Question 1

Why are scientists unable to grow the majority of Bacteria and Archaea in pure culture in a laboratory setting?

Accepted Answer

A) Most microorganisms reside in extreme environments that are toxic to human life, so samples cannot be collected for cultivation of the microbial inhabitants in the laboratory. 
B) Many species have metabolic requirements that are difficult to fulfill in the laboratory. 
C) DNA sequencing technology was not sufficiently advanced to give scientists the ability to identify prokaryotic species in nature, a requirement for growing microbes in the laboratory. 
D) Cells with unusual morphological characteristics cannot be grown in the laboratory. 
A) Most microorganisms reside in extreme environments that are toxic to human life, so samples cannot be collected for cultivation of the microbial inhabitants in the laboratory. 
B) Many species have metabolic requirements that are difficult to fulfill in the laboratory. 
C) DNA sequencing technology was not sufficiently advanced to give scientists the ability to identify prokaryotic species in nature, a requirement for growing microbes in the laboratory. 
D) Cells with unusual morphological characteristics cannot be grown in the laboratory. B

Question 2

Generating a phylogeny that represents the traditional groupings of bacteria requires sequencing and comparing the entire genome of each organism and cannot rely on single-gene phylogenies generated from 16S rRNA datasets.

Accepted Answer

A) True 
 B)False  False

Question 3

Wolbachia belongs to the Proteobacteria group.

Accepted Answer

A) True 
 B)False  True

Question 4

Antibiotics can kill _____ in the human body, which may sometimes lead to health problems such as inflammatory bowel disease.

Accepted Answer

A) harmful bacteria 
B) beneficial bacteria 
C) both harmful and beneficial bacteria 
D) fungi 
E) archaeons 
A) harmful bacteria 
B) beneficial bacteria 
C) both harmful and beneficial bacteria 
D) fungi 
E) archaeons

Question 5

Bacteria contain neither organelle-associated membranes nor a cell membrane.

Accepted Answer

A) True 
 B)False

Question 6

Phylogenies can be generated from molecular sequence data derived either from single genes or from entire genomes.

Accepted Answer

A) True 
 B)False

Question 7

Stromatolites are not the only rocks that provide evidence regarding ancient microbial life. Intact fossilized bacteria-and even fossilized biomolecules-are also found in the fossil record.

Accepted Answer

A) True 
 B)False

Question 8

Consider the chemical reactions of the sulfur cycle shown in Figure 26.10.   Reduction of CO2 to generate carbohydrates can occur when coupled to the oxidation of reduced sulfur compounds (e.g., H2S). This latter process is carried out by what type of microorganism(s)?

Accepted Answer

A) cyanobacteria 
B) purple bacteria 
A) cyanobacteria 
B) purple bacteria

Question 9

Which of the following statements is TRUE regarding the bacteria present in the stomachs or intestines of humans?

Accepted Answer

A) Some stomach bacteria have been associated with cancers. 
B) Many intestinal bacteria aid in digestion. 
C) Intestinal bacteria can produce important vitamins. 
D) Intestinal bacteria may play a role in immune system function. 
E) All of these choices are correct. 
A) Some stomach bacteria have been associated with cancers. 
B) Many intestinal bacteria aid in digestion. 
C) Intestinal bacteria can produce important vitamins. 
D) Intestinal bacteria may play a role in immune system function. 
E) All of these choices are correct.

Question 10

Archaeons are often found in environments where exploitable energy sources cannot maintain eukaryotes, but can maintain bacteria.

Accepted Answer

A) True 
 B)False

Question 11

Which is NOT a difference between anoxygenic photosynthetic organisms and oxygenic photosynthetic organisms?

Accepted Answer

A) source of electrons 
B) type of chlorophyll 
C) number of photosystems 
D) wavelengths at which light is absorbed. 
E) need for a source of carbon 
A) source of electrons 
B) type of chlorophyll 
C) number of photosystems 
D) wavelengths at which light is absorbed. 
E) need for a source of carbon

Question 12

Imagine that you traveled back in time and searched the early Earth for signs of life. You would MOST likely find early microorganisms:

Accepted Answer

A) at the polar caps. 
B) in the soil at the equator. 
C) floating in the atmosphere. 
D) near hydrothermal vents in the ocean. 
E) in temperate, freshwater lakes. 
A) at the polar caps. 
B) in the soil at the equator. 
C) floating in the atmosphere. 
D) near hydrothermal vents in the ocean. 
E) in temperate, freshwater lakes.

