36
Explain the relationship between Earth’s ancient atmosphere and the evolution of some of the first life forms on Earth. Use the terms anaerobicandphototrophic, and explain the effect of cyanobacteria on the atmosphere.
  1. Phototrophic organisms appeared during the first two billion years of Earth’s existence. Anaerobic organisms appeared within one billion years of Earth’s formation. From these organisms evolved the cyanobacteria which produce oxygen as a by-product of photosynthesis, leading to the oxygenation of the atmosphere.
  2. For the first two billion years of Earth’s existence, the atmosphere had no molecular oxygen. Thus, the first organisms were anaerobic. Cyanobacteria appeared within one billion years of Earth’s formation. From these evolved the phototrophic organisms which produce oxygen as a by-product of photosynthesis, leading to the oxygenation of the atmosphere.
  3. For the first two billion years of Earth’s existence, the atmosphere had no molecular oxygen. Thus, the first organisms were anaerobic. Phototrophic organisms appeared within one billion years of Earth’s formation. From these organisms evolved the cyanobacteria, which produce oxygen as a by-product of photosynthesis, leading to the oxygenation of the atmosphere.
  4. For the first two billion years of Earth’s existence, the atmosphere had no molecular oxygen. Thus, the first organisms were anaerobic. Cyanobacteria which produce oxygen as a by-product of photosynthesis, leading to the oxygenation of the atmosphere, appeared within one billion years of Earth’s formation. From these organisms evolved phototrophic organisms.
37
Extremophiles are considered an important area for research in the development of therapeutic drugs or industrial applications. Why do you think this is so?
  1. Extremophiles can be altered genetically in vitro to allow them to live in extreme conditions and this capability of alteration can be used to help humans. For example, some water-resistant prokaryotes have developed DNA repair mechanisms. Also, they could be developed and used in the treatment of human disease.
  2. Extremophiles have specialized adaptations that allow them to live in extreme conditions. These adaptations can be mobilized to help humans. For example, some water-resistant prokaryotes have developed DNA repair mechanisms. Also, they could be developed and used in the treatment of human disease.
  3. Extremophiles can be altered genetically in vitro to allow them to live in extreme conditions and this capability of alteration can be used to help humans. For example, some radiation-resistant prokaryotes have developed DNA repair mechanisms. Also, they could be developed and used in the treatment of human disease.
  4. Extremophiles have specialized adaptations that allow them to live in extreme conditions. These adaptations can be mobilized to help humans. For example, some radiation-resistant prokaryotes have developed DNA repair mechanisms. Also, they could be developed and used in the treatment of human disease.
38
Describe briefly how you would detect the presence of a non culturable prokaryote in an environmental sample.
  1. Recombinant DNA techniques are used to detect the presence of a non-culturable prokaryote in an environmental sample. Polymerase chain reaction is used to amplify selected portions of prokaryotic DNA.
  2. Molecular biology techniques are used to detect the presence of a non-culturable prokaryote in an environmental sample. Electrophoresis is used to amplify selected portions of prokaryotic DNA.
  3. Molecular biology techniques are used to detect the presence of a non-culturable prokaryote in an environmental sample. Polymerase chain reaction is used to amplify selected portions of prokaryotic DNA.
  4. Recombinant DNA techniques are used to detect the presence of a non-culturable prokaryote in an environmental sample. Electrophoresis is used to amplify selected portions of prokaryotic DNA.
39
Why do scientists believe that the first organisms on Earth were extremophiles?
  1. Earth’s early environment was full of extreme places with much oxygen in the atmosphere, no ozone to shield Earth’s surface from mutagenic radiation, much geologic upheaval and volcanic activity. Extremophiles are bacteria and archaea that are adapted to grow in extreme environments.
  2. Earth’s early environment was full of extreme places with little oxygen in the atmosphere, no ozone to shield Earth’s surface from mutagenic radiation, much geologic upheaval and volcanic activity. Extremophiles are bacteria and archaea that are adapted to grow in extreme environments.
