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Which organisms are known to live in symbiosis with sulfur-oxidizing bacteria near hydrothermal vents? A) Clams B) Mussels C) Tube worms (Riftia pachyptila) D) Giant squids E) Sea turtles
C) Tube worms (Riftia pachyptila) Explanation: The giant tube worms, Riftia pachyptila, live in symbiosis with sulfur-oxidizing bacteria, which provide nourishment to the worms by harnessing geochemical energy.
What defines a gene in the context of DNA? A) A sequence that codes for multiple proteins only. B) A segment of DNA that corresponds to a single protein or RNA molecule. C) A non-coding region of DNA. D) A sequence that is always transcribed into mRNA. E) A regulatory sequence that controls transcription.
B) A segment of DNA that corresponds to a single protein or RNA molecule. Explanation: A gene is defined as a segment of DNA that encodes for a specific protein or RNA molecule, including variants and non-coding functions.
1/68
p.12
Diversity of Living Organisms

Which organisms are known to live in symbiosis with sulfur-oxidizing bacteria near hydrothermal vents?
A) Clams
B) Mussels
C) Tube worms (Riftia pachyptila)
D) Giant squids
E) Sea turtles

C) Tube worms (Riftia pachyptila)
Explanation: The giant tube worms, Riftia pachyptila, live in symbiosis with sulfur-oxidizing bacteria, which provide nourishment to the worms by harnessing geochemical energy.

p.7
Heredity and Genetic Information

What defines a gene in the context of DNA?
A) A sequence that codes for multiple proteins only.
B) A segment of DNA that corresponds to a single protein or RNA molecule.
C) A non-coding region of DNA.
D) A sequence that is always transcribed into mRNA.
E) A regulatory sequence that controls transcription.

B) A segment of DNA that corresponds to a single protein or RNA molecule.
Explanation: A gene is defined as a segment of DNA that encodes for a specific protein or RNA molecule, including variants and non-coding functions.

p.3
RNA and Protein Synthesis

What is the significance of the directionality of DNA strands?
A) It allows for random pairing of bases
B) It determines the sequence of amino acids in proteins
C) It guides the processes of DNA interpretation and copying
D) It prevents mutations from occurring
E) It allows for the formation of RNA

C) It guides the processes of DNA interpretation and copying
Explanation: The directionality of DNA strands is crucial for the consistent reading and copying of genetic information, similar to how text is read from left to right.

p.4
Structure and Function of DNA

Which sugar is found in RNA but not in DNA?
A) Glucose
B) Ribose
C) Deoxyribose
D) Fructose
E) Sucrose

B) Ribose
Explanation: RNA contains ribose as its sugar component, while DNA contains deoxyribose, which is a key difference between the two nucleic acids.

p.10
Mechanisms of DNA Replication

How does a cell replicate its DNA?
A) By synthesizing RNA
B) By separating DNA strands and using them as templates
C) By creating proteins
D) By undergoing mitosis
E) By absorbing nutrients

B) By separating DNA strands and using them as templates
Explanation: The cell replicates its DNA by separating the paired strands and using each as a template for creating a new complementary DNA strand.

p.7
RNA and Protein Synthesis

What role do transfer RNAs (tRNAs) play in protein synthesis?
A) They transcribe DNA into mRