Name: 
 

pretest



Multiple Choice
Identify the choice that best completes the statement or answers the question.
 

 1. 

Which of the following correctly lists the order in which cellular components will be found in the pellet when homogenized cells are treated with increasingly rapid spins in a centrifuge?
a.
ribosomes, nucleus, mitochondria
b.
chloroplasts, ribosomes, vacuoles
c.
nucleus, ribosomes, chloroplasts
d.
vacuoles, ribosomes, nucleus
e.
nucleus, mitochondria, ribosomes
 

 2. 

Under which of the following conditions would you expect to find a cell with a predominance of free ribosomes?
a.
a cell that is secreting proteins
b.
a cell that is producing cytoplasmic enzymes
c.
a cell that is constructing its cell wall or extracellular matrix
d.
a cell that is digesting food particles
e.
a cell that is enlarging its vacuole
 

 3. 

Which of the following is a compartment that often takes up much of the volume of a plant cell?
a.
lysosome
b.
vacuole
c.
mitochondrion
d.
Golgi apparatus
e.
peroxisome
 

 4. 

Motor proteins provide for molecular motion in cells by interacting with what types of cellular structures?
a.
sites of energy production in cellular respiration
b.
membrane proteins
c.
ribosomes
d.
cytoskeletons
e.
cellulose fibers in the cell wall
 

 5. 

When biological membranes are frozen and then fractured, they tend to break along the middle of the bilayer. The best explanation for this is that
a.
the integral membrane proteins are not strong enough to hold the bilayer together.
b.
water that is present in the middle of the bilayer freezes and is easily fractured.
c.
hydrophilic interactions between the opposite membrane surfaces are destroyed on freezing.
d.
the carbon-carbon bonds of the phospholipid tails are easily broken.
e.
the hydrophobic interactions that hold the membrane together are weakest at this point.
 

 6. 

Which of the following is one of the ways that the membranes of winter wheat are able to remain fluid when it is extremely cold?
a.
by increasing the percentage of unsaturated phospholipids in the membrane
b.
by increasing the percentage of cholesterol molecules in the membrane
c.
by decreasing the number of hydrophobic proteins in the membrane
d.
by co-transport of glucose and hydrogen
e.
by using active transport
 

 7. 

Which of the following span the phospholipids bilayer, usually a number of times?
a.
transmembrane proteins
b.
integral proteins
c.
peripheral proteins
d.
integrins
e.
glycoproteins
 

 8. 

Which of the following is a characteristic feature of a carrier protein in a plasma membrane?
a.
It is a peripheral membrane protein.
b.
It exhibits a specificity for a particular type of molecule.
c.
It requires the expenditure of cellular energy to function.
d.
It works against diffusion.
e.
It has few, if any, hydrophobic amino acids.
 
 
Use the diagram of the U-tube in Figure 7.2 to answer the questions that follow.

The solutions in the two arms of this U-tube are separated by a membrane that is permeable to water and glucose but not to sucrose. Side A is half filled with a solution of 2 M sucrose and 1 M glucose. Side B is half filled with 1 M sucrose and 2 M glucose. Initially, the liquid levels on both sides are equal.

nar001-1.jpg

Figure 7.2
 

 9. 

Celery stalks that are immersed in fresh water for several hours become stiff and hard. Similar stalks left in a salt solution become limp and soft. From this we can deduce that the cells of the celery stalks are
a.
hypotonic to both fresh water and the salt solution.
b.
hypertonic to both fresh water and the salt solution.
c.
hypertonic to fresh water but hypotonic to the salt solution.
d.
hypotonic to fresh water but hypertonic to the salt solution.
e.
isotonic with fresh water but hypotonic to the salt solution.
 

 10. 

Glucose diffuses slowly through artificial phospholipid bilayers. The cells lining the small intestine, however, rapidly move large quantities of glucose from the glucose-rich food into their glucose-poor cytoplasm. Using this information, which transport mechanism is most probably functioning in the intestinal cells?
a.
simple diffusion
b.
phagocytosis
c.
active transport pumps
d.
exocytosis
e.
facilitated diffusion
 

 11. 

In order for a protein to be an integral membrane protein it would have to be which of the following?
a.
hydrophilic
b.
hydrophobic
c.
amphipathic
d.
completely covered with phospholipids
e.
exposed on only one surface of the membrane
 

 12. 

You are working on a team that is designing a new drug. In order for this drug to work, it must enter the cytoplasm of specific target cells. Which of the following would be a factor that determines whether the molecule enters the cell?
a.
blood or tissue type of the patient
b.
non-polarity of the drug molecule
c.
lack of charge on the drug molecule
d.
similarity of the drug molecule to other molecules transported by the target cells
e.
lipid composition of the target cells' plasma membrane
 

 13. 

When a plant cell, such as one from a peony stem, is submerged in a very hypotonic solution, what is likely to occur?
a.
the cell will burst
b.
the cell membrane will lyse
c.
plasmolysis will shrink the interior
d.
the cell will become flaccid
e.
the cell will become turgid
 



 
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