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Chapter 7 Test Bank
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____
1. Who used a compound microscope to see chambers within cork and named them “cells”?
a. Anton van Leeuwenhoek
b. Robert Hooke
c. Matthias Schleiden
d. Rudolf Virchow
____
2. What advance in technology made the discovery of cells possible?
a. the centrifuge
b. the particle accelerator
c. the ultraviolet light
d. the microscope
____
3. Which of the following is NOT a principle of the cell theory?
a. Cells are the basic units of life.
b. All living things are made of cells.
c. Very few cells are able to reproduce.
d. All cells are produced from existing cells.
____
4. Which of these is NOT true of cells?
a. They are much like empty rooms.
b. They were first discovered in the 1600s.
c. They can be found in pond water.
d. They contain a huge array of working parts.
____
5. Electron microscopes can reveal details
a. only in specimens that are still alive.
b. about the different colors of cell structures.
c. of cell structures only once they are stained.
d. 1000 times smaller than those visible in light microscopes.
____
6. Which type of microscope can produce three-dimensional images of a cell’s surface?
a. transmission electron microscope
b. scanning electron microscope
c. simple light microscope
d. compound light microscope
____
7. Colors seen in images made from electron microscopes are
a. true to life.
b. the colors of electrons.
c. added to make certain structures easier to see.
d. added so scientists can trace living cells through the body.
____
8. Looking at a cell under a microscope, you note that it is a prokaryote. How do you know?
a. The cell lacks cytoplasm.
b. The cell lacks a cell membrane.
c. The cell lacks a nucleus.
d. The cell lacks genetic material.
____
9. Which of the following enclose their DNA in a nucleus?
a. prokaryotes
b. bacteria
c. eukaryotes
d. viruses
____ 10. Not all cells are alike. Which of the following is NOT a true statement about differences between cells?
a. Cells come in many different shapes.
b. Different kinds of cells are different sizes.
c. Some cells have a nucleus, but others do not.
d. Most cells have a membrane, but some do not.
____ 11. Which of the following organisms are prokaryotes?
a. plants
b. animals
c. bacteria
d. fungi
Figure 7–1
____ 12. Which of the following conclusions could you draw about the cell shown in Figure 7–1?
a. The cell is eukaryotic because it has a nucleus.
b. The cell is prokaryotic because it has a nucleus.
c. The cell is eukaryotic because it does not have a nucleus.
d. The cell is prokaryotic because it does not have a nucleus.
____ 13. Which of the following is a function of the nucleus?
a. stores DNA
b. stores sugars
c. builds proteins
d. packages proteins
____ 14. Which of the following best describes the relationship between the nucleus and the cytoplasm?
a.
b.
c.
d.
The cytoplasm is a fluid that fills the inside of the nucleus.
The cytoplasm is an organelle that is usually found near the nucleus.
The nucleus is an organelle that is surrounded by the cytoplasm.
The nucleus is a fluid and it mixes with the fluid cytoplasm.
____ 15. Which of the following statements about the nucleus is NOT true?
a. The nucleus stores the coded instructions for making the cell’s proteins.
b. The nucleus usually contains a nucleolus region which is where ribosome assembly
begins.
c. The nucleus is the site of protein assembly.
d. The nucleus is surrounded by a nuclear envelope that lets materials in and out.
____ 16. Which organelle breaks down organelles that are no longer useful?
a. Golgi apparatus
b. lysosome
c. endoplasmic reticulum
d. mitochondrion
____ 17. Which of the following is a function of the cytoskeleton?
a. helps a cell keep its shape
b. contains DNA
c. surrounds the cell
d. helps make proteins
____ 18. Which structures are involved in cell movement?
a. cytoplasm and ribosomes
b. nucleolus and nucleus
c. microtubules and microfilaments
d. chromosomes
Figure 7–2
____ 19. Which structure in the cell shown in Figure 7–2 above stores materials, such as water, salts, proteins, and
carbohydrates?
