Biology 182 Answers

Question 1
Part A
Miller and Urey’s experiments that attempted to recreate conditions on early Earth were significant because _____.

Hint 1.
They gave credence to the idea of abiotic synthesis.

ANSWER:

• they showed how polymers could form spontaneously on a clay substrate
• they produced the first protocells
• they showed how radiometric dating could be used to give the absolute ages of rocks and fossils
• proved the endosymbiotic theory
• they showed that organic molecules such as amino acids could be produced from inorganic molecules

Correct
Miller and Urey showed that under conditions postulated to have existed on early Earth, it was possible to spontaneously form essential organic molecules.

Question 2
Part A
Why do some scientists believe that RNA, rather than DNA, was the first genetic material?

Hint 1.
Which is structurally simpler?

ANSWER:

• RNA can replicate more accurately than DNA.
• RNA could have evolved into DNA.
• All the proto-cells on early Earth contained RNA.
• RNA has both information storage and catalytic properties.
• RNA contains uracil in place of thymine

Correct
RNA has been shown to catalyze certain reactions (as part of ribosomes, rRNA participates in the catalysis of the peptide bonds that form proteins). It can also store information and perform some self-replication.

Question 5
Part A
Earth probably formed _____ years ago, and the first life evolved as early as _____ years ago.

Hint 1.
How long has life had to evolve?

ANSWER:

• 4.5 billion years ago … 3.9 billion years ago
• 10 billion years ago … 4.5 billion years ago
• Humans observed neither event, so there is no way to tell.
• 3.9 million years ago … 2.0 billion years ago
• 6,000 years ago … 6,000 years ago

Correct
Because fossils of bacterial communities have been discovered that are 3.5 billion years old, it is reasonable to assume life originated around 3.9 billion years ago.

Question 3
Part A
The oldest fossils usually _____.

Hint 1.

Think about messy desktops with papers piled on them.

ANSWER:

• contain more radioactive isotopes than younger fossils
• are found in the deepest strata
• are found in sediments formed during the Cenozoic era
• are found above younger fossils
• have the longest half-lives

Correct
Younger sediments are deposited over older sediments; thus, relatively older fossils are found in deeper strata than relatively younger fossils.

Question 4
Part A
Radiometric dating _____.

Hint 1.
How can absolute ages be determined, and what are the limits of different radiometric techniques?

ANSWER:

• relies on the fact that the daughter isotope decays to the parent isotope at a constant rate
• allows us to determine an absolute, errorless date
• only works on rocks younger than 75,000 years
• allows us to indirectly date fossils up to billions of years old based on minerals in surrounding volcanic strata
• can be used to directly date fossils in sedimentary rock

Correct
By dating minerals in volcanic strata above and below the fossils, we can determine a reasonable age range for the fossils.

Question 11
Part A
Approximately how far back in time does the fossil record extend?

ANSWER:

• 5.0 million years
• 5.0 billion years
• 3.5 billion years
• 3.5 million years

Correct

Question 46

Part A
The following question refers to the paragraph below.

A sediment core is removed from the floor of an inland sea. The sea has been in existence, off and on, throughout the entire time that terrestrial life has existed. Researchers wish to locate and study the terrestrial organisms fossilized in this core. The core is illustrated as a vertical column, with the top of the column representing the most recent strata and the bottom representing the time when land was first colonized by life.

• Assuming the existence of fossilized markers for each of the following chemicals, what is the sequence in which they should be found in this sediment core, working from ancient sediments to recent sediments?
  1. chitin coupled with protein
  2. chlorophyll
  3. bone
  4. cellulose

ANSWER:

• 4, 2, 1, 3
• 2, 4, 3, 1
• 4, 2, 3, 1
• 2, 4, 1, 3
  All attempts used; correct answer displayed

Question 6
Part A
The earliest organisms were most likely _____.

Hint 1.
Simpler forms arose first.

ANSWER:

• eukaryotic
• plants and fungi
• multicellular
• prokaryotic
• proto-cells

Correct
Prokaryotes originated a few hundred million years after Earth’s crust cooled and solidified.

Question 7
Part A
The atmosphere of early Earth probably contained no O2 until the emergence of organisms that _____.

Hint 1.
Consider the name of the process that releases oxygen into the atmosphere.

ANSWER:

• were oxygen respiring
• used water as an electron source for photosynthesis
• were chemoautotrophic
• had chloroplasts
• used hydrogen sulfide as an energy source

Correct
Oxygen began to accumulate in the atmosphere due to the action of photosynthetic cyanobacteria.

Question 14
Part A
An early consequence of the release of oxygen gas by plant and bacterial photosynthesis was to

ANSWER:

• make it easier to maintain reduced molecules.
• prevent the formation of an ozone layer.
• generate intense lightning storms.
• change the atmosphere from oxidizing to reducing.
• cause iron in ocean water and terrestrial rocks to rust (oxidize).

Correct

Question 15
Part A
Which of the following statements provides the strongest evidence that prokaryotes evolved before eukaryotes?

ANSWER:

• Prokaryotic cells lack nuclei.
• Laboratory experiments have produced liposomes abiotically.
• Liposomes closely resemble prokaryotic cells.
• The meteorites that have struck Earth contain fossils only of prokaryotes.
• The oldest fossilized cells resemble prokaryotes.
  Correct
• Question 17
  Part A
  What is thought to be the correct sequence of these events, from earliest to most recent, in the evolution of life on Earth?
  1. origin of mitochondria
  2. origin of multicellular eukaryotes
  3. origin of chloroplasts
  4. origin of cyanobacteria
  5. origin of fungal-plant symbioses

ANSWER:

• 4, 3, 1, 2, 5
• 4, 3, 1, 5, 2
• 4, 1, 3, 2, 5
• 4, 1, 2, 3, 5
• 4, 3, 2, 1, 5

Correct

Question 20
Part A
Which of these observations gives the most support to the endosymbiotic theory for the origin of eukaryotic cells?

ANSWER:

• the similarity in size between the cytosolic ribosomes of prokaryotes and the ribosomes within mitochondria and chloroplasts
• the size disparity between most prokaryotic cells and most eukaryotic cells
• the existence of structural and molecular differences between the plasma membranes of prokaryotes and the internal membranes of mitochondria and chloroplasts
• the observation that some eukaryotic cells lack mitochondria

Correct

Question 44
Part A
The following question refers to the paragraph below.

