,OpenStax Concepts of Biology Instructor Answer Guide
Concepts of Biology
Unit 1. The Cellular Foundation of Life
Chapter 1: Introduction to Biology
Art Connection Questions
1. Figure 1.8
Which of the following statements is false?
A. Tissues exist within organs which exist within organ systems.
B. Communities exist within populations which exist within ecosystems.
C. Organelles exist within cells which exist within tissues.
,OpenStax Concepts of Biology Instructor Answer Guide
D. Communities exist within ecosystems which exist in the biosphere.
Answer
B. Communities exist within populations which exist within ecosystems.
2. Figure 1.18
In the example below, the scientific method is used to solve an everyday problem.
Which part in the example below is the hypothesis? Which is the prediction? Based on
the results of the experiment, is the hypothesis supported? If it is not supported,
propose some alternative hypotheses.
1. My toaster doesn’t toast my bread.
2. Why doesn’t my toaster work?
3. There is something wrong with the electrical outlet.
4. If something is wrong with the outlet, my coffeemaker also won’t work when plugged
into it. 5. I plug my coffeemaker into the outlet.
6. My coffeemaker works.
Answer
The hypothesis is #3 (there is something wrong with the electrical outlet), and the
prediction is #4 (if something is wrong with the outlet, then the coffeemaker also won’t
work when plugged into the outlet). The original hypothesis is not supported, as the
coffee maker works when plugged into the outlet. Alternative hypotheses may include
(1) the toaster might be broken or (2) the toaster wasn’t turned on
,OpenStax Concepts of Biology Instructor Answer Guide
Review Questions
3. The smallest unit of biological structure that meets the functional requirements of “living” is
the ________.
Answer
C. cell
4. Which of the following sequences represents the hierarchy of biological organization from the
most complex to the least complex level?
Answer
D. biosphere, ecosystem, community, population, organism
5. A suggested and testable explanation for an event is called a ________.
Answer
A. hypothesis
6. The type of logical thinking that uses related observations to arrive at a general conclusion is
called ________.
Answer
D. inductive reasoning
Critical Thinking Questions
7. Using examples, explain how biology can be studied from a microscopic approach to a global
approach.
Answer
Researchers can approach biology from the smallest to the largest, and everything in
between. For instance, an ecologist may study a population of individuals, the
population’s community, the community’s ecosystem, and the ecosystem’s part in the
biosphere. When studying an individual organism, a biologist could examine the cell and
its organelles, the tissues that the cells make up, the organs and their respective organ
systems, and the sum total—the organism itself.
8. Give an example of how applied science has had a direct effect on your daily life.
Answer
Answers will vary. One example of how applied science has had a direct effect on daily
life is the presence of vaccines. Vaccines to prevent diseases such polio, measles,
tetanus, and even the influenza affect daily life by contributing to individual and societal
health.
,OpenStax Concepts of Biology Instructor Answer Guide
Concepts of Biology
Unit 1. The Cellular Foundation of Life
Chapter 2: Chemistry of Life
Art Connection Questions
1. Figure 2.3. How many neutrons do (K) potassium-39 and potassium-40 have,
respectively?
Answer
Potassium-39 has twenty neutrons. Potassium-40 has twenty one neutrons.
Review Questions
2. Magnesium has an atomic number of 12. Which of the following statements is true of
a neutral magnesium atom?
Answer
A. It has 12 protons, 12 electrons, and 12 neutrons.
3. Which type of bond represents a weak chemical bond?
Answer
A. hydrogen bond
4. An isotope of sodium (Na) has a mass number of 22. How many neutrons does it have?
,OpenStax Concepts of Biology Instructor Answer Guide
Answer
A. 11
5. Which of the following statements is not true?
Answer
D. Water is the most abundant atom in Earth’s atmosphere.
6. Using a pH meter, you find the pH of an unknown solution to be 8.0. How would you describe
this solution?
Answer
C. weakly basic
7. The pH of lemon juice is about 2.0, whereas tomato juice's pH is about 4.0. Approximately
how much of an increase in hydrogen ion concentration is there between tomato juice and lemon
juice?
Answer
C. 100 times
8. An example of a monosaccharide is ________.
Answer
D. all of the above (fructose, glucose, galactose)
9. Cellulose and starch are examples of ________.
Answer
D. polysaccharides
10. Phospholipids are important components of __________.
Answer
A. the plasma membrane of cells
11. The monomers that make up proteins are called _________.
Answer
C. amino acids
Critical Thinking Questions
12. Why are hydrogen bonds and van der Waals interactions necessary for cells?
Answer
Hydrogen bonds and van der Waals interactions form weak associations between
different molecules. They provide the structure and shape necessary for proteins and
DNA within cells so that they function properly. Hydrogen bonds also give water its
unique properties, which are necessary for life.
