Download 1 PRE-TEST

1
Name___________________________________
PRE-TEST
Directions: Circle the letter indicating whether the following statements are either true ("T") or false
("F").
T
F
1.
A closed glass jar of pickles is a closed system.
T
F
2.
Cellular respiration only occurs in animal cells.
T
F
3.
Diffusion is a process which results as a result of unequal concentration of
particles in a given space.
T
F
4.
All cells are surrounded by a protective cell wall.
T
F
5.
Water is released from plant cells through the process of transpiration.
T
F
6.
Plant cells exchange matter and energy through their cell membrane.
T
F
7.
The process of water and minerals moving into a plant cell is call active
transport.
T
F
8.
Diffusion and osmosis depend upon a concentration gradient.
T
F
9.
Cellular respiration and combustion reactions have no common elements.
T
F
10.
Cell membranes are described as being permeable because they allow
unrestricted movement of matter in and out of the cell.
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2
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GLOSSARY
Active transport – movement of matter into, or out of, a cell which requires energy from the cell; usually this involves
movement against the concentration gradient
Adenosine triphosphate (ATP) – the molecule used in cell processes as a supply of energy; it is produced by cells during
cellular respiration
Alveoli – microscopic air sacs in the lungs; the site where most gas exchange occurs
Capillaries – microscopic blood vessels; most matter exchange between body cells and the blood occurs through the walls
of the capillaries
Carrier protein – a molecule in the cell membrane that allows materials to pass through it
Cell membrane – the outer semipermeable covering of the cell; it is very thin and flexible
Cellular respiration – the process that converts the potential energy of food into other useful forms; its most important
product is ATP
Concentration gradient – a difference in concentration of a particle at two points in a space
Diffusion – net movement of particles from an area of high concentration to an area of low concentration
Endocytosis – a process cells use to capture large particles; the cell membrane wraps around the particle and encloses it
Epidermis – an outer layer of cells covering plants and animals; its primary function is protection
Exocytosis – a process cells use to expel material; a vacuole connects to the cell membrane and opens so its content is now
outside of the cell
Guard cells – the specialized plant cells which surround, and control the opening and closing of, the stoma
Lenticels – small pores visible on the stems of many plants; important for gas exchange
Metabolic rate – the rate at which an organism is converting energy
Osmosis – diffusion of water through a membrane
Passive transport – diffusion of materials across a membrane requiring no energy input
Root hairs – microscopic extensions from the surface cells of roots
Semipermeable membrane – a pliable tissue which allows some materials to pass, but stops others; cell membranes are
semipermeable
Stomata (singular: stoma) – small openings on the surface of plant leaves which can open and close to control the movement of gases, particularly water vapor
Surface area to volume ratio – a value calculated by dividing the surface area of an object by
the volume it contains; this ratio is large for cells efficient at exchanging materials with
their surroundings
© 1997 Alberta Education
Distributed by AGC/United Learning
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3
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CELLULAR RESPIRATION
Write the balanced chemical equation for cellular respiration.
C6H12O6(s) + 6O2(g) → 6CO2(g) + 6H2O(l) + energy
Material constantly enters and leaves plant cells. Water, oxygen, carbon dioxide and nutrients pass
through the cell membrane easily. Because some materials are able to pass through and some are
stopped, the cell membrane is “semipermeable.”
Check your understanding of this segment by completing the following. Use the back of the sheet if
necessary.
1. Compare a single-celled organism, Amoeba, with a multicellular organism, a fish. Explain what
special problems each must overcome to get the nutrients it requires.
© 1997 Alberta Education
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4
Name___________________________________
GAS EXCHANGE IN PLANTS
Plant leaves have a thick outer layer to protect them from the drying air. To allow gas exchange, there
are small holes on the surface of the leaf. These holes are called stomata. They open when two beanshaped cells (known as guard cells) around the stoma fill with water.
guard
cells
closed
stoma
open
Plant Root Systems
The stem of a plant has openings called lenticels.
You can often see them on new shoots in the
spring, or at the base of spruce trees.
Roots also exchange gases. Finger-like projections
called root hairs extend from the surface of the
root. These increase the surface area enormously
and speed up the exchange. The root hairs absorb
gases dissolved in water in the soil.
leaves
stem
root
root tip
root hairs
Check your understanding of this segment by completing the following. Use the back of the sheet if
necessary.
2. The epidermis of a plant leaf is tough and waxy and makes gas exchange more difficult. What
benefit does an epidermis have for the plant?
3. Most plants have many more stomata than lenticels. Why?
4. Why must roots be wet to function properly?
5. Would you expect carbon dioxide to diffuse into or out of stomata during the daylight hours? What
about oxygen?
