Question 1

Which of the following is NOT correct about endolithic microorganisms?

Accepted Answer

A)  They have been found in mines as deep as 3 kilometers. 
B)  Their discovery elicited interest in NASA scientists seeking life on Mars. 
C)  They can grow in Earth's core. 
D)  The term "endolithic" means living "within rocks." 
E)  They metabolize by oxidizing e- donors generated through decay of radioactive metals. 
A)  They have been found in mines as deep as 3 kilometers. 
B)  Their discovery elicited interest in NASA scientists seeking life on Mars. 
C)  They can grow in Earth's core. 
D)  The term "endolithic" means living "within rocks." 
E)  They metabolize by oxidizing e- donors generated through decay of radioactive metals. C

Question 2

The elements that formed initial microbial life originated from

Accepted Answer

A)  oceans. 
B)  lightning. 
C)  supernovas. 
D)  the sun. 
E)  ozone. 
A)  oceans. 
B)  lightning. 
C)  supernovas. 
D)  the sun. 
E)  ozone. C

Question 3

A dichotomous key is a

Accepted Answer

A)  battery of biochemical tests used to identify organisms in a particular taxon. 
B)  detailed description of a taxon with diagnostic purposes. 
C)  registered valid name for a specific taxon. 
D)  comprehensive list of characteristics that define a taxonomic category. 
E)  series of yes/no choices that successively narrows down a possible taxonomic category. 
A)  battery of biochemical tests used to identify organisms in a particular taxon. 
B)  detailed description of a taxon with diagnostic purposes. 
C)  registered valid name for a specific taxon. 
D)  comprehensive list of characteristics that define a taxonomic category. 
E)  series of yes/no choices that successively narrows down a possible taxonomic category. E

Question 4

A clade could best be described as a

Accepted Answer

A)  random but neutral DNA mutation. 
B)  hypothesis that early evolution happened faster than later evolution. 
C)  group of related organisms producing a monophyletic group. 
D)  hypothesis of how life began on Earth. 
E)  group of genes unselected for in evolution. 
A)  random but neutral DNA mutation. 
B)  hypothesis that early evolution happened faster than later evolution. 
C)  group of related organisms producing a monophyletic group. 
D)  hypothesis of how life began on Earth. 
E)  group of genes unselected for in evolution.

Question 5

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 6

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 7

Which of the following would be considered a gene product of an "informational gene"?

Accepted Answer

A)  Staphylococcus toxic shock toxin 
B)  siderophore transport protein 
C)  hexokinase enzyme for glycolysis 
D)  Escherichia coli O157:H7 attachment pili 
E)  16S ribosomal RNA 
A)  Staphylococcus toxic shock toxin 
B)  siderophore transport protein 
C)  hexokinase enzyme for glycolysis 
D)  Escherichia coli O157:H7 attachment pili 
E)  16S ribosomal RNA

Question 8

Which of the following is a highly speculative issue about the early origin of life?

Accepted Answer

A)  Sufficient evidence exists that RNA might have been the first informational molecule. 
B)  Amino acids could have originated by Krebs cycle acids complexed to a dinucleotide. 
C)  Bacterial redox metabolism can be evidenced through 34S/32S ratios from 3.47 Gyr ago. 
D)  Ancestors of methanogens using H2 and CO2 to make CH4 and H2O evolved early. 
E)  Panspermia, life forms originated elsewhere, were seeded on Earth by meteorites. 
A)  Sufficient evidence exists that RNA might have been the first informational molecule. 
B)  Amino acids could have originated by Krebs cycle acids complexed to a dinucleotide. 
C)  Bacterial redox metabolism can be evidenced through 34S/32S ratios from 3.47 Gyr ago. 
D)  Ancestors of methanogens using H2 and CO2 to make CH4 and H2O evolved early. 
E)  Panspermia, life forms originated elsewhere, were seeded on Earth by meteorites.