  3. Earth’s early environment was full of extreme places with little oxygen in the atmosphere, no ozone to shield Earth’s surface from mutagenic radiation, less geologic upheaval and volcanic activity. Extremophiles are bacteria and archaea that are adapted to grow in extreme environments.
  4. For the first two billion years of Earth’s existence, the atmosphere had no molecular oxygen.
40
Describe a typical prokaryotic cell.
  1. It has a cell wall enclosing cell membrane, cytoplasm, ribosomes and nucleoid region with genetic material. It may have a protective capsule, flagellum, pili and plasmids.
  2. It has a cell wall enclosing cell membrane, cytoplasm, ribosomes and nucleus containing genetic material. It may have a protective capsule, flagellum, pili and plasmids.
  3. It has a cell wall enclosing nuclear membrane, cytoplasm, ribosomes and nucleoid region with genetic material. It may have a protective capsule, flagellum, pili and plasmids.
  4. It has a cell wall enclosing nuclear membrane, cytoplasm, mitochondria, vacuoles and nucleoid region with genetic material. It may have a protective capsule, flagellum, pili and plasmids.
41
Explain the statement that both Archaea and Bacteria have the same basic structures, but these structures are built from different chemical components.
  1. Typical cells in Archaea and Bacteria contain a cell wall, cell membrane, nucleoid region, ribosomes, and often a capsule, flagellum, and pili. However, these are sometimes made from different chemical compounds. Cell walls of Bacteria contain peptidoglycan while Archaea do not. Plasma membrane lipids of Bacteria are fatty acids while those of Archaea are phytanyl groups.
  2. Typical cells in Archaea and Bacteria contain a cell wall, cell membrane, nucleoid region and often a capsule, flagellum, and pili but in some instances different chemical compounds make them. Cell walls of Bacteria contain peptidoglycan while Archaea do not. Bacteria contain 70S ribosomes while Archaea contain 80S ribosomes.
  3. Typical cells in Archaea and Bacteria contain a cell wall, nuclear membranes, nucleoid region and often a capsule, flagellum, and pili but in some instances different chemical compounds make them. Cell walls of Bacteria contain peptidoglycan while Archaea do not. Plasma membrane lipids of bacteria are fatty acids, while the plasma membrane lipids of Archaea are phytanyl groups.
  4. Typical cells in Archaea and Bacteria contain a cell wall, cell membrane, nucleoid region and often a capsule, flagellum, and pili but in some instances different chemical compounds make them. Cell walls of Bacteria contain peptidoglycan while Archaea do not. Plasma membrane lipids of Bacteria are phytanyl groups, while the plasma membrane lipids of Archaea are fatty acids.
42
Three basic prokaryotic categories are cocci, spirilli, and bacilli. Describe the basic structural features of each category.
  1. These three prokaryote groups have similar basic structural features. They typically have cell walls enclosing nuclear membranes, cytoplasm, ribosomes, mitochondria and nucleoid region with genetic material. They may have a protective capsule, flagellum, pili and plasmids.
  2. Cocci and spirilli have similar basic structural features. They typically have cell walls enclosing cell membranes, a flagellum for locomotion and pili for attachment. Bacilli are rod shaped which contain ribosomes and a nucleoid region with genetic material.
  3. These three prokaryote groups have similar basic structural features. They typically have cell walls enclosing cell membranes, cytoplasm, ribosomes and a nucleoid region with chromosomes. They may have a protective capsule, flagellum, pili and plasmids.
  4. Bacilli and spirilli have similar basic structural features. They typically have cell walls enclosing nuclear membranes, a flagellum for locomotion and pili for attachment. Cocci are spherical containing ribosomes and a nucleoid region with genetic material.
43
Which macronutrient do you think is most important? What evidence can you offer to support your choice?
  1. Carbon because it represents 12 percent of the total dry weight of a typical cell and is a component of all macromolecules.
