Question 1

Which energy-production reactions were likely to have been present in the earliest cells?

Accepted Answer

A)  glycolysis, Entner-Doudoroff pathway, and Krebs cycle 
B)  glycolysis, respiration, and bacteriochlorophyll-based photosynthesis 
C)  respiration and chlorophyll-based photosynthesis in PSI and PSII 
D)  oxidation-reduction, light-driven ion pumps, and methanogenesis 
E)  chemiosmosis, substrate-level phosphorylation, and oxygenic photosynthesis 
A)  glycolysis, Entner-Doudoroff pathway, and Krebs cycle 
B)  glycolysis, respiration, and bacteriochlorophyll-based photosynthesis 
C)  respiration and chlorophyll-based photosynthesis in PSI and PSII 
D)  oxidation-reduction, light-driven ion pumps, and methanogenesis 
E)  chemiosmosis, substrate-level phosphorylation, and oxygenic photosynthesis

Question 2

In the domains of life, archaea and bacteria differ from each other in that

Accepted Answer

A)  archaea contain membrane-bound organelles, bacteria do not. 
B)  bacteria can be extreme thermophiles, archaea cannot. 
C)  archaea contain ester-linked membrane fatty acids, bacteria do not. 
D)  bacteria start protein production with formylmethionine, archaea do not. 
E)  bacteria have introns, archaea do not. 
A)  archaea contain membrane-bound organelles, bacteria do not. 
B)  bacteria can be extreme thermophiles, archaea cannot. 
C)  archaea contain ester-linked membrane fatty acids, bacteria do not. 
D)  bacteria start protein production with formylmethionine, archaea do not. 
E)  bacteria have introns, archaea do not.

Question 3

Oparin at Moscow University, Miller and Urey at the University of Chicago, and Juan Oró at the University of Houston performed experiments throughout the twentieth century to prove that

Accepted Answer

A)  organic macromolecules can arise from abiotic conditions. 
B)  micelle formation generated the first membranes. 
C)  RNA was the catalytic molecule of early Earth. 
D)  TCA cycle generates amino acids. 
E)  iron band formations were caused by photoferrotrophy. 
A)  organic macromolecules can arise from abiotic conditions. 
B)  micelle formation generated the first membranes. 
C)  RNA was the catalytic molecule of early Earth. 
D)  TCA cycle generates amino acids. 
E)  iron band formations were caused by photoferrotrophy.

Question 4

How can plants be so efficient photosynthetically if the chloroplast genome has fewer genes when compared with free-living cyanobacteria?

Accepted Answer

Chloroplast DNA encodes mainly essential

Question 5

In the study of rapid adaptive evolution through exposure to strongly selective environments, the energy cost to an organism that emerges as the fittest is that it is

Accepted Answer

A)  slowed by the demands of the stress response. 
B)  slowed as a result of decreasing respiratory activities. 
C)  slow growth as a result of impaired DNA replication. 
D)  uncontrolled growth due to an inability to regulate mRNA translation. 
E)  uncontrolled growth due to an inability to regulate binary fission. 
A)  slowed by the demands of the stress response. 
B)  slowed as a result of decreasing respiratory activities. 
C)  slow growth as a result of impaired DNA replication. 
D)  uncontrolled growth due to an inability to regulate mRNA translation. 
E)  uncontrolled growth due to an inability to regulate binary fission.

Question 6

Evidence of life left in the geological record is known as

Accepted Answer

A)  biosignatures. 
B)  genetic markers. 
C)  abiotic artifacts. 
D)  enzyme markers. 
E)  molecular weight markers. 
A)  biosignatures. 
B)  genetic markers. 
C)  abiotic artifacts. 
D)  enzyme markers. 
E)  molecular weight markers.

Question 7

Evidence for microbial life on Earth dates back to ________ ago.

Accepted Answer

A)  14 gigayears 
B)  5 gigayears 
C)  3.48 gigayears 
D)  1.5 gigayears 
E)  500 megayears 
A)  14 gigayears 
B)  5 gigayears 
C)  3.48 gigayears 
D)  1.5 gigayears 
E)  500 megayears

Question 8

The disease filariasis is caused by the ________, which harbors Wolbachia endosymbionts.

