Question 1

According to the principle of complementary base pairing, purines always pair with

Accepted Answer

A)  deoxyribose sugars. 
B)  uracil. 
C)  pyrimidines. 
D)  adenine. 
E)  guanine. 
A)  deoxyribose sugars. 
B)  uracil. 
C)  pyrimidines. 
D)  adenine. 
E)  guanine.

Question 2

Refer to the figures below representing nitrogenous bases found in the structures of RNA and DNA.   The bases that can be grouped into the pyrimidines are shown in figures _______.

Accepted Answer

The answer of Refer to the figures below representing nitrogenous...

Question 3

DNA carries genetic information in its

Accepted Answer

A)  helical form. 
B)  sequence of bases. 
C)  tertiary sequence. 
D)  sequence of amino acids. 
E)  phosphate groups. 
A)  helical form. 
B)  sequence of bases. 
C)  tertiary sequence. 
D)  sequence of amino acids. 
E)  phosphate groups.

Question 4

Which statement about the results from Miller's cold chemistry experiment is true?

Accepted Answer

A)  Biomolecules could have formed from inorganic molecules at cold temperatures in very short time periods. 
B)  High temperatures are required for the synthesis of biomolecules. 
C)  Biomolecules can form at -78°C as long as oxygen is also present. 
D)  The experiment proved the possibility that life originated outside Earth. 
E)  Biomolecules were formed that were also formed in the Miller-Urey experiment. 
A)  Biomolecules could have formed from inorganic molecules at cold temperatures in very short time periods. 
B)  High temperatures are required for the synthesis of biomolecules. 
C)  Biomolecules can form at -78°C as long as oxygen is also present. 
D)  The experiment proved the possibility that life originated outside Earth. 
E)  Biomolecules were formed that were also formed in the Miller-Urey experiment.

Question 5

Refer to the figure below, showing the enzyme cAMP-dependent phosphodiesterase converting cAMP to AMP.Chemical compounds that inhibit this enzyme are used as drugs to stimulate heart rate in patients with weak hearts.   Which biological function does the nucleotide cAMP provide in this instance?

Accepted Answer

A)  Agent of energy transfer 
B)  Signaling agent in muscle contraction 
C)  Carrier in the metabolism of carbohydrates and lipids 
D)  Energy storage molecule 
E)  Regulator of glucose metabolism 
A)  Agent of energy transfer 
B)  Signaling agent in muscle contraction 
C)  Carrier in the metabolism of carbohydrates and lipids 
D)  Energy storage molecule 
E)  Regulator of glucose metabolism

Question 6

What is the relationship between chemical evolution and evaporation in hot pools at the edges of oceans?

Accepted Answer

A)  Following evaporation, exposure to the atmosphere may have catalyzed chemical reactions. 
B)  Evaporation may have concentrated monomers to the point of polymerization. 
C)  Dehydration may have caused RNA molecules to "crinkle" into catalytic three-dimensional shapes. 
D)  Evaporation may have exposed catalytic silicates on the large surface areas of clays. 
E)  Evaporation-related loss of oxygen in these pools may have facilitated catalytic activity of metals such as iron and nickel. 
A)  Following evaporation, exposure to the atmosphere may have catalyzed chemical reactions. 
B)  Evaporation may have concentrated monomers to the point of polymerization. 
C)  Dehydration may have caused RNA molecules to "crinkle" into catalytic three-dimensional shapes. 
D)  Evaporation may have exposed catalytic silicates on the large surface areas of clays. 
E)  Evaporation-related loss of oxygen in these pools may have facilitated catalytic activity of metals such as iron and nickel.

Question 7

Hot water containing iron and nickel emerges from below Earth's crust at deep ocean hydrothermal vents where there is no oxygen.These metals catalyze the polymerization of amino acids in the absence of oxygen.This evidence supports the hypothesis of

Accepted Answer

A)  the prebiotic synthesis of large molecules in Earth's early environment. 
B)  photosynthesis by cyanobacteria 3.5 billion years ago. 
C)  the prebiotic synthesis of small molecules in the ice of Europa, a moon of Jupiter. 
D)  the evolution of whales. 
E)  an extraterrestrial origin of life. 
A)  the prebiotic synthesis of large molecules in Earth's early environment. 
B)  photosynthesis by cyanobacteria 3.5 billion years ago. 
C)  the prebiotic synthesis of small molecules in the ice of Europa, a moon of Jupiter. 
D)  the evolution of whales. 
E)  an extraterrestrial origin of life.