A sediment core is removed from the floor of an inland sea. The sea has been in existence, off and on, throughout the entire time that terrestrial life has existed. Researchers wish to locate and study the terrestrial organisms fossilized in this core. The core is illustrated as a vertical column, with the top of the column representing the most recent strata and the bottom representing the time when land was first colonized by life.

If arrows indicate locations in the column where fossils of a particular type (see key above) first appear, then which core in the figure has the most accurate arrangement of fossils?

ANSWER:

• core A
• core B
• core C
• core D
  Correct

Question 8
Part A
How does continental drift affect living organisms?

Hint 1.
What effect does the environment have on evolution?

ANSWER:

• It causes climate change, which puts selective pressure on organisms.
• It causes changes in habitats, such as when large amounts of shallow marine habitat were lost in the formation of Pangaea.
• It may cause an increase or decrease in competition among different species.
• It happens so slowly that it does not affect living organisms.
• All but one of these are correct.

Correct
Continental drift affects organisms by changing the current environment in all of these ways. Organisms may have to adapt, move, or go extinct.

Question 37
Part A
Fossil evidence indicates that several kinds of flightless dinosaurs possessed feathers. If some of these feather-bearing dinosaurs incubated clutches of eggs in carefully constructed nests, this might be evidence supporting the claim that

ANSWER:

• the earliest reptiles could fly, and the feathers of flightless dinosaurs were vestigial flight surfaces.
• their feathers originally served as insulation, and only later became flight surfaces.
• dinosaurs were as fully endothermal (warm-blooded) as modern birds and mammals.
• the feathers were plucked from the bodies of other adults to provide nest-building materials.
• all fossils with feathers are actually some kind of bird.

Correct

Question 1
Part A
Fossilized stromatolites

ANSWER:

• formed around deep-sea vents.
• provide evidence that plants moved onto land in the company of fungi around 500 million years ago.
• contain the first undisputed fossils of eukaryotes and date from 2.1 billion years ago.
• all date from 2.7 billion years ago.
• resemble structures formed by bacterial communities that are found today in some warm, shallow, salty bays.

Correct

Question 2
Part A
The oxygen revolution changed Earth’s environment dramatically. Which of the following took advantage of the presence of free oxygen in the oceans and atmosphere?

ANSWER:

• the evolution of chloroplasts after early protists incorporated photosynthetic cyanobacteria
• the evolution of photosynthetic pigments that protected early algae from the corrosive effects of oxygen
• the persistence of some animal groups in anaerobic habitats
• the evolution of multicellular eukaryotic colonies from communities of prokaryotes
• the evolution of cellular respiration, which used oxygen to help harvest energy from organic molecules

Correct

Question 3
Part A
Which factor most likely caused animals and plants in India to differ greatly from species in nearby southeast Asia?

ANSWER:

• Life in India was wiped out by ancient volcanic eruptions.
• India is in the process of separating from the rest of Asia.
• The species became separated by convergent evolution.
• India was a separate continent until 45 million years ago.
• The climates of the two regions are similar.

Correct

Question 4
Part A
Adaptive radiations can be a direct consequence of four of the following five factors. Select the exception.

ANSWER:

• genetic drift
• evolutionary innovation
• an adaptive radiation in a group of organisms (such as plants) that another group uses as food
• vacant ecological niches
• colonization of an isolated region that contains suitable habitat and few competitor species

Correct

Question 123
Part A
Which of the following statements supports the hypothesis of “an RNA world” on early Earth?

ANSWER:

• Single-stranded RNA molecules are linear and cannot form three-dimensional shapes.
• Some RNA molecules are important catalysts in modern cells.
• The oldest known fossils contain traces of RNA molecules.

Correct
This is one of the main lines of evidence that support the hypothesis of an RNA world. In addition, single-stranded RNA molecules can assume a variety of three-dimensional shapes specified by their nucleotide sequences. Read about the origin of life on Earth.

Question 124
Part A
What was the “oxygen revolution,” which took place 2.3 billion years ago?

ANSWER:

• The “oxygen revolution” was the rapid increase in atmospheric oxygen that took place 2.3 billion years ago, immediately preceding the origin of animals.
• The “oxygen revolution” was the rapid increase in atmospheric oxygen that took place 2.3 billion years ago, dooming many prokaryotic groups.
• The “oxygen revolution” was the rapid increase in atmospheric oxygen that took place 2.3 billion years ago, with the origin of plants.

Correct
Read about photosynthesis and the oxygen revolution.

Chapter 27 Pre-Test
Question 1
Part A
What is the function of fimbriae?

Hint 1.
Fimbriae are located on the outer part of the bacterium.

ANSWER:

• They are used in motility.
• They protect the cell from dehydration.
• They are used to transfer DNA during conjugation.
• They are components of the outer cell wall in gram-negative bacteria.
• They are used to attach the cell to its substrate or to other prokaryotes.

Correct
They are hair-like projections that aid in attachment. They are also known as attachment pili to distinguish them from the pili used in conjugation.

Chapter 27
Question 2
Part A
Though plants, fungi, and prokaryotes all have cell walls, we place them in different taxa. Which of these observations comes closest to explaining the basis for placing these organisms in different taxa, well before relevant data from molecular systematics became available?

ANSWER:

• Some have cell walls only for support.
• Their cell walls are composed of very different biochemicals.
• Some have cell walls only to control osmotic balance.
• Some closely resemble animals, which lack cell walls.
• Some have cell walls only for protection from herbivores.