Accepted Answer

A)  flatworm Taenia solium 
B)  ciliate protist Paramecium bursaria 
C)  flagellate protist Guilladia theta 
D)  bacterium Staphylococcus aureus 
E)  nematode Brugia malayi 
A)  flatworm Taenia solium 
B)  ciliate protist Paramecium bursaria 
C)  flagellate protist Guilladia theta 
D)  bacterium Staphylococcus aureus 
E)  nematode Brugia malayi

Question 9

Molecular clocks use genes that

Accepted Answer

A)  code for TCA cycle enzymes. 
B)  are found primarily on plasmid DNA. 
C)  are involved in transcription and translation. 
D)  are acquired through transduction. 
E)  encode enzymes for glycolysis. 
A)  code for TCA cycle enzymes. 
B)  are found primarily on plasmid DNA. 
C)  are involved in transcription and translation. 
D)  are acquired through transduction. 
E)  encode enzymes for glycolysis.

Question 10

Briefly discuss the types of geological evidence of early life and their advantages and limitations.

Accepted Answer

Stromatolites: Fossil microbial mats, wh

Question 11

Which branch of taxonomy deals with the sorting of life-forms into bins (categories) based on genetic relatedness and traits of the organisms?

Accepted Answer

A)  identification 
B)  classification 
C)  nomenclature 
D)  biogeography 
E)  ethnology 
A)  identification 
B)  classification 
C)  nomenclature 
D)  biogeography 
E)  ethnology

Question 12

The term "pan-genome" can best be defined as

Accepted Answer

A)  the world DNA genomic databank. 
B)  the sum total of all expected genes in all possible isolates of a given species. 
C)  genomic islands found in pathogenic organisms. 
D)  the entire genomic sequence of all known organisms. 
E)  differences in RNA transcription between species. 
A)  the world DNA genomic databank. 
B)  the sum total of all expected genes in all possible isolates of a given species. 
C)  genomic islands found in pathogenic organisms. 
D)  the entire genomic sequence of all known organisms. 
E)  differences in RNA transcription between species.

Question 13

What are stromatolites?

Accepted Answer

A)  fossil Nautilus shells formed by deposits of hydroxyapatite 
B)  FeO in banded iron formations 
C)  bulbous masses of layered CaCO3 accreted by microbial mats 
D)  accumulations of fossil trilobites 
E)  fossils from the Hadean eon 
A)  fossil Nautilus shells formed by deposits of hydroxyapatite 
B)  FeO in banded iron formations 
C)  bulbous masses of layered CaCO3 accreted by microbial mats 
D)  accumulations of fossil trilobites 
E)  fossils from the Hadean eon

Question 14

Fossil stromatolites and microfossils are used as evidence in studies of early life on Earth. What is a disadvantage of using these rock formations in these types of studies?

Accepted Answer

A)  Paleontologists have to dig deep into Earth's crust to find them. 
B)  Abiotic processes lead to the formation of stromatolite-like structures or objects that resemble microfossils. 
C)  They must be destroyed in order to obtain samples for analysis. 
D)  Their analysis requires expensive and inconvenient radioisotope detection. 
E)  They are extremely fragile when exposed to air. 
A)  Paleontologists have to dig deep into Earth's crust to find them. 
B)  Abiotic processes lead to the formation of stromatolite-like structures or objects that resemble microfossils. 
C)  They must be destroyed in order to obtain samples for analysis. 
D)  Their analysis requires expensive and inconvenient radioisotope detection. 
E)  They are extremely fragile when exposed to air.

Question 15

Why and how is the gene for small subunit ribosomal RNA (SSU 16S rRNA) used to determine molecular phylogeny?

Accepted Answer

SSU rRNA gene sequences are widely used

Question 16

What trait do all cells on Earth NOT have in common?

Accepted Answer

A)  double-stranded DNA 
B)  cell wall of varying composition 
C)  universal gene code, common ancestral rRNAs, and elongation factors 
D)  common ancestral functional domains in proteins 
E)  cytoplasm, an aqueous compartment enclosed by a membrane 
A)  double-stranded DNA 
B)  cell wall of varying composition 
C)  universal gene code, common ancestral rRNAs, and elongation factors 
D)  common ancestral functional domains in proteins 
E)  cytoplasm, an aqueous compartment enclosed by a membrane

Question 17

The figure below shows two ways to represent phylogenetic relationships using rRNA from several thermophiles from Obsidian Pool in Yellowstone National Park. The principal advantage to unrooted trees, when compared to rooted trees, is that they

Accepted Answer

A)  are more readable. 
B)  are easier to draw. 
C)  are more precise. 
D)  indicate the position of a common ancestor. 
E)  are more precise regarding mutation rates. 
A)  are more readable. 
B)  are easier to draw. 
C)  are more precise. 
D)  indicate the position of a common ancestor. 
E)  are more precise regarding mutation rates.