13. Why can some insects walk on water?
Answer
Some insects can walk on water, although they are heavier (denser) than water,
because of the surface tension of water. Surface tension results from cohesion, or the
attraction between water molecules at the surface of the body of water [the liquid-air
(gas) interface].
14. Explain why water is an excellent solvent.
Answer
Water molecules are polar, meaning they have separated partial positive and negative
charges. Because of these charges, water molecules are able to surround charged
particles created when a substance dissociates. The surrounding layer of water
,OpenStax Concepts of Biology Instructor Answer Guide
molecules stabilizes the ion and keeps differently charged ions from reassociating, so
the substance stays dissolved.
15. Explain at least three functions that lipids serve in plants and/or animals.
Answer
Fat serves as a valuable way for animals to store energy. It can also provide insulation.
Phospholipids and steroids are important components of cell membranes.
16. Explain what happens if even one amino acid is substituted for another in a polypeptide
chain. Provide a specific example.
Answer
A change in gene sequence can lead to a different amino acid being added to a
polypeptide chain instead of the normal one. This causes a change in protein structure
and function. For example, in sickle cell anemia, the hemoglobin β chain has a single
amino acid substitution. Because of this change, the disc-shaped red blood cells
assume a crescent shape, which can result in serious health problems.
,OpenStax Concepts of Biology Instructor Answer Guide
Concepts of Biology
Unit 1. The Cellular Foundation of Life
Chapter 3: Cell Structure and Function
Art Connection Questions
1. Figure 3.7. What structures does a plant cell have that an animal cell does not have?
What structures does an animal cell have that a plant cell does not have?
,OpenStax Concepts of Biology Instructor Answer Guide
Answer
, OpenStax Concepts of Biology Instructor Answer Guide
Plant cells have plasmodesmata, a cell wall, a large central vacuole, chloroplasts, and
plastids. Animal cells have lysosomes and centrosomes.
2. Figure 3.13. Why does the cis face of the Golgi not face the plasma membrane?
Answer
Because that face receives chemicals from the ER, which is toward the center of the
cell.
3. Figure 3.22. A doctor injects a patient with what he thinks is isotonic saline solution. The
patient dies, and autopsy reveals that many red blood cells have been destroyed. Do you think the
solution the doctor injected was really isotonic?
Concepts of Biology
Unit 1. The Cellular Foundation of Life
Chapter 1: Introduction to Biology
Art Connection Questions
1. Figure 1.8
Which of the following statements is false?
A. Tissues exist within organs which exist within organ systems.
B. Communities exist within populations which exist within ecosystems.
C. Organelles exist within cells which exist within tissues.
,OpenStax Concepts of Biology Instructor Answer Guide
D. Communities exist within ecosystems which exist in the biosphere.
Answer
B. Communities exist within populations which exist within ecosystems.
2. Figure 1.18
In the example below, the scientific method is used to solve an everyday problem.
Which part in the example below is the hypothesis? Which is the prediction? Based on
the results of the experiment, is the hypothesis supported? If it is not supported,
propose some alternative hypotheses.
1. My toaster doesn’t toast my bread.
2. Why doesn’t my toaster work?
3. There is something wrong with the electrical outlet.
4. If something is wrong with the outlet, my coffeemaker also won’t work when plugged
into it. 5. I plug my coffeemaker into the outlet.
6. My coffeemaker works.
Answer
The hypothesis is #3 (there is something wrong with the electrical outlet), and the
prediction is #4 (if something is wrong with the outlet, then the coffeemaker also won’t
work when plugged into the outlet). The original hypothesis is not supported, as the
coffee maker works when plugged into the outlet. Alternative hypotheses may include
(1) the toaster might be broken or (2) the toaster wasn’t turned on
,OpenStax Concepts of Biology Instructor Answer Guide
Review Questions
3. The smallest unit of biological structure that meets the functional requirements of “living” is
the ________.
Answer
C. cell
4. Which of the following sequences represents the hierarchy of biological organization from the
most complex to the least complex level?
Answer
D. biosphere, ecosystem, community, population, organism
5. A suggested and testable explanation for an event is called a ________.
Answer
A. hypothesis
6. The type of logical thinking that uses related observations to arrive at a general conclusion is
called ________.
Answer
D. inductive reasoning
Critical Thinking Questions
7. Using examples, explain how biology can be studied from a microscopic approach to a global
approach.
Answer
Researchers can approach biology from the smallest to the largest, and everything in
between. For instance, an ecologist may study a population of individuals, the
population’s community, the community’s ecosystem, and the ecosystem’s part in the
biosphere. When studying an individual organism, a biologist could examine the cell and
its organelles, the tissues that the cells make up, the organs and their respective organ
systems, and the sum total—the organism itself.
