Exam 3 Test Questions

Question 1

Of the following, the motor protein that interacts with microtubules is
A.	kinesin
B.	vimentin
C.	myosin
D.	lamin
E.	keratin

Answer 1

A. kinesin

Question 2

Actin and myosin
A.	interact to move cilia and flagella
B.	are the basis for contraction in muscle cells
C.	are employed for motion in the amoeba
D.	A and B
E.	B and C

Answer 2

E. B and C

Question 3

Dynein and tubulin
A. interact to move cilia and flagella
B. are the basis for contraction in muscle cells
C. are employed for motion in the Paramecium and Trypanosome
D. A and C
E. B and C

Answer 3

D. A and C

Question 4

Which is NOT true about integral membrane proteins?
A. They are less tightly bound to the membrane than peripheral ones.
B. They move laterally in the plane of the membrane according to the fluid mosaic model
C. They generally have an intracellular domain, an extracellular domain, and a transmembrane domain
D. They include carrier and channel proteins involved in membrane transport
E. All of the above are true

Answer 4

A. They are less tightly bound to the membrane than peripheral ones.

Question 5

A membrane is made more fluid by having phospholipids with
A.	unsaturated fatty acids
B.	saturated fatty acids
C.	long fatty acids
D.	A and C
E.	B and C

Answer 5

A. unsaturated fatty acids

Question 6

The fluid mosaic model
A. states that membrane lipids are free to move around in the plane of the phospholipid bilayer
B. states that membrane proteins are free to move into and out of the phospholipid bilayer
C. states that the cytoskeleton holds pieces of the membrane lipids in fixed places, much like the pieces in a mosaic of tile or stained glass
D. A and B
E. B and C

Answer 6

A. states that membrane lipids are free to move around in the plane of the phospholipid bilayer

Question 7

Cells that form layers surrounding the lumen of an internal cavity in metazoans (higher animals)
A. are called epithelial cells
B. are connected to neighboring cells by hemiplasmodesmatoids that prevent the leakage of material from the lumen into the rest of the body
C. are separated from the rest of the body by a basal lamina (basement membrane)
D. A and B
E. A and C

Answer 7

E. A and C

Question 8

Suppose a monolayer of phospholipids spreads out into an area equal to the surface area of the red blood cells that the phospholipids came from. Which of the following would be true? (Hint, assume the plasma membrane has constant thickness.)
A. the plasma membrane of the red blood cells would be one molecule thick
B. the plasma membrane of the red blood cells would be two molecules thick
C. the plasma membrane of the red blood cells would be three molecules thick
D. the plasma membrane of the red blood cells would be four molecules thick
E. the plasma membrane of the red blood cells would be a bilayer

Answer 8

A. the plasma membrane of the red blood cells would be one molecule thick

Question 9

Plasma membranes
A.	cover only eukaryotic cells
B.	contain only phospholipid
C.	are thin, flexible coverings
D.	all of the above
E.	none of the above

Answer 9

C. are thin, flexible coverings

Question 10

A membrane includes a channel protein for facilitated diffusion that is always active and specific for K+ ions. This membrane will
A. Transport more K+ ions when the concentration of K+ ions increases, but only up to a point where the rate of transport doesn’t increase further
B. Transport proportionately more K+ ions when the concentration of K+ ions increases without a limit to the increase in the rate of transport
C. Show saturation kinetics for K+ transport
D. A and C
E. B and C

Answer 10

B. transport proportionately more K+ ions when the concentration of K+ ions increases without a limit to the increase in the rate of transport

Question 11

Solution A is hypertonic compared to a cell. Which of the following is true?
A. Solution A has a lower concentration of solutes than the cell does
B. Solution A has a higher concentration of solutes than the cell does
C If the cell is put in solution A, the cell will gain water and may burst
D. A and C
E. B and C

Answer 11

B. solution A has a higher concentration of solutes than the cell does

Question 12

If a molecule is not permeable to a lipid bilayer and present in higher concentration inside than outside the cell, what mechanism could it use to get into a cell?
A. simple diffusion
B. facilitated diffusion via a channel or carrier protein
C. active transport via a transporter protein
D. A and C
E. B and C

Answer 12

C. active transport via a transporter protein

Question 13

Cashew trees grow in warmer environments than almond trees. As a result the triglycerides in cashews
A. have more saturated fatty acids than in almonds
B. have more unsaturated fatty acids than in almonds
C. have shorter fatty acids than in almonds
D. A and B
E. B and C

Answer 13

A. have more saturated fatty acids than in almonds

Question 14

Facilitated diffusion
A. is movement of molecules that are permeable to the lipid bilayer down the concentration gradient
B. is movement of molecules through carriers or channels down the concentration gradient
C. is movement of molecules from low to high concentration using energy
D. always shows linear kinetics
E. is often coupled to active transport

Answer 14

B. is movement of molecules through carriers or channels down the concentration gradient

Question 15

Simple diffusion
A. is movement of molecules through carriers or channels down the concentration gradient
B. is movement of molecules from low to high concentration using energy
C. is movement of molecules that are permeable to the lipid bilayer down the concentration gradient
D. transports glucose through the membrane
E. C and D

Answer 15

C. is movement of molecules that are permeable to the lipid bilayer down the concentration gradient

Question 16

Which of the following is not a form of potential energy?
A. a gradient of K+ ions across a membrane
B. unusable, disordered heat energy (“waste heat”)
C. a rock rolled up a hill
D. two positive electrical charges pushed together
E. energy stored in chemical bonds

Answer 16

B. unusable, disordered heat energy (“waste heat”)

Question 17

The second law of thermodynamics
A. says entropy can’t be created or destroyed
B. has an associated equation, ∆S > 0, which is precisely true at any time in any isolated system (S is always increasing)
C. regulates the amount of energy
D. A and B
E. B and C

Answer 17

B. has an associated equation, ∆S > 0, which is precisely true at any time in any isolated system (S is always increasing)

Question 18

Which of the following is not a kind of usable energy?
A. heat energy
B. light (radiant) energy
C. entropy
D. potential energy stored against any of the four fundamental forces
E. free energy

Answer 18

C. entropy

Question 19

A cell is placed in a hypotonic solution of membrane impermeable solutes; in response
A. membrane impermeable solutes will leave the cell
B. water will LEAVE the cell both directly through the membrane and through water-specific channels (aquaporins).
C. membrane impermeable solutes will enter the cell
D. water will ENTER the cell both directly through the membrane and through water-specific channels (aquaporins).
E. water will ENTER the cell, but only through water-specific channels (aquaporins), not directly through the membrane

Answer 19

D. water will enter the cell both directly through the membrane and through water-specific channels (aquaporins).

Question 20

Gap junctions
A. make an impermeable seal around the outside of cells
B. create a gap in the seal made by tight junctions
C. allow molecules and signals to move between animal cells
D. allow molecules and signals to move between plant cells
E. none of the above

Answer 20

C. allow molecules and signals to move between animal cells

Question 21

In metazoans (higher animals) a layer of epithelial cells surrounds the lumen of the intestines. The contents of the intestines are kept from leaking into the rest of the body by
A. tight junctions that connect all the epithelial cells
B. a basal lamina that is secreted from the apical surface of the cells
C. a basal lamina that is secreted from the basal surface of the cells
D. an extracellular matrix that is secreted by blood cells
E. none of the above

Answer 21

A. tight junctions that connect all the epithelial cells

Question 22

The change in free energy
A. is positive for the formation of steam from water at temperatures > 100 deg. C
B. can be calculated with the equation ∆G = ∆S - T∆H
C. is calculated as ending G minus beginning G
D. A and C
E. B and C

Answer 22

C. is calculated as ending G minus beginning G

Question 23

The free energy concept and the second law of thermodynamics are related in that (hint, read the underlined words carefully)
A. DECREASING entropy is the requirement for a spontaneous reaction in an isolated system, while INCREASING free energy is the requirement for a spontaneous reaction in any system
B. INCREASING entropy is the requirement for a spontaneous reaction in an isolated system, and INCREASING free energy is the requirement for a spontaneous reaction in any system
C. INCREASING entropy is the requirement for a spontaneous reaction in an isolated system, while DECREASING free energy is the requirement for a spontaneous reaction in any system
D. DECREASING entropy is the requirement for a spontaneous reaction in an isolated system, and DECREASING free energy is the requirement for a spontaneous reaction in any system
E. none of the above, there is no relationship between free energy and the second law

Answer 23

C. INCREASING entropy is the requirement for a spontaneous reaction in an isolated system, while DECREASING free energy is the requirement for a spontaneous reaction in any system

Question 24

Which of the following is(are) correct expression(s) employing the concept of free energy?
A. ∆G = ∆H - T∆S
B. ∆H = ∆G - T∆S
C. total energy = free energy - usable energy
D. A and C
E. B and C

Answer 24

A. ∆G = ∆H - T∆S

Question 25

Which of these situations has the smallest entropy?
A. a nonworking refrigerator where inside and outside are the same temperature
B. a junked refrigerator where everything is one temperature and the atoms in the components have been all melted together
C. a working refrigerator, where cold and warm are separated
D. they all have the same entropy
E. not enough information to tell

Answer 25

C. a working refrigerator, where cold and warm are separated

Question 26

Which of the following thermodynamic situations will always hold in an isolated system, where energy can be neither gained nor lost?
A. ∆E = 0, the amount of energy is constant in an isolated system
B. ∆S = 0, the amount of entropy is constant in an isolated system
C. reactions that show a decrease in free energy will always be spontaneous and rapid
D. A and C
E. B and C

Answer 26

A. ∆E = 0, the amount of energy is constant in an isolated system

Question 27

In coupling a reaction to ATP hydrolysis
A. cells can convert a normally slow reaction into a rapid one
B. the ∆G of the coupled reaction is reduced by 7.3 kcal/mole compared to the reaction without ATP hydrolysis
C. free energy released by ATP hydrolysis is used to move the equilibrium of the reaction towards the reactants
D. A and B
E. B and C

Answer 27

B. the ∆G of the coupled reaction is reduced by 7.3 kcal/mole compared to the reaction without ATP hydrolysis

Question 28

ADP
A. consists of a base, a ribose sugar and two phosphate groups
B. consists of a base, a ribose sugar and three phosphate groups
C. contains unstable covalent bonds between the phosphate groups
D. A and C
E. B and C

Answer 28

A. consists of a base, a ribose sugar and two phosphate groups

Question 29

Reactions where ∆G is negative
A. are called exergonic
B. favor the products of the reaction at equilibrium
C. have more free energy at the end of the reaction than at the beginning
D. A and B
E. B and C

Answer 29

D. A and B

Question 30

The energy that is stored in the synthesis of ATP from ADP
A. is an example of entropy
B. is an example of potential energy stored against the fundamental force of electromagnetism
C. makes the ATP molecule unstable (rapidly broken down by hydrolysis)
D. A and C
E. B and C

Answer 30

B. is an example of potential energy stored against the fundamental force of electromagnetism

Question 31

Life on earth involves the production and maintenance of order (reduction of entropy) on a large scale. This is possible
A. because living things are special and don’t have to follow the 2nd law of thermodynamics
B. because the earth is an isolated system that doesn’t have to follow the 2nd law of thermodynamics
C. because earth receives an enormous amount of energy from the sun that is associated with increasing entropy in the solar system (an isolated system)
D. because reducing entropy in an open system is required by the 2nd law of thermodynamics
E. none of the above

Answer 31

C. because earth receives an enormous amount of energy from the sun that is associated with increasing entropy in the solar system (an isolated system)

Question 32

Reactions that are slow
A. can only be accelerated by heat
B. can be accelerated by the addition of a catalyst
C. always have a large activation energy barrier
D. A and C
E. B and C

Answer 32

E. B and C

Question 33

Which of the following is not true about enzymes?
A. they can reduce the height of the activation energy barrier by stabilizing the transition state
B. they accelerate reactions by destabilizing the transition state
C. they are often named by substrate or function with the suffix ‘ase
D. they are usually proteins, but can be RNA
E. all of the above are true

Answer 33

B. they accelerate reactions by destabilizing the transition state