Which is the best evidence that prokaryotes evolved about 3 billion years ago?

1. Scientists believe photosynthesis evolved about 3.0 billion years ago.
2. There is fossil evidence of mammalian forms going back about 4.0 billion years.
3. Earth and its Moon are thought to be about 4.5 billion years old.
4. There is fossil evidence of microbial mats—large multi-layered sheets of prokaryotes—starting about 3.5 billion years ago.

1. The atmosphere contained much less molecular oxygen.
2. Strong volcanic activity was common.
3. It was subject to mutagenic radiation from the Sun.
4. There was little to no geologic activity.

1. alkaliphiles
2. thermophiles
3. hyperthermophiles
4. psychrophiles

1. extremely low temperature
2. hypersalinity
3. high doses of radiation
4. normal drought

Over ________ percent of bacteria and archaea cannot be successfully cultured in a laboratory setting.

1. 9
2. 19
3. 91
4. 99

The most substantial difficulty in culturing prokaryotes in laboratory settings is related to ________.

1. the lack of knowledge about their needs for growth
2. growth requirements that are too difficult to meet
3. inefficient methods for resuscitation of viable-but-nonculturable (VBNC) organisms
4. the expense of techniques such as polymerase chain reaction (PCR)

1. hydrothermal vent
2. microbial mat
3. meteorite
4. stromatolite

1. The atmosphere of early Earth was very different from today’s atmosphere, but most other conditions (such as geologic upheaval and volcanic activity) were very much the same.
2. The atmosphere of early Earth was very much like today’s atmosphere, but many other conditions (such as geologic upheaval and volcanic activity) were very different.
3. Early Earth had a very different atmosphere, was subject to extreme radiation, and had a lot of geologic upheaval and volcanic activity.
4. Early Earth had a very different atmosphere and was subject to extreme radiation, but there was very little geologic upheaval or volcanic activity.

Halophiles prefer conditions in which there is a ________.

1. high sugar concentration
2. salt concentration of at least 0.2 M
3. p^H of three or below
4. high level of radiation

The presence of a membrane-enclosed nucleus is a characteristic of ________.

1. prokaryotic cells
2. eukaryotic cells
3. all cells
4. viruses

All prokaryotic and eukaryotic cells have four structures in common: the plasma membrane, the cytoplasm, nucleic acid, and ________.

1. the cell wall
2. ribosomes
3. the nucleus
4. organelles

1. The cytoplasm of both bacterial and archaean prokaryotic cells has a high concentration of dissolved solutes.
2. Osmotic pressure in both types of prokaryotic cells is relatively high.
3. The domains Bacteria and Archaea differ in the use of fatty acids versus phytanal groups in their cell membranes.
4. The domains Bacteria and Archaea have very similar cell wall structure.

Pseudopeptidoglycan is a characteristic of the walls of some ________.

1. eukaryotic cells
2. bacterial prokaryotic cells
3. archaean prokaryotic cells
4. bacterial and archaean prokaryotic cells

The cell wall, a feature of most prokaryotes, is ________.

1. interior to the cell membrane
2. exterior to the cell membrane
3. a part of the cell membrane
4. interior or exterior, depending on the particular cell

1. Boron is required in small amounts by some prokaryotic organisms.
2. Manganese is required in small amounts by some prokaryotic organisms.
3. Iron is required in small amounts by some prokaryotic organisms.
4. Sulfur is needed in large amounts by prokaryotic organisms. It is part of the structure of some amino acids and is also present in some vitamins and coenzymes.

1. Carbon is a macronutrient and major element in all macromolecules.
2. Nitrogen is a macronutrient and necessary component of proteins and nucleic acids.
3. Hydrogen is a macronutrient and key component of many organic compounds, including water.
4. Iron is a macronutrient necessary for the function of cytochromes.

1. phototrophs
2. autotrophs
3. chemotrophs
4. heterotrophs

1. chemolithotrophs
2. photoautotrophs
3. photoheterotrophs
4. chemoorganotrophs

A primary role of many prokaryotes in the carbon cycle is that of ________.