  2. Oxygen because it is necessary and is a major component for all macromolecules. It also accounts for 50% of the total composition of a cell.
  3. Carbon because it is necessary and is a major component for all macromolecules. It also accounts for 50% of the total composition of a cell.
  4. Nitrogen because it is necessary and is a major component for all macromolecules. It also accounts for 50% of the total composition of a cell.
44
A bacterium requires only a particular amino acid as an organic nutrient and lives in a completely lightless environment. What mode of nutrition (free energy and carbon) does it use? Justify your response.
  1. Chemoheterotroph, as it must rely on chemical sources of energy living in a lightless environment and a heterotroph if it uses organic compounds for its carbon source.
  2. Chemoorganotroph, as it must rely on chemical sources of energy living in a lightless environment and an organotroph if it uses organic compounds other than carbon dioxide for its carbon source.
  3. Chemolitoautotroph, as it must rely on chemical sources of energy living in a lightless environment and an autotroph if it uses organic compounds other than carbon dioxide for its carbon source.
  4. Chemoheterotroph, as it must rely on chemical sources of energy living in a lightless environment and a heterotroph if it uses organic compounds other than carbon dioxide for its carbon source.
45
Assuming that you could synthesize all of the nitrogen-containing compounds needed if you had nitrogen, what might you eat for a typical meal if you could fix nitrogen like some prokaryotes?
  1. My meal might be fruits or vegetables and water as nitrogen is present in the highest amount in water.
  2. My meal might be fruits or vegetables, water and air as atmospheric nitrogen could be simply absorbed.
  3. My meal might be fruits or vegetables, cheese, meat, water, and air as atmospheric nitrogen could be simply absorbed.
  4. My meal might be cheese or meat, water, and air as atmospheric nitrogen could be simply absorbed.
46
Which are more important: macronutrients or micronutrients? Explain your reasoning.
  1. Neither are important, as cells can survive as well as carry out essential functions without both types of nutrients.
  2. Micronutrients, even though they are required in lesser amounts, without them cells cannot survive and carry out functional processes.
  3. Macronutrients, as they are required in larger amounts by cells and thus are more essential than micronutrients.
  4. Neither is more important as both types of nutrients are absolutely necessary for prokaryotic cell structure and function.
47
Identify and discuss a bacterial disease that caused a historically important plague or epidemic. What is the modern distribution of this disease?
  1. Bubonic plague caused by Yersinia pestis was a pandemic that occurred in the 14th century. In modern times, there are only about 100 cases of bubonic plague each year. The bacterium responds well to modern antibiotics.
  2. Bubonic plague caused by Yersinia enterocolitica was a pandemic that occurred in the 14th century. In modern times, there are about 1,000 to 3,000 cases of bubonic plague each year. The bacterium responds well to modern antibiotics.
  3. Pneumonic plague caused by Yersinia pestis was a pandemic that occurred in the 14th century. In modern times, there are about 1,000 to 3,000 cases of pneumonic plague each year. The bacterium responds well to modern antibiotics.
  4. Bubonic plague caused by Yersinia pestis was a pandemic that occurred in the 14th century. In modern times, there are about 1,000 to 3,000 cases of bubonic plague each year. The bacterium responds well to modern antibiotics.
48
Have foodborne illnesses related to biofilms changed over time? Explain.
  1. Yes, better sterilization and canning procedures have reduced the incidence of botulism. Most cases of foodborne illness now are related to small-scale food production.
  2. No, better sterilization and canning procedures have reduced the incidence of botulism. Most cases of foodborne illness now are related to small-scale food production.
  3. No, better sterilization and canning procedures have increased the incidence of botulism. Most cases of foodborne illnesses now are related to large-scale food production.
  4. Yes, better sterilization and canning procedures have reduced the incidence of botulism. Most cases of foodborne illnesses now are related to large-scale food production.
49
What is the relationship between MRSA and the problem of antibiotic resistance?