Question 13

As many bacterial molecular sequences evolve quickly and/or continuously, creating a bacterial phylogenetic tree based on molecular sequences can be difficult.

Accepted Answer

A) True 
 B)False

Question 14

Which of the following statements is TRUE regarding anammox?

Accepted Answer

A) It can be carried out by both eukaryotes and archaeons. 
B) It generates less energy compared to respiration. 
C) It is performed in oxygen-rich environments. 
D) It is identical to nitrogen fixation. 
E) All of these choices are correct. 
A) It can be carried out by both eukaryotes and archaeons. 
B) It generates less energy compared to respiration. 
C) It is performed in oxygen-rich environments. 
D) It is identical to nitrogen fixation. 
E) All of these choices are correct.

Question 15

Molecular phylogenies can be reconstructed for both cultured and nonculturable bacteria.

Accepted Answer

A) True 
 B)False

Question 16

Cyanobacteria are the most diverse group of bacteria, containing gram-positive bacteria, purple sulfur bacteria, and firmicutes.

Accepted Answer

A) True 
 B)False

Question 17

Which of the following are "usable" forms of nitrogen (N) and sulfur (S) that plants and animals can assimilate to build proteins?

Accepted Answer

A) both N2 and NO3 
B) both S2 and S3 
C) both SO4 and NO3 
D) both NH3 and S2 
E) both N2 and S2 
A) both N2 and NO3 
B) both S2 and S3 
C) both SO4 and NO3 
D) both NH3 and S2 
E) both N2 and S2

Question 18

Recall that Archaea and Bacteria used to be grouped in the same category. How were archaeons FIRST distinguished from other prokaryotes?

Accepted Answer

A) through differences in cell size and shape 
B) through the fact that archaeons have linear and not circular chromosomes 
C) through differences in ribosomal RNA sequences 
D) through the lack of horizontal gene transfer in archaeons 
E) through the observation that archaea cell size is independent of diffusion 
A) through differences in cell size and shape 
B) through the fact that archaeons have linear and not circular chromosomes 
C) through differences in ribosomal RNA sequences 
D) through the lack of horizontal gene transfer in archaeons 
E) through the observation that archaea cell size is independent of diffusion

Question 19

DNA sequences can change at different rates for the same gene in different microorganisms, falsely grouping Bacteria based on the amount of sequence divergence rather than common ancestry.

Accepted Answer

A) True 
 B)False

Question 20

A high school student in Nepal is accepted to-and eventually attends-college in the United States. His diet changes from one that is rich in vegetables and grains to one that primarily consists of meat and sugars. What will happen to the bacteria living in his intestines?

Accepted Answer

A) There will be more Firmicutes inhabiting his intestinal tract. 
B) There will be more Bacteroidetes inhabiting his intestinal tract. 
C) Nothing will happen; there is no relationship between bacteria in the intestines and diet. 
D) Bacteria will no longer inhabit his intestines. 
A) There will be more Firmicutes inhabiting his intestinal tract. 
B) There will be more Bacteroidetes inhabiting his intestinal tract. 
C) Nothing will happen; there is no relationship between bacteria in the intestines and diet. 
D) Bacteria will no longer inhabit his intestines.

Exam 26: Bacteria and Archaea

Why are scientists unable to grow the majority of Bacteria and Archaea in pure culture in a laboratory setting?

Generating a phylogeny that represents the traditional groupings of bacteria requires sequencing and comparing the entire genome of each organism and cannot rely on single-gene phylogenies generated from 16S rRNA datasets.

Wolbachia belongs to the Proteobacteria group.

Antibiotics can kill _____ in the human body, which may sometimes lead to health problems such as inflammatory bowel disease.

Bacteria contain neither organelle-associated membranes nor a cell membrane.

