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Test 2: Cell Transport & Structure

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

 1. 
A cell is exposed to a substance that prevents it from dividing. The cell becomes larger and larger. This situation
a.
will eventually be problematic since the cell's ability to absorb nutrients through its outer membrane will not keep increasing as quickly as its cytoplasmic needs.
b.
should present no problem to the cell since it can continue to perform all other necessary functions.
c.
should present no problem to the cell because the surface area of the cell will increase as the volume of the cell increases and provide the necessary amount of nutrients for top functioning.
d.
should be beneficial since the cell will be able to divert the ATP normally used for cell division to other processes.
e.
None of the choices are correct.
 

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

 3. 
You are told that the cells on a microscope slide are plant, animal, or bacterial. You look at them through a microscope and see cell walls and membrane-bound organelles. You conclude that the cells
a.
could be either plant or bacterial.
b.
could be plant, animal, or bacterial.
c.
are animal cells.
d.
are plant cells.
e.
are bacteria.
 

 4. 
The Endosymbiotic Theory states that at certain periods in history two types of prokaryotic cells were engulfed that later evolved into the mitochondria and chloroplast. What evidence do scientists hold to support this theory?
a.
Both organelles contain circular DNA
b.
Both organelles have ribosomes similar to those in bacteria
c.
Both organlles have the same shape as bacteria
d.
a and b
e.
a, b, and c
 

 5. 
In eukaryotic cells, internal membranes
a.
provide additional area where many metabolic processes occur.
b.
form membranous compartments called organelles.
c.
greatly increase a cell's total membrane area.
d.
contain proteins essential for metabolic processes.
e.
All of the choices are correct.
 

 6. 
Which one of the following statements is false? The endomembrane system
a.
includes the rough and smooth endoplasmic reticulum.
b.
includes the nuclear envelope.
c.
is a system of interrelated membranes that are all physically connected.
d.
is involved in the synthesis, storage, and export of important molecules.
e.
divides the cell into compartments.
 

 7. 
Hair is a remarkable structure made up of the protein keratin. These hair cells thus contain a lot of __________.  The cells that produce the oils that coat the hair contain a lot of __________.
a.
nuclei . . . DNA
b.
smooth endoplasmic reticulum . . . lysosomes
c.
cytoskeleton . . . lysosomes
d.
smooth endoplasmic reticulum . . . rough endoplasmic reticulum
e.
rough endoplasmic reticulum . . . smooth endoplasmic reticulum
 

 8. 
The two main functions of the rough endoplasmic reticulum are the production of
a.
mitochondria and proteins that are to be secreted by the cell.
b.
ribosomes and steroid hormones.
c.
DNA and mitochondria.
d.
hydrogen peroxide and steroid hormones secreted by the cell.
e.
membranous vesicles and proteins to be secreted by the cell.
 

 9. 
Which one of the following statements is false? The Golgi apparatus
a.
sorts molecules according to their destination.
b.
works closely with the endoplasmic reticulum.
c.
modifies chemicals received from the endoplasmic reticulum.
d.
decreases in size when a cell increases its protein production.
e.
serves as a molecular warehouse and finishing factory.
 

 10. 
Lysosomes
a.
destroy harmful bacteria engulfed by white blood cells.
b.
fuse with food vacuoles to expose nutrients to lysosomal enzymes.
c.
help to digest worn-out or damaged organelles.
d.
recycle materials within the cell.
e.
All of the choices are correct.
 

 11. 
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.
 

 12. 
The __________ of a mitochondrion is/are an adaptation that increases the surface area and enhances a mitochondrion's ability to produce ATP.
a.
intermembrane space
b.
matrix
c.
cristae
d.
stroma
e.
grana
 

 13. 
Cyanide inhibits mitochondrial function; as a result, the rate of
a.
ATP synthesis would increase.
b.
lipid synthesis would increase.
c.
protein synthesis would increase.
d.
ATP synthesis would decrease.
e.
photosynthesis would increase.
 

 14. 
Which one of the following statements about the cytoskeleton is false?
a.
The cytoskeleton helps to support cells.
b.
The cytoskeleton  plays an important role in amoeboid motion.
c.
The cytoskeleton  is composed of three types of fibers: microfilaments, microtubules, and intermediate filaments.
d.
Once laid down, the elements of the cytoskeleton are fixed and remain permanently in place.
e.
The cytoskeleton is involved in phagocytosis.
 

 15. 
Plasmodesmata
a.
penetrate plant cell walls.
b.
carry nutrients between plant cells.
c.
carry chemical messages between plant cells.
d.
allow for cytoplasmic streaming.
e.
All of the choices are correct.
 

 16. 
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.
 

