Question 1

Astronomers believe that the solar system began forming 4.6 billion years ago, when a star exploded to form bodies called _______.

Accepted Answer

The answer of Astronomers believe that the solar system began...

Question 2

Which of these substances, present in the prebiotic environment on Earth, could have been critical in making the chemical synthesis of biologically important polymers more favorable?

Accepted Answer

A)  Water 
B)  Sodium ions 
C)  Methane 
D)  Nickel ions 
E)  Hydrogen 
A)  Water 
B)  Sodium ions 
C)  Methane 
D)  Nickel ions 
E)  Hydrogen

Question 3

Complementary base pairing occurs due to

Accepted Answer

A)  covalent bonds between bases. 
B)  pairing of a purine with a pyrimidine. 
C)  hydrophobic interactions. 
D)  hydrogen bonds between sugar residues. 
E)  pairing of two purines or two pyrimidines. 
A)  covalent bonds between bases. 
B)  pairing of a purine with a pyrimidine. 
C)  hydrophobic interactions. 
D)  hydrogen bonds between sugar residues. 
E)  pairing of two purines or two pyrimidines.

Question 4

In the DNA double helix, the bases in one strand are complementary to the bases in the other strand.Therefore,

Accepted Answer

A)  a purine in one strand will attach to any pyrimidine in the other strand. 
B)  the bases in one strand will be the same as those of the other strand. 
C)  a pyrimidine in one strand will attach to any pyrimidine in the other strand. 
D)  a purine in one strand will attach to a different purine in the other strand. 
E)  a purine in one strand will attach to only one type of pyrimidine in the other strand. 
A)  a purine in one strand will attach to any pyrimidine in the other strand. 
B)  the bases in one strand will be the same as those of the other strand. 
C)  a pyrimidine in one strand will attach to any pyrimidine in the other strand. 
D)  a purine in one strand will attach to a different purine in the other strand. 
E)  a purine in one strand will attach to only one type of pyrimidine in the other strand.

Question 5

Which may have facilitated the polymerization of the large molecules of life on primitive Earth?

Accepted Answer

A)  Ice crystals 
B)  Evaporation in hot pools at the edges of oceans 
C)  Ribozymes 
D)  Early proteins 
E)  Lightning strikes in an anaerobic environment of methane, ammonia, hydrogen, and water vapor. 
A)  Ice crystals 
B)  Evaporation in hot pools at the edges of oceans 
C)  Ribozymes 
D)  Early proteins 
E)  Lightning strikes in an anaerobic environment of methane, ammonia, hydrogen, and water vapor.

Question 6

Nucleotides

Accepted Answer

A)  are the monomers of DNA and RNA. 
B)  are normally present in polysaccharides. 
C)  are composed of amino acids. 
D)  do not contain a sugar. 
E)  contain sulfur. 
A)  are the monomers of DNA and RNA. 
B)  are normally present in polysaccharides. 
C)  are composed of amino acids. 
D)  do not contain a sugar. 
E)  contain sulfur.

Exam 4: Nucleic Acids and the Origin of Life

Astronomers believe that the solar system began forming 4.6 billion years ago, when a star exploded to form bodies called _______.

Which of these substances, present in the prebiotic environment on Earth, could have been critical in making the chemical synthesis of biologically important polymers more favorable?

Complementary base pairing occurs due to

In the DNA double helix, the bases in one strand are complementary to the bases in the other strand.Therefore,

Which may have facilitated the polymerization of the large molecules of life on primitive Earth?

Nucleotides

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

Filters