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CHAPTER 1
CYU 1.1 p.6
1. No, volcanoes are not living things. Although they appear to possess some of the characteristics of living things,
such as growth and breathing out waste gases, they do not possess all the characteristics. For example, volcanoes
are not made of cells.
2. Many answers are possible. A sample answer is provided below.
Characteristic of living things
Non-living things
Living things require energy.
Light bulbs require electricity to work.
Living things respond to the environment.
The wind moves clothes on a clothesline.
Living things reproduce, grow, and repair
A volcano appears to grow.
themselves.
Living things have a lifespan.
Rocks erode and seem to disappear.
Living things produce wastes.
Wastes are produced during the extraction of gold
from ore.
Living things are composed of cells.
Only living things have cells.
3. A living thing is composed of a cell or a number of cells, it requires energy, it responds to environmental stimuli, it
can reproduce, it produces wastes, and it has a finite lifespan. Non-living things may have one or more of these
characteristics. Something is not considered to be a living thing, however, unless it shows all the characteristics.
4. (a) The plant responds to an environmental stimulus, the light.
(b) Living things produce offspring like themselves. Eventually, the tadpole matures into a frog. Also, living things have
a lifespan. The tadpole is one of the life stages of the frog.
(c) Living things produce wastes. Carbon dioxide is a waste that is expelled from the body.
(d) Living things require energy. The seed provides chemical energy for the blue jay.
(e) Living things produce offspring like themselves.
CYU 1.3 p.13HECK YOUR UNDERSTANDING—SUGGESTED ANSWERS
1.
Structure
Function
nucleus
is control centre of cell; directs cell activities
Animal cell
Plant cell
✓
✓
chromosome
contains genetic material
✓
✓
cell membrane
controls movement of materials into and out of cell
✓
✓
cytoplasm
✓
✓
vacuole
allows materials to be transported between cell structures; stores
wastes before disposal
stores water and nutrients
✓
✓
cell wall
protects and supports a plant cell
✓
chloroplast
produces food using light from the Sun
✓
flagellum
allows movement
✓
cilia
cilia allows movement of liquid or other substances around the cell
✓
2.
Similarities between plant and animal cell structures:
• Both plant and animal cells have a cell membrane.
• Both have a nucleus that contains chromosomes.
• Both contain cytoplasm.
• Both contain organelles.
Differences between plant and animal cell structures:
• Plants contain chloroplasts.
• Plants have a cell wall.
• The vacuole is proportionately larger in plant cells.
• Some animal cells have cilia or a flagellum.
3. The genetic material is found in the chromosomes of the nucleus.
4. Accept a wide variety of conclusions, such as the following:
• The cell has mutated.
• The cell is dividing.
• This type of cell has two nuclei. (Some cells, such as cardiac muscle cells and moulds, are multinucleated.)
5. The cell would not be able to receive any nutrients and would not be able to eliminate wastes. The cell would die.
6. The cells lining the trachea (windpipe) might have cilia. Cilia would prevent dust and debris from entering the lungs
and clogging the alveoli (small sacs), where oxygen is absorbed.
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CYU 1.5 p. 18
1. Two lenses permit greater magnification without reducing clarity. Remind students that thicker lenses distort light
more than thinner lenses. By using two lenses, magnification is increased by multiplying the ocular lens by the object
lens.
2. Living objects can be viewed using the scanning electron microscope. This microscope has a wider field of view, and
objects do not have to be encased in plastic.
3. A single-lens microscope shows the arrangement of the cells. A light microscope shows some internal structures of
the algae cells. A transmission electron microscope shows the internal structures in greater detail. A scanning electron
microscope shows the three-dimensional structure of the algae cells.
4. Students’ answers may vary. Examples are provided.
(a) Transmission electron microscope—the nucleus is small, and a TEM provides the greatest magnification.
(b) Light microscope—slide preparation is quick and easy, and does not kill the cell.
CYU 1.6 p.21
1. Organelles are specialized structures that are found in the cytoplasm of a cell.
2. Students’ concept maps will vary. Accept all connections that students can reasonably explain. Check that students
have included most of the following terms: cell membrane, cell wall, control, chloroplasts, cytoplasm, endoplasmic
reticulum, energy, food production, Golgi apparatus, lysosomes, material storage, material transport, mitochondria,
nuclear membrane, nucleus, protein manufacturing, protein storage, protection, ribosomes, recycling, rough, surrounds,
vacuole.
3. No energy would be available to the cell. Any cell function that requires energy would be impaired. The cell would die.
4. Stomach cells make protein. You would expect cells that secrete enzymes (proteins) to have many Golgi
apparatuses, because protein is stored inside the Golgi apparatus.
CYU 1.7 p.24
1. Diffusion can be explained as the movement of molecules from an area of higher concentration to an area of lower
concentration.
2. Impermeable materials do not allow any substances through. Selectively permeable membranes allow some
substances through, but not others. Permeable membranes allow all substances in contact with them to move through.
3. Cells have a selectively permeable membrane. The cell membrane permits some substances to enter, but keeps
other substances out.
4. Pores of different sizes allow different-sized molecules through the membrane.
Smaller molecules move through smaller pores.
5. Cells could not survive without diffusion because diffusion allows nutrients to enter the cell and waste materials to
leave the cell—both essential processes for keeping cells alive.