Question 9

Taxonomy can be defined as the

Accepted Answer

A)  classifying of life forms into different categories with shared traits. 
B)  recognition of the class of a given microbe isolated in pure culture. 
C)  identification of a species in a sample or collection. 
D)  recognition of different classes of life. 
E)  testing of metabolic reactions to predict pathogenicity. 
A)  classifying of life forms into different categories with shared traits. 
B)  recognition of the class of a given microbe isolated in pure culture. 
C)  identification of a species in a sample or collection. 
D)  recognition of different classes of life. 
E)  testing of metabolic reactions to predict pathogenicity.

Question 10

Explain how studying the evolutionary rate of RNA viruses in comparison to DNA viruses can help explain the evolutionary rate in early Earth.

Accepted Answer

RNA viruses (such as HIV or influenza) m

Question 11

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 12

All of the following are examples of "operational genes," EXCEPT ________ genes.

Accepted Answer

A)  metabolic 
B)  ribosomal RNA 
C)  stress response 
D)  pathogenicity 
E)  resistance 
A)  metabolic 
B)  ribosomal RNA 
C)  stress response 
D)  pathogenicity 
E)  resistance

Question 13

The ancestral organism that gave rise to the modern-day chloroplast was

Accepted Answer

A)  rickettsia. 
B)  a cyanobacterium. 
C)  Wolbachia. 
D)  a rhizobial bacteroid. 
E)  a methanogen. 
A)  rickettsia. 
B)  a cyanobacterium. 
C)  Wolbachia. 
D)  a rhizobial bacteroid. 
E)  a methanogen.

Question 14

What criteria must be met in order to prove that two bacterial strains belong in the same species?

Accepted Answer

Similarity of the sequences of their SSU

Question 15

Define the term "metagenomics" and explain why growth in this field has led to an increase in SSU rRNA species designations.

Accepted Answer

Metagenomics is the practice of sequenci

Question 16

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

Question 17

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 18

Discuss what horizontal gene transfer is. How does it occur and how might it obscure phylogenetic relationships among taxa?

Accepted Answer

The acquisition of a piece of DNA from a

Question 19

Appearance of a new trait in experimental evolution consists of which three basic stages?

Accepted Answer

A)  fixing, staining, and decolorizing 
B)  disabling gene expression, regulation, slow cell growth 
C)  potentiation, actualization, and refinement 
D)  gene amplification, purification, and subcloning 
E)  restriction digestion, agarose gel electrophoresis, and staining 
A)  fixing, staining, and decolorizing 
B)  disabling gene expression, regulation, slow cell growth 
C)  potentiation, actualization, and refinement 
D)  gene amplification, purification, and subcloning 
E)  restriction digestion, agarose gel electrophoresis, and staining

Question 20

Explain how banded iron formations could arise in the geologic record due to photoferrotrophy.

Accepted Answer

Photoferrotrophy is a form of anaerobic

Exam 17: Origins and Evolution

Which of the following is NOT correct about endolithic microorganisms?

The elements that formed initial microbial life originated from

A dichotomous key is a

A clade could best be described as a

Molecular clocks use genes that

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

Which of the following would be considered a gene product of an "informational gene"?

Which of the following is a highly speculative issue about the early origin of life?

Taxonomy can be defined as the

Explain how studying the evolutionary rate of RNA viruses in comparison to DNA viruses can help explain the evolutionary rate in early Earth.

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

All of the following are examples of "operational genes," EXCEPT ________ genes.

The ancestral organism that gave rise to the modern-day chloroplast was

What criteria must be met in order to prove that two bacterial strains belong in the same species?

Define the term "metagenomics" and explain why growth in this field has led to an increase in SSU rRNA species designations.

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

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

Discuss what horizontal gene transfer is. How does it occur and how might it obscure phylogenetic relationships among taxa?

Appearance of a new trait in experimental evolution consists of which three basic stages?

Explain how banded iron formations could arise in the geologic record due to photoferrotrophy.

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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