Question 8

Pasteur used swan-neck flasks in his experiments to test the validity of spontaneous generation.Suppose that after allowing the flasks to sit for a day, he had tilted one of these flasks so that the sterile broth entered the swan neck.Suppose he had then tilted the flask back to allow the broth to settle back into the round bowl of the flask before leaving it to sit undisturbed for another few days.What would have happened, and how would these results have affected conclusions about spontaneous generation?

Accepted Answer

A)  The broth would have become cloudy from growth of microbes present in the flask neck, and that would have supported the idea that life comes from preexisting life. 
B)  The broth would have become cloudy from growth of microbes present in the flask neck, and that would have supported the concept of spontaneous generation. 
C)  The broth would have become cloudy as the result of microbes present in the original broth, and that would have supported the idea that life comes from preexisting life. 
D)  The broth would have remained clear as the result of sterilization by high heat, and that would have supported the idea that life comes from preexisting life. 
E)  The broth would have remained clear as the result of sterilization by high heat, and that would have supported the concept of spontaneous generation. 
A)  The broth would have become cloudy from growth of microbes present in the flask neck, and that would have supported the idea that life comes from preexisting life. 
B)  The broth would have become cloudy from growth of microbes present in the flask neck, and that would have supported the concept of spontaneous generation. 
C)  The broth would have become cloudy as the result of microbes present in the original broth, and that would have supported the idea that life comes from preexisting life. 
D)  The broth would have remained clear as the result of sterilization by high heat, and that would have supported the idea that life comes from preexisting life. 
E)  The broth would have remained clear as the result of sterilization by high heat, and that would have supported the concept of spontaneous generation.

Question 9

The diversity in DNA molecules is due to

Accepted Answer

A)  physical shape differences. 
B)  differences in size between A-T and G-C base pairs. 
C)  base sequence differences. 
D)  hydrogen bonding differences. 
E)  the ability of each base to pair with any of the other three bases. 
A)  physical shape differences. 
B)  differences in size between A-T and G-C base pairs. 
C)  base sequence differences. 
D)  hydrogen bonding differences. 
E)  the ability of each base to pair with any of the other three bases.

Question 10

Fungi and plants were classified as belonging to the same group of organisms in the nineteenth and twentieth centuries.Now, fungi are known to be more closely related to animals than to plants.A comparison of which property of fungi, animals, and plants could have prompted this change in scientific thinking?

Accepted Answer

A)  Multicellularity 
B)  Motility 
C)  Genome 
D)  Reproduction 
E)  Organ systems 
A)  Multicellularity 
B)  Motility 
C)  Genome 
D)  Reproduction 
E)  Organ systems

Question 11

DNA structure depends on base pairing of its four nucleotides, A, C, T, and G.Nucleotide A pairs with T, and nucleotide C pairs with G.This forms a four-letter DNA "alphabet." Because DNA codes for amino acids in sets of three nucleotides, there are 4 cubed (43), or 64, possible combinations, coding for 20 different amino acids.What is the best explanation for why there is no selective advantage for DNA to have five nucleotides (e.g., A, C, T, G, and E) with C pairing with either G or functionally equivalent E?

Accepted Answer

A)  There would be a five-letter alphabet with 125 combinations, which is too numerous. 
B)  It would be impossible to form the DNA molecule, because it must have an equal number of Cs and Gs. 
C)  Replication would be inaccurate because sometimes C would bond with G and sometimes C would bond with E. 
D)  Because G and E have the same role, there would still be four functional letters of the alphabet. 
E)  It is impossible because there are not five known nucleotides in the cell. 
A)  There would be a five-letter alphabet with 125 combinations, which is too numerous. 
B)  It would be impossible to form the DNA molecule, because it must have an equal number of Cs and Gs. 
C)  Replication would be inaccurate because sometimes C would bond with G and sometimes C would bond with E. 
D)  Because G and E have the same role, there would still be four functional letters of the alphabet. 
E)  It is impossible because there are not five known nucleotides in the cell.

Question 12

Some RNA molecules can act as catalysts.Catalytic RNA, or _______, can catalyze a variety of chemical reactions on their nucleotides.

Accepted Answer

The answer of Some RNA molecules can act as catalysts.Catalytic...

Question 13

Refer to the figure below showing a simplified time line of the origin of life.   Which event could have occurred before the evolution of RNA?

