Download Unit 3B: Cell Transport Homework Packet Name: ______KEY

Unit 3B:
Cell Transport
Homework Packet
Name: _______
0
KEY________________________
1
Cell Transport HW #1
The picture below represents a tiny blood vessel (called a capillary) with body cells surrounding it. Blood within the
capillary will transport substances to the cells and collect wastes from cells.
Use the following 4 choices for questions 1 & 2:
a) nutrients
b) oxygen
c) carbon dioxide
d) waste materials
1) Which of the above materials will diffuse from the blood into the cells? _____A & B________________
2) Which of the above materials will diffuse from the cells into the blood? ______C & D________________
3) In order for oxygen to diffuse into the cells, what must the concentration of oxygen in the cell be in
comparison to the concentration of oxygen in the blood?
_____Higher concentration of O2 in the blood, lower concentration of O2 in the cells. O2 diffuses from high to low
(out of blood, into cells)._________________________________________________________
4) In order for carbon dioxide to diffuse out of the cells, what must the concentration of carbon dioxide in the
blood be? _____ Higher concentration of CO2 in the cells, lower concentration of CO2 in the blood. CO2 diffuses
from high to low (out of cells, into the blood).____________________________________________________
2
Cell Transport HW #2
______ 1. What two types of organic molecules is the cell membrane mostly composed of? (choose two)
a. carbohydrates
b. lipids
c. proteins
d. nucleic acids
______2. Cellular transport takes place in which of the following organisms?
a)
b)
c)
d)
unicellular only
multicellular only
only organisms which have a circulatory system
all organisms
3. Cells must be able to exchange materials into and out of cells in order to maintain a state of balance
otherwise known as
homeostasis
4. Any type of cell transport which does NOT require an input of cellular energy is called
__passive____transport.
______ 5. A cell membrane allows substance X into the cell. It does not allow substance Y into
the cell. Which of the following are true? (Draw a picture if it will help.)
A. the membrane is impermeable to both X and Y
B. the membrane is permeable to both X and Y
C. the membrane is permeable to Y but impermeable to X
D. the membrane is selectively permeable
3
6. Fill in the blanks of the diagram using the word bank given.
WORD BANK:
phospholipid
membrane proteins
hydrophobic tail
carbohydrate
hydrophilic head
lipid bilayer
inside
outside
Hydrophilic head
phospholipid
Hydrophobic tail
Outside
Carbohydrate markers
Membrane proteins
Phospholipid bilayer
Inside
7. Which term means “water-loving”?
hydrophilic
8. We know that the “heads” of the phospholipids face out towards the environment and cell cytoplasm. Which
parts of the phospholipids are in the interior of the cell membrane?__hydrophobic fatty acids tails__
_______9. Choose which of the following statements is FALSE.
a. Nucleic acids are important components of the cell membrane.
b. Carbohydrates on the outside surface of the cell membrane help cells identify each other.
c. Proteins in the membrane may form channels or pumps to help transport certain materials.
d. Some proteins attach to the cytoskeleton and help a cell to move or change shape.
_______10. Which of the following is NOT a type of passive transport?
a. diffusion
b. osmosis
c. facilitated diffusion
d. none of these
4
Cell Transport HW #3

Two sides of a container are separated by a membrane permeable to both water and iodine.
BEGINNING OF THE EXPERIMENT:
The left side of the membrane contains solution of
water( H2O) and iodine (KI).

The right side of the membrane contains pure
water.
The picture below shows the apparatus after it is allowed to sit for a period of time.
END OF THE EXPERIMENT
1) In the illustration above, which substance (water or iodine) is the solute? ___iodine____________
2) Which substance is the solvent? ___water_________________
3) In the top illustration, which side of the membrane (left or right) shows a true solution – meaning it has
both a solute and a solvent?
______Left – side A__________________________________________________________________
4) Fill out the following chart:
Number of Molecules at the
Beginning of the Experiment
5
Number of Molecules at
the End of the Experiment
Left Side
Right Side
Left Side
Right Side
Iodine
12
0
6
6
Water
11
23
17
17
5) Did diffusion take place during this experiment? ___Yes____________Which molecules (water, iodine)
diffused during this experiment? _____Both________________________________________________
6) Describe the movement of water and iodine molecules during this experiment.