Correct

Chapter 27
Question 4
Part A
The predatory bacterium, Bdellovibrio bacteriophorus, drills into a prey bacterium and, once inside, digests it. In an attack upon a gram-negative bacterium that has a slimy cell covering, what is the correct sequence of structures penetrated by B. bacteriophorus on its way to the prey’s cytoplasm?
1. membrane composed mostly of lipopolysaccharide
2. membrane composed mostly of phospholipids
3. peptidoglycan
4. capsule

ANSWER:

• 4, 1, 3, 2
• 1, 3, 4, 2
• 2, 4, 3, 1
• 1, 4, 3, 2
• 4, 3, 1, 2

Correct

Chapter 27
Question 7
Part A
Which two structures play direct roles in permitting bacteria to adhere to each other, or to other surfaces?
1. capsules
2. endospores
3. fimbriae
4. plasmids
5. flagella

ANSWER:

• 2 and 3
• 1 and 2
• 3 and 5
• 3 and 4
• 1 and 3

Correct

Chapter 27
Question 8
Part A
The typical prokaryotic flagellum features

ANSWER:

• a basal body that is similar in structure to the cell’s centrioles.
• a membrane-enclosed organelle with motor proteins.
• a complex “motor” embedded in the cell wall and plasma membrane.
• an external covering provided by the plasma membrane.
• an internal 9 + 2 pattern of microtubules.

Correct

Chapter 27
Question 10
Part A
Which statement about the genomes of prokaryotes is correct?

ANSWER:

• Prokaryotic genomes are diploid throughout most of the cell cycle.
• Prokaryotic chromosomes are sometimes called plasmids.
• Prokaryotic cells have multiple chromosomes, “packed” with a relatively large amount of protein.
• The prokaryotic chromosome is not contained within a nucleus but, rather, is found at the nucleolus.
• Prokaryotic genomes are composed of circular chromosomes.
• All attempts used; correct answer displayed

Chapter 27
Question 13
Part A
Prokaryotes’ essential genetic information is located in the

ANSWER:

• nucleosome.
• plasmids.
• nucleolus.
• nucleoid.
• exospore.
• Correct

Chapter 27
Question 16
Part A
In a hypothetical situation, the genes for sex pilus construction and for tetracycline resistance are located together on the same plasmid within a particular bacterium. If this bacterium readily performs conjugation involving a copy of this plasmid, then the result should be

ANSWER:

• a bacterium that has undergone transduction.
• the production of endospores among the bacterium’s progeny.
• the rapid spread of tetracycline resistance to other bacteria in that habitat.
• the subsequent loss of tetracycline resistance from this bacterium.
• the temporary possession by this bacterium of a completely diploid genome.

Correct

Chapter 27
Question 55
Part A
Use the information in the following paragraph to answer the question.

A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan.

What should be true of the cell wall of this bacterium?

ANSWER:

• It is mostly composed of a complex, cross-linked polysaccharide.
• After it has been subjected to Gram staining, the cell should remain purple.
• Its innermost layer is composed of a phospholipid bilayer.
• It has an outer membrane of lipopolysaccharide.
• Two of the responses above are correct.

Correct

Chapter 27
Question 57
Part A
Use the information in the following paragraph to answer the question.

A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan.

In which feature(s) should one be able to locate a complete chromosome of this bacterium?
1. nucleolus
2. prophage
3. endospore
4. nucleoid

ANSWER:

• 4 only
• 3 and 4
• 2 and 3
• 1 and 3
• 2, 3, and 4

Correct

1. Chapter 27
   Question 63
   Part A
   The following table depicts characteristics of five prokaryotic species (AE). Use the information in the table to answer the following question. Trait
   Species A
   Species B
   Species C
   Species D
   Species E
   Plasmid F
   None R
   None
   Gram Staining Results
   Variable
   Variable
   Negative
   Negative
   Negative
   Nutritional Mode
   Chemoheterotroph
   Chemoautotroph
   Chemoheterotroph
   Chemoheterotroph
   Photoautotroph
   Specialized Metabolic Pathways
   Aerobic methanotroph (obtains carbon and energy from methane)
   Anaerobic methanogen
   Anaerobic butanolic fermentation
   Anaerobic lactic acid fermentation
   Anaerobic nitrogen fixation and aerobic photosystems
   I and II
   Other Features
   Fimbriae
   Internal membranes
   Flagellum
   Pili
   Thylakoids

Which two species should have much more phospholipid, in the form of bilayers, in their cytoplasms than most other bacteria?

ANSWER:

• species A and B
• species A and C
• species B and E
• species C and D
• species C and E

Correct

1. Chapter 27
   Question 65
   Part A
   The following table depicts characteristics of five prokaryotic species (AE). Use the information in the table to answer the following question. Trait
   Species A
   Species B
   Species C
   Species D
   Species E
   Plasmid R
   None
   R
   F
   None
   Gram Staining Results
   Variable
   Variable
   Negative
   Negative
   Negative
   Nutritional Mode
   Chemoheterotroph
   Chemoautotroph
   Chemoheterotroph
   Chemoheterotroph
   Photoautotroph
   Specialized Metabolic Pathways
   Aerobic methanotroph (obtains carbon and energy from methane)
   Anaerobic methanogen
   Anaerobic butanolic fermentation
   Anaerobic lactic acid fermentation
   Anaerobic nitrogen fixation and aerobic photosystems
   I and II
   Other Features
   Fimbriae
   Internal membranes
   Flagellum
   Pili
   Thylakoids

How many of these species probably have a cell wall that partly consists of an outer membrane of lipopolysaccharide?

ANSWER:

• only one species
• two species
• three species
• four species
• all five species

Correct

Chapter 27 Pre-Test
Question 2
Part A
How does the large amount of genetic variation observed in prokaryotes arise?

Hint 1.
Consider how bacteria reproduce. Is this mode of reproduction consistent with high genetic variation?

ANSWER:

• The mutation rate in prokaryotes is much higher than in eukaryotes.
• They have extremely short generation times and large populations.
• They can exchange DNA with many types of prokaryotes by way of horizontal gene transfer.
• They have a relatively small genome.
• The second and third answers are correct.
• Correct
  The short generation times and large population sizes in most prokaryotic species, coupled with their ability to exchange genes, helps to increase genetic variability beyond what we would expect in asexually reproducing organisms.

Chapter 27 Pre-Test
Question 3
Part A
Genes for the resistance of antibiotics are usually located _____.

Hint 1.
The correct answer to this question is utilized by DNA biotechnology.

ANSWER:

• on the main chromosome
• on the outside of the cell wall
• on plasmids
• in eukaryotic cells
• in mitochondria

Correct
Genes for the resistance of antibiotics are usually located on plasmids.

Chapter 27
Question 18
Part A
Which of these statements about prokaryotes is correct?