Phylogenies can be generated from molecular sequence data derived either from single genes or from entire genomes.

Stromatolites are not the only rocks that provide evidence regarding ancient microbial life. Intact fossilized bacteria-and even fossilized biomolecules-are also found in the fossil record.

Consider the chemical reactions of the sulfur cycle shown in Figure 26.10. Reduction of CO2 to generate carbohydrates can occur when coupled to the oxidation of reduced sulfur compounds (e.g., H2S). This latter process is carried out by what type of microorganism(s)?

Which of the following statements is TRUE regarding the bacteria present in the stomachs or intestines of humans?

Archaeons are often found in environments where exploitable energy sources cannot maintain eukaryotes, but can maintain bacteria.

Which is NOT a difference between anoxygenic photosynthetic organisms and oxygenic photosynthetic organisms?

Imagine that you traveled back in time and searched the early Earth for signs of life. You would MOST likely find early microorganisms:

As many bacterial molecular sequences evolve quickly and/or continuously, creating a bacterial phylogenetic tree based on molecular sequences can be difficult.

Which of the following statements is TRUE regarding anammox?

Molecular phylogenies can be reconstructed for both cultured and nonculturable bacteria.

Cyanobacteria are the most diverse group of bacteria, containing gram-positive bacteria, purple sulfur bacteria, and firmicutes.

Which of the following are "usable" forms of nitrogen (N) and sulfur (S) that plants and animals can assimilate to build proteins?

Recall that Archaea and Bacteria used to be grouped in the same category. How were archaeons FIRST distinguished from other prokaryotes?

DNA sequences can change at different rates for the same gene in different microorganisms, falsely grouping Bacteria based on the amount of sequence divergence rather than common ancestry.

A high school student in Nepal is accepted to-and eventually attends-college in the United States. His diet changes from one that is rich in vegetables and grains to one that primarily consists of meat and sugars. What will happen to the bacteria living in his intestines?

Life: Chemical, Cellular, and Evolutionary Foundations

The Molecules of Life

Nucleic Acids and Transcription

Translation and Protein Structure

Organizing Principles: Lipids, Membranes, and Cell Compartments

Making Life Work: Capturing and Using Energy

Cellular Respiration: Harvesting Energy From Carbohydrates and Other Fuel Molecules

Photosynthesis: Using Sunlight to Build Carbohydrates

Cell Signaling

Cell and Tissue Architecture: Cytoskeleton, Cell Junctions, and Extracellular Matrix

Cell Division: Variations, Regulation, and Cancer

Dna Replication and Manipulation

Genomes

Mutation and Dna Repair

Genetic Variation

Mendelian Inheritance

Inheritance of Sex Chromosomes, Linked Genes, and Organelles

The Genetic and Environmental Basis of Complex Traits

Genetic and Epigenetic Regulation

Genes and Development

Evolution: How Genotypes and Phenotypes Change Over Time

Species and Speciation

Evolutionary Patterns: Phylogeny and Fossils

Human Origins and Evolution

Cycling Carbon

Eukaryotic Cells: Origins and Diversity

Being Multicellular

Plant Structure and Function: Moving Photosynthesis Onto Land

Plant Reproduction: Finding Mates and Dispersing Young

Plant Growth and Development

Plant Defense: Keeping the World Green

Plant Diversity

Fungi: Structure, Function, and Diversity

Animal Nervous Systems

Animal Sensory Systems and Brain Function

Animal Movement: Muscles and Skeletons

Animal Endocrine Systems

Animal Cardiovascular and Respiratory Systems

Animal Metabolism, Nutrition, and Digestion

Animal Renal Systems: Water and Waste

Animal Reproduction and Development

Animal Immune Systems

Animal Diversity

Animal Behavior

Population Ecology

Species Interactions, Communities, and Ecosystems

Biomes and Global Ecology

The Anthropocene: Humans As a Planetary Force

Filters

Consider the chemical reactions of the sulfur cycle shown in Figure 26.10. Reduction of CO₂ to generate carbohydrates can occur when coupled to the oxidation of reduced sulfur compounds (e.g., H₂S). This latter process is carried out by what type of microorganism(s)?