a. structure A
b. structure B
c. structure C
d. structure D
____ 20. Which structure makes proteins using coded instructions that come from the nucleus?
a. Golgi apparatus
b. mitochondrion
c. vacuole
d. ribosome
____ 21. Which sequence correctly traces the path of a protein in the cell?
a. ribosome, endoplasmic reticulum, Golgi apparatus
b. ribosome, endoplasmic reticulum, chloroplast
c. endoplasmic reticulum, lysosome, Golgi apparatus
d. ribosome, Golgi apparatus, endoplasmic reticulum
Figure 7–3
____ 22. Which structure in the cell shown in Figure 7–3 above modifies, sorts, and packages proteins and other
materials for storage or release from the cell?
a. structure A
b. structure B
c. structure C
d. structure D
____ 23. Which organelle converts the chemical energy stored in food into compounds that are more convenient for the
cell to use?
a. chloroplast
b. Golgi apparatus
c. endoplasmic reticulum
d. mitochondrion
____ 24. Which organelles are involved in energy conversion?
a. mitochondria and chloroplasts
b. mitochondria and ribosomes
c. smooth and rough endoplasmic reticulum
d. Golgi apparatus and chloroplasts
____ 25. Which organelle would you expect to find in plant cells but not animal cells?
a. mitochondrion
b. ribosome
c. chloroplast
d. smooth endoplasmic reticulum
____ 26. The primary function of the cell wall is to
a. support and protect the cell.
b. store DNA.
c. direct the activities of the cell.
d. help the cell move.
____ 27. Unlike the cell membrane, the cell wall is
a. found in all organisms.
b. composed of a lipid bilayer.
c. selectively permeable.
d. a rigid structure.
____ 28. You will NOT find a cell wall in which of these kinds of organisms?
a. plants
b. animals
c. fungi
d. bacteria
____ 29. Which of the following structures serves as the cell’s boundary from its environment?
a. mitochondrion
b. cell membrane
c. chloroplast
d. channel protein
____ 30. Which of the following is a function of the cell membrane?
a. breaks down lipids, carbohydrates, and proteins from foods
b. stores water, salt, proteins, and carbohydrates
c. keeps the cell wall in place
d. regulates the movement of materials into and out of the cell
____ 31. The cell membrane contains channels and pumps that help move materials from one side to the other. What
are these channels and pumps made of?
a. carbohydrates
b. lipids
c. bilipids
d. proteins
____ 32. Diffusion occurs because
a. molecules are attracted to one another.
b. molecules constantly move and collide with each other.
c. cellular energy forces molecules to collide with each other.
d. cellular energy pumps molecules across the cell membrane.
____ 33. During diffusion, when the concentration of molecules on both sides of a membrane is the same, the
molecules will
a. move across the membrane to the outside of the cell.
b. stop moving across the membrane.
c. continue to move across the membrane in both directions.
d. move across the membrane to the inside of the cell.
____ 34. The diffusion of water across a selectively permeable membrane is called
a. osmotic pressure.
b. osmosis.
c. pinocytosis.
d. active transport.
____ 35. An animal cell that is surrounded by fresh water will burst because the osmotic pressure causes
a. water to move into the cell.
b. water to move out of the cell.
c. solutes to move into the cell.
d. solutes to move out of the cell.
____ 36. Which means of particle transport requires input of energy from the cell?
a. diffusion
b. osmosis
c. facilitated diffusion
d. active transport
Figure 7–4
____ 37. Which means of particle transport is shown in Figure 7–4 above?
a. diffusion
b. osmosis
c. facilitated diffusion
d. active transport
Figure 7–5
____ 38. Which means of particle transport is shown in Figure 7–5 above?
a. endocytosis
b. exocytosis
c. facilitated diffusion
d. protein pump
____ 39. Which of the following activities is NOT a way that unicellular organisms maintain homeostasis?
a. reproduction
b. growth
c. cell specialization
d. response to the environment
____ 40. Which term describes the relatively constant internal physical conditions of an organism?
a. cell specialization
b. homeostasis
c. organ system
d. unicellularity
____ 41. The cells of unicellular organisms are
a. specialized to perform different tasks.
b. larger than those of multicellular organisms.
c. able to carry out all of the functions necessary for life.
d. unable to respond to changes in their environment.