Accepted Answer

A)  Formation of DNA 
B)  Evolution of cells 
C)  Prebiotic synthesis of amino acids 
D)  Development of ribozymes 
E)  Rise of protocells 
A)  Formation of DNA 
B)  Evolution of cells 
C)  Prebiotic synthesis of amino acids 
D)  Development of ribozymes 
E)  Rise of protocells

Question 14

The table below was created to summarize properties of the nitrogenous bases found in DNA and RNA.   Which statement best evaluates the accuracy of information presented in the table?

Accepted Answer

A)  The information is completely accurate. 
B)  The base names are assigned incorrectly to the purine and pyrimidine classes. 
C)  The structural descriptions of purines and pyrimidines are reversed. 
D)  The hydrogen bond properties are classified incorrectly. 
E)  The information listed for occurrence in DNA and RNA is inaccurate. 
A)  The information is completely accurate. 
B)  The base names are assigned incorrectly to the purine and pyrimidine classes. 
C)  The structural descriptions of purines and pyrimidines are reversed. 
D)  The hydrogen bond properties are classified incorrectly. 
E)  The information listed for occurrence in DNA and RNA is inaccurate.

Question 15

Five pieces of information about early Earth are stated below.Which could be used as justification for a condition used by Miller and Urey in their experiments to test the possibility of organic molecule formation during Earth's earliest history?

Accepted Answer

A)  Impacts by comets and meteorites on Earth's surface were frequent. 
B)  Oxygen was absent in Earth's atmosphere until photosynthetic organisms arose. 
C)  Earth was formed about 4.6 billion years ago, and life arose on Earth about 4 billion years ago. 
D)  Earth underwent many physical changes during its earliest history. 
E)  Geological evidence has helped scientists develop hypotheses about how Earth's atmosphere has changed over time. 
A)  Impacts by comets and meteorites on Earth's surface were frequent. 
B)  Oxygen was absent in Earth's atmosphere until photosynthetic organisms arose. 
C)  Earth was formed about 4.6 billion years ago, and life arose on Earth about 4 billion years ago. 
D)  Earth underwent many physical changes during its earliest history. 
E)  Geological evidence has helped scientists develop hypotheses about how Earth's atmosphere has changed over time.

Question 16

In modern cells, proteins are known to bind to RNA oligonucleotides.Furthermore, the binding is specific, since each oligonucleotide binds only to certain proteins, and changing the sequence of bases in an RNA oligonucleotide can eliminate its ability to bind to a particular protein.This characteristic of RNA oligonucleotides supports the "RNA world" hypothesis that RNA molecules could have acted as _______ in the synthesis of primitive polypeptides.

Accepted Answer

The answer of In modern cells, proteins are known to...

Question 17

The Miller-Urey experiments demonstrated that

Accepted Answer

A)  under specific conditions, the basic building blocks of life can form. 
B)  life on Earth came from other bodies in the solar system. 
C)  CO2, N2, H2S, and SO2 were probably present in Earth's early atmosphere. 
D)  volcanic eruptions may have released CO2, N2, H2S, and SO2 into Earth's early atmosphere. 
E)  ice is present in meteorites and on Mars. 
A)  under specific conditions, the basic building blocks of life can form. 
B)  life on Earth came from other bodies in the solar system. 
C)  CO2, N2, H2S, and SO2 were probably present in Earth's early atmosphere. 
D)  volcanic eruptions may have released CO2, N2, H2S, and SO2 into Earth's early atmosphere. 
E)  ice is present in meteorites and on Mars.

Question 18

Consider the following double-stranded DNA region: 5ʹ-TGCCAT-3ʹ
3ʹ-ACGGTA-5ʹ
If the lower strand is transcribed, which strand will result?

Accepted Answer

A)  TGCCAT 
B)  TCGGTA 
C)  UGCCAU 
D)  UGCCUA 
E)  TCGGUT 
A)  TGCCAT 
B)  TCGGTA 
C)  UGCCAU 
D)  UGCCUA 
E)  TCGGUT

Question 19

Evaporation may have concentrated chemical monomers to the point where polymerization was favored in which type of environment?

Accepted Answer

A)  Hydrothermal vents deep in the ocean 
B)  Inclusions of water within frozen ice on early Earth 
C)  Hot pools at the edges of oceans 
D)  The large surface areas of solid mineral surfaces, such as powderlike clays 
E)  Cooling lava produced by volcanoes 
A)  Hydrothermal vents deep in the ocean 
B)  Inclusions of water within frozen ice on early Earth 
C)  Hot pools at the edges of oceans 
D)  The large surface areas of solid mineral surfaces, such as powderlike clays 
E)  Cooling lava produced by volcanoes

Question 20

Which of the following statements about DNA and RNA is true?