In which direction did the iodine molecules diffuse? ( left to right , right to left ) circle one

In what direction did the water molecules diffuse? ( left to right , right to left ) circle one
 Iodine molecules moved from an area of ______________ (high,low) concentration of iodine to an area
of ________________(high, low) concentration of iodine.
 Water molecules moved from an area of high ________________(water, iodine) concentration to an
area of low _______________(water, iodine) concentration.

Movement is always from ___________(high, low) to _____________(high, low).

Always compare movement of _______________(like, unlike) molecules.
7) At the beginning of the experiment (on the first page), the two sides of the apparatus have differences in
the concentrations of solute particles. What is this difference called? ___concentration gradient___
8) Does the movement of water or iodine in this experiment require energy other than the heat found
naturally in the molecules?____No additional energy needed (passive transport)________
9) What is another term for the type of transport that does not require metabolic energy (ATP)?
(circle answer)
10)
Passive transport
Active transport
Describe the concentrations of iodine and water molecules in the two sides of the container at
the end of the experiment. __equal concentrations of like substances on both sides of the membrane__________
11)
What term do we use to describe this condition?_____dynamic equilibrium__________________
12)
At the end of the experiment, are molecules of iodine and water still moving? Explain.
_________Yes – equally in all directions (molecules and atoms NEVER stop moving).
_______________________________________________________________________________
6
Cell Transport HW #4
______ 1. Which of the following is true of facilitated diffusion?
A. Protein channels assist the diffusion of substances
B. Molecules can move into or out of the cell freely
C. Substances do not move because of the concentration gradient
D. Water moves only into the cell
2. Which of the following statements tells how facilitated diffusion differs from simple diffusion?
A. Particles move through cell membranes without the use of energy by cells.
B. Particles tend to move from high concentration to lower concentration.
C. Particles move within channel proteins that pass through cell membranes.
D. Particles tend to move more slowly than they would be expected to move.
3. Place a check mark in the table below to indicate whether the example given illustrates osmosis or diffusion. Yes, yes we know
that osmosis is a type of diffusion but let’s just see if you can distinguish osmosis from “regular” (non-osmotic) diffusion.
Is it osmosis?
Is it (non-osmotic) diffusion?
X
The smell of pizza wafting
through the air
A plant wilting
X
Food coloring spreading out
through a beaker of water
You smell the scent of a skunk as
you drive by some roadkill
Pickles are smaller than the
cucumbers that they started out as
X
X
X
______ 4. If the membrane in the picture is impermeable to substances X and Y, BUT
permeable to water, then:
A. osmosis will occur from solution 1 to solution 2
Solution 1
X
Y
Y
Y
Y
B. osmosis will occur from solution 2 to solution 1
Y
X
Y
C. no net movement of water will occur
X
Y
Y
Y
X = 3, Y = 8 (total = 11)
7
Y
Solution 2
Y
X
Y
X
Y
X = 2, Y = 5 (total = 7)
5. COMPLETE A VENN DIAGRAM COMPARING OSMOSIS, DIFFUSION AND FACILIATED TRANSPORT. Write the letters
that represent the words/phrases below to save space in the diagram.
A. passive – no ATP required
D. substances move WITH gradient
B. water transport
E. requires protein channels
C. solute transport
F. movement of particles across a membrane
Osmosis
Facilitated Diffusion
(non-osmotic)
B, E
ALL of these
C, E
A, D, F
Simple Diffusion
C
______6. Because it is a type of passive transport, osmosis requires:
a. only thermal (kinetic) energy of molecules
8
b. cellular energy
Cell Transport HW #5
What happened to dinner?
Jenny’s family planned to attend her brother’s basketball game on a school night. Her mother cooked spaghetti sauce.
Jenny offered to make the salad and cook the spaghetti. First, Jenny washed the lettuce. Then, he sliced tomatoes,
cucumbers, and radishes. Next, Jenny put some pepper, herbs, oil, and vinegar on the vegetables. Finally, he tossed the
salad, covered it, and placed it in the refrigerator. Jenny read the directions for cooking a pound of spaghetti. He was
surprised to see that he needed five quarts of water to boil the spaghetti. Jenny read the label on the box and found that
the food was made from ground-up plants. Jenny slid the dry spaghetti into the boiling water and waited while it
cooked. He drained the spaghetti. It took up much more space now than it had before it was cooked. Almost all the
water in the pot was gone. What had happened to the water and the dry spaghetti? Jenny took the salad from the
