Study Guide QUESTIONS AND
CORRECT ANSWERS
Researchers claimed that a particular organelle originated from a free-living
prokaryotic cell that was engulfed by a larger cell, as shown in Figure 1.
Figure 1. A model showing a cell engulfing a smaller cell
Which of the following provides evidence to best support the researchers'
claim? - CORRECT ANSWERS The organelle has a double membrane.
The illustration shows the active transport of hydrogen ions through a
membrane protein.
Which of the following best predicts the effect of not having ATP available to
supply energy to this process? - CORRECT ANSWERS H+ ions will
stop moving through the protein.
The active transport pump used to move sodium ions across the membranes of
gill cells in a freshwater fish has each of the following characteristics EXCEPT:
- CORRECT ANSWERS The active transport pump used to move
sodium ions across the membranes of gill cells in a freshwater fish has each of
the following characteristics EXCEPT:
Figure 1 shows a model of how a channel protein influences the movement of a
particle across a cell's plasma membrane.
Figure 1. A section of a cell's plasma membrane, showing a channel protein and
a concentration gradient across the membrane
An investigator wants to understand whether a newly found membrane protein
is involved in membrane transport of a certain particle.
, Which investigation will help determine whether the new membrane protein is a
channel protein involved in membrane transport? - CORRECT ANSWERS
Add more of the proteins to the plasma membrane and measure the rate
of the particle movement.
Aquaporins are channel proteins that facilitate the transport of water across the
cell membrane. One group of researchers hypothesizes that without functional
aquaporins, no water will be able to enter the cell. A different group proposes an
alternative hypothesis, stating that even with nonfunctional aquaporins, a small
amount of water will still cross the cell membrane. An experiment is set up in
which plant cells with mutated (nonfunctional) aquaporins and plant cells with
normally functioning aquaporins are both placed in distilled water.
Which of the following data would support the alternative hypothesis? -
CORRECT ANSWERS Cells with mutated aquaporins exhibit moderate
turgor pressure and are hypertonic.
Which of the following components of the cell membrane is responsible for
active transport? - CORRECT ANSWERS Protein
Plant cell walls are composed of cellulose, while fungal cell walls are composed
of chitin. A group of scientists hypothesize that this difference means the cell
wall has largely different functions in plant cells and fungal cells. Alternatively,
another group of scientists hypothesize that despite their biochemical
differences, plant and fungal cell walls serve similar functions.
Which of the following observations would best support the alternative
hypothesis described above? - CORRECT ANSWERS In both plant cells
and fungal cells, the cell wall surrounds the outside of the cell membrane.
When a substance moves across the plasma membrane along a concentration
gradient at a rate faster than would be expected by simple diffusion alone but