Question 1

A steroid hormone would most likely enter a cell by:

Accepted Answer

A)   active transport.
B)   osmosis.
C)   facilitated diffusion.
D)   vesicle-mediated transport.
E)   simple diffusion.

Question 2

The most abundant sterol in the plant cell membrane is:

Accepted Answer

A)   lectin.
B)   cholesterol.
C)   triglyceride.
D)   stigmasterol.
E)   phospholipid

Question 3

In receptor-mediated endocytosis, what happens immediately after the substance to be transported binds to a receptor?

Accepted Answer

A)   The substance is broken down enzymatically.
B)   The coated pit invaginates to form a coated vesicle.
C)   The receptor releases the substance inside the cell.
D)   The coated vesicle sheds its coat.
E)   The receptor is broken down enzymatically.

Question 4

Wall pressure:

Accepted Answer

A)   is the same as turgor pressure.
B)   develops within a cell and pushes outward against the wall.
C)   develops outside the cell wall and pushes inward against the wall.
D)   is an outwardly directed pressure of the wall.
E)   is an inwardly directed pressure of the wall.

Question 5

Aquaporins are found in the plasma membrane and the:

Accepted Answer

A)   inner mitochondrial membrane only.
B)   inner chloroplast membrane only
C)   tonoplast only.
D)   endoplasmic reticulum only.
E)   the mitochondrial membrane, the chloroplast membrane, the tonoplast, and the ER.

Question 6

If the concentration of glucose is higher inside a cell than outside, glucose will enter the cell only by:

Accepted Answer

A)   simple diffusion.
B)   active transport.
C)   facilitated diffusion.
D)   osmosis.
E)   passive cotransport.

Question 7

Which of the following substances is LEAST likely to diffuse across the plasma membrane?

Accepted Answer

A)   water
B)   a small, uncharged polar molecule
C)   an ion
D)   carbon dioxide
E)   oxygen

Question 8

Primary plasmodesmata are different from secondary plasmodesmata in that primary plasmodesmata:

Accepted Answer

A)   are narrow strands of cytoplasm.
B)   are formed during cytokinesis.
C)   are typically branched.
D)   connect the protoplasts of neighboring cells.
E)   may be connected by a cavity in the region of the middle lamella.

Question 9

Which of the following statements about diffusion is FALSE?

Accepted Answer

A)   When the diffusing molecules become evenly distributed, their movement stops.
B)   Each of the diffusing molecules moves randomly and independently of the others.
C)   It is more rapid at higher than at lower temperatures.
D)   It involves the net movement of a substance.
E)   It is more rapid in gases than in liquids.

Question 10

The steeper the concentration gradient, the more rapid the rate of diffusion.

Accepted Answer

A) True 
 B)False

Question 11

Typically a second messenger is located on the outside, rather than the inside, of a cell.

Accepted Answer

A) True 
 B)False

Question 12

Which of the following statements about an electrochemical gradient is FALSE?

Accepted Answer

A)   It involves a concentration gradient and the membrane potential.
B)   It involves a concentration gradient and the total electrical gradient.
C)   It is the driving force for the movement of charged and uncharged substances across a membrane.
D)   Plant cells maintain an electrochemical gradient across the plasma membrane.
E)   Plant cells maintain an electrochemical gradient across the tonoplast.

Question 13

Which of the following statements concerning plasmodesmata is FALSE?

Accepted Answer

A)   They can mediate the transport of proteins and RNA.
B)   Their openings can be regulated by actin and myosin..
C)   They serve as paths for electrical signaling.
D)   Their permeability can be controlled by callose.
E)   Their similar symplastic domains cause them to be passive structures.

Question 14

If the concentration of K+ is higher outside a plant cell than inside, K+ will enter the cell by:

Accepted Answer

A)   facilitated diffusion through channel proteins.
B)   simple diffusion through channel proteins.
C)   facilitated diffusion via carrier proteins.
D)   active transport through channel proteins.
E)   active transport via carrier proteins.

Question 15

Two of the most common second messengers are:

Accepted Answer

A)   hormones and ATP.
B)   ATP and cyclic AMP.
C)   calcium ions and cyclic AMP.
D)   lectins and calcium ions.
E)   lectins and clathrin.

Question 16

Which of the following statements concerning the desmotubule is FALSE?

Accepted Answer

A)   It has the appearance of a tubular strand.
B)   It may contain a central rod.
C)   It is continuous with the endoplasmic of adjacent cells.
D)   It is a main channel for transporting materials.
E)   It is found within a plasmodesma.

Question 17

The apoplast consists of all the interconnected protoplasts of the plant body together with their plasmodesmata.

Accepted Answer

A) True 
 B)False

Question 18

Which of the following statements about solute movement in cells is FALSE?

Accepted Answer

A)   Once a substance is inside a cell, it moves through the cell by diffusion.
B)   Diffusion is an effective way to move substances between distantly separated cells.
C)   Transport of substances within a cell may be speeded up by cytoplasmic streaming.
D)   Metabolic activities help maintain steep concentration gradients between the inside and outside of the cell.
E)   Within a cell, a substance may be produced in one place and used in another, thus maintaining an intracellular concentration gradient.

Question 19

Passive diffusion can occur down a concentration gradient but not down an electrochemical gradient.

Accepted Answer

A) True 
 B)False

Question 20

In the plasma membrane, proteins can move laterally but lipids cannot.

Accepted Answer

A) True 
 B)False

Exam 4: The Movement of Substances Into and Out of Cells

Aquaporins are found in the plasma membrane and the:

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Wall pressure:

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The most abundant sterol in the plant cell membrane is:

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If the concentration of glucose is higher inside a cell than outside, glucose will enter the cell only by:

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Which of the following statements about an electrochemical gradient is FALSE?

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Passive diffusion can occur down a concentration gradient but not down an electrochemical gradient.

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In the plasma membrane, proteins can move laterally but lipids cannot.

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Which of the following statements concerning plasmodesmata is FALSE?

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Typically a second messenger is located on the outside, rather than the inside, of a cell.

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Which of the following statements concerning the desmotubule is FALSE?

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If the concentration of K+ is higher outside a plant cell than inside, K+ will enter the cell by:

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Which of the following substances is LEAST likely to diffuse across the plasma membrane?

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Primary plasmodesmata are different from secondary plasmodesmata in that primary plasmodesmata:

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In receptor-mediated endocytosis, what happens immediately after the substance to be transported binds to a receptor?

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Which of the following statements about solute movement in cells is FALSE?

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Which of the following statements about diffusion is FALSE?

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A steroid hormone would most likely enter a cell by:

Correct AnswerverifiedShow Answer

The steeper the concentration gradient, the more rapid the rate of diffusion.

Correct AnswerverifiedShow Answer

The apoplast consists of all the interconnected protoplasts of the plant body together with their plasmodesmata.

Correct AnswerverifiedShow Answer

Two of the most common second messengers are:

Correct AnswerverifiedShow Answer

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If the concentration of K⁺ is higher outside a plant cell than inside, K⁺ will enter the cell by:

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