____ 42. Which of the following is an example of an organ?
a. heart
b. epithelial tissue
c. digestive system
d. nerve cell
____ 43. A group of similar cells that perform a particular function is called
a. an organ.
b. an organ system.
c. a tissue.
d. a division of labor.
____ 44. An organ system is a group of organs that
a. are made up of similar cells.
b. are made up of similar tissues.
c. work together to perform a specific function.
d. work together to perform all the functions in a multicellular organism.
____ 45. Which list represents the levels of organization in a multicellular organism from the simplest level to the most
complex level?
a. cell, tissue, organ system, organ
b. organ system, organ, tissue, cell
c. tissue, organ, organ system, cell
d. cell, tissue, organ, organ system
Modified True/False
Indicate whether the statement is true or false. If false, change the identified word or phrase to make the statement true.
____
1. Viruses are not made up of cells. Therefore, viruses are not considered to be living things.
_________________________
____
2. A scanning electron microscope allows light to pass through a specimen and focuses it using two lenses to
form an image. _________________________
____
3. Prokaryotic and eukaryotic cells are surrounded by a thin, flexible barrier called a cell membrane.
_________________________
____
4. The assembly of ribosomes begins in a small dense structure called the chromatin.
_________________________
____
5. Flagella made up of microtubules help organize cell division. _________________________
____
6. Cilia and flagella are made of protein filaments called endoplasmic reticulum. _________________________
Figure 7–6
____
7. Structure D represented in Figure 7–6 is the smooth endoplasmic reticulum. _________________________
____
8. Ribosomes that synthesize proteins are found on the smooth endoplasmic reticulum.
_________________________
____
9. Plant cells have chloroplasts but not mitochondria. _________________________
____ 10. Water, carbon dioxide, oxygen, and some other substances can pass through the cell wall.
_________________________
____ 11. Once equilibrium is reached, roughly equal numbers of molecules move in either direction across a
semipermeable membrane, and there is no further change in concentration on either side of the membrane.
_________________________
____ 12. Proteins called aquaporins are important to the movement of water through cell membranes. These proteins
participate in active transport. _________________________
____ 13. Moving materials from an area of low concentration to an area of high concentration requires active transport.
_________________________
____ 14. A cell in a multicellular organism must be able to carry out all of the functions necessary for life in order for
the organism to survive. _________________________
____ 15. There is a division of labor among the cells of multicellular organisms. _________________________
Completion
Complete each statement.
1. According to the cell theory, all cells come from existing ____________________.
2. Electrons pass through thin slices of cells or tissues and produce flat, two-dimensional images in
____________________ electron microscopy.
3. Depending on whether they have a ____________________, unicellular organisms are classified as either
eukaryotes or prokaryotes.
Figure 7–7
4. The small, dense region indicated in Figure 7–7 by the letter D is called the ____________________.
5. Most of the time, the cell’s genetic information is found as threadlike _________________________ in the
cell’s nucleus.
Figure 7–6
6. The storage structure indicated in Figure 7–6 by the letter F is a(an) ____________________ .
7. Cells that need to make a lot of protein are expected to have a large number of ________________.
8. In plants, ____________________ capture energy from sunlight and convert it into chemical energy, whereas
____________________ convert chemical energy into compounds that are convenient for the cell to use.
9. The cell takes in food and water and eliminates wastes through its selectively permeable
_________________________.
10. Molecules tend to move from an area where they are more concentrated to an area where they are less
concentrated. This process is called ____________________.
11. Large molecules, such as glucose, that cannot cross the lipid bilayer can still move across the membrane
through a type of passive transport called _________________________.
12. Some materials can move across the cell membrane against a concentration gradient by
____________________.
13. A cell’s relatively constant internal physical and chemical conditions are called
_________________________.
14. The cells in a multicellular organism have specific jobs. This is called cell _________________________.
15. Cells within a multicellular organism communicate by chemical signals. In order to receive and respond to a
certain chemical signal, a cell must have a ________________ for that chemical.
Short Answer
1. What does the cell theory say?
2. What kinds of microscopes could you use to look at the structure of DNA? Could you study the structure of
DNA in a living specimen? Why or why not?
