Chapter 1: Review Questions
Karp, 8th edition
Section 1.1
1) When Robert Hooke first described cells, what was he actually looking at?
Answer: Hooke was actually looking at cell walls of dead plant tissue, which he obtained from
cork.
2) What are the three components of cell theory?
Answer: The three main components of cell there are (1) all organisms are composed of cells, (2)
the cell is the structural unit of life, and (3) cells can only arise by division of pre-existing cells.
Section 1.2
1) List the fundamental properties shared by all cells. Describe the importance of each of these
properties.
Answer:
Alive. Cells are generally the smallest unit of life. Individual cells can be removed from a
plant or animal and grown (sometimes indefinitely) in culture, but this cannot generally
be done with individual cell parts.
Highly complex and organized. The complexity means that the cell can perform
intricate functions with a great deal of regulation and control. The organization of cells is
visible at all levels: atomic, molecular, polymeric, complexes, organellar, and cellular.
The organization is important for the function of cells.
Genetic Information. All the genetic information needed by the organism is packaged
within the cell.
Growth and Reproduction. Cells are capable of expanding their biomass and producing
more cells.
Energy. Cells are able to use energy to perform their functions (either by obtaining it
directly from external sources or making it from other energy sources such as the sun).
Metabolism. Cells are capable of performing chemical reactions that would not occur or
would only occur slowly outside of the cell.
Movement. All cells are able to move materials within their boundaries and some cells
are able to move themselves.
, Responsive. Cells will respond to internal and external stimuli in order to maintain a
steady state or homeostasis.
2) Describe the features of cells that suggest that all living organisms are derived from a common
ancestor.
Answer: The fact that all cells use DNA as their information storage molecule is the key
indicator that all cells descend from a common ancestor. The lack of huge deviation in the
genetic sequence of common, ubiquitous housekeeping genes is another indicator. Structures
common to all cells such as the RNA-ribosome complex for protein synthesis, or plasma
membranes also suggest a common ancestor.
3) What is the source of energy that supports life on Earth? How is this energy passed from one
organism to the next?
Answer: Electromagnetic radiation from the sun. Plants convert and store this energy in energy-
rich carbohydrates. The energy is passed in the form of other biomolecules from one organism to
the next.
Section 1.3
1) Compare a prokaryotic and eukaryotic cell on the basis of structural, functional, and metabolic
differences.
Answer: Structural Differences: Prokaryotes have a cell envelope enclosing their cell, a naked
genome stored in the nucleoid, free ribosomes and no membrane-bound organelle. Eukaryotes
have nuclear envelope dividing nucleus from cytoplasm, complex membranous organelles,
structurally complex chromosomes, free and membrane-localized ribosomes, complex
cytoskeleton with motor proteins, complex flagella and cilia, plant cell walls have cellulose,
mitotic spindle, at least two copies of nuclear genome, and three different RNA polymerases.
Functional Differences: Prokaryotes typically divide by binary fission and obtain nutrients using
simple diffusion across their cell envelope, and can only modify their genome through mutation
or conjugation. Eukaryotes have complex mechanism for cell division (mitosis), are able to
ingest fluid and particulates (endocytosis and phagocytosis), and may have sexual reproduction
requiring meiosis and fertilization.
Metabolic Differences: Similar metabolic pathways (e.g. glycolysis and TCA cycle) but
prokaryotes are capable of surviving in unusual habitats and are also capable of nitrogen fixation.
2) What is the importance of cell differentiation?
Answer: Cell differentiation delegates specific functions to various cell types. This is the shift
from pleuripotency to the final cell state. It is typically not reversible.
Section 1.4
1) Which group of prokaryotes is best known for containing many extremophiles?
,Answer: Archaea.
Section 1.5
1) What is the importance of cell differentiation?
Answer: Differentiation allows all of the different cell types in our bodies to be produced,
starting from a single cell – the fertilized egg.
Section 1.7
1) Why are cells almost always microscopic?
Answer: As a cell increases in size, its surface/volume ratio decreases and the distance between
the surface and interior of the cell may increase. If a cell were to grow too large, its surface may
not be able to take up materials (such as oxygen or nutrients) at a sufficient rate, or the distance
from the surface and the interior of the cell may result in diffusion rates that are too slow to
support the cell’s activities.
