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Name:_________________practice test_______________ Cell Biology Test #2: 50 points
Multiple Choice: Choose the one best answer, circle the answer on your test and fill in the
appropriate blank on your scantron. 1 point each
Match the researcher and year to their discovery:
A) Gorter and Grendel B)Davson and Danielli C)Singer and Nicolson D)Langmuir E)Overton
1) ____1890s: Lipid soluble molecules pass into cell, but water soluble molecules don’t:
conclusion is that membrane is selectively permeable and a lipid
2) ____1908: Amphipathic membrane phospholipids solubilized in benzene, which were then
evaporated, could reconstitute a film that was similar to a cell membrane. Polar heads towards
water, tails away from water.
3) ____1972: Fluid mosaic model explains why lipids and proteins in membranes of fused cells
move freely and mix after fusion.
4) a) True b) False: Cholesterol is important in maintaining the fluidity of plasma membranes
of plant cells.
5) Which of the following are likely to be observed in the cells of a salmon (fish) which was
living at a temperature of 10 C migrated into a river with a temperature of 25 C?
a) Initial increase in membrane fluidity
b) Replacement of short membrane fatty acids with long ones
c) Enhanced rate of synthesis of saturated fatty acids
d) All of above
5) The typical intracellular potassium concentration is about _______ mM and the typical
extracellular concentration is about________ mM.
a) 140, 40 b) 40, 14 c) 140, 4 d) 4, 140
6) a) True b) False: Sphingosine is commonly used to link membrane fatty acid tail or
polysaccharide to a polar head.
7) Trans-fatty acids increase the membrane transition temperature (Decrease membrane
fluidity) and promote heart disease because they…..
a) ….have long chain lengths.
b) ….stack more tightly than cis-polyunsaturated fatty acids.
c) ….contain cholesterol.
8) Which fatty acid would be best for making a thick plasma membrane?
a) 12 carbon long lauric acid
b) 16 carbon long palmtic acid
c) 18 carbon long stearic acid
d) All of above equally effective
9) On a typical transmembrane protein the amino (+) end of the protein chain is on the
_________side of the cell and the carboxyl (-) end is on the _______ side of the cell.
a) inside, outside b) outside, inside
10) a) True b) False: The ratio of protein to lipid is relatively constant for all cells.
11) Which amino acid has a functional group that is used to create glycosidic N-linkages?
a) Serine b) Threonine c) Asparagine d) Cysteine
12) What kind of amino acids predominate in the region of a protein that passes through the
plasma membrane?
a) Acidic b) Basic c) Polar d) Non-polar
13) a) True b) False: All facilitated transport proteins require ATP hydrolysis to ADP + Pi in
order for them to move materials across a membrane.
14) a) True b) False: Osmosis occurs across a membrane when water can move down its
concentration gradient.
15) If you observed that the movement of glucose across a membrane could be saturated (you
observed a saturated maximum transport rate into the cell). You would conclude that glucose
transport is occurring via….
a) Simple diffusion
b) Facilitated transport
16) a) True b) False: Flux is decreased if the surface area of a cell is increased.
17) Aquaporin is a membrane protein that makes tiny pores in the epithelial cells of the
collecting duct of the kidney permeable to water. It is an example of a _______type of
transport protein.
a) Carrier protein b) Channel protein c) Active transport protein
18) The Na+/K+-ATPase of the eukaryotic membrane is what type of “classic” ATPase?
a) P-type ATPase b) ABC-type ATPase
19) The Na+/K+-ATPase pumps ____sodium ions out of a cell and ___potassium ions into a
cell for each ATP used.
a) 1,1 b) 2,3 c) 3,2 d) 3,3
e) 2,2
20) a) True b) False: Glycolysis requires oxygen for ATP synthesis to occur.
21) How many ATP are required for the preparatory phase of glycolysis?
a) One b) Two c) Three d) Four
----------------------------------------------------------------------------------------A
B
C
D
22) Which structure represents the electron carrying portion of a reduced nicotinamide
(NADH)?
A B C or D
---------------------------------------------------------------------------------------------23) Glucose is converted to glucose-6-phosphate by what enzyme?
a) Hexokinase b) Aldolase c) Lactate dehydrogenase d) Glucose permease
24) a) True b) False: Because ATP is hydrophilic it readily diffuses across the plasma
membrane into or out of a cell if a concentration gradient is present.
25) a) True b) False: If both glycolysis and gluconeogenesis occurred in the same cell at the
same time a futile cycle would occur. Allosteric regulation helps prevent this.
26) For eukaryotic cells glycolysis occurs in the ______and the tricarboxylic acid cycle occurs
in the ______.
a) Mitochondria, Chloroplast
b) Cytosol, Golgi apparatus
c) Cytosol, Smooth endoplasmic reticulum
d) Cytosol, Mitochondria
27) A) True/ B) False: Glucose represents a wonderful source of energy for oxidation because it
is water soluble, easily transported in the blood, can be stored as glycogen in the liver, can be
readily created from some amino acids during starvation.
28) Which of the following glycolytic enzymes is allosterically inhibited by ATP and acetylCoA, yet allosterically stimulated by fructose-1,6-bisphosphate?
A) Aldolase B) Lactate dehydrogenase C) Pyruvate kinase D) Glucose-6-phosphatase
29) In glycolysis, the enzyme phosphoglycerate kinase makes what product?
A
B
C
D
E
30) In glycolysis, the enzyme ________hydrolyzes fructose-1,6-bisphosphate to its products
dihydroxyacetone phosphate and glyceraldehyde-3-phosphate.
A) Hexokinase
B) Triose phosphate isomerase
C) Aldolase
D) Phospholipase
E) Phosphofructokinase
31) Which of the following is NOT an enzyme required for gluconeogenesis?
A) Pyruvate kinase
B) Glucose-6-phosphatase
C) Aldolase
D) Phosphoglycerate mutase
E) All are required
32) Which metabolite stimulates pyruvate carboxylase and gluconeogenesis?
a) ATP
b) Fructose-1,6-bisphosphate c) Acetyl-CoA d) ADP e) Acetyl-CoA
33) a) True b) False: Allosteric regulation occurs when a compound forms a covalent bond
with the target enzyme at its active site, causing a permanent change in target enzyme function.
34) The _______cycle permits lactic acid to travel from hypoxic skeletal muscle cells to the
liver where it is converted back to glucose via gluconeogenesis and delivery back to the skeletal
muscle.
a) Fermentation b) Krebs
c) Cori
d) Ethanol
Name:____________________________
Written Questions: Please use the paper provided, ask for additional paper if you need it.
35) With respect to the melting point of different types of lipid, what is membrane fluidity
(2pts: 10-15 words
36) Describe four different things that could INCREASE membrane fluidity. (4 pts: 30-50
words)
37) What is the Fluid Mosaic Model of a cell membrane? How do cell limit or regulate mobility
of membrane parts in or across the membrane (5 pts: 30-50 words)
38) With respect to glycolysis, many of the chemical reactions have a positive ∆G’o value.
Describe three things that a cell could use to improve product formation? (5 points: 30-50
words)
Extra Credit: 4 pts Name all the products, substrates, and enzymes that permit one glucose to
become two molecules of lactic acid (you need not draw structures, this will take too long).