8. Give an example of how applied science has had a direct effect on your daily life.
Answer
Answers will vary. One example of how applied science has had a direct effect on daily
life is the presence of vaccines. Vaccines to prevent diseases such polio, measles,
tetanus, and even the influenza affect daily life by contributing to individual and societal
health.
,OpenStax Concepts of Biology Instructor Answer Guide
Concepts of Biology
Unit 1. The Cellular Foundation of Life
Chapter 2: Chemistry of Life
Art Connection Questions
1. Figure 2.3. How many neutrons do (K) potassium-39 and potassium-40 have,
respectively?
Answer
Potassium-39 has twenty neutrons. Potassium-40 has twenty one neutrons.
Review Questions
2. Magnesium has an atomic number of 12. Which of the following statements is true of
a neutral magnesium atom?
Answer
A. It has 12 protons, 12 electrons, and 12 neutrons.
3. Which type of bond represents a weak chemical bond?
Answer
A. hydrogen bond
4. An isotope of sodium (Na) has a mass number of 22. How many neutrons does it have?
,OpenStax Concepts of Biology Instructor Answer Guide
Answer
A. 11
5. Which of the following statements is not true?
Answer
D. Water is the most abundant atom in Earth’s atmosphere.
6. Using a pH meter, you find the pH of an unknown solution to be 8.0. How would you describe
this solution?
Answer
C. weakly basic
7. The pH of lemon juice is about 2.0, whereas tomato juice's pH is about 4.0. Approximately
how much of an increase in hydrogen ion concentration is there between tomato juice and lemon
juice?
Answer
C. 100 times
8. An example of a monosaccharide is ________.
Answer
D. all of the above (fructose, glucose, galactose)
9. Cellulose and starch are examples of ________.
Answer
D. polysaccharides
10. Phospholipids are important components of __________.
Answer
A. the plasma membrane of cells
11. The monomers that make up proteins are called _________.
Answer
C. amino acids
Critical Thinking Questions
12. Why are hydrogen bonds and van der Waals interactions necessary for cells?
Answer
Hydrogen bonds and van der Waals interactions form weak associations between
different molecules. They provide the structure and shape necessary for proteins and
DNA within cells so that they function properly. Hydrogen bonds also give water its
unique properties, which are necessary for life.
13. Why can some insects walk on water?
Answer
Some insects can walk on water, although they are heavier (denser) than water,
because of the surface tension of water. Surface tension results from cohesion, or the
attraction between water molecules at the surface of the body of water [the liquid-air
(gas) interface].
14. Explain why water is an excellent solvent.
Answer
Water molecules are polar, meaning they have separated partial positive and negative
charges. Because of these charges, water molecules are able to surround charged
particles created when a substance dissociates. The surrounding layer of water
,OpenStax Concepts of Biology Instructor Answer Guide
molecules stabilizes the ion and keeps differently charged ions from reassociating, so
the substance stays dissolved.
15. Explain at least three functions that lipids serve in plants and/or animals.
Answer
Fat serves as a valuable way for animals to store energy. It can also provide insulation.
Phospholipids and steroids are important components of cell membranes.
16. Explain what happens if even one amino acid is substituted for another in a polypeptide
chain. Provide a specific example.
Answer
A change in gene sequence can lead to a different amino acid being added to a
polypeptide chain instead of the normal one. This causes a change in protein structure
and function. For example, in sickle cell anemia, the hemoglobin β chain has a single
amino acid substitution. Because of this change, the disc-shaped red blood cells
assume a crescent shape, which can result in serious health problems.
,OpenStax Concepts of Biology Instructor Answer Guide
Concepts of Biology
Unit 1. The Cellular Foundation of Life
Chapter 3: Cell Structure and Function
Art Connection Questions
1. Figure 3.7. What structures does a plant cell have that an animal cell does not have?
What structures does an animal cell have that a plant cell does not have?
,OpenStax Concepts of Biology Instructor Answer Guide
Answer
, OpenStax Concepts of Biology Instructor Answer Guide
Plant cells have plasmodesmata, a cell wall, a large central vacuole, chloroplasts, and
plastids. Animal cells have lysosomes and centrosomes.
2. Figure 3.13. Why does the cis face of the Golgi not face the plasma membrane?
Answer
Because that face receives chemicals from the ER, which is toward the center of the
cell.
3. Figure 3.22. A doctor injects a patient with what he thinks is isotonic saline solution. The
patient dies, and autopsy reveals that many red blood cells have been destroyed. Do you think the
solution the doctor injected was really isotonic?