© 1997 Alberta Education
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5
Name___________________________________
GAS EXCHANGE IN ANIMALS
All of our cells require oxygen, which we absorb in our lungs. Predict how the oxygen gets from the
lungs to all the cells of the body.
Gases and other nutrients are carried in the blood to all parts of the body.
Large organisms, like human beings, need to absorb gases. We also require a method of moving the
absorbed gas around the body.
Lungs are structured to allow efficient gas exchanges. Lungs are not empty sacks, but tissues that are
finely divided. This increases the surface area of the lung, allowing for speedy gas exchange. Once
absorbed, gases must be transported to all parts of the body. For that reason the alveoli are surrounded
by blood-carrying capillaries.
A fish’s gills act in the same way. They are red because they are filled with blood-carrying capillaries.
Gases exchange between the water and the blood by diffusing through the membranes of the gills.
Gill Filament
water flow
capillaries
deoxygenated blood
lamella
oxygenated
blood
Check your understanding of this segment by completing the following. Use the back of the sheet if
necessary.
6. Do fish and humans exchange the same gases with their environments?
7. Why would gills not function properly for land animals?
8. Why are gills and lungs both surrounded by capillaries?
9. Investigate the gas exchange system of a grasshopper.
© 1997 Alberta Education
Distributed by AGC/United Learning
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6
Name___________________________________
PASSIVE TRANSPORT
Pour a teaspoon full of vinegar onto a paper towel or cloth and put it into a plastic bag. Close the bag
and wait about five minutes. Hold the bag at arm’s length in a room without any breeze or draft.
Slowly remove the cloth from the bag. Count how many breaths you can take before you smell the
vinegar.
This gives you a rough idea of the speed of diffusion of vinegar molecules through air.
Inside and outside cells, water will diffuse from higher to lower concentration until it reaches equilibrium. This is called osmosis.
The cytoplasm of a cell has many materials dissolved in it. When the cell is placed in pure water, the net
flow of water by osmosis is into the cell.
Check your understanding of this segment by completing the following. Use the back of the sheet if
necessary.
10. Compare and contrast diffusion and osmosis.
11. Food can be preserved by salting it. What would happen to the water inside bacteria when they are
in an extremely salty environment?
12. The contractile vacuole of a Paramecium constantly pumps water out of the cell. Why would a
Paramecium need to remove water?
13. After a long bath your finger tips look all wrinkled. Why?
14. “Reverse osmosis” is a method of purifying water. Considering the meaning of osmosis, explain
how reverse osmosis would make water more pure.
15. Some people claim to “learn by osmosis” – does this make sense?
© 1997 Alberta Education
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7
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ACTIVE TRANSPORT
If a microscope is available, mix household yeast with water and a drop of food colouring. Prepare a
wet mount slide and observe the yeast cells.
Now boil the yeast and water (a microwave oven will work).
Observe the yeast under the microscope once again.
Compare the yeast cells before and after boiling.
The living yeast cells use active transport to remove dye molecules. Because of this, they do not become coloured.
Once killed by boiling, the cells are no longer able to do active transport and will pick up the colour of the dye.
Cells use endocytosis and ectocytosis to acquire and remove large particles which cannot be accommodated by diffusion.
Endocytosis
Ectocytosis
Check your understanding of this segment by completing the following. Use the back of the sheet if
necessary.
16. Explain the difference between endocytosis and exocytosis.
17. What two organelles are involved in endocytosis?
18. What is the role of adenosine triphosphate (ATP) in active transport?
19. A Paramecium’s contractile vacuole pumps water out of the cell. Is this active or passive transport?
20. Describe the role of carrier proteins in active transport.
© 1997 Alberta Education
Distributed by AGC/United Learning
AGC/United Learning • 1560 Sherman Ave., Suite 100 • Evanston, IL 60201 • 800-323-9084
8
Name___________________________________
CELL SIZE
Place your hand, with your fingers together, flat on a blank page and trace it with a pencil. Measure
the length of the line you drew. (Use a piece of string!)
Now do the same thing again, except spread out your fingers.
Compare the length of the two lines.
Describe how this activity demonstrates the ideas of surface area and volume.
The length of the line corresponds to the surface area. The space your hand occupies corresponds to the volume.
By spreading your fingers you increased the surface area, but the volume of your hand remained unchanged.
This shows that dividing objects into smaller pieces increases the surface area to volume ratio.
Calculating surface area to volume ratio of a cube.
1. Find the surface area to volume ratio of a sugar cube with sides 1.0 cm in length.
surface area
volume
=
=
=
=
=
number of sides × area of one side
volume
n(l • w)
l•w•h
6(1.0 cm)(1.0 cm)
(1.0 cm)(1.0 cm)(1.0 cm)
6.0 cm2
1.0 cm3
6.0*
* Note that surface area to volume ratios are reported without units.
