C H A P T E R
1
R E V I E W
Chapter Expectations
Language of Biology
Briefly explain each of the following points.
Write a sentence using each of the following words or
terms. Use any six terms in a concept map to show
your understanding of how they are related.
• The subunits of every organic
macromolecule contain carbon. (1.1)
• Carbohydrates provide energy storage. (1.1)
• The structure of proteins allows them to
play important roles in an organism. (1.1)
• Indicators form the basis of standard tests
for biochemical compounds. (1.1)
• The nucleic acids in DNA have a different
monosaccharide base than the ones in
RNA. (1.1)
• Three-dimensional models of molecules
allow scientists to better understand the
structure of and interactions between
molecules. (1.1)
• The fact that phospholipids do not dissolve
in water and have a polar and a nonpolar
component makes them a useful material
from which to make cell membranes. (1.2)
• Without the proteins, cholesterol, and other
molecules in its fluid-mosaic structure, the
cell membrane could not perform its
functions. (1.2)
• As a form of passive transport, osmosis
relies on a concentration gradient. (1.3)
• In facilitated diffusion, the cell membrane
transports specific molecules in or out
without expending energy. (1.3)
• Endocytosis and exocytosis allow cells to
move large or very polar materials in and
out. (1.4)
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biochemistry
polar
nonpolar
organic compound
macromolecule
carbohydrate
monosaccharide
disaccharide
polysaccharide
starch
glycogen
cellulose
lipid
fatty acid
saturated
unsaturated
protein
amino acid
peptide bond
polypeptide
denatured
essential amino acids
nucleic acids
nucleotides
electron microscope
• phospholipid
• phospholipid bilayer
• fluid-mosaic membrane
model
• selectively permeable
membrane
• homeostasis
• extracellular fluid
• diffusion
• concentration gradient
• osmosis
• lysis
• plasmolysis
• carrier protein
• facilitated diffusion
• channel protein
• active transport
• endocytosis
• vesicle
• phagocytosis
• pinocytosis
• receptor-assisted
endocytosis
• membrane receptor
• exocytosis
UNDE RSTAN DIN G CON CEPTS
1. List the cell processes necessary for life.
2. Describe the unique properties of water that
allow life to exist.
3. Identify examples of a monosaccharide, a
disaccharide, and a polysaccharide.
4. Identify the three main types of lipids. Explain
the importance of each type.
5. Draw a diagram of a phospholipid. Label the
polar and non-polar ends.
6. What is a positive test to detect the presence of
a protein?
8. Many biological molecules are polymers, or
long chains made with repeating subunits. List
three types of polymers commonly found in
cells. Identify the subunit for each molecule.
9. (a) Draw a diagram of a water molecule. Show
how this molecule is polar.
(b) Draw a diagram of a carbon dioxide
molecule.
(c) Explain why carbon dioxide is not polar
but water is.
10. Explain how the polarity of water organizes
phospholipids into a bilayer.
7. Use a sketch to show how a single strand of
nucleic acids looks.
Exploring the Micro-universe of the Cell • MHR
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11. List three molecules that are found on or in the
cell membrane other than phospholipds.
12. Cholesterol acts to maintain the cell
membrane’s fluid consistency in extreme
environments. Suggest reasons why this is
important to the cell.
17. (a) Explain what happens to a cell placed in a
hypotonic solution.
(b) Will this be the same for a plant cell as an
animal cell? Explain.
18. What is a channel protein? Why are channel
proteins important to cells?
13. How is homeostasis important for the cell?
19. Use examples to explain how facilitated
diffusion is different from diffusion.
14. Explain the process of diffusion across a
membrane.
20. Describe the three types of endocytosis.
15. The cells in your body live in an environment
with an almost constant temperature. How
does this affect diffusion?
21. How is bulk transport different from either
passive transport or active transport?
16. Define osmosis as a special case of diffusion.
IN QU IRY
23. The effects of different solvents and of
varying solvent concentrations on membrane
permeability can be studied using beet root.
Slices of beet root were placed into one of
three solvent solutions for 10 minutes. Then
a colorimeter was used to measure the
concentration (absorbency) of each solution by
comparing its colour to that of a standard beet
solution. The tabulated data from the
experiment appear below.
(a) Which alcohol damaged the beet the most
at the lowest concentrations?