1. producers
2. decomposers
3. fixers
4. synthesizers

Ammonification is the process by which ________.

1. ammonia is released during the decomposition of nitrogen-containing organic compounds
2. ammonium is converted in to nitrite and nitrate in soils
3. nitrate from soil is transformed to gaseous nitrogen compounds
4. gaseous nitrogen is fixed to yield ammonia

1. phosphorus
2. iron
3. chromium
4. boron

A disease that is constantly present in a population is called ________.

1. pandemic
2. endemic
3. emerging
4. re-emerging

1. diphtheria, bubonic plague, yellow fever
2. yellow fever, dengue fever, bubonic plague
3. bubonic plague, diphtheria, cholera
4. cholera, diphtheria, dengue fever

1. dental plaque
2. dry scalp
3. skin rash
4. prosthetic discomfort

1. Biofilms are related to foodborne illnesses because they colonize food surfaces and food-processing equipment.
2. In healthcare environments, biofilms grow on ventilators, shunts, and other medical equipment.
3. Biofilms tend to colonize medical devices such as prostheses, contact lenses, and catheters.
4. Biofilms form in open wounds, burned tissue, or internal medical devices such as pacemakers.

1. It is becoming too expensive to manufacture effective antibiotics.
2. It takes too much time to develop effective antibiotics; infections spread before treatment is available.
3. Bacteria are increasingly resistant to antibiotics used to treat and eradicate infections.
4. People are increasingly allergic to antibiotics commonly used in treatment.

1. The excessive use of antibiotics has resulted in the natural selection of resistant forms of bacteria.
2. Antibiotics are used by patients with colds or the flu, the treatment for which antibiotics are useless.
3. There is excessive use of antibiotics in livestock and in animal feed.
4. Antibiotics are used by patients of different ages and the fact that their ages differ increases resistance.

1. An epidemic is a disease that occurs in a high number of individuals in a population at a time.
2. A pandemic is a widespread, usually worldwide, epidemic.
3. An endemic disease is a disease that is constantly present, usually at high incidence, in a population.
4. An emerging disease is a disease that has appeared in a population for the first time.

1. Prokaryotes cannot use gaseous nitrogen to synthesize macromolecules, so it must be converted into ammonia.
2. Prokaryotes cannot use ammonia to synthesize macromolecules, so it must be converted into gaseous nitrogen.
3. Eukaryotes cannot use ammonia to synthesize macromolecules, so it must be converted into gaseous nitrogen.
4. Eukaryotes cannot use gaseous nitrogen to synthesize macromolecules, so it must be converted into ammonia.

1. It can be accomplished abiotically, as a result of lightning.
2. It can be accomplished abiotically, as a result of industrial processes.
3. It can be accomplished biologically, by algae.
4. It can be accomplished biologically, by cyanobacteria.

1. cheese, yogurt, and milk
2. cheese, yogurt, and bread
3. wine, bread, and butter
4. milk, wine, and beer

1. The foods taste better.
2. Nutrients are preserved.
3. The food is less stable.
4. Nutrients were safer.

1. the use of microbial metabolism to clean up oil spills
2. the use of microbial metabolism to ferment food
3. the use of microbial metabolism to remove pollutants
4. the use of microbial metabolism to fix nitrogen

1. It includes removing agricultural chemicals.
2. It includes removing industrial by-products.
3. It includes cleaning up oil spills.
4. It includes cleaning up ammonia in soil.

Nitrogen is an essential element that is widely available in the atmosphere. Because eukaryotes cannot use nitrogen in its gaseous form, they benefit from prokaryotes’ conversion of gaseous nitrogen to ________.

1. nitrates, a form of nitrogen they can use
2. phosphate, a different essential element they can use
3. ammonia, a form of nitrogen they can use
4. hydrogen, a different essential element they can use