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Parts of A Cell, Membrane Dynamics, Enzymes

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

 1. 
As cell size increases, the
a.
volume and surface area decrease.
b.
surface area increases faster than the volume.
c.
volume increases faster than the surface area.
d.
surface area and volume increase at the same rate.
e.
None of the choices are correct.
 

 2. 
Which one of the following is not found in prokaryotic cells?
a.
a capsule
b.
pili
c.
a membrane-bound nucleus
d.
a cell wall
e.
ribosomes
 

 3. 
Unlike animal cells, plant cells have __________ and __________.  Unlike plant cells, animal cells have __________.
a.
chloroplasts . . . cell walls . . . a nucleus
b.
centrioles . . . cell walls . . . large central vacuoles
c.
centrioles . . . chloroplasts . . . cell walls
d.
chloroplasts . . . cell walls . . . centrioles
e.
chloroplasts . . . cell walls . . . cell membranes
 

 4. 
The Golgi apparatus
a.
is composed of stacks of membranous vesicles that are continuous with one another.
b.
is the site of carbohydrate breakdown.
c.
stores, modifies, and packages proteins.
d.
forms fats from glycerols and fatty acids.
e.
strings together amino acids to produce proteins.
 

 5. 
Insulin is a protein that is produced by pancreatic cells and secreted into the bloodstream. Which of the following choices best describes the route of insulin from its production to its exit from the cell?
a.
rough ER, transport vesicles, cell membrane
b.
rough ER, lysosomes, transport vesicles, cell membrane
c.
rough ER, Golgi apparatus, smooth ER, cell membrane
d.
rough ER, transport vesicles, Golgi apparatus, transport vesicles, cell membrane
e.
None of the choices are correct.
 

 6. 
What is the basic difference between exergonic and endergonic reactions?
a.
Exergonic reactions release energy; endergonic reactions absorb it.
b.
Exergonic reactions involve the breaking of bonds; endergonic reactions involve the formation of bonds.
c.
In exergonic reactions, the reactants have less chemical energy than the products; in endergonic reactions, the opposite is true.
d.
Exergonic reactions involve ionic bonds; endergonic reactions involve covalent bonds.
e.
Exergonic reactions involve the formation of bonds; endergonic reactions involve the breaking of bonds.
 

 7. 
When an enzyme catalyzes a reaction,
a.
it acts as a reactant.
b.
it raises the activation energy of the reaction.
c.
it lowers the activation energy of the reaction.
d.
it becomes a product.
e.
None of the choices are correct.
 

 8. 
Which one of the following is false?
a.
An enzyme's function depends on its three-dimensional shape.
b.
Enzymes are very specific for certain substrates.
c.
Enzymes are used up in chemical reactions.
d.
An enzyme binds to its substrate at the enzyme's active site.
e.
Enzymes emerge unchanged from the reactions they catalyze.
 

 9. 
Which one of the following is true?
a.
All enzymes depend on protein cofactors to function.
b.
An enzyme's function is unaffected by changes in pH.
c.
Enzymes are inorganic.
d.
Enzymes catalyze specific reactions.
e.
Enzymes are the reactants in a chemical reaction.
 

 10. 
Small, nonpolar, hydrophobic molecules such as fatty acids
a.
easily pass through a membrane's lipid bilayer.
b.
require transport proteins to pass through a membrane's lipid bilayer.
c.
usually enter the cell via endocytosis.
d.
very slowly diffuse through a membrane's lipid bilayer.
e.
are actively transported across cell membranes.
 

 11. 
If placed in tap water, an animal cell will undergo lysis, whereas a plant cell will not. What accounts for this difference?
a.
the relative impermeability of the plant cell wall to water
b.
the relative impermeability of the plant cell membrane to water
c.
the fact that plant cells are isotonic to tap water
d.
the relative inelasticity and strength of the plant cell wall
e.
expulsion of water by the plant cell's central vacuole
 

 12. 
Certain cells that line the stomach synthesize a digestive enzyme and secrete it into the stomach. This enzyme is a protein. Which of the following processes could be responsible for its secretion?
a.
exocytosis
b.
endocytosis
c.
pinocytosis
d.
diffusion
e.
passive transport
 
 
The two images below both show the structure of the cell membrane composed of two layers of phospholipids.  Recall the chemical characteristics of a phospholipid and its role in the function of the membrane.  The labels (numbers 1 through 5) for the two diagrams correspond to the same “part” of the two diagrams. 
nar001-1.jpg
 

 13. 
Which of the labeled regions identifies a single phospholipid molecule?
a.
1
b.
2
c.
3
d.
4
e.
5
 

 14. 
Which region of the lipid bilayer is responsible for preventing polar molecules from freely passing through?  Choose the answer that identifies the correct region along with the best explanation for this characteristic of the lipid bilayer.
a.
3.  The nonpolar fatty acids chains prevents polar molecules from passing through.
b.
3.  The polar phosphate heads interact with polar molecules, preventing them from passing through.
c.
3.  The polar fatty acids chains interact with polar molecules, preventing them from passing through.
d.
4.  The polar phosphate heads interact with polar molecules, preventing them from passing through.
e.
4.  The polar fatty acids chains interact with polar molecules, preventing them from passing through.
 