ANSWER:

• Genetic variation in bacteria is not known to occur, because of their asexual mode of reproduction.
• The persistence of bacteria throughout evolutionary time is due to their genetic homogeneity (in other words, sameness).
• Their genetic material is confined within vesicles known as plasmids.
• Bacterial cells conjugate to mutually exchange genetic material.
• They divide by binary fission, without mitosis or meiosis.

Correct

Chapter 27
Question 46
Part A
The figure depicts changes to the amount of DNA present in a recipient cell that is engaged in conjugation with an Hfr cell. Hfr cell DNA begins entering the recipient cell at Time A. Assume that reciprocal crossing over occurs (in other words, a fragment of the recipient’s chromosome is exchanged for a homologous fragment from the Hfr cell’s DNA). Use the figure to answer the following question.

What is occurring at Time C that is decreasing the DNA content?

ANSWER:

• degradation of DNA that was not retained in the recipient’s chromosome
• reversal of the direction of conjugation
• crossing over
• cytokinesis
• meiosis

Correct

Chapter 27 Pre-Test
Question 4
Part A
Bacteria that live around deep-sea, hot-water vents obtain energy by oxidizing inorganic hydrogen sulfide belched out by the vents. They use this energy to build organic molecules from carbon obtained from the carbon dioxide in seawater. These bacteria are _____.

Hint 1.
Consider the source of energy for the construction of organic compounds.

ANSWER:

• chemoheterotrophs
• chemoautotrophs
• photoautotrophs
• photoheterotrophs

Correct
They use inorganic molecules (in redox reactions) for energy, and carbon dioxide for carbon.

Chapter 27 Pre-Test
Question 5
Part A
Which statement is true about obligate anaerobes?

Hint 1.
Think about it—they are obligated to be anaerobic.

ANSWER:

• They live exclusively by cellular respiration or by anaerobic respiration.
• They use O2 for cellular respiration and cannot grow without it.
• They will use O2 if it is present, but can obtain energy by fermentation if needed.
• They are poisoned by O2.
• They obtain energy by oxidizing ferrous ions.

Correct
Some obligate anaerobes live exclusively by fermentation; others extract chemical energy by anaerobic respiration, in which substances other than O2 accept electrons at the “downhill” end of electron transport chains.

Chapter 27
Question 15
Part A
Chloramphenicol is an antibiotic that targets prokaryotic (70S) ribosomes, but not eukaryotic (80S) ribosomes. Which of these questions stems from this observation, plus an understanding of eukaryotic origins?

ANSWER:

• If chloramphenicol inhibits prokaryotic ribosomes, should it not also inhibit mitochondrial ribosomes?
• Why aren’t prokaryotic ribosomes identical to eukaryotic ribosomes?
• How is translation affected in ribosomes that are targeted by chloramphenicol?
• Can chloramphenicol also be used to control human diseases that are caused by archaeans?
• Can chloramphenicol pass through the capsules possessed by many cyanobacteria?

Correct

Chapter 27
Question 22
Part A
Match the numbered terms to the description that follows. Choose all appropriate terms.
1. autotroph
2. heterotroph
3. phototroph
4. chemotroph a prokaryote that obtains both energy and carbon as it decomposes dead organisms

ANSWER:

• 2 and 4
• 1 and 3
• 1, 3, and 4
• 1 only
• 4 only

Correct

• Chapter 27
  Question 23
  Part A
  Match the numbered terms to the description that follows. Choose all appropriate terms.
  1. autotroph
  2. heterotroph
  3. phototroph
  4. chemotroph an organism that obtains both carbon and energy by ingesting prey

ANSWER:

• 4 only
• 1 and 3
• 1 only
• 1, 3, and 4
• 2 and 4

Correct

Chapter 27
Question 24
Part A
Match the numbered terms to the description that follows. Choose all appropriate terms.
1. autotroph
2. heterotroph
3. phototroph
4. chemotroph an organism that obtains energy from light

ANSWER:

• 2 and 4
• 1 and 3
• 3 only
• 1 only
• 1, 3, and 4

Correct

Chapter 27 Pre-Test
Question 6
Part A
The prokaryotic organisms most likely to be found living in salt ponds are the _____.

Hint 1.
They would have to love salt.

ANSWER:

• extremophiles
• methanogens
• Korarchaeota
• thermophiles
• halophiles

Correct
These archaea live in salty environments such as the Dead Sea.

Chapter 27 Pre-Test
Question 7
Part A
How are archaeans most similar to bacteria?

Hint 1.
What is a common feature of almost all prokaryotes?

ANSWER:

• the occurrence of introns in their chromosomes
• the structure of their cell walls
• the shape of their chromosomes and plasmids
• methanogenesis
• nucleotide sequence of small subunit ribosomal RNA

Correct
Prokaryotes typically have circular chromosomes and plasmids

Chapter 27
Question 26
Part A
Mitochondria are thought to be the descendants of certain alpha
proteobacteria. They are, however, no longer able to lead independent lives because most genes originally present on their chromosome have moved to the nuclear genome. Which phenomenon accounts for the movement of these genes?

ANSWER:

• horizontal gene transfer
• endocytosis
• conjugation
• translation
• plasmolysis

Correct

Chapter 27
Question 30
Part A
Which of the following traits do archaeans and bacteria share?
1. composition of the cell wall
2. presence of plasma membrane
3. lack of a nuclear envelope
4. identical rRNA sequences

ANSWER:

• 3 only
• 2 and 4
• 1 only
• 1 and 3
• 2 and 3

Correct

Chapter 27 Pre-Test
Question 8
Part A
An ecological relationship between organisms of different species that are in direct contact can best be described as _____.

Hint 1.
What is the general term for species living in direct contact with each other?

ANSWER:

• taxis
• parasitic
• symbiotic
• mutualistic
• commensal

Correct
This is the definition of symbiosis.

Chapter 27
Question 14
Part A
Which of the following is an important source of endotoxin in gram-negative species? ANSWER:

• flagellum
• capsule
• cell wall
• endospore
• sex pilus

Correct

Chapter 27
Question 39
Part A
Broad-spectrum antibiotics inhibit the growth of most intestinal bacteria. Consequently, assuming that nothing is done to counter the reduction of intestinal bacteria, a hospital patient who is receiving broad-spectrum antibiotics is most likely to become

ANSWER:

• deficient in certain vitamins and nutrients.
• unable to fix carbon dioxide.
• unable to fix nitrogen.
• unable to synthesize peptidoglycan.
• antibiotic resistant.

