Chapter 5 – Cell Transport Study Guide

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Chapter 5 Cell Transport studyguide

 

 

Modified True/False
Indicate whether the statement is true or false.  If false, change the identified word or phrase to make the statement true.
 1.
One way that cells maintain homeostasis is by controlling the movement of substances across the cell membrane. _________________________


 2.
The cell membrane is made up of a double layer called the DNA bilayer. _________________________


 3.
A phospholipid is made up of a lipid “head” and two fatty acid “tails.” _________________________


 4.
The nonpolar tails of a phospholipid are attracted to water. _________________________


 5.
Cell-surface markers face the inside of the cell. _________________________


 6.
A concentration gradient exists when one area has a higher concentration of a substance than another area does. _________________________


 7.
The movement down a concentration gradient is called diffusion. _________________________


 8.
When the solute concentration outside a cell is equal to the solute concentration inside the cell, the cell’s environment is hypotonic. _________________________


 9.
A cell placed in a high salt solution would swell because of osmosis. _________________________


 10.
Osmosis is the diffusion of starch molecules through a selectively permeable membrane. _________________________


 11.
To pass through a cell membrane, water requires carrier proteins. _________________________


 12.
Facilitated diffusion is an active process that requires a cell to expend a great deal of energy. _________________________


 13.
Passive transport uses ATP to move molecules against their concentration gradient. _________________________


 14.
Exocytosis is a process that uses vesicles to capture substances and bring them into a cell. _________________________


 15.
Cells use exocytosis to export proteins modified by the Golgi apparatus. _________________________


 16.
Cells communicate by sending chemical signals that carry information to other cells. _________________________


 17.
Receptor proteins bind only to signals that match the specific color of the binding site. _________________________


 18.
Receptor proteins may cause the formation of a second messenger molecule inside the cell. _________________________


 

