ESSENTIAL CELL BIOLOGY, EDITION CHAPTER 1:
CELLS: THE FUNDAMENTAL UNITS OF LIFE
Unity and Diversity of Cells
1-1 Living systems are incredibly diverse in size, shape, environment, and behavior. It is
estimated that there are between 10 million and 100 million different species. Despite this
wide variety of organisms, it remains difficult to define what it means to say something is
alive. Which of the following can be described as the smallest living unit?
(a) DNA
(b) cell
(c) organelle
(d) protein
1-2 Indicate whether the following statements are true or false. If the statement is false,
explain why it is false.
A. The Paramecium is a multicellular microorganism covered with hairlike cilia.
B. Cells of different types can have different chemical requirements.
C. The branchlike extensions that sprout from a single nerve cell in a mammalian
brain can extend over several hundred micrometers.
1-3 For each of the following sentences, fill in the blanks with the best word or phrase
selected from the list below. Not all words or phrases will be used; each word or phrase
should be used only once.
Cells can be very diverse: superficially, they come in various sizes, ranging from
bacterial cells such as Lactobacillus, which is a few __________________ in
length, to larger cells such as a frog’s egg, which has a diameter of about one
__________________. Despite the diversity, cells resemble each other to an
astonishing degree in their chemistry. For example, the same 20
__________________ are used to make proteins. Similarly, the genetic
information of all cells is stored in their __________________. Although
__________________ contain the same types of molecules as cells, their inability
to reproduce themselves by their own efforts means that they are not considered
living matter.
amino acids micrometer(s) viruses
DNA millimeter(s) yeast
fatty acids plants
meter plasma membranes
,1-4 How does cellular specialization serve multicellular organisms and how might a high
degree of specialization be detrimental?
Page 1 of 21
,1-5 The flow of genetic information is controlled by a series of biochemical reactions that
result in the production of proteins, each with its own specific order of amino acids.
Choose the correct series of biochemical reactions from the options presented here.
(a) replication, transcription, translation
(b) replication, translation, transcription
(c) translation, transcription, replication
(d) translation, replication, transcription
1-6 Proteins are important architectural and catalytic components within the cell, helping to
determine its chemistry, its shape, and its ability to respond to changes in the
environment. Remarkably, all of the different proteins in a cell are made from the same
20 __________. By linking them in different sequences, the cell can make protein
molecules with different conformations and surface chemistries, and therefore different
functions.
(a) nucleotides.
(b) sugars.
(c) amino
acids.
(d) fatty acids.
1-7 Which statement is NOT true about mutations?
(a) A mutation is a change in the DNA that can generate offspring less fit for survival
than their parents.
(b) A mutation can be a result of imperfect DNA duplication.
(c) A mutation is a result of sexual reproduction.
(d) A mutation is a change in the DNA that can generate offspring that are as fit for
survival as their parents are.
1-8 Changes in DNA sequence from one generation to the next may result in offspring that
are altered in fitness compared with their parents. The process of change and selection
over the course of many generations is the basis of __________.
(a) mutation.
(b) evolution.
(c) heredity.
(d) reproduction.
1-9 Select the option that best finishes the following statement: “Evolution is a process
__________.”
(a) that can be understood based on the principles of mutation and selection.
(b) that results from repeated cycles of adaptation over billions of years.
(c) by which all present-day cells arose from 4–5 different ancestral cells.
(d) that requires hundreds of thousands of years.
, 1-10 Select the option that correctly finishes the following statement: “A cell’s genome
_________________.”
(a) is defined as all the genes being used to make protein.
(b) contains all of a cell’s DNA.
Page 2 of 21
CELLS: THE FUNDAMENTAL UNITS OF LIFE
Unity and Diversity of Cells
1-1 Living systems are incredibly diverse in size, shape, environment, and behavior. It is
estimated that there are between 10 million and 100 million different species. Despite this
wide variety of organisms, it remains difficult to define what it means to say something is
alive. Which of the following can be described as the smallest living unit?
(a) DNA
(b) cell
(c) organelle
(d) protein
1-2 Indicate whether the following statements are true or false. If the statement is false,
explain why it is false.
A. The Paramecium is a multicellular microorganism covered with hairlike cilia.
B. Cells of different types can have different chemical requirements.
C. The branchlike extensions that sprout from a single nerve cell in a mammalian
brain can extend over several hundred micrometers.
1-3 For each of the following sentences, fill in the blanks with the best word or phrase
selected from the list below. Not all words or phrases will be used; each word or phrase
should be used only once.
Cells can be very diverse: superficially, they come in various sizes, ranging from
bacterial cells such as Lactobacillus, which is a few __________________ in
length, to larger cells such as a frog’s egg, which has a diameter of about one
__________________. Despite the diversity, cells resemble each other to an
astonishing degree in their chemistry. For example, the same 20
__________________ are used to make proteins. Similarly, the genetic
information of all cells is stored in their __________________. Although
__________________ contain the same types of molecules as cells, their inability
to reproduce themselves by their own efforts means that they are not considered
living matter.
amino acids micrometer(s) viruses
DNA millimeter(s) yeast
fatty acids plants
meter plasma membranes
,1-4 How does cellular specialization serve multicellular organisms and how might a high
degree of specialization be detrimental?
Page 1 of 21
,1-5 The flow of genetic information is controlled by a series of biochemical reactions that
result in the production of proteins, each with its own specific order of amino acids.
Choose the correct series of biochemical reactions from the options presented here.
(a) replication, transcription, translation
(b) replication, translation, transcription
(c) translation, transcription, replication
(d) translation, replication, transcription
1-6 Proteins are important architectural and catalytic components within the cell, helping to
determine its chemistry, its shape, and its ability to respond to changes in the
environment. Remarkably, all of the different proteins in a cell are made from the same
20 __________. By linking them in different sequences, the cell can make protein
molecules with different conformations and surface chemistries, and therefore different
functions.
(a) nucleotides.
(b) sugars.
(c) amino
acids.
(d) fatty acids.
1-7 Which statement is NOT true about mutations?
(a) A mutation is a change in the DNA that can generate offspring less fit for survival
than their parents.
(b) A mutation can be a result of imperfect DNA duplication.
(c) A mutation is a result of sexual reproduction.
(d) A mutation is a change in the DNA that can generate offspring that are as fit for
survival as their parents are.
1-8 Changes in DNA sequence from one generation to the next may result in offspring that
are altered in fitness compared with their parents. The process of change and selection
over the course of many generations is the basis of __________.
(a) mutation.
(b) evolution.
(c) heredity.
(d) reproduction.
1-9 Select the option that best finishes the following statement: “Evolution is a process
__________.”
(a) that can be understood based on the principles of mutation and selection.
(b) that results from repeated cycles of adaptation over billions of years.
(c) by which all present-day cells arose from 4–5 different ancestral cells.
(d) that requires hundreds of thousands of years.
, 1-10 Select the option that correctly finishes the following statement: “A cell’s genome
_________________.”
(a) is defined as all the genes being used to make protein.
(b) contains all of a cell’s DNA.
Page 2 of 21