Figure 7–8
3. Is the cell in Figure 7–8 above a prokaryote or a eukaryote? What features help you determine your answer?
4. How do prokaryotes and eukaryotes differ?
5. How is the nucleus of a cell like the main office of a large factory?
6. List two functions of the cytoskeleton.
Figure 7–7
7. Identify each of the cell structures indicated in Figure 7–7. Use these terms: nucleus, mitochondrion,
ribosome, cell membrane, smooth endoplasmic reticulum, rough endoplasmic reticulum, nucleolus, Golgi
apparatus, cytoplasm.
Figure 7–9
8. Which structures in the cells shown in Figure 7–9 above are responsible for meeting the cells’ energy needs?
Based on the presence or absence of these structures, identify which cell is a plant cell.
9. What advantages do cell walls provide plant cells that contact fresh water?
10. What would happen if a cell’s membrane became impermeable?
11. Suppose you add a teaspoon of sugar to a cup of coffee, and the sugar molecules disperse themselves
throughout the hot coffee. What process has occurred? How do you know?
12. Explain, in terms of osmosis, why a raisin placed in a cup of pure water overnight will puff up with water.
13. What would happen to an animal cell with an internal salt concentration of 0.8% if it were placed in a salt
solution with a concentration of 0.2%? Why?
14. How are endocytosis and exocytosis similar? How are they different?
15. List the four levels of organization in a multicellular organism in order from simplest to most complex.
Science Skills
A student put together the experimental setup shown below. The selectively permeable membrane is
permeable to water, but not the solute shown.
Figure 7–10
1. Interpret Visuals Describe the experimental setup shown in Figure 7–10.
2. Compare and Contrast How does the solution on Side A of the apparatus shown in Figure 7–10 differ from
the solution on Side B?
3. Predict Look at Figure 7–10. Describe the movement of water in the experimental setup. What will happen to
the concentration of water over time?
4. Predict What will the apparatus shown in Figure 7–10 look like when equilibrium is reached?
5. Predict Once equilibrium is reached in the apparatus shown in Figure 7–10, will the water molecules
continue to move? Explain your answer.
Figure 7–11
6. Interpret Visuals Which drawing in Figure 7–11, I or II, contains structures that carry out photosynthesis?
What is this structure labeled in the diagram?
7. Compare and Contrast Look at Figure 7–11. Which structure in drawing I corresponds to structure L in
drawing II? What is the name of this structure?
8. Compare and Contrast Which three structures are found in drawing II of Figure 7–11 but not in drawing I?
What are the names of these structures?
9. Interpret Visuals Which organelle is labeled K in Figure 7–11? What is the function of this organelle?
10. Interpret Visuals Do the drawings in Figure 7–11 represent prokaryotes or eukaryotes? How do you know?
The experimental setup below shows an osmometer. An osmometer is a device used to measure the amount of
osmotic pressure exerted by a liquid passing through a semipermeable membrane. The graph shows one lab
group’s results compared with the results of the rest of the class combined. Line A represents the results of the
single lab group. Line B represents the data of the rest of the class.
Figure 7–12
11. Compare and Contrast Look at the graph in Figure 7–12. Compare the lab results of the single lab group
with those collected by the rest of the class.
12. Analyze Data Which results in the graph in Figure 7–12 are more likely to be accurate, those represented by
line A or by line B? Why?
13. Evaluate and Revise What could account for the difference in lines A and B in the graph in Figure 7–12?
14. Predict Look at the graph in Figure 7–12. How would the results differ if a sucrose solution with twice the
concentration of the one used to collect the results represented by line A were used?
15. Calculate How might you use the graph in Figure 7–12 to calculate the rate of osmosis observed? What units
would you use to report the rate?
Essay
1. Summarize three statements from the cell theory. Explain the significance of the cell theory to biology.
2. Describe the cell membrane, cell wall, nucleus, and cytoplasm. Which of these structures are you likely to
find in a prokaryotic cell? Eukaryotic cell? Plant cell? Animal cell?
3. Distinguish between microtubules and microfilaments. Describe two functions of each kind of structure.
4. Compare and contrast the structure and function of the cell wall with that of the cell membrane.
5. Why is the cell membrane sometimes compared to mosaic art?
Figure 7-13
6. The diagrams in Figure 7-13 above show a normal blood cell before and after it is placed in a solution.
Describe what could cause the cell to react the way that it did.