2) If a mitochondrion were 2 µm in length, how many angstroms would it be? How many
nanometers? How many millimeters?
Answer: 200 Å; 2000nm; .002 mm.
Section 1.8
1) What properties distinguish a virus from a bacterium?
Answer: Viruses are usually smaller than bacteria and are not considered to be organisms or
alive. They cannot metabolize or reproduce unless present within a host cell.
2) What types of infections are viruses able to cause?
Answer: Lytic or integrative (pro-viral) infection.
3) Compare and contrast: nucleoid and nucleus; the flagellum of a bacterium and a sperm; an
archaebacterium and a cyanobacterium; nitrogen fixation and photosynthesis; bacteriophages and
tobacco mosaic virus; a provirus and a virion.
Answer:
Nucleoid/nucleus. Both are ways of organizing a cell’s genetic material. A nucleoid is
found in prokaryotes and is a non-membranous area containing the cell’s genetic material.
A nucleus is found in eukaryotes and is a complex membrane-bound structure.
, Bacterial flagellum/sperm flagellum. Both are structures involved in motility but the
prokaryotic flagellum is simpler in structure than the eukaryotic flagellum. The flagella of
each type of cell also generates movement by a different mechanism.
Archaebacterium/cyanobacterium. Both are prokaryotes. Cyanobacteria are the most
complex prokaryotes and are photosynthetic. Archaebacteria are ancient prokaryotes and
contain the extremophiles.
Nitrogen fixation/photosynthesis. Both metabolic processes can be carried out by
prokaryotes and one group (cyanobacteria) can perform both. Nitrogen fixation involves
converting nitrogen gas into reduced forms of nitrogen that can be used by plants.
Photosynthesis involved the use of the sun’s energy to produce energy-rich carbohydrates.
Bacteriophages/tobacco mosaic virus. Both are types of viruses. Bacteriophages infect
bacteria while tobacco mosaic virus infects plants.
Provirus/virion. Both are forms of a virus. A provirus is the name given to the stage when
an infecting virus inserts its DNA in the host cell’s DNA. A virion refers to the inanimate
viral particle and consists of the genetic material of the virus and its surrounding protein
capsid.
Karp, 8th edition
Section 1.1
1) When Robert Hooke first described cells, what was he actually looking at?
Answer: Hooke was actually looking at cell walls of dead plant tissue, which he obtained from
cork.
2) What are the three components of cell theory?
Answer: The three main components of cell there are (1) all organisms are composed of cells, (2)
the cell is the structural unit of life, and (3) cells can only arise by division of pre-existing cells.
Section 1.2
1) List the fundamental properties shared by all cells. Describe the importance of each of these
properties.
Answer:
Alive. Cells are generally the smallest unit of life. Individual cells can be removed from a
plant or animal and grown (sometimes indefinitely) in culture, but this cannot generally
be done with individual cell parts.
Highly complex and organized. The complexity means that the cell can perform
intricate functions with a great deal of regulation and control. The organization of cells is
visible at all levels: atomic, molecular, polymeric, complexes, organellar, and cellular.
The organization is important for the function of cells.
Genetic Information. All the genetic information needed by the organism is packaged
within the cell.
Growth and Reproduction. Cells are capable of expanding their biomass and producing
more cells.
Energy. Cells are able to use energy to perform their functions (either by obtaining it
directly from external sources or making it from other energy sources such as the sun).
Metabolism. Cells are capable of performing chemical reactions that would not occur or
would only occur slowly outside of the cell.
Movement. All cells are able to move materials within their boundaries and some cells
are able to move themselves.
, Responsive. Cells will respond to internal and external stimuli in order to maintain a
steady state or homeostasis.
2) Describe the features of cells that suggest that all living organisms are derived from a common
ancestor.
Answer: The fact that all cells use DNA as their information storage molecule is the key
indicator that all cells descend from a common ancestor. The lack of huge deviation in the
genetic sequence of common, ubiquitous housekeeping genes is another indicator. Structures
common to all cells such as the RNA-ribosome complex for protein synthesis, or plasma
membranes also suggest a common ancestor.
3) What is the source of energy that supports life on Earth? How is this energy passed from one
organism to the next?
Answer: Electromagnetic radiation from the sun. Plants convert and store this energy in energy-
rich carbohydrates. The energy is passed in the form of other biomolecules from one organism to
the next.
Section 1.3
1) Compare a prokaryotic and eukaryotic cell on the basis of structural, functional, and metabolic
differences.
Answer: Structural Differences: Prokaryotes have a cell envelope enclosing their cell, a naked
genome stored in the nucleoid, free ribosomes and no membrane-bound organelle. Eukaryotes
have nuclear envelope dividing nucleus from cytoplasm, complex membranous organelles,
structurally complex chromosomes, free and membrane-localized ribosomes, complex
cytoskeleton with motor proteins, complex flagella and cilia, plant cell walls have cellulose,
mitotic spindle, at least two copies of nuclear genome, and three different RNA polymerases.
Functional Differences: Prokaryotes typically divide by binary fission and obtain nutrients using
simple diffusion across their cell envelope, and can only modify their genome through mutation
or conjugation. Eukaryotes have complex mechanism for cell division (mitosis), are able to
ingest fluid and particulates (endocytosis and phagocytosis), and may have sexual reproduction
requiring meiosis and fertilization.
Metabolic Differences: Similar metabolic pathways (e.g. glycolysis and TCA cycle) but
prokaryotes are capable of surviving in unusual habitats and are also capable of nitrogen fixation.
2) What is the importance of cell differentiation?
Answer: Cell differentiation delegates specific functions to various cell types. This is the shift
from pleuripotency to the final cell state. It is typically not reversible.
Section 1.4
1) Which group of prokaryotes is best known for containing many extremophiles?
,Answer: Archaea.
Section 1.5
1) What is the importance of cell differentiation?
Answer: Differentiation allows all of the different cell types in our bodies to be produced,
starting from a single cell – the fertilized egg.
Section 1.7
1) Why are cells almost always microscopic?
Answer: As a cell increases in size, its surface/volume ratio decreases and the distance between
the surface and interior of the cell may increase. If a cell were to grow too large, its surface may
not be able to take up materials (such as oxygen or nutrients) at a sufficient rate, or the distance
from the surface and the interior of the cell may result in diffusion rates that are too slow to
support the cell’s activities.
2) If a mitochondrion were 2 µm in length, how many angstroms would it be? How many
nanometers? How many millimeters?
Answer: 200 Å; 2000nm; .002 mm.
Section 1.8
1) What properties distinguish a virus from a bacterium?
Answer: Viruses are usually smaller than bacteria and are not considered to be organisms or
alive. They cannot metabolize or reproduce unless present within a host cell.
2) What types of infections are viruses able to cause?
Answer: Lytic or integrative (pro-viral) infection.
3) Compare and contrast: nucleoid and nucleus; the flagellum of a bacterium and a sperm; an
archaebacterium and a cyanobacterium; nitrogen fixation and photosynthesis; bacteriophages and
tobacco mosaic virus; a provirus and a virion.
Answer:
Nucleoid/nucleus. Both are ways of organizing a cell’s genetic material. A nucleoid is
found in prokaryotes and is a non-membranous area containing the cell’s genetic material.
A nucleus is found in eukaryotes and is a complex membrane-bound structure.
, Bacterial flagellum/sperm flagellum. Both are structures involved in motility but the
prokaryotic flagellum is simpler in structure than the eukaryotic flagellum. The flagella of
each type of cell also generates movement by a different mechanism.
Archaebacterium/cyanobacterium. Both are prokaryotes. Cyanobacteria are the most
complex prokaryotes and are photosynthetic. Archaebacteria are ancient prokaryotes and
contain the extremophiles.
Nitrogen fixation/photosynthesis. Both metabolic processes can be carried out by
prokaryotes and one group (cyanobacteria) can perform both. Nitrogen fixation involves
converting nitrogen gas into reduced forms of nitrogen that can be used by plants.
Photosynthesis involved the use of the sun’s energy to produce energy-rich carbohydrates.
Bacteriophages/tobacco mosaic virus. Both are types of viruses. Bacteriophages infect
bacteria while tobacco mosaic virus infects plants.
Provirus/virion. Both are forms of a virus. A provirus is the name given to the stage when
an infecting virus inserts its DNA in the host cell’s DNA. A virion refers to the inanimate
viral particle and consists of the genetic material of the virus and its surrounding protein
capsid.