 
Answer the following questions based on the diagram below.  1, 2, and 3 represent the process.  4 and 5 represents the highlighted structure.
nar002-1.jpg
 

 15. 
Which part(s) of the diagram represents facilitated diffusion?
a.
1
b.
2
c.
3
d.
Both 1 and 2
e.
All 1, 2, and 3
 

 16. 
Which part(s) of the diagram represents a type of passive transport?
a.
1
b.
2
c.
3
d.
Both 1 and 2
e.
All 1, 2, 3
 

 17. 
Which part of the diagram represents a type of transport that is able to establish an area of higher solute concentration by moving molecules against a concentration gradient?
a.
1
b.
2
c.
3
d.
All 1, 2, and 3
e.
None of the above
 

 18. 
The structures labeled (4) and (5)
a.
are types of proteins.
b.
are channel proteins.
c.
contain hydrophobic amino acids that help the remain stabilized in the lipid bilayer.
d.
are made up of amino acids.
e.
All of the above.
 
 
Answer the following questions based on the diagram below and your understanding of the mechanisms of diffusion and osmosis.  It will help to recall the observations made during the diffusion lab.

A beaker is set up with the following initial conditions.  The bag in the beaker is made up of dialysis tubing. 
nar003-1.jpg
 

 19. 
Starch is not able to pass through this membrane; IKI, glucose, sucrose, and water can.  Which of the following will be false?
a.
After 60 minutes, only the water in the beaker will be stained a dark black.
b.
After 60 minutes, only the water in the bag will be stained black.
c.
After 60 minutes, the IKI will diffuse into the bag.
d.
After 60 minutes, both the water in the beaker and the bag will test positive with Benedicts.
e.
The water initially placed in the beaker will test positive for Benedicts.
 

 20. 
Imagine the same experimental setup as the earlier question.  In this experiment, both starch and sucrose are not able to pass through the membrane.  IKI, glucose, and water can still pass through.

Which of the following will be true about the appearance and characteristics of the system after 60 minutes?
a.
The water in the beaker will show a positive IKI test.
b.
The water inside the bag will test negative with Benedicts.
c.
There will be a net movement of water into the bag.
d.
There will be a net movement of water out of the bag.
e.
There will be no net movement of water between the bag and the beaker.
 
 

Answer the following questions using the diagram below.  Each question may require you to make different assumptions for the conditions represented in the diagram.  Read the question carefully before selecting an answer.
nar004-1.jpg
 

 21. 
The dialysis bag is filled with 20% sucrose solution.  Which beaker contains a solution that is hypotonic to the solution inside the dialysis bag?
a.
Beaker 1
b.
Beaker 2
c.
Beaker 3
d.
Both beaker 2 and 3
e.
Not enough information to determine
 

 22. 
The dialysis bag is filled with a 20% glucose solution.  Glucose is able to pass through the dialysis membrane.  Which of the three beakers would resemble the appearance of the bag after being placed in pure water for 30 minutes?
a.
Beaker 1
b.
Beaker 2
c.
Beaker 3
d.
None of the above
e.
Not enough information to determine
 

 23. 
The process seen here is the movement of water across a selectively permeable membrane because of a difference in solute concentration.  This is called:
a.
Osmosis.
b.
Active transport.
c.
Endocytosis.
d.
Bulk transport.
e.
Mass transit.
 
 
nar005-1.jpg
 

 24. 
The lipid embrane functions as the boundary for many intracellular structures as well as the boundary for the cell itself. Many structures within the lipid bilayer function to help the cell membrane’s regulatory function. Which of the labeled structures would function in transport of polar molecules into the cell?
a.
7
b.
4
c.
6
d.
3
e.
5
 

 25. 
Which of the identified parts corresponds to glycolipid?
a.
1
b.
2
c.
3
d.
4
e.
6
 

 26. 
Which structures of the lipid membrane labeled above are involved in membrane stabilization?
a.
8
b.
7
c.
6
d.
4
e.
5
 

 27. 
Identify which identified parts of the image corresponds to the term “phospholipid”?
a.
8
b.
7
c.
5
d.
4
e.
3
 
 
nar006-1.jpg
 

 28. 
Using the graph above, the average mass of the potato core soaked in pure water tends to
a.
gain mass
d.
lose water
b.
lose mass
e.
both a and c
c.
gain water
f.
both b and d
 

 29. 
The potato cores in ..25 M concentration of sucrose are said to be in  ----.
a.
isotonic solution since they lose mass
b.
hypotonic solution since they gain mass
c.
hypertonic solution since the lose mass
d.
saline solution since the cores gain mass
e.
both b and d are correct
 

 30. 
Which of the following statement(s)  is/are correct?
a.
The area marked A is referring to a hypertonic solution
b.
The area marked B is referring to an isotonic solution
c.
The area marked C is referred to as a weak solution
d.
The area marked D is referred to as a hypertonic solution
e.
Both B and D are corrent
 



 
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