7. What are aquaporins? How are they important to cells?
8. How do facilitated diffusion and active transport differ? Is osmosis an example of facilitated diffusion or
active transport?
9. Compare a cell from a unicellular organism with a cell from a multicellular organism in terms of cell
specialization.
10. Discuss the levels of organization in multicellular organisms and explain why these levels are not used to
describe unicellular organisms.
Chapter 7 Test Bank
Answer Section
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knowledge
comprehension
comprehension
synthesis
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comprehension
comprehension
application
knowledge
comprehension
comprehension
application
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synthesis
analysis
comprehension
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application
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synthesis
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analysis
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synthesis
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application
knowledge
comprehension
analysis
MODIFIED TRUE/FALSE
1. ANS: T
2. ANS: F, light
PTS: 1
BLM: application
PTS: 1
3. ANS: T
4. ANS: F, nucleolus
BLM: comprehension
PTS: 1
BLM: knowledge
PTS: 1
5. ANS: F, centrioles
BLM: comprehension
PTS: 1
BLM: comprehension
6. ANS: F, microtubules
PTS: 1
7. ANS: F, rough
BLM: comprehension
PTS: 1
8. ANS: F, rough
BLM: application
PTS: 1
9. ANS: F, and
BLM: comprehension
PTS: 1
10. ANS: T
11. ANS: T
12. ANS: F
passive transport
facilitated diffusion
osmosis
BLM: synthesis
PTS: 1
PTS: 1
PTS: 1
BLM: comprehension
13. ANS: T
PTS: 1
14. ANS: F, unicellular
PTS: 1
15. ANS: T
COMPLETION
1. ANS: cells
BLM: comprehension
BLM: comprehension
BLM: synthesis
BLM: synthesis
PTS: 1
BLM: comprehension
PTS: 1
BLM: comprehension
2. ANS: transmission
PTS: 1
3. ANS: nucleus
BLM: comprehension
PTS: 1
4. ANS: nucleolus
BLM: synthesis
PTS: 1
BLM: knowledge
5. ANS: chromosomes
PTS: 1
BLM: comprehension
6. ANS: vacuole or central vacuole
PTS: 1
7. ANS: ribosomes
BLM: synthesis
PTS: 1
BLM: analysis
8. ANS: chloroplasts, mitochondria
PTS: 1
BLM: synthesis
9. ANS: cell membrane
PTS: 1
10. ANS: diffusion
BLM: comprehension
PTS: 1
BLM: knowledge
11. ANS: facilitated diffusion
PTS: 1
BLM: synthesis
12. ANS: active transport
PTS: 1
13. ANS: homeostasis
BLM: comprehension
PTS: 1
BLM: knowledge
14. ANS: specialization
PTS: 1
15. ANS: receptor
PTS: 1
SHORT ANSWER
1. ANS:
BLM: knowledge
BLM: comprehension
The cell theory says that all living things are composed of cells. It also says that cells are the basic units of
structure and function in living things and that new cells come from existing cells.
PTS: 1
BLM: knowledge
2. ANS:
DNA is too small to see with a light microscope, so an electron microscope is needed to examine its structure.
Electron microscopes cannot be used to look at living specimens, so the structure of DNA cannot be studied
in a living specimen.
PTS: 1
BLM: application
3. ANS:
This cell is a prokaryote. It has a cell wall, indicated by the letter B, and its DNA, indicated by the letter C, is
not enclosed in a nucleus.
PTS: 1
BLM: evaluation
4. ANS:
Prokaryotes are generally simpler and smaller than eukaryotes, whereas eukaryotes enclose their DNA in a
nucleus and have other specialized organelles.
PTS: 1
BLM: analysis
5. ANS:
The nucleus is the control center of the cell and contains nearly all the cell’s DNA, which gives the cell the
instructions it needs to make proteins and other molecules.
PTS: 1
BLM: analysis
6. ANS:
The cytoskeleton helps the cell maintain its shape and internal organization. It is also involved in many forms
of cell movement.