Correct

Chapter 27
Question 1
Part A
Genetic variation in bacterial populations cannot result from

ANSWER:

• meiosis.
• mutation.
• transduction.
• transformation.
• conjugation.

Correct

Chapter 27
Question 2
Part A
Photoautotrophs use

ANSWER:

• N2 as an energy source and CO2 as a carbon source.
• light as an energy source and CO2 as a carbon source.
• CO2 as both an energy source and a carbon source.
• H2S as an energy source and CO2 as a carbon source.
• light as an energy source and methane as a carbon source.

Correct

Chapter 27
Question 3
Part A
Which of the following statements is not true?

ANSWER:

• Both archaea and bacteria generally lack membrane-enclosed organelles.
• Archaea and bacteria have different membrane lipids.
• Only some archaea use CO2 to oxidize H2, releasing methane.
• The cell walls of archaea lack peptidoglycan.
• Only bacteria have histones associated with DNA.

Correct

Chapter 27
Question 6
Part A
Plantlike photosynthesis that releases O2 occurs in

ANSWER:

• chlamydias.
• chemoautotrophic bacteria.
• actinomycetes.
• cyanobacteria.
• archaea.

Correct

Misconception
Question 134
Part A
Identify the thylakoid membrane of the cyanobacterium shown here.

ANSWER:

• The thylakoid membrane of the cyanobacterium is a chloroplast membrane.
• The thylakoid membrane of the cyanobacterium is a nucleoid membrane.
• The thylakoid membrane of the cyanobacterium is an infolded plasma membrane.

Correct
Although prokaryotic cells lack the complex compartmentalization of eukaryotic cells, some prokaryotic cells do have specialized foldings of the plasma membrane, which perform metabolic functions. For example, photosynthetic prokaryotes called cyanobacteria have thylakoid membranes similar to those in the chloroplasts of photosynthetic eukaryotes. Read about the internal and genomic organization of prokaryotes.

Misconception
Question 135
Part A
Which of the following processes contributes to genetic recombination in prokaryotes?

ANSWER:

• Transduction
• Meiosis
• Mutation

Correct
In transduction, bacteriophages carry bacterial genes from one host cell to another, producing a recombinant bacterial genome. Read about the other processes that contribute to genetic recombination in prokaryotes.

Chapter 29 Pre-Test
Question 2
Part A
The closest algal relatives of land plants are _____.

Hint 1.
Which type of algae have rings of cellulose-synthesizing complexes, peroxisome enzymes, and other unique traits shared only with land plants?

ANSWER:

• rhodophytes
• psilophytes
• bacillariophytes
• charophytes
• chrysophytes

Correct
These green algae and plants share many homologous features.

Chapter 29 Pre-Test
Question 3
Part A
Which of the following traits was most important in enabling the first plants to move onto land?

Hint 1.
Think about the problems that needed to be solved in order for an aquatic organism such as algae to be able to make it on land.

ANSWER:

• apical meristems
• alternation of generations
• the development of sporopollenin to prevent the desiccation of zygotes
• peroxisome enzymes that minimize losses from photorespiration
• rings of cellulose-synthesizing complexes

Correct
Without sporopollenin, plant reproduction on land would have been much more difficult. This was one of the first problems that had to be solved in order for plants to take advantage of the habitats available on land.

Chapter 29 Pre-Test
Question 4
Part A
Seedless plants include _____.

Hint 1.
Review the highlights of plant evolution.

ANSWER:

• bryophytes and gymnosperms
• only nonvascular plants
• mosses and angiosperms
• only lycophytes and pterophytes
• bryophytes, lycophytes, ferns, whisk ferns, and horsetails

Correct
Seedless plants include nonvascular plants, such as mosses, liverworts, and hornworts, and vascular plants, such as lycophytes, ferns, horsetails, and whisk ferns.

Chapter 29
Question 1
Part A
The structural integrity of bacteria is to peptidoglycan as the structural integrity of plant spores is to

ANSWER:

• cellulose.
• lignin.
• sporopollenin.
• secondary compounds.

Correct

Chapter 29
Question 2
Part A
All of the following are common to both charophytes and vascular land plants except

ANSWER:

• sporopollenin.
• chlorophyll b.
• cellulose.
• lignin.
• chlorophyll a.

Correct

Chapter 29
Question 4
Part A
On a field trip, a student in a marine biology class collects an organism that has differentiated organs, cell walls of cellulose, and chloroplasts with chlorophyll a. Based on this description, the organism could be a brown alga, a red alga, a green alga, a charophyte recently washed into the ocean from a freshwater or brackish water source, or a land plant washed into the ocean. The presence of which of the following features would definitively identify this organism as a land plant?

ANSWER:

• rings of cellulose-synthesizing complexes
• embryos
• flagellated sperm
• sporopollenin
• alternation of generations

Correct

Chapter 29
Question 5
Part A
Some green algae exhibit alternation of generations. All land plants exhibit alternation of generations. No charophytes exhibit alternation of generations. Keeping in mind the recent evidence from molecular systematics, the correct interpretation of these observations is that

ANSWER:

• scientists have no evidence to indicate whether or not land plants evolved from any kind of alga.
• alternation of generations cannot be beneficial to charophytes.
• charophytes are not related to either green algae or land plants.
• land plants evolved directly from the green algae that perform alternation of generations.
• plants evolved alternation of generations independently of green algae.

Correct

Chapter 29
Question 7
Part A
The functional role of sporopollenin is primarily to

ANSWER:

• repel toxic chemicals.
• make spores less dense and able to disperse more readily.
• provide nutrients to spores.
• reduce dehydration.
• comprise spore surface structures that catch the wind and assist in spore dispersal.

Correct

Chapter 29
Question 9
Part A
Which of the following were probably factors that permitted early plants to successfully colonize land?
1. the relative number of potential predators (herbivores)
2. the relative number of competitors
3. the relative availability of symbiotic partners
4. air’s relative lack of support, compared to water’s support

ANSWER:

• 3 and 4
• 1, 2, and 4
• 2 and 3
• 1, 2, and 3
• 1 and 2

Correct

Chapter 29
Question 11
Part A
The following are all adaptations in plants to life on land except

:ANSWER

• tracheids.
• multicellular, dependent embryos.
• cuticles.
• reduced gametophyte generation.
• rings of cellulose-synthesizing complexes.