refrigerator. The vegetables were no longer crisp. There was more liquid in the salad bowl than he had added. What had
happened to the veggies?
Analyzing the Problem:
1. How did the dry spaghetti increase in size? ___water diffused into the spaghetti (plant cells)________
2. Where did the liquid in the salad bowl come from? ___water diffused out of the salad cells (because the salad
dressing was hypertonic to the cells)____________
Solving the Problem:
1.
When Jenny made the salad, were more water molecules inside or outside the plant cells? Choose one.
inside
2.
What happens when the number of water molecules is greater inside a cell than outside?
Water diffuses, by osmosis, out of the cell (from high to low).
3.
How does your answer to number 2 help to explain what happened to the vegetables in the salad?
The vegetables became limp (plasmolysis occurred).
9
4.
When Jenny put dry spaghetti into boiling water, was there more water inside or outside the food?
More water outside
5.
What happens when the number of water molecules is greater in one area than another area?
There is a high concentration gradient, and the water molecules diffuse from high to low.
6.
How does your answer to number 5 help to explain what happened to the spaghetti?
The water diffused, by osmosis, into the spaghetti (plant cells).
10
Cell Transport HW #6
______ 1. Water moves into a cell when the solution surrounding the cell is:
A. hypertonic
B. hypotonic
C. isotonic
D. concentrated
_______2. Cells placed in a hypotonic solution will ___________ while cells placed in a hypertonic
solution will ______________.
a)
b)
c)
d)
e)
shrink, swell
swell, shrink
shrink, stay the same
stay the same, swell
none of the above
_______3. A raw potato slice placed in a solution of salt and water will become wilted or limp because
a)
b)
c)
d)
e)
water in the potato cells moves out into the salt solution
water in the salt solution moves into the potato cells
the salt moves into the potato cells
the salt absorbs the water from the cells
the salt “sucks” the water out of the cell
4. Label the pictures below (isotonic, hypertonic, or hypotonic environments)
__Hypotonic________
__Hypertonic_______
___Isotonic______
5. HYPERtonic environment means there is a GREATER concentration of solute molecules OUTSIDE the cell than
inside.
6. HYPOtonic environment means there is a LOWER concentration of solute molecules OUTSIDE the cell than inside.
7. ISOtonic environment means there is the SAME concentration of solute molecules OUTSIDE the cell as inside.
11
8. The pressure inside a plant cell caused by water pushing against the cell wall is called
___osmotic pressure (turgor)______ pressure.
9. The SWELLING AND BURSTING of animal cells when water enters
is called __cytolysis_(don’t need to know for test)__.
10. This happens when a cell is placed in a __hypo_______tonic solution.
11. Placing plant cells in a HYPOTONIC solution causes
the osmotic pressure to _______________.
increase
decrease
12. The SHRINKING of plant cells when water leaves so the cell membrane
pulls away from the cell wall is called ___plasmolysis_______. It happens when a plant cell is
placed into ___hyper_______tonic solution.
13. When water leaves a plant cell, the osmotic pressure will ___________________.
increase
decrease
14. The shrinking of ANIMAL cells that are placed in a HYPERTONIC solution is
called __plasmolysis____________________.
12
13
Apply the Big idea
Most sports drinks are isotonic in relation to human body fluids. Explain why athletes should drink solutions that
are isotonic to body fluids when they exercise rather than ones that are hypotonic to body fluids (contain a greater
proportion of water in comparison to the fluids in and around human body cells).
Athletes lose a tremendous amount of fluids when they exercise. They should replenish these fluids with a
solution that is isotonic to the cells (similar to the fluid they lost). A hypotonic solution would not be
beneficial, because a lot of water would diffuse into their cells (and they could be damaged by the osmotic
pressure – or even burst!)
14
Cell Transport HW #8
Active Transport
Facilitated diffusion takes place when a substance diffuses across the cell membrane through a protein channel.
Active transport takes place when the cell uses energy to carry a substance across the cell membrane against a
concentration difference.
Follow the directions.
1. Label each diagram as either facilitated diffusion or active transport.
Facilitated diffusion
active transport (molecular)
Glucose molecules
Molecule to
be carried
Energy
Molecule
being carried
Answer the questions. Circle the correct answer.
2. Which process can move molecules from a lower concentration solution on one side of the membrane to a
higher concentration solution on the other side?
active transport
facilitated diffusion
3. Which process does not require energy?
active transport
15
facilitated diffusion