PTS: 1
BLM: knowledge
7. ANS:
(A) rough endoplasmic reticulum; (B) cytoplasm; (C) smooth endoplasmic reticulum; (D) nucleolus; (E)
nucleus; (F) mitochondrion; (G) Golgi apparatus; (H) ribosome; (I) cell membrane
PTS: 1
BLM: application
8. ANS:
The structure identified with the letter E is a chloroplast, which captures energy from sunlight and converts it
into chemical energy. The structures identified with the letter D are mitochondria, which convert chemical
energy into compounds more convenient for the cell to use. The cell with the chloroplasts is a plant cell.
PTS: 1
BLM: evaluation
9. ANS:
Cell walls protect the plant cells from expanding even under tremendous osmotic pressure.
PTS: 1
BLM: synthesis
10. ANS:
The cell would die because needed nutrients, such as food and water, could not get inside the cell and wastes
would accumulate inside the cell.
PTS: 1
BLM: evaluation
11. ANS:
Diffusion has occurred; because diffusion is the movement of a substance from an area of high concentration
to an area of lower concentration.
PTS: 1
BLM: application
12. ANS:
Because the concentration of water in the cup is greater than the concentration of water in the raisin, water
will flow from the cup into the raisin.
PTS: 1
BLM: application
13. ANS:
The cell would swell and burst, because the 0.2% salt solution is hypotonic with respect to the cell, causing a
net movement of water into the cell.
PTS: 1
BLM: synthesis
14. ANS:
Both are forms of active transport of large molecules carried out by movements of the cell membrane.
Endocytosis involves taking material into the cell, whereas exocytosis involves moving material out of the
cell.
PTS: 1
BLM: analysis
15. ANS:
cell, tissue, organ, organ system
PTS: 1
BLM: knowledge
SCIENCE SKILLS
1. ANS:
The experimental setup shows a solution with differing concentrations of solute separated by a selectively
permeable membrane. The membrane is permeable to water but not the solute.
PTS: 1
BLM: analysis
2. ANS:
The solution on Side A has fewer solute particles than the solution on Side B. Both solutions have the same
amount of water, so the solution on Side A is hypotonic compared to the solution on Side B.
PTS: 1
BLM: analysis
3. ANS:
The membrane is permeable to water so water can cross the membrane in both directions. Over time, there
will be a net movement of water toward Side B, which has a higher concentration of solute particles.
PTS: 1
BLM: application
4. ANS:
At equilibrium, Side A will have less water than Side B and the concentration of solute molecules will be
equal on either side of the selectively permeable membrane.
PTS: 1
5. ANS:
BLM: analysis
Yes, the water molecules will continue to move across the membrane; however, there will not be a net
movement from one side to the other.
PTS: 1
BLM: application
6. ANS:
Drawing II—a plant cell—contains the structure described (a chloroplast). The structure is labeled N.
PTS: 1
BLM: knowledge
7. ANS:
Structure I. They both represent the cell membrane.
PTS: 1
BLM: analysis
8. ANS:
Structures J, N, and O. Structure J is the cell wall, structure N is a chloroplast, and structure O is a vacuole.
PTS: 1
BLM: analysis
9. ANS:
The organelle labeled K is the nucleus. The nucleus stores DNA and directs the activities of the cell.
PTS: 1
BLM: knowledge
10. ANS:
Both drawings represent eukaryotes, as shown by the presence of a nucleus.
PTS: 1
BLM: application
11. ANS:
Line A shows that the single group’s results are quite different from the results of the rest of the class. Over a
half-hour period, the lab group found that the solution traveled 25 mm, whereas the rest of the class found a
distance of only 12 mm over the same period of time. The distance traveled in the lab group’s data also kept
increasing, whereas the class’ data leveled out at about 10 minutes.
PTS: 1
BLM: analysis
12. ANS:
The rest of the class’s results (line B) are more likely to be accurate because they represent a larger sample
size.
PTS: 1
BLM: evaluation
13. ANS:
The lab group (line A) might have used a more concentrated solution of sucrose or a membrane with a
different permeability.