  1. Indiscriminate use of antibiotics results in the population growth of resistant bacteria like MRSA.
  2. Infrequent use of antibiotics results in the population growth of resistant bacteria like MRSA.
  3. Indiscriminate use of antibiotics results in the population decline of resistant bacteria like MRSA.
  4. Infrequent use of antibiotics results in the population stability of resistant bacteria like MRSA.
50
What was the Plague of Athens? What is the modern distribution of this disease?
  1. The Plague of Athens was a disease caused by Yersinia pestis that killed one-quarter of Athenian troops in 430 BC. Between 10 and 15 million cases of typhoid fever occur today, resulting in over 10, 000 deaths annually.
  2. The Plague of Athens was a disease caused by Salmonella entericaserovar typhi that killed one-quarter of Athenian troops in 430 BC. Between 5 and 10 million cases of typhoid fever occur today, resulting in over 20, 000 deaths annually.
  3. The Plague of Athens was a disease caused by Yersinia pestis that killed one-quarter of Athenian troops in 430 BC. Between 16 and 33 million cases of typhoid fever occur today, resulting in over 200,000 deaths annually.
  4. The Plague of Athens was a disease caused by Salmonella entericaserovar typhi that killed one-quarter of Athenian troops in 430 BC. Between 16 and 33 million cases of typhoid fever occur today, resulting in over 200,000 deaths annually.
51
Identify three beneficial results of symbiotic nitrogen fixation.
  1. Plants benefit from an endless supply of nitrogen; soils benefit from being naturally fertilized; and bacteria benefit from using potassium from plants.
  2. Plants benefit from a limited supply of nitrogen; soils benefit from being naturally fertilized, and bacteria benefit from using photosynthates from plants.
  3. Plants benefit from an endless supply of carbon; soils benefit from being naturally fertilized; and bacteria benefit from using photosynthates from plants.
  4. Plants benefit from an endless supply of nitrogen; soils benefit from being naturally fertilized; and bacteria benefit from using photosynthates from plants.
52
Why is the processing of foods with prokaryotes considered an example of early biotechnology?
  1. Prokaryotes have been used to only make specific food products like cheese, wine, bread, beer and yogurt since before the term biotechnology was coined.
  2. Prokaryotes have been used to make and alter specific food products like cheese, wine, single cell proteins, beer and yogurt since before the term biotechnology was coined.
  3. As prokaryotes have been used to make and alter specific food products like cheese, wine, bread, beer and yogurt since before the term biotechnology was coined.
  4. As prokaryotes have been used to alter specific food products like cheese, wine, bread, beer and yogurt since before the term biotechnology was coined.
53
On what does the success of bioremediation of oil spills depend?
  1. Success depends on the presence of only aromatic and highly branched hydrocarbon chain compounds and the temperature.
  2. Success depends on the presence of less nonvolatile and more aromatic and highly branched hydrocarbon chain compounds and the temperature.
  3. Success depends on the type of oil compounds, the presence of naturally-occurring oil-solubilizing prokaryotes in the ocean, and the type of water body.
  4. Success depends on the type of oil compounds, the presence of naturally-occurring oil-solubilizing prokaryotes in the ocean and the temperature.
54
Why is the relationship between sustainable agriculture and nitrogen fixers called a mutualism?
  1. Due to agrobacterium which are nitrogen fixers, plants benefit from an endless supply of nitrogen; soils benefit from being naturally fertilized and bacteria benefit from using photosynthates from plants.
  2. Due to rhizobia, which are nitrogen fixers, plants benefit from an endless supply of nitrogen; soils benefit from being naturally fertilized and bacteria benefit from using photosynthates from plants.
  3. Due to rhizobia, which are nitrogen fixers, plants benefit from an endless supply of nitrogen; soils benefit from being naturally fertilized and bacteria benefit from using potassium from plants.
  4. Due to rhizobia, which are nitrogen fixers, plants benefit from a limited supply of nitrogen; soils benefit from being naturally fertilized and bacteria benefit from using potassium from plants.