Accepted Answer

A)  DNA has uracil, whereas RNA has thymine. 
B)  DNA usually has one polynucleotide strand, whereas RNA usually has two strands. 
C)  DNA contains pentose sugars, whereas RNA contains hexose sugars. 
D)  DNA is a polymer, whereas RNA is a monomer. 
E)  In DNA, A pairs with T, whereas in RNA, A pairs with U. 
A)  DNA has uracil, whereas RNA has thymine. 
B)  DNA usually has one polynucleotide strand, whereas RNA usually has two strands. 
C)  DNA contains pentose sugars, whereas RNA contains hexose sugars. 
D)  DNA is a polymer, whereas RNA is a monomer. 
E)  In DNA, A pairs with T, whereas in RNA, A pairs with U.

Exam 4: Nucleic Acids and the Origin of Life

According to the principle of complementary base pairing, purines always pair with

Refer to the figures below representing nitrogenous bases found in the structures of RNA and DNA. The bases that can be grouped into the pyrimidines are shown in figures _______.

DNA carries genetic information in its

Which statement about the results from Miller's cold chemistry experiment is true?

Refer to the figure below, showing the enzyme cAMP-dependent phosphodiesterase converting cAMP to AMP.Chemical compounds that inhibit this enzyme are used as drugs to stimulate heart rate in patients with weak hearts. Which biological function does the nucleotide cAMP provide in this instance?

What is the relationship between chemical evolution and evaporation in hot pools at the edges of oceans?

Hot water containing iron and nickel emerges from below Earth's crust at deep ocean hydrothermal vents where there is no oxygen.These metals catalyze the polymerization of amino acids in the absence of oxygen.This evidence supports the hypothesis of

The diversity in DNA molecules is due to

Some RNA molecules can act as catalysts.Catalytic RNA, or _______, can catalyze a variety of chemical reactions on their nucleotides.

Refer to the figure below showing a simplified time line of the origin of life. Which event could have occurred before the evolution of RNA?

The table below was created to summarize properties of the nitrogenous bases found in DNA and RNA. Which statement best evaluates the accuracy of information presented in the table?

Five pieces of information about early Earth are stated below.Which could be used as justification for a condition used by Miller and Urey in their experiments to test the possibility of organic molecule formation during Earth's earliest history?

The Miller-Urey experiments demonstrated that

Consider the following double-stranded DNA region: 5ʹ-TGCCAT-3ʹ 3ʹ-ACGGTA-5ʹ If the lower strand is transcribed, which strand will result?

Evaporation may have concentrated chemical monomers to the point where polymerization was favored in which type of environment?

Which of the following statements about DNA and RNA is true?

Studying Life

Small Molecules and the Chemistry of Life

Proteins, Carbohydrates, and Lipids

Cells: the Working Units of Life

Cell Membranes

Cell Communication and Multicellularity

Energy, Enzymes, and Metabolism

Pathways That Harvest Chemical Energy

Photosynthesis: Energy From Sunlight

The Cell Cycle and Cell Division

Inheritance, Genes, and Chromosomes

Dna and Its Role in Heredity

From Dna to Protein: Gene Expression

Gene Mutation and Molecular Medicine

Regulation of Gene Expression

Genomes

Recombinant Dna and Biotechnology

Mechanisms of Evolution

Reconstructing and Using Phylogenies

Speciation

Evolution of Genes and Genomes

The History of Life on Earth

Bacteria, Archaea, and Viruses

The Origin and Diversification of Eukaryotes

Plants Without Seeds: From Water to Land

The Evolution of Seed Plants

The Evolution and Diversity of Fungi

Animal Origins and the Evolution of Body Plans

Protostome Animals

Deuterostome Animals

The Plant Body

Transport in Plants

Plant Nutrition

Regulation of Plant Growth

Reproduction in Flowering Plants

Plant Responses to Environmental Challenges

Physiology, Homeostasis, and Temperature Regulation

Animal Hormones

Immunology: Animal Defense Systems

Animal Reproduction

Animal Development

Neurons, Glia, and Nervous Systems

Sensory Systems

The Mammalian Nervous System: Structure and Higher Functions

Musculoskeletal Systems

Gas Exchange

Circulatory Systems

Nutrition, Digestion, and Absorption

Salt and Water Balance and Nitrogen Excretion

Animal Behavior

The Physical Environment and Biogeography of Life

Populations

Species Interactions

Communities

Ecosystems

A Changing Biosphere

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