AP Bio Unit 2
Which of the following is evidence that eukaryotes and prokaryotes share a common ancestor?
All eukaryotes and prokaryotes contain ribosomes.
Which of the following best explains how the extensive folding of the inner mitochondrial membrane benefits a eukaryotic cell?
It increases the area available for proteins involved in energy transfer.
The manner in which several different ions and molecules move through a cell membrane is shown in the diagram below. For each ion or molecule, the relative concentration on each side of the membrane is indicated. Which of the following accurately describes one of the movements taking place?
Na⁺ transport out of the cell requires ATP hydrolysis.
The figure shows a representation of a protein embedded in a cell membrane. The numbers indicate different structural regions of the protein. Based on the figure, which of the following statements best describes the relationship between regions 1 and 2 of the protein?
Region 1 is hydrophilic because it interacts with an aqueous environment, whereas region 2 is hydrophobic because it interacts with the interior of the membrane.
Paramecia are unicellular protists that have contractile vacuoles to remove excess intracellular water. In an experimental investigation, paramecia were placed in salt solutions of increasing osmolarity. The rate at which the contractile vacuole contracted to pump out excess water was determined and plotted against osmolarity of the solutions, as shown in the graph. Which of the following is the correct explanation for the data?
The contraction rate increases as the osmolarity decreases because the amount of water entering the paramecia by osmosis increases.
How do unsaturated fatty acids help keep any membrane more fluid at lower temperatures?
The double bonds form kinks in the fatty acid tails that prevent adjacent lipids from packing tightly together.
An accident victim has lost a lot of blood due to a serious injury. Replacement of the lost body fluids with distilled water would have which of the following results?
The patient's red blood cells will swell and lyse because the blood fluid has become hypotonic compared to the cells.
Which of the following best explains how the phospholipid bilayer of a transport vesicle contributes to cellular functions?
The phospholipid bilayer allows the vesicle to fuse with the Golgi apparatus and the plasma membrane, allowing the exocytosis of proteins.
The primary function of the kidney is to exchange molecules across a membrane between the blood and the urine. One type of kidney cell has a basic rectangular shape, except for a single surface, which is lined with tiny, finger-like projections that extend into the surrounding extracellular space. Which of the following best explains the advantage these projections provide the cell?
The projections increase the surface area-to-volume ratio of the cell, which allows for more efficient nutrient exchange with the environment.
Which of the following transport mechanisms will be affected most directly by a temporary shortage of ATP molecules inside the cell?
The transport of glucose molecules against a concentration gradient.
A scientist designed an experiment to test an artificial membrane that mimics the phospholipid bilayer of a cell. The scientist built a tube that was divided by an artificial membrane and filled with distilled water. The scientist put a known amount of a protein into the water on one side of the membrane. After some time, the scientist measured the concentration of the protein on either side of the membrane but found that there had been no change. Which of the following experimental changes would allow the scientist to observe transport of a solute across the artificial membrane?
Use a small, nonpolar solute instead of a protein.
14. Which of the following molecules would you expect to diffuse through the lipid bilayer of a plasma membrane most slowly, if at all?
an amino acid
The figure below shows a series of microscope images taken over time of ovalbumin production in chick oviduct cells in response to stimulation with estrogen. The ovalbumin protein was detected using a fluorescent dye as shown by the white areas in the time-lapse sequence. The microscope images indicate that ovalbumin
crosses the endoplasmic reticulum membrane as it is translated, then moves to the Golgi apparatus, then to vesicles from which it is secreted.
The movement of the hydrophobic (nonpolar) gas nitrous oxide (N₂O), also known as laughing gas, into a cell is an example of
diffusion through the lipid bilayer.
Which of the following structures will be found in nearly all eukaryotic cells?
mitochondria
The total volume of plant cells is often significantly greater than the total volume in animal cells. The most reasonable explanation for this observation is that
plant cells contain a large vacuole that occupies much of the volume of the cell
Which of the following correctly describes the pathway taken by a protein destined for secretion from an animal cell?
rough ER --> transport vesicle --> Golgi apparatus --> transport vesicle --> plasma membrane
12. What kinds of molecules pass through a cell membrane most easily?
small nonpolar