6. If a cell membrane were permeable instead of selectively permeable, then all sorts of molecules could enter the cell,
including molecules of substances that might be harmful to the cell.
7. (a) When a glass of lemonade is spilled in a swimming pool, the molecules of lemonade gradually diffuse throughout
the pool. The concentration of lemonade molecules in the pool is so low that you would not be able to detect the
lemonade.
(b) If poisonous chemicals were dumped into a lake from which a town draws its water supply, the chemicals would
spread throughout the lake by diffusion and by wind and currents mixing the water. Eventually these chemicals would
make their way into the homes of the town through the town’s water supply system. This might pose a health risk,
depending on the amount (concentration) of the poisonous chemicals in the lake.
8. Two situations where substances are spread around by diffusion are the aroma of cooking or baking at home and
smoke or pollution in the atmosphere (also spread by wind or air currents).
CYU 1.8 p.28
1. Osmosis is the movement of water through a selectively permeable membrane. Diffusion involves the movement of
solutes and does not require a selectively permeable membrane.
2. Water moves from an area of high concentration to an area of low concentration.
3. The cell wall prevents a plant cell from bursting when it is full of water.
4. Plant cells have a supportive structure, the cell wall, but animal cells do not.
5. Turgor pressure is the water pressure exerted on a cell wall.
6. The higher concentration on the outside causes water to move into the plant cells, increasing turgor pressure and
thereby making the plant firmer.
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CHAPTER 1 REVIEW ANSWERS p.38
1. The two main ideas in the cell theory are that all things are composed of one or more cells and that all cells arise only
from cells that already exist.
2. No, large animals do not necessarily have larger cells than small animals. Large animals do have more cells than
small animals, however. Most animals are multicellular; their cells are specialized to perform specific functions.
3. Students’ diagrams should show that the plant cell has shrunk, and the cell membrane has pulled away from the cell
wall. The animal cell will also shrink, but there is no cell wall. The cell appears to shrivel because water is lost from the
cytoplasm.
4. (a) T
(b) F: The light microscope allows scientists to see cells.
(c) F: It is easy to tell animal cells from plant cells, because all plant cells have a cell wall and many plant cells have
chloroplasts.
(d) F: All plant cells are surrounded by a cell wall.
(e) T
(f) T
(g) F: Diffusion occurs when molecules move from an area of high concentration to an area of low concentration.
(h) T
5. Water enters the red blood cell by osmosis. The cell bursts when too much water has entered it.
6. (a) animal
(b) plant
(c) plant
(d) plant
(e) animal
(f) animal
7. The cell membrane must be permeable to sugar. It takes time for the sugar concentration to reach equilibrium (equal
concentration inside and outside the cell). The cell uses sugar.
8. In hemodialysis, the patient’s bloodstream is connected to a machine. The blood is circulated through the machine,
and wastes diffuse out of the blood. In peritoneal dialysis, 2 L of dialysis solution is poured inside the patient’s abdominal
cavity, and wastes diffuse out of the cells of the cavity membranes into the solution. After a while, the solution with the
wastes is drained from the abdominal cavity. Hemodialysis may be more efficient because the wastes are removed
directly from the blood. The patient has to go to a hospital or clinic, however, and be connected to the machine for 3 or 4
h, two or three times a week. Peritoneal dialysis can be done at home, but it has to be done daily. As peritoneal dialysis
is occurring, the patient can continue with less strenuous activities.
9. To keep the organism within the field of view, the slide should be moved toward D.
10. (a) If athletes drink pure water after exercise, their red blood cells swell because the pure water creates a solution in
which the concentration of solute molecules outside the cells is less than the concentration of solute molecules inside
the cells. Water moves into the red blood cells by osmosis, and the red blood cells swell.
(b) Immerse red blood cells in solutions of varying solute concentrations. Observe the cells after a period of time. Those
that do not change in shape (i.e., do not shrink or expand) are in the most suitable concentration of solutes.
11. Students’ answers will vary. For example, a microscope that could see inside cells without killing the cells would
benefit society. Such a microscope could look inside the cells of a living organism without harming the cells or the
organism. This would be helpful for diagnosing diseases such as cancer.
12. Muscles work by contracting. The long thin shape of the cell in diagram C is better suited for contraction.
13. (a) The student was attempting to answer a question such as “How does temperature affect the rate of fluid
movement in plants?”
(b) If fluids are at higher temperatures, then the rate of fluid movement in plants increases.
(c) The independent variable is the temperature of the fluid. The dependent variable is the rate of fluid movement.
(d) The rates of diffusion are indicated by the rates at which the dye moves up the celery stalks.
(e) The celery stalk in the 40 ºC solution would have the greatest movement of dye. Molecules move faster at higher
temperatures.
(f) Errors could be made in the measurement of the distance the dye moves. The experimental design could be
improved by having celery stalks that are the same size and the same health.
14. Scientists would need to consider whether it displays all the characteristics of living things before they could classify
it as an organism.
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15. Students’ answers will vary. Students should mention the importance of controlling all variables (other than the
independent variable) that might possibly have an effect on the outcome. This would enable them to draw more valid
conclusions, since these variables would be eliminated as a possible explanation of the results. Students should also
mention the importance of making accurate observations and measurements. As well, students may indicate that
repeating an investigation will produce more accurate or reliable results.
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