Question 18

Use the figure below to discuss how catalytic activity in enzyme proteins could have evolved from catalytic RNA.

Accepted Answer

During the RNA world, earliest cells wou

Question 19

Which of the following is NOT used as a criterion to define a prokaryotic species?

Accepted Answer

A)  Phylogenetic relatedness is not a criterion. 
B)  Members of different species cannot interbreed. 
C)  The average nucleotide identity (ANI) of orthologs ³ 95%. 
D)  Organisms with >95% identity have a shared ecotype. 
E)  SSU rRNA similarity ³ 95%. 
A)  Phylogenetic relatedness is not a criterion. 
B)  Members of different species cannot interbreed. 
C)  The average nucleotide identity (ANI) of orthologs ³ 95%. 
D)  Organisms with >95% identity have a shared ecotype. 
E)  SSU rRNA similarity ³ 95%.

Question 20

Describe the intracellular endosymbiosis between algae of the genus Chlorella and Paramecium. Why is this symbiosis considered reversible?

Accepted Answer

Chlorella cells are much smaller than th

Exam 17: Origins and Evolution

Which energy-production reactions were likely to have been present in the earliest cells?

In the domains of life, archaea and bacteria differ from each other in that

Oparin at Moscow University, Miller and Urey at the University of Chicago, and Juan Oró at the University of Houston performed experiments throughout the twentieth century to prove that

How can plants be so efficient photosynthetically if the chloroplast genome has fewer genes when compared with free-living cyanobacteria?

In the study of rapid adaptive evolution through exposure to strongly selective environments, the energy cost to an organism that emerges as the fittest is that it is

Evidence of life left in the geological record is known as

Evidence for microbial life on Earth dates back to ________ ago.

The disease filariasis is caused by the ________, which harbors Wolbachia endosymbionts.

Molecular clocks use genes that

Briefly discuss the types of geological evidence of early life and their advantages and limitations.

Which branch of taxonomy deals with the sorting of life-forms into bins (categories) based on genetic relatedness and traits of the organisms?

The term "pan-genome" can best be defined as

What are stromatolites?

Fossil stromatolites and microfossils are used as evidence in studies of early life on Earth. What is a disadvantage of using these rock formations in these types of studies?

Why and how is the gene for small subunit ribosomal RNA (SSU 16S rRNA) used to determine molecular phylogeny?

What trait do all cells on Earth NOT have in common?

The figure below shows two ways to represent phylogenetic relationships using rRNA from several thermophiles from Obsidian Pool in Yellowstone National Park. The principal advantage to unrooted trees, when compared to rooted trees, is that they

Use the figure below to discuss how catalytic activity in enzyme proteins could have evolved from catalytic RNA.

Which of the following is NOT used as a criterion to define a prokaryotic species?

Describe the intracellular endosymbiosis between algae of the genus Chlorella and Paramecium. Why is this symbiosis considered reversible?

Microbial Life: Origin and Discovery

Observing the Microbial Cell

Cell Structure and Function

Bacterial Culture, Growth, and Development

Environmental Influences and Control of Microbial Growth

Viruses

Genomes and Chromosomes

Transcription, Translation, and Bioinformatics

Gene Transfer, Mutations, and Genome Evolution

Molecular Regulation

Viral Molecular Biology

Biotechniques and Synthetic Biology

Energetics and Catabolism

Electron Flow in Organotrophy, Lithotrophy, and Phototrophy

Biosynthesis

Food and Industrial Microbiology

Bacterial Diversity

Archaeal Diversity

Eukaryotic Diversity

Microbial Ecology

Microbes in Global Elemental Cycles

Human Microbiota and Innate Immunity

The Adaptive Immune Response

Microbial Pathogenesis

Microbial Diseases

Antimicrobial Therapy

Clinical Microbiology and Epidemiology

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