 17. 
A child is brought to the hospital with a fever of 107°F. Doctors immediately order an ice bath to lower the child's temperature. Which explanation offers the most logical reason for this action?
a.
Elevated body temperatures may denature enzymes. This would interfere with the cell's abilities to catalyze and carry out various reactions.
b.
Elevated body temperature will increase reaction rates in the child's cells and overload the limited number of enzymes found in the cell.
c.
Elevated body temperatures easily break the covalent bonds linking biologically important molecules. This will cause a general breakdown of cell structures.
d.
Elevated body temperatures will increase the energy of activation needed to start various chemical reactions in the body. This will interfere with the ability of enzymes to catalyze vital chemical reactions.
e.
Elevated body temperatures cause molecules to vibrate more quickly and prevent enzymes from easily attaching to reactants. This would slow vital body reactions.
 

 18. 
Plasma membranes are selectively permeable. This means that
a.
glucose cannot enter the cell.
b.
plasma membranes must be very thick.
c.
anything can pass into or out of a cell as long as the membrane is intact and the cell is healthy.
d.
the plasma membrane allows some substances to enter or leave a cell more easily than others.
e.
cholesterol cannot enter the cell.
 

 19. 
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.
 

 20. 
The cholesterol associated with cell membranes
a.
helps to make the cell membrane more compact at body temperature.
b.
is attached to membrane proteins and extends into the watery environment surrounding the cell.
c.
makes the cell membrane maintain its fluidity at cold temperature.
d.
is an abnormality resulting from a diet high in cholesterol.
e.
None of the choices are correct.
 

 21. 
When physicians perform an organ transplant, they choose a donor whose tissues match those of the recipient as closely as possible. Which of the following cell components are being matched?
a.
glycoproteins
b.
plasma membrane phospholipids
c.
plasma membrane cholesterols
d.
plasma membrane proteins
e.
cytoskeletal elements
 

 22. 
In lab, you use a special balloon that is permeable to water but not sucrose to make an "artificial cell." The balloon is filled with a solution of 20% sucrose and 80% water and is immersed in a beaker containing a solution of 40% sucrose and 60% water. Which of the following will occur?
a.
Sucrose will enter the balloon.
b.
Sucrose will leave the balloon.
c.
Water will enter the balloon.
d.
Water will leave the balloon.
e.
None of the choices will occur.
 

 23. 
Some protozoans have special organelles called contractile vacuoles that continually eliminate excess water from the cell. The presence of these organelles tells you that the environment
a.
contains a higher concentration of solutes than the protozoan.
b.
is hypertonic to the protozoan.
c.
is hypotonic to the protozoan.
d.
is isotonic to the protozoan.
e.
None of the choices are correct.
 

 24. 
You are adrift in the Atlantic Ocean, and, being thirsty, drink the surrounding seawater. As a result,
a.
you quench your thirst.
b.
you dehydrate yourself.
c.
your cells lyse, due to the excessive intake of salt.
d.
your cells become turgid.
e.
None of the choices are correct.
 
 
Answer the following questions based on the diagram below:
nar001-1.jpg
 

 25. 
Which statement(s) are true?
a.
Enzymes facilitate reactions by lowering activation energy.
b.
This single enzyme is able to catalyze many different reactions by binding various substrates.
c.
Once an enzyme catalyzes a reaction, it is disabled or “used up”.
d.
Enzymes are lipids.
e.
Enzymes only catalyzes reactions that break down molecules.
 

 26. 
What binds to the region labeled (2)?
a.
Substrate.
b.
Competitive inhibitor.
c.
Noncompetitive inhibitor.
d.
Both (a) and (b).
e.
All of the above.
 
 
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. 
nar002-1.jpg
 

 27. 
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.
 
 
The diagram below shows a transmembrane protein (a protein embedded in the lipid bilayer) that acts as a channel to transport molecules across the membrane. You should recognize the parts of the lipid bilayer by comparing them to an earlier question which shows the membrane in the same view.

The boxed area highlights details of the protein chain that sits in the membrane.  Each “R” represents a separate sidechain and is labeled 1 through 5.  Answer the following questions based on your understanding of the structure and characteristics of amino acids, proteins, and the lipid bilayer.
nar003-1.jpg
 

 28. 
The sidechains labeled 4 and 5 can possibly belong to which of the following amino acids?
a.
Aspartic acid, glutamic acid, and valine.
b.
Alanine, glycine, and proline.
c.
Asparagine, glutamine, and threonine.
d.
Both (a) and (b) above.
e.
None of the above.
 
 
Answer the following questions based on the diagram below.  1, 2, and 3 represent the process.  4 and 5 represents the highlighted structure.
nar004-1.jpg
 

 29. 
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
 

 30. 
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
 

 31. 
Which part of the diagram represents a type of transport that is able to establish/create 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
 

 32. 
The structures labeled (4) and (5)
a.
are types of proteins.
b.
are channel/transport 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.
 

 33. 
The function of ATP synthase, an enzyme found in the inner membrane of the mitochondria, is dependent on the movement of hydrogen ions moving down a concentration gradient.  Which of the illustrations best describes the movement of hydrogen ions through ATP synthase.
a.
1.
b.
2.
c.
3.
d.
1 and 2.
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. 
nar005-1.jpg
 

 34. 
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.
 

 35. 
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.
 



 
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