Check your understanding of this segment by completing the following. Use the back of the sheet if
necessary.
21. Find the surface area to volume ratio for a cube with sides 0.20 cm long.
22. Does the surface area to volume ratio increase or decrease as a cell gets larger?
23. What is more efficient for exchange of materials with the surroundings, a large or
a small surface area to volume ratio?
24. Sketch a scale diagram of two cells with a volume of 12 cm3: one with dimensions of 3 cm x 2 cm x
2 cm, the second with dimensions 12 cm x 1 cm x 1 cm.
25. Which of the two cells you sketched has the greater surface area to volume ratio? Which cell would
be more efficient at exchanging materials with the environment?
© 1997 Alberta Education
Distributed by AGC/United Learning
AGC/United Learning • 1560 Sherman Ave., Suite 100 • Evanston, IL 60201 • 800-323-9084
Name___________________________________
9a
POST-TEST
MULTIPLE CHOICE
Directions: Decide which of the choices best completes the statement or answers the question,
then circle the letter that corresponds to your choice. (3 marks each)
1.
The guard cells control the opening and closing of
a.
b.
c.
d.
2.
For cells with a volume of 16 cm3, the shape with the most efficient surface-to-volume ratio is
a.
b.
c.
d.
3.
contractile vacuoles
oral grooves
lenticels
stomata
1 cm x 1 cm x 16 cm
1 cm x 2 cm x 8 cm
1 cm x 4 cm x 4 cm
2 cm x 2 cm x 4 cm
Carrier or transport proteins facilitate
a.
b.
c.
d.
osmosis
diffusion
active transport
passive transport
4.
Cells absorb large particles or molecules which are essential for life functions, but cannot pass
through the cell membrane directly, by the process of
a.
b.
c.
d.
5.
exocytosis
endocytosis
active transport
passive transport
Plant roots absorb minerals by means of
a.
b.
c.
d.
osmosis
diffusion
active transport
passive transport
© 1997 Alberta Education
Distributed by AGC/United Learning
AGC/United Learning • 1560 Sherman Ave., Suite 100 • Evanston, IL 60201 • 800-323-9084
9b
Name___________________________________
POST-TEST
LONG ANSWER
Directions: Answer the following questions in the spaces provided. Use the back of the sheet if
necessary.
1.
Cell membranes are considered semipermeable because _____________________________
_________________________________________________________________.(4 marks)
2.
_____________________________________ is the process which provides cells with the energy
required for life functions. (3 marks)
3.
Plants have openings in the stem called ___________________________ for the purpose of gas
exchange with the environment. (3 marks)
4.
The specialized root cells which facilitate the exchange of gases, water and nutrients are the
__________________________________. (3 marks)
5.
Oxygen in the air is exchanged for carbon dioxide in the blood in the __________________ of our
lungs. (3 marks)
6.
The movement of materials across a cell membrane which requires no energy input from the
cell is called ________________________________. (3 marks)
7.
Explain why a red blood cell begins to swell shortly after being placed into a saline solution. (10
marks)
8.
Osmosis is ________________________________________________________________. (3 marks)
9.
The acronym ATP stands for __________________________________________________ which
provides the energy for active transport. (3 marks)
10.
A student, examining to types of cells, estimates the surface-to-volume ratio for each. Cell
"A" has a ratio of 2500:1 and cell "B" a ratio of 750:1. Cell _______________ is more efficient than cell
_________________ in carrying out its life functions. (6 marks)
© 1997 Alberta Education
Distributed by AGC/United Learning
AGC/United Learning • 1560 Sherman Ave., Suite 100 • Evanston, IL 60201 • 800-323-9084
Name___________________________________
9c
POST-TEST
11.
List three examples of anatomical, or technological, structures which take advantage of the surface-to-volume ratio principle. (9 marks)
_______________________________________
_______________________________________
_______________________________________
12.
The second law of thermodynamics states that heat flows from matter at a higher temperature to
matter at a lower temperature. How does this compare to the process of diffusion. (9 marks)
13.
A Paramecium uses a ____________________________________ to remove water from
the cell. This is an example of ___________________________ transport. (6 marks)
14.
Why is moisture in the soil essential for proper root function? (8 marks)
15.
A plant cell is placed into a salt solution. Water molecules will most likely move
_________________________________________ through the membrane into
____________________________ by ______________________________. (6 marks)
16.
In animals with a closed circulatory system the capillaries are the site of
_____________________________________________________ between the blood and
__________________________________________. (6 marks)
© 1997 Alberta Education
Distributed by AGC/United Learning
AGC/United Learning • 1560 Sherman Ave., Suite 100 • Evanston, IL 60201 • 800-323-9084