Correct

Chapter 29
Question 12
Part A
Mitotic activity by the apical meristem of a root makes which of the following more possible?

ANSWER:

• increased number of chloroplasts in roots.
• effective lateral growth of the stem.
• decreased absorption of mineral nutrients.
• increase of the aboveground stem.
• increased absorption of CO2.

Correct

Chapter 29
Question 13
Part A
Which event during the evolution of land plants probably made the synthesis of secondary compounds most beneficial?

ANSWER:

• the rise of herbivory
• the rise of wind pollination
• the association of the roots of land plants with fungi
• the greenhouse effect present throughout the Devonian period
• the reverse-greenhouse effect during the Carboniferous period

Correct

Chapter 29
Question 34
Part A
Arrange the following terms from most inclusive to least inclusive. 1. embryophytes
2. green plants
3. seedless vascular plants
4. ferns
5. tracheophytes

ANSWER:

• 2, 1, 5, 4, 3
• 1, 2, 5, 3, 4
• 2, 1, 5, 3, 4
• 2, 5, 1, 3, 4
• 1, 4, 2, 5, 3

Correct

Chapter 29
Question 46
Part A
Big Bend National Park in Texas is mostly Chihuahuan desert, where rainfall averages about 10 inches per year. Yet, it is not uncommon when hiking in this bone-dry desert to encounter mosses and ferns. One such plant is called “flower of stone.” It is not a flowering plant, nor does it produce seeds.
Under arid conditions, its leaflike structures curl up. However, when it rains, it unfurls its leaves, which form a bright green rosette on the desert floor. Consequently, it is sometimes called the “resurrection plant.” At first glance, it could be a fern, a true moss, or a spike moss.

What feature of both true mosses and ferns makes it most surprising that they can survive for many generations in dry deserts?

ANSWER:

• a gametophyte generation that is dominant
• lack of true roots
• flagellated sperm
• lack of cuticle
• lack of vascular tissues
• All attempts used; correct answer displayed

Chapter 29 Pre-Test
Question 5
Part A
In seedless plants, a fertilized egg will develop into _____.

Hint 1.
Review alternation of generations in your textbook.

ANSWER:

• a gametophyte
• spores
• gametes
• a fruit
• a sporophyte

Correct
The fertilized egg will develop into a sporophyte that releases haploid
spores.

Chapter 29 Pre-Test
Question 6
Part A
The diploid generation of the plant life cycle always _____.

Hint 1.
Review alternation of generations in your text.

ANSWER:

• is larger and more conspicuous than the haploid stage
• is called the gametophyte
• produces spores
• produces eggs and sperm
• develops from a spore

Correct
The diploid generation of the plant life cycle always produces spores.

Chapter 29
Question 14
Part A
Which of the following statements is true of archegonia?

ANSWER:

• They may temporarily contain sporophyte embryos.
• They are the sites where male gametes are produced.
• They are asexual reproductive structures.
• They are the same as sporangia.
• They are the ancestral versions of animal gonads.

Correct

Chapter 29
Question 24
Part A
In which of the following taxa does the mature sporophyte depend completely on the gametophyte for nutrition?

ANSWER:

• horsetail (Equisetum)
• Bryophyta
• Pterophyta
• Pterophyta, Bryophyta, and horsetail (Equisetum)
• Pterophyta and Bryophyta

Correct

Chapter 29 Pre-Test
Question 7
Part A
Most bryophytes, such as mosses, differ from all other plants in that they _____.

Hint 1.
Consider the height to which mosses grow.

ANSWER:

• lack true leaves and roots
• do not produce flowers
• have cones but no seeds
• have flagellated sperm
• produce spores

Correct
The bryophytes generally lack true leaves and roots, which all other plants have.

Chapter 29 Pre-Test
Question 8
Part A
In contrast to bryophytes, in vascular plants the dominant stage of the life
cycle is the _____.

Hint 1.
Review the different plant groups described in your text.

ANSWER:

• archegonium
• spore
• antheridium
• gametophyte
• sporophyte

Correct
The diploid sporophyte generation is dominant in vascular plants; in bryophytes the haploid gametophyte generation is dominant.

Chapter 29 Pre-Test
Question 9
Part A
What evolutionary development allowed plants to grow tall?

Hint 1.
Can you build a tall building without a strong frame?

ANSWER:

• sporophylls
• rhizoids
• lignified vascular tissue
• leaves
• the waxy cuticle

Correct
The polymer lignin strengthens the xylem and phloem, giving the plant more support and allowing it to grow taller.

Chapter 29 Pre-Test
Question 10
Part A
During the Carboniferous period, forests consisting mainly of _____ produced vast quantities of organic matter, which was buried and later became coal.

Hint 1.
What plants were dominant during the Carboniferous? Had seed plants evolved yet?

ANSWER:

• early angiosperms
• gymnosperms and early angiosperms
• gymnosperms
• giant mosses
• ferns and other seedless plants

Correct
These were the dominant plant types of the time.

Chapter 29
Question 8
Part A
If the kingdom Plantae is someday expanded to include the charophytes, then the shared derived characteristics of the kingdom will include
1. rings of cellulose-synthesizing complexes.
2. chlorophylls a and b.
3. alternation of generations.
4. cell walls of cellulose.
5. ability to synthesize sporopollenin.

ANSWER:

• 1, 3, and 5
• 1, 4, and 5
• 1 and 5
• 1, 2, 4, and 5
• 1, 2, and 3

Correct

Chapter 29
Question 27
Part A
A botanist discovers a new species of plant in a tropical rain forest. After observing its anatomy and life cycle, he notes the following characteristics: flagellated sperm, xylem with tracheids, separate gametophyte and sporophyte generations with the sporophyte dominant, and no seeds. This plant is probably most closely related to

ANSWER:

• charophytes.
• mosses.
• ferns.
• flowering plants.
• gymnosperms.

Correct

Chapter 29
Question 28
Part A
You are hiking in a forest and come upon a mysterious plant, which you determine is either a lycophyte sporophyte or a pterophyte sporophyte. Which of the following would be most helpful in determining the correct classification of the plant?