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 19.
cell membrane : cell ::
a.
window : house
c.
door : house
b.
roof : house
d.
wall : house
 20.
Which type of molecule forms the cell membrane?
a.
protein
c.
nucleic acid
b.
phospholipid
d.
carbohydrate
 21.
Phospholipids are molecules that have
a.
one polar phosphate head and two polar fatty acid tails.
b.
one polar phosphate head and two nonpolar fatty acid tails.
c.
one polar phosphate head and one polar fatty acid tail.
d.
one nonpolar phosphate head and two polar fatty acid tails.
 22.
The interior of the lipid bilayer of a cell membrane forms a nonpolar zone that
a.
allows most polar molecules to pass through the membrane.
b.
allows food to pass through the membrane.
c.
repels ions and most polar molecules.
d.
makes the membrane permeable to most molecules.
nar001-1.jpg
 23.
Refer to the illustration above. The structure labeled A is composed of
a.
lipids.
c.
proteins.
b.
carbohydrates.
d.
DNA.
 24.
Refer to the illustration above. The structure labeled D is a(n)
a.
cell-surface marker.
c.
enzyme.
b.
receptor protein.
d.
transport protein.
 25.
Refer to the illustration above. The structure labeled C is a(n)
a.
cell-surface marker.
c.
enzyme.
b.
receptor protein.
d.
transport protein.
 26.
Proteins in the cell membrane that identify the cell are called
a.
cell-surface markers.
c.
enzymes.
b.
receptor proteins.
d.
transport proteins.
 27.
As a result of diffusion, the concentration of many types of substances
a.
always remains greater inside a membrane.
b.
eventually becomes balanced on both sides of a membrane.
c.
always remains greater outside of a membrane.
d.
becomes imbalanced on both sides of a membrane.
nar002-1.jpg
 28.
Refer to the illustration above. The process shown is called
a.
osmosis.
c.
active transport.
b.
facilitated diffusion.
d.
diffusion.
 29.
Diffusion is the movement of a substance
a.
only through a lipid bilayer membrane.
b.
from an area of low concentration to an area of higher concentration.
c.
only in liquids.
d.
from an area of high concentration to an area of lower concentration.
 30.
The dispersal of ink in a beaker of water is an example of
a.
diffusion.
c.
active transport.
b.
osmosis.
d.
endocytosis.
 31.
Proteins that serve as tunnels for specific substances through the lipid bilayer are
a.
cell-surface markers.
c.
receptor proteins.
b.
channel proteins.
d.
enzymes.
 32.
Sugar molecules cross the cell membrane by
a.
active transport.
c.
osmosis.
b.
facilitated diffusion.
d.
simple diffusion.
 33.
Which of the following does not require energy?
a.
diffusion
c.
active transport
b.
endocytosis
d.
sodium-potassium pump
 34.
Ions move through ion channels by
a.
endocytosis.
c.
passive transport.
b.
simple diffusion.
d.
active transport.
 35.
The diffusion of water into or out of a cell is called
a.
solubility.
c.
selective transport.
b.
osmosis.
d.
endocytosis.
 36.
Osmosis is a type of
a.
active transport.
c.
simple diffusion.
b.
passive transport.
d.
endocytosis.
 37.
How does water pass through the cell membrane?
a.
directly through the lipid bilayer
b.
through a water ion pump
c.
through water carrier proteins
d.
through channel proteins just for water
 38.
Which of the following statements about an isotonic solution and a cell is correct?
a.
The solution has the same solute concentration that the cytoplasm does.
b.
The solution has a higher solute concentration than the cytoplasm does.
c.
A cell in the solution will lose water.
d.
A cell in the solution will gain water.
 39.
Unlike passive transport, active transport
a.
requires energy.
b.
moves substances down their concentration gradient.
c.
does not involve carrier proteins.
d.
moves water across the cell membrane.
 40.
Both active transport and facilitated diffusion involve
a.
ATP.
b.
movement against a concentration gradient.
c.
carrier proteins.
d.
channel proteins.
 41.
Which of the following is a form of active transport?
a.
osmosis
c.
facilitated diffusion
b.
simple diffusion
d.
sodium-potassium pump
 42.
The sodium-potassium pump
a.
is a carrier protein.
c.
is located in the cytoplasm of a cell.
b.
uses passive transport.
d.
transports sugar molecules.
 43.
The sodium-potassium pump usually pumps
a.
potassium ions out of the cell.
b.
sodium ions into the cell.
c.
potassium ions into the cell.
d.
only potassium ions and sugar molecules.
 44.
How many potassium ions does the sodium-potassium pump move into a cell if it moves six sodium ions out of the cell?
a.
two
c.
six
b.
four
d.
eight
 45.
Proteins and polysaccharides that are too large to move into a cell through diffusion or active transport move in by
a.
exocytosis.
c.
the sodium-potassium pump.
b.
endocytosis.
d.
channel proteins.
 46.
Molecules that are too large to be moved across a cell membrane can be removed from the cell by
a.
diffusion.
c.
endocytosis.
b.
exocytosis.
d.
osmosis.
 47.
Removing materials from a cell in vesicles is called
a.
osmosis.
c.
exocytosis.
b.
diffusion.
d.
endocytosis.
 48.
Which of the following descriptions of hormones is correct?
a.
signal molecules distributed throughout the body
b.
signal molecules that affect all cells in the body
c.
target molecules that communicate through direct contact
d.
target molecules that originate outside the body
nar003-1.jpg
 49.
Refer to the illustration above. What happens when the structure labeled A binds to the structure labeled B?
a.
Information is sent into the cell.
c.
The cell begins to swell.
b.
Proteins enter the cell.
d.
Ions enter the cell.
 50.
Refer to the illustration above. The structure labeled B in the diagram is an example of a(n)
a.
channel protein.
c.
receptor protein.
b.
signal molecule.
d.
ion pump.
 51.
Signal molecules bind to
a.
carbohydrates.
c.
receptor proteins.
b.
marker proteins.
d.
transport proteins.
 52.
Which of the following transmit information into a cell by binding to signal molecules?
a.
channel proteins
c.
marker proteins
b.
receptor proteins
d.
signal proteins
 53.
What change takes place in the cell membrane if a signal molecule causes a transport protein to open?
a.
permeability change
c.
formation of a second messenger
b.
activation of an enzyme
d.
change in chemical reactions
 

Completion
Complete each statement.
 54.
One way cells maintain homeostasis is by controlling the movement of substances across the cell ____________________.

 55.
A(n) ____________________ is a specialized lipid made of a phosphate head and two fatty acid tails.

 56.
The phosphate head of a phospholipid is attracted to water because it is ____________________.

 57.
The fatty acid tails of a phospholipid are repelled by water because they are ____________________.

 58.
The phospholipids form a barrier through which only small, ____________________ substances can pass.

 59.
Ions and most polar molecules are repelled by the ____________________ interior of the lipid bilayer.

 60.
____________________ – ____________________ markers are attached to the cell surface and have sugars attached to their protein.

 61.
Proteins that aid in moving substances into and out of cells are called ____________________ proteins.

 62.
____________________ are proteins in the cell membrane that help with important biochemical reactions inside the cell.

 63.
____________________ proteins enable a cell to sense its surroundings by binding to certain substances outside the cell.

 64.
To reach equilibrium, substances always flow from an area of high concentration to an area of ____________________ concentration.

 65.
When one area has a higher concentration than another area does, a concentration ____________________ exists.

 66.
Substances diffuse through a cell membrane either through the lipid bilayer or through ____________________ proteins.