(b) Which of the three alcohols seems to affect
the beet cell membranes the most? How did
you come to this conclusion?
(c) Make a line graph for this data that would
properly identify the independent and
dependent variables.
Methanol
Ethanol
Propanol
1
0
250
250
250
2
20
300
270
262
3
40
500
350
299
4
60
625
453
366
5
80
625
630
500
6
100
628
628
600
Trial
40
Absorbency (nm)
Concentration
(%)
MHR • Cellular Functions
24. A scientist conducted an experiment that
investigated the nature of a nerve impulse
within a giant squid axon (an extension of a
nerve cell). Key to the nerve impulse is the
maintenance of sodium and potassium ion
concentrations on either side of the cell
membrane. Under normal conditions, there is
about 30 times more potassium outside of the
cell than inside and about 10 times more
sodium inside the cell than outside. The result
is that a nerve cell has an electric potential
(known as the resting potential) of about
−70 mV (millivolts) across its cell membrane.
In this experiment, dinitrophenol (DNRP) was
added incrementally to a squid axon and the
resting potential was monitored. The results
of the experiment are illustrated in the graph
below.
(a) Interpret the results.
(b) Propose a hypothesis and develop an
experiment that would investigate the
mechanism of DNRP action within the axon.
Resting Potential (mV)
22. You are interested in identifying the
macromolecules present in a popular energy
drink used by athletes. Prepare an observation
chart that lists the indicators you need to carry
out this test. Justify your choices.
35
0
0.01
0.02
0.03
0.04
0.05
−35
−70
Concentration of DNRP (mmol/L)
25. You studied osmosis with an artificial
membrane. How would the results change
with a living membrane? If a shell is carefully
removed from an egg, the membrane
underneath is left intact. Design a lab to
explore osmosis with this living membrane.
Clearly identify your predictions.
26. Three cubes of potato are placed in beakers
with different types of solution: hypertonic,
hypotonic, and isotonic. Make diagrams to
show the movement of water across the cell
membranes of the potato cells. Predict any
changes that will happen to the potato cubes
over a period of two days.
COMMU N ICATIN G
27. Figure 1.5 depicts the consequences of the fact
that water is less dense in its solid than in its
liquid state. Find out how the polarity of water
molecules accounts for this special property of
water. Then create a computer-generated
diagram to explain this.
28. Make and complete a chart to compare and
contrast active transport with passive transport.
Include a column for sample molecules.
33. The condition of the cell pictured on the right
below is called plasmolysis.
(a) Illustrate what happened to this cell using
circles of one colour to represent water
molecules, triangles of another colour for
solute molecules, and arrows to show the
direction of molecule movement.
(b) Explain why plasmolysis kills cells.
A
B
29. Draw a concept map to describe how material
from outside the cell can get inside the cell.
30. Design a poster of a cell membrane. Include
information about the function of different
parts of the cell membrane.
31. Construct a model of a protein using several
different forms for the amino acids. Explain
how your model works to a few classmates. As
a small group, decide which of the models
worked best. Justify your choice.
32. Suppose that you are a non-phospholipid in a
cell membrane. The cell is restructuring and
needs to downsize. Write a short promotional
speech to save your position.
(A) Healthy plant cell (B) Plasmolysis has occurred
M A KIN G CON N ECTION S
34. Bacteria and moulds do not grow in honey or
pickle jars, even after their containers have
been opened. Explain why.
35. Bananas are a good source of potassium ions.
Potassium is common in other foods too. What
processes would be affected by limited
amounts of potassium in the body? Use one
or more sources to find health problems
connected to such a situation.
36. Find the nutrition chart for several breakfast
cereals. Rank the cereals in order of the highest
level of carbohydrates to lowest. Look at the
marketing approach used on the cereal box.
Decide which age group is the target market for
each cereal. Suggest reasons for this.
37. Some organisms live in shallow ponds that dry
up after a few weeks of hot, dry weather. This
means that the concentration of solutes in the
water will change. How will this create
problems for the cells of organisms for whom
the pond water is their extracellular fluid?
38. All cells use combinations of the same
fundamental macromolecules. This means that
cells share common building blocks. The
molecules in your cells are much like the
molecules in a pine tree. How might this fact
be of benefit to the environment?
Exploring the Micro-universe of the Cell • MHR
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