ANSWER:

• whether or not it has seeds
• whether it has microphylls or megaphylls
• its height
• whether or not it has chlorophyll a
• whether or not it has true leaves

Correct

Chapter 29
Question 2
Part A
Which of the following characteristics of plants is absent in their closest relatives, the charophyte algae?

ANSWER:

• cellulose in cell walls
• alternation of multicellular generations
• formation of a cell plate during cytokinesis
• sexual reproduction
• chlorophyll b

Correct

Chapter 29
Question 3
Part A
In plants, which of the following are produced by meiosis?

ANSWER:

• haploid sporophytes
• diploid spores
• haploid gametes
• haploid spores
• diploid gametes

Correct

Misconception
Question 142
Part A
Which of these facts provides the best support for the hypothesis that plants evolved from green algae?

ANSWER:

• Plants and green algae have chloroplasts.
• Plants and green algae are photosynthetic.
• The chloroplasts of plants and green algae all have both chlorophyll a and b.

Correct
Of the three choices, this statement does provide the best support for the hypothesis that plants evolved from green algae. In addition to green algae and plants, euglenids and a few dinoflagellates have chlorophyll a and b. The very best evidence for the hypothesis is the derived traits shared by charophytes (a taxon of green algae) and plants.

Misconception
Question 143
Part A
Select the correct statement about plant life cycles.

ANSWER:

• Over evolutionary time, the sporophyte has replaced the gametophyte in plant life cycles.
• At some point in the life cycle of all plants, the sporophyte is dependent on its gametophyte parent.
• Meiosis in plant life cycles is a sexual process, producing gametes.

Correct
This dependence defines plants as embryophytes.

Misconception
Question 144
Part A
Select the correct statement contrasting gametophytes and sporophytes.

ANSWER:

• Sporophytes are vascular, whereas gametophytes are nonvascular.
• Sporophytes are diploid, whereas gametophytes are haploid.
• Sporophytes are larger than gametophytes.

Correct
Look at the basic sexual life cycle of plants and the life cycles of nonvascular and seedless vascular plants.

Misconception
Question 145
Part A
Select the correct statement about the life cycle of a fern.

ANSWER:

• Plant sporophytes grow from haploid spores.
• Plant gametophytes are haploid multicellular bodies.
• In ferns, meiosis results in the formation of egg and sperm cells.

Correct
Plant gametophytes vary in size, but they are haploid and multicellular in all plant life cycles. Look for plant gametophytes in the basic sexual life cycle of plants and in the life cycles of nonvascular and seedless vascular plants.

Chapter 30 Pre-Test
Question 1
Part A
When you look at a pine or maple tree, the plant you see is a _____.

Hint 1.
A pine tree is a gymnosperm.

ANSWER:

• triploid endosperm
• diploid sporophyte
• haploid sporophyte
• diploid gametophyte
• haploid gametophyte

Correct
The sporophyte generation is the dominant generation of vascular plants.

Chapter 30 Pre-Test
Question 2
Part A
All seed plants _____.

Hint 1.
The correct answer also applies to some seedless vascular plants.

ANSWER:

• produce antheridia and archegonia on the same gametophyte
• produce flowers
• exhibit a dominant gametophyte generation
• are nonvascular
• are heterosporous

Correct
All seed plants produce separate male and female spores.

Chapter 30 Pre-Test
Question 3
Part A
The adaptation that made possible the colonization of dry land environments by seed plants is most likely the result of the evolution of _____.

Hint 1.
Think about reproduction and flagellated sperm.

ANSWER:

• heterospory
• sporophylls
• cones
• ovules
• pollen

Correct
In bryophytes and seedless vascular plants, flagellated sperm must swim through a film of water to reach the egg cells. In seed plants, the use of airborne pollen to bring gametes together is a terrestrial adaptation.

Chapter 30
Question 1
Part A
Which group is noted for the independence of gametophyte and sporophyte generations from each other?

ANSWER:

• mosses, hornworts, and liverworts
• charophytes
• gymnosperms
• ferns
• angiosperms

Correct

Chapter 30
Question 7
Part A
In seed plants, which of the following is part of a pollen grain and has a function most like that of the seed coat?

ANSWER:

• sporangium
• stigma
• sporophyll
• sporopollenin
• male gametophyte

Correct

Chapter 30
Question 52
Part A
The following question refers to the generalized life cycle for land plants shown in the figure. Each number within a circle or square represents a specific plant or plant part, and each number over an arrow represents either meiosis, mitosis, or fertilization.

In the figure, which number represents the mature gametophyte?

ANSWER:

• 7
• 5
• 1
• 3
• 11

Correct

Chapter 30
Question 53
Part A
The following question refers to the generalized life cycle for land plants shown in the figure. Each number within a circle or square represents a specific plant or plant part, and each number over an arrow represents either meiosis, mitosis, or fertilization.

In the figure, which number represents an embryo?

ANSWER:

• 9
• 7
• 1
• 11
• 3

Correct

Chapter 30
Question 56
Part A
The following question refers to the generalized life cycle for land plants shown in the figure. Each number within a circle or square represents a specific plant or plant part, and each number over an arrow represents either meiosis, mitosis, or fertilization.

ANSWER:

• mitosis.
• nuclear fission.
• fertilization.
• binary fission.
• meiosis.

Correct

Chapter 30 Pre-Test
Question 5
Part A
In gymnosperms megaspores develop into _____ .
Hint 1.
Consider the nonvascular plants discussed in your text.

ANSWER:

• pollen grains
• ovulate cones
• male gametophytes
• female gametophytes
• female sporophytes

Correct
Even though the gametophyte stage of alternation of generations is minimized in gymnosperms and angiosperms, spores still give rise to gametophytes.

Chapter 30 Pre-Test
Question 6
Part A
In pine, the embryo develops within the _____.

Hint 1.
Consider whether the male gamete goes to the female or the female gamete goes to the male. ANSWER:

• microsporophyll
• macrogametophyte
• staminate cone
• female gametophyte
• male gametophyte

Correct
Large ovulate cones make megaspores that develop into female gametophytes, where one fertilized egg will develop into an embryo.

Chapter 30
Question 16
Part A
Which of the following can be found in gymnosperms?