 67.
Oxygen and carbon dioxide pass through the lipid bilayer by ____________________ diffusion.

 68.
Diffusion of ions through ion channels is a form of ____________________ transport.

 69.
Carrier proteins change ____________________ to transport substances to the interior of cells.

 70.
A cell does not expend ____________________ when diffusion takes place.

 71.
The diffusion of ____________________ through cell membranes is called osmosis.

 72.
When the concentration of free water molecules is higher outside a cell than inside the cell, water will diffuse ____________________ the cell.

 73.
If a cell is placed in a(n) ____________________ solution, water will flow out of the cell.

 74.
If a cell is placed in a(n) ____________________ solution, water will flow into the cell.

 75.
If a cell is placed in a(n) ____________________ solution, water flows into the cell at a rate that is equal to the rate at which water flows out of the cell.

 76.
Active transport requires the use of ____________________ by a cell.

 77.
The ____________________ – ____________________ pump transports ions against their concentration gradients.

 78.
The sodium-potassium pump uses energy supplied by ____________________.

 79.
The sodium-potassium pump prevents the accumulation of ____________________ ions inside the cell.

 80.
The movement of a substance into a cell by a vesicle is called ____________________.

nar004-1.jpg
A
B
 81.
Refer to the illustration above. The process shown in figure B is called ____________________.

 82.
Refer to the illustration above. The process shown in figure A is called ____________________.

 83.
A signaling cell produces a signal that is detected by a ____________________ cell.

 84.
Light is an environmental ____________________ for the flowering of some plants.

 85.
In the cell membrane, proteins that bind to specific signal molecules and respond are called ____________________ proteins.

 86.
Receptor proteins can change the ____________________ of the cell membrane.

 87.
Receptor proteins may act as ____________________, triggering certain chemical reactions inside the cell.

 

Short Answer
 88.
In addition to its function as a gatekeeper, what are three other functions of the cell membrane?

 89.
What makes up the lipid bilayer?

 90.
In the lipid bilayer, what causes one layer of polar heads to face the cell’s cytoplasm and the other layer of heads to face the cell’s surroundings?

 91.
What characteristic of membrane proteins causes them to be held in the cell membrane?

 92.
What are four types of proteins in cell membranes?

 93.
What exists across a cell membrane if equilibrium is not reached?

 94.
What is the difference between how a molecule crosses the cell membrane in simple diffusion and in facilitated diffusion?

 95.
What are two types of transport proteins?

 96.
Why are some water molecules not free to move across the cell membrane?

 97.
Explain why osmosis is a form of facilitated diffusion.

 98.
What specific carrier protein moves sodium ions out of a cell and potassium ions into a cell?

 99.
What is the function of the cell membrane during endocytosis?

 100.
What are hormones, how are they distributed, and what cells do they affect?

 101.
What happens to a receptor protein once it binds to a signal molecule?

 102.
How can the cell’s response to a signal cause a permeability change?

 

Problem
 103.

A biologist conducts an experiment designed to determine whether a particular type of molecule is transported into cells by simple diffusion, facilitated diffusion, or active transport. He collects the following information:

1. The molecule is very small.
2. The molecule is polar.
3. The molecule can accumulate inside a cell, even when its concentration inside the cell initially is higher than it is outside the cell.
4. Cells use up more energy when the molecule is present in the environment around the cells than when it is not present.

The biologist concludes that the molecule moves across cell membranes by facilitated diffusion. Do you agree with his conclusion? Why or why not?

Paramecia are unicellular protists. They have a number of characteristics also found in animals, such needing to ingest food in order to obtain energy and being surrounded by a cell membrane but not by a rigid cell wall. Paramecia have organelles found in animal cells, including a nucleus, mitochondria, ribosomes, and cilia. In addition, they have star-shaped organelles, called contractile vacuoles, that expel excess water. The illustration below depicts a paramecium.

nar005-1.jpg

 104.

Refer to the illustration above. The data presented in the table below were obtained in an experiment in which paramecia were placed in salt water with different concentrations of salt and the rate at which their contractile vacuoles contracted to pump out excess water was recorded.

Salt Concentration
Number of contractile vacuole contractions/minute
Very high
2
High
8
Medium
15
Low
22
Very low
30

 

a. How can you explain the observed relationship between salt concentration and rate of contractile vacuole contraction?
b. If something happened to a paramecium that caused its contractile vacuoles to stop contracting, what would you expect to happen? Would this result occur more quickly if the paramecium was in water with a high salt concentration or in water with a low salt concentration? Why?

 

Essay
 105.
Distinguish between facilitated diffusion and active transport.

 106.
Compare the processes of sodium ions moving through the cell membrane by an ion channel and by an ion pump.

 107.
Why do dissolved particles on one side of a membrane result in the diffusion of water across the membrane?

 108.
Why is it dangerous for humans to drink seawater?

nar004-1.jpg
A
B
 109.
Refer to the illustration above. Identify and explain the processes taking place in figure A and figure B.

 110.
Describe three ways in which the binding of a signal molecule to a receptor protein can change the functioning of a cell.

 

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