 16

In 1909, Karl Correns found that the
presence or absence of white or yellow
patches on the leaves of an otherwise
green plant was determined only by the
maternal parent. Which of the following
is the most likely explanation for this
observation?

Back 16

The gene for colored patches is
located in DNA found in the
plastids of the cell rather than in
the nucleus.

Front 17

Geospiza fuliginosa and Geospiza fortis
are species of Galápagos finch with overlapping
ranges. When only one of the
two species is found on an island, it has
a medium-sized beak. However, on
islands where both species are found,
G. fuliginosa has a smaller beak and
G. fortis a larger one. This phenomenon
is an example of:

Back 17

character displacement.

Front 18

Which of the following is the best
example of the effects of diversifying
selection?

Back 18

In regions where malaria is
endemic, individuals who are
heterozygous for the sickle cell
allele are more fit than either
homozygote.

Front 19

In the study of evolution, which of
the following observations is likely to
provide evidence in favor of the theory
of punctuated equilibrium?

Back 19

A subpopulation that becomes
geographically isolated from its
parent population often undergoes
rapid genetic change.

Front 20

Which of the following adaptations was
most essential for enabling aquatic algae
to evolve into plants capable of surviving
in a variety of terrestrial environments?

Back 20

the development of vascular tissue
that transports water and nutrients

Front 21

Which of the following is the most
accurate method for classifying two
organisms according to their degree
of relationship?

Back 21

Compare similarities and
differences in the DNA of
both organisms.

Front 22

A biologist has hypothesized that a
structure in the digestive tract of birds is
homologous to a structure in the digestive
tract of certain mammals. Which of the
following findings would provide the best
evidence in favor of this view?

Back 22

The two structures appear almost
identical at an early stage of
embryonic development.

Front 23

On a class field trip, students encounter
some brightly colored shelf-like structures
attached to the trunk of a dead
tree. Which of the following is the
best description of how this organism
obtains matter and energy from its
environment?

Back 23

It obtains energy, carbon, and
water from the dead wood.

Front 24

Human vegetarians who do not eat any
animal products must pay close attention
to their diet because:

Back 24

no single plant species provides all
of the amino acids essential for
building proteins.

Front 25

A scientist recruits human volunteers to
spend several weeks as experimental
subjects in her lab. The subjects will stay
in a windowless area with no access to
clocks or watches. Their activities will be
unstructured, and they will be free to eat,
sleep, and exercise whenever they choose.
A likely purpose of this experiment is to
determine whether:

Back 25

the human wake/sleep cycle is
regulated by internal or external
signals.

Front 26

In various species of mammal, if a mother
and her offspring are kept apart for a brief
period after birth and then reunited, the
mother will then reject the offspring. The
likely function of this rejection by the
mother is to:

Back 26

decrease the probability that she will
expend resources raising offspring
that are not her own.

Front 27

An ethologist wishes to investigate the
relative importance of innate and learned
components of canine behavior. Which
of the following criteria can be used to
distinguish innate behaviors from learned
behaviors?

Back 27

the success with which the behavior
is performed the first time it is
attempted

Front 28

When an agricultural field is abandoned,
it usually undergoes ecological succession
involving a sequence of changes in
vegetation. In most of North America,
species of pine tree tend to be characteristic
of early stages of succession,
while hardwoods such as oak, beech,
and maple are more often found in later
stages. Which of the following best
explains this pattern of succession?

Back 28

Pine seeds and seedlings germinate
and grow more rapidly in open,
sunny areas. The shade from the
mature pine trees eventually favors
the establishment and growth of the
shade-tolerant hardwood species.