Cell Transport Homework Packet

Unit 3B:

Cell Transport Homework Packet

Name: ______KEY______

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).______

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) unicellular only

b) multicellular only

c) only organisms which have a circulatory system

d) 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 ashomeostasis

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

6. Fill in the blanks of the diagram using the word bank given.

WORD BANK:phospholipidcarbohydrateinside

membrane proteinshydrophilic headoutside

hydrophobic taillipid bilayer

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

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 / 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)Passive transport Active transport

10) 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).

______

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?
The smell of pizza wafting through the air / X
A plant wilting / X
Food coloring spreading out through a beaker of water / X
You smell the scent of a skunk as you drive by some roadkill / X
Pickles are smaller than the cucumbers that they started out as / 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

B. osmosis will occur from solution 2 to solution 1

C. no net movement of water will occur

X = 3, Y = 8 (total = 11) 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.

______6. Because it is a type of passive transport, osmosis requires:

a. only thermal (kinetic)energy of moleculesb. 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)______

1. 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

1. 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).

1. How does your answer to number 2 help to explain what happened to the vegetables in the salad?

The vegetables became limp (plasmolysis occurred).

1. When Jenny put dry spaghetti into boiling water, was there more water inside or outside the food?

More water outside

1. 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.

1. 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).

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) shrink, swell

b) swell, shrink

c) shrink, stay the same

d) stay the same, swell

e) none of the above

______3. A raw potato slice placed in a solution of salt and water will become wilted or limp because

a) water in the potato cells moves out into the salt solution

b) water in the salt solution moves into the potato cells

c) the salt moves into the potato cells

d) the salt absorbs the water from the cells

e) 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 moleculesOUTSIDE the cell than inside.

7. ISOtonic environment means there is the SAME concentration of solute moleculesOUTSIDE the cell as inside.

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______.

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!)

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 diffusionactive transport (molecular)

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 transportfacilitated diffusion

3. Which process does not require energy?

active transport facilitated diffusion

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