PTS: 1
BLM: evaluation
14. ANS:
The more concentrated the solution, the longer distance the solution will travel over the same period of time.
Thus, a more concentrated solution would produce a longer distance.
PTS: 1
BLM: synthesis
15. ANS:
The rate of osmosis could be calculated by dividing the distance traveled by time. The units would be
mm/min.
PTS: 1
BLM: analysis
ESSAY
1. ANS:
The cell theory states that all living things are composed of cells. It also says that cells are the basic units of
structure and function in living things, and that new cells come from existing cells. The cell theory is
significant to biology because all living thing are made of cells. Differences in the structure and function of
different life forms are reflected in differences in their cell structures.
PTS: 1
BLM: analysis
2. ANS:
The cell membrane is a thin, flexible barrier around the cell. The cell wall is a strong layer that surrounds the
cell membrane in some cells. The nucleus is a large structure found in some cells. It contains the cell’s genetic
material and controls the cell’s activities. The fluid portion of the cell outside the nucleus (if present), is the
cytoplasm. All cells have a cell membrane and cytoplasm. Only eukaryotes have a nucleus. Animal cells do
not have a cell wall, but plant cells and some prokaryotes do.
PTS: 1
BLM: synthesis
3. ANS:
Microtubules are hollow tubes of protein that help maintain the shape of a cell. Microtubules also make up
cilia and flagella, which function in cell movement. Microfilaments are long, thin fibers that are narrower than
microtubules. Microfilaments function in the movement and support of the cell.
PTS: 1
BLM: synthesis
4. ANS:
The cell wall lies outside the cell membrane of many cells, including those of plants, algae, and fungi. It
supports and protects the cell and often allows water, oxygen, carbon dioxide, and other materials to pass
through it. Most cell walls are rigid and made of carbohydrates and proteins. In contrast, the cell membrane is
a thin, flexible membrane made of a lipid bilayer with proteins that run through it and carbohydrate chains
attached to proteins poking out on the outer surface of the cell membrane. Like the cell wall, the cell
membrane provides protection and support to the cell and allows materials to pass through it. In fact, the cell
membrane regulates the movement of materials into and out of the cell.
PTS: 1
BLM: analysis
5. ANS:
Like a piece of mosaic art, which is made of different tiles, the cell membrane is made up of many different
kinds of molecules. The background is a lipid bilayer. Within this bilayer are proteins that form channels and
pumps that help move materials from one side of the membrane to the other. Carbohydrates on the outer
surface of the membrane act like chemical identification cards and allow cells to identify one another.
PTS: 1
BLM: analysis
6. ANS:
When a normal red blood cell is placed in a hypertonic solution, one that has a higher solute concentration
than inside the cell, there is a net movement of water out of the cell. The cell will shrink due to osmotic
pressure.
PTS: 1
7. ANS:
BLM: application
Aquaporins are proteins that form channels in cell membranes. These channels allow water molecules to pass
through the membrane. This is important because the lipid bilayer that makes up cell membranes is
hydrophobic, so water molecules have a hard time getting through it. Aquaporins allow water to pass through
the membrane by facilitated diffusion.
PTS: 1
BLM: application
8. ANS:
Facilitated diffusion involves the movement of molecules across a membrane through protein channels. The
molecules move from an area of high concentration to an area of lower concentration. Facilitated diffusion
does not require additional energy. Active transport is the movement of particles across the cell membrane
using energy. Molecules can move from an area of low concentration to an area of higher concentration in
active transport. Osmosis is an example of facilitated diffusion.
PTS: 1
BLM: analysis
9. ANS:
The cell from the unicellular organism carries out all the life processes of the organism. It is not specialized.
The cell from the multicellular organism is specialized and carries out only certain functions in the organism,
while relying on other cells in the multicellular organism to complete other life processes.
PTS: 1
BLM: analysis
10. ANS:
The levels of organization in a multicellular organism include cells, tissues, organs, and organ systems.
Similar cells are grouped into tissues; tissues that work together form organs; a group of organs that work
together make up an organ system. Unicellular organisms cannot have cell specialization. Instead, all of the
activities of the organism must be carried out by the single cell.
PTS: 1
BLM: analysis