ANSWER:

• triploid endosperm
• pollen
• nonfertile flower parts
• fruits
• carpels

Correct

Chapter 30
Question 19
Part A
Which structure is common to both gymnosperms and angiosperms?

ANSWER:

• anthers
• ovule
• ovary
• carpel
• stigma

Correct

Chapter 30
Question 26
Part A
Which of the following sex and generation combinations most directly produces the fruit?

ANSWER:

• female gametophyte
• male gametophyte
• female sporophyte
• male sporophyte

Correct

Chapter 30 Pre-Test
Question 7
Part A
The major difference between angiosperms and gymnosperms comes from the _____.

Hint 1.
Consider the meaning of the term “gymnosperm.”

ANSWER:

• presence or absence of vascular structures
• presence or absence of a protective covering over the ovule
• production of microspores versus megaspores
• presence or absence of alternation of generations
• dominance or lack of dominance of the sporophyte generation

Correct
Angiosperms have a protective covering over the ovule. Gymnosperms do not. All the other traits listed are shared by both groups.

Chapter 30 Pre-Test
Question 8
Part A
Angiosperms are different from all other plants because only they have _____.

Hint 1.
Think of roses.

ANSWER:

• a sporophyte phase
• seeds
• flowers
• a vascular system
• a life cycle that involves alternation of generations

Correct
Angiosperms are recognized on the basis of being flowering plants.

Chapter 30 Pre-Test
Question 9
Part A
Unlike most angiosperms, grasses are pollinated by wind. As a consequence, some unnecessary parts of grass flowers have almost disappeared. Which of the following parts would you expect to be most reduced in a grass flower?

Hint 1.
If a plant is wind-pollinated, does it need to waste energy attracting pollinators?

ANSWER:

• petals
• anthers
• carpels
• stamens
• ovaries

Correct
Petals play a role in attracting pollinators.

Chapter 30
Question 29
Part A
What adaptations should one expect of the seed coats of angiosperm species whose seeds are dispersed by frugivorous (fruit-eating) animals, as opposed to angiosperm species whose seeds are dispersed by other means?
1. The exterior of the seed coat should have barbs or hooks.
2. The seed coat should contain secondary compounds that irritate the lining of the animal’s mouth.
3. The seed coat should be able to withstand low pH’s.
4. The seed coat, upon its complete digestion, should provide vitamins or nutrients to animals.
5. The seed coat should be resistant to the animals’ digestive enzymes.

ANSWER:

• 4 only
• 1 and 2
• 2 and 3
• 3, 4, and 5
• 3 and 5
• Correct

Chapter 30
Question 34
Part A
The generative cell of male angiosperm gametophytes is haploid. This cell divides to produce two haploid sperm cells. What type of cell division does the generative cell undergo to produce these sperm cells?

ANSWER:

• binary fission
• meiosis without subsequent cytokinesis
• mitosis
• meiosis
• mitosis without subsequent cytokinesis

Correct

Chapter 30
Question 37
Part A
How have fruits contributed to the success of angiosperms?

ANSWER:

• by facilitating dispersal of seeds
• by producing triploid cells via double fertilization
• by nourishing the plants that make them
• by attracting insects to the pollen inside
• by producing sperm and eggs inside a protective coat

Correct

• Chapter 30
  Question 41
  Part A
  Which of the following flower parts develops into a seed?

ANSWER:

• ovule
• ovary
• stamen
• fruit

Correct

Chapter 30
Question 42
Part A
Which of the following flower parts develops into the pulp of a fleshy fruit?

ANSWER:

• ovary
• ovule
• style
• stigma
• micropyle

Correct

Chapter 30
Question 43
Part A
Angiosperms are the most successful terrestrial plants. Which of the following features is unique to them and helps account for their success?

ANSWER:

• fruits enclosing seeds
• wind pollination
• dominant gametophytes
• embryos enclosed within seed coats
• sperm cells without flagella

Correct

Chapter 30
Question 45
Part A
Many mammals have skins and mucous membranes that are sensitive to phenolic secretions of plants like poison oak (Rhus). These secondary compounds are primarily adaptations that

ANSWER:

• prevent desiccation.
• favor pollination.
• decrease competition.
• foster seed dispersal.
• inhibit herbivory.

Correct

Chapter 30
Question 70
Part A
The question refers to the following description. Match the animal features with the appropriate angiosperm analog.

Oviparous (egg-laying) animals have internal fertilization (sperm cells encounter eggs within the female’s body). Yolk and/or albumen is (are) provided to the embryo, and a shell is then deposited around the embryo and its food source. Eggs are subsequently deposited in an environment that promotes their further development, or are incubated by one or both parents.

The yolk and/or albumen of an animal egg is what type of angiosperm analog?

ANSWER:

• integuments
• carpels
• fruit
• endosperm
• pollen tube and sperm nuclei

Correct

Chapter 30
Question 71
Part A
The question refers to the following description. Match the animal features with the appropriate angiosperm analog.

Oviparous (egg-laying) animals have internal fertilization (sperm cells encounter eggs within the female’s body). Yolk and/or albumen is (are) provided to the embryo, and a shell is then deposited around the embryo and its food source. Eggs are subsequently deposited in an environment that promotes their further development, or are incubated by one or both parents.

The shell of an animal egg is what type of angiosperm analog?

ANSWER:

• integuments
• endosperm
• carpels
• fruit

pollen tube and sperm nuclei

Correct

Chapter 30
Question 48
Part A
The cutting and burning of tropical rain forests leads to which of the following?
1. addition of CO2 to the atmosphere
2. decreased removal of CO2 from the atmosphere
3. greenhouse effect
4. global warming
5. decreasing sea level

ANSWER:

• 1, 2, 3, and 4
• 1 and 2
• 1 only
• 1, 2, and 3
• 2, 3, 4, and 5

Correct

Chapter 30
Question 75
Part A
Harold and Kumar are pre-med and pre-pharmacy students, respectively. They complain to their biology professor that they should not have to study about plants because plants have little relevance to their chosen professions.

Kumar, especially, might be well advised to learn more about

ANSWER:

• plant secondary compounds.
• cell wall components, such as lignins and pectins.
• sporopollenin.
• accessory photosynthetic pigments.
• the wax of cuticles.

Correct