CHAPTER 1 CELLS: THE FUNDAMENTAL UNITS OF LIFE
UNITY AND DIVERSITY OF CELLS
1.1.aCompare, with examples, some ways in which cells may vary in appearance and function.
1.1.bOutline, with examples, ways in which cells share a basic fundamental chemistry.
1.1.cExplain how the relationship between DNA, RNA, and protein—as laid out in the central dogma—
makes the self-replication of living cells possible.
1.1.dSummarize how the processes of mutation and selection promote the gradual evolution of individuals best suited for survival in a wide range of habitats.
1.1.eExplain how differentiated cell types can vary widely in form and function despite having the same genome sequence.
CELLS UNDER THE MICROSCOPE
1.2.aList the three tenets of cell theory and explain their ramifications for the study of cell biology.
1.2.bContrast light microscopy, super-resolution fluorescence light microscopy, and electron microscopy in terms of the cell components that can generally be distinguished using each.
1.2.cCompare how samples are prepared for light versus electron microscopy and explain how these preparations affect whether the technique can be used for viewing living cells or tissues.
THE PROKARYOTIC CELL
1.3.aDescribe the structural differences between prokaryotes and eukaryotes.
1.3.bAnalyze how eukaryotic cells and organisms rely on the function of prokaryotic cells and their descendants.
1.3.cCompare prokaryotes and eukaryotes in terms of their relative preponderance on Earth, their range
of habitat, and their tendency toward multicellularity.
1.3.dJustify the division of prokaryotes into bacteria and archaea.
THE EUKARYOTIC CELL
1.4.aState the function of the nucleus and describe its structural features.
1.4.bExplain how the structure of the mitochondrion supports its function.
1.4.cOutline the evolution of mitochondria and chloroplasts and cite the evidence for these origins.
1.4.dExplain how chloroplasts and mitochondria cooperate as plant cells convert light energy into chemical energy.
1.4.eCompare the function of lysosomes and peroxisomes.
1.4.fCompare the structure, location, and function of the endoplasmic reticulum and Golgi apparatus.
1.4.gOutline the role that transport vesicles play in endocytosis, exocytosis, and the movement of materials between one membrane-enclosed organelle and another.
1.4.hRelate the location of the cytosol with respect to the cell’s membrane-enclosed organelles.
1.4.iList the three major filaments of the cytoskeleton and contrast the roles they have in animal cells.
1.4.jOutline the role the cytoskeleton has in plant cells.
1.4.kDescribe the ancestral cell that likely engulfed the aerobic bacteria that gave rise to mitochondria and explain why this event is thought to have preceded the acquisition of chloroplasts.
MODEL ORGANISMS
1.5.aReview why scientists study model organisms.
1.5.bCompare E. coli, S. cerevisiae, and A. thaliana and list the types of discoveries made by studying each.
1.5.cCompare flies, worms, fish, and mice as model organisms and name a benefit of studying each.
1.5.dReview the benefits of studying cultured human cells.
1.5.eAssess the relationship between genome size and gene number.
1.5.fExplain the significance of homologous genes and proteins.
1.5.gSummarize the roles played by the nucleotide sequences contained in an organism’s genome.
1.5.hOutline an experiment that would allow investigators to determine whether proteins from different eukaryotes are functionally interchangeable.
MULTIPLE CHOICE
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
ANS: b DIF: Easy REF: 1.1 OBJ: 1.1.b Outline, with examples, ways in which cells share a basic fundamental chemistry. MSC: Understanding 2.The central dogma provides a framework for thinking about how genetic information is copied and used
to produce structural and catalytic components of the cell. From the choices below, select the order of biochemical processes that best correlates with the tenets of the central dogma.
a.replication, transcription, translation
b.replication, translation, transcription
c.translation, transcription, replication
d.translation, replication, transcription
ANS: A DIF: Easy REF: 1.1 OBJ: 1.1.c Explain how the relationship between DNA, RNA, and protein—as laid out in the central dogma—makes the self-replication of living cells possible. MSC: Understanding
3.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
ANS: C DIF: Easy REF: 1.1 OBJ: 1.1.b Outline, with examples, ways in which cells share a basic fundamental chemistry. MSC: Remembering
4.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.
ANS: C DIF: Easy REF: 1.1 OBJ: 1.1.d Summarize how the processes of mutation and selection promote the gradual evolution of individuals best suited for survival in a wide range of habitats. MSC: Analyzing
5.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.
ANS: B DIF: Easy REF: 1.1 OBJ: 1.1.d Summarize how the processes of mutation and selection promote the gradual evolution of individuals best suited for survival in a wide range of habitats. MSC: Understanding 6.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.
ANS: A DIF: Moderate REF: 1.1 OBJ: 1.1.d Summarize how the processes of mutation and selection promote the gradual evolution of individuals best suited for survival in a wide range of habitats. MSC: Analyzing
7.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.
c.constantly changes, depending upon the cell’s environment.
d.is altered during embryonic development.
ANS: B DIF: Easy REF: 1.1 OBJ: 1.1.b Outline, with examples, ways in which cells share a basic fundamental chemistry. MSC: Remembering
8.Which statement is NOT true about the events/conclusions from studies during the mid-1800s surrounding the discovery of cells?
a.Cells came to be known as the smallest universal building block of living organisms.
b.Scientists came to the conclusion that new cells can form spontaneously from the remnants of ruptured cells.
c.Light microscopy was essential in demonstrating the commonalities between plant and animal tissues.
d.New cells arise from the growth and division of previously existing cells.
ANS: B DIF: Easy REF: 1.2 OBJ: 1.2.a List the three tenets of cell theory and explain their ramifications for the study of cell biology. MSC: Remembering
9.What unit of length would you generally use to measure a typical plant or animal cell?
a.centimeters
b.nanometers
c.millimeters
d.micrometers
ANS: D DIF: Easy REF: 1.1 OBJ: 1.1.a Compare, with examples, some ways in which cells may vary in appearance and function. | 1.2.a List the three tenets of cell theory and explain their ramifications for the study of cell biology.
MSC: Remembering
10.Cell biologists employ targeted fluorescent dyes or modified fluorescent proteins in both standard fluorescence microscopy and confocal microscopy to observe specific details in the cell. Even though fluorescence permits better visualization, the resolving power is essentially the same as that of a standard light microscope because the resolving power of a fluorescent microscope is still limited by
