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WorksheetsBIO 181 Chapter 7
Total questions: 12
Worksheet time: 6mins
Which best describes a biological membrane?
two layers of phospholipids with proteins embedded between the two layers
a mixture of covalently linked phospholipids and proteins that determines which solutes can cross the membrane and which cannot
two layers of phospholipids with proteins either spanning the layers or on the surface of the layers
a fluid structure in which phospholipids and proteins move freely between sides of the membrane
Which statement about osmosis is correct?
If a cell is placed in an isotonic solution, more water will enter the cell than leaves the cell.
Osmotic movement of water into a cell would likely occur if the cell accumulates water from its environment.
The presence of aquaporins (proteins that form water channels in the membrane) should speed up the process of osmosis.
If a solution outside the cell is hypertonic compared to the cytoplasm, water will move into the cell by osmosis.
Which molecule will diffuse most quickly across a lipid bilayer membrane?
H2O
O2
H2PO4–
glucose
Na+
Cells such as bacteria are taken up by other cells such as white blood cells by which mechanism?
pinocytosis
exocytosis
receptor-mediated endocytosis
phagocytosis
facilitated diffusion
Two solutions with similar solute concentrations are separated by a membrane that only water can pass through. One solution (B) is of greater volume than the other (A). What will happen next?
The pressure gradient will drive water to A, which will cause the solute concentration of B to increase.
Water will pass to B, increasing its volume.
Any water that passes to A will create a tension on B, pulling the water back.
The water will flow to A, down its pressure gradient, until the two sides achieve equal height.
Since there is no concentration gradient present, there will be no net movement of water.
A correct distinction between facilitated diffusion and active transport is that
active transport requires conformational changes in the transport protein associated with the transport process, and facilitated diffusion does not.
active transport requires an integral membrane protein to carry out the transport, and facilitated diffusion does not.
facilitated diffusion requires a protein-lined pore in the membrane, and active transport does not.
facilitated diffusion depends on an existing energy gradient acting on the transported substance, while active transport makes such a gradient.
A cell that has a contractile vacuole is likely, at times, to have
too much membrane.
too much water.
too much salt.
too little pigment.
none of the above.
You are studying a pump protein in the lab. What should you order to make sure that the pump will operate?
salt
glucose
DNA
pure water
ATP
You are studying a unicellular eukaryote recently discovered in pond water, and you notice that it contains many coated vesicles. Immunological studies show that the vesicles mostly lack transmembrane proteins. These cells probably do a lot of
pumping
pinocytosis
receptor-mediated endocytosis.
phagocytosis
b and c
Which part of the cell is most crucial for getting membrane proteins to their proper location?
plasma membrane
mitochondrion
chloroplast
Golgi apparatus
lysosome
After an hour, a freshwater unicellular eukaryote dropped into seawater will be
plasmolyzed
swollen
unchanged
a or b; you can’t tell from the question.
How is a brick starting to fall from the fourth floor of a building most like a glucose molecule in a cell containing lots of glucose that is about to exit the cell?
The brick needs a carrier.
Both are moving down a potential energy gradient.
Both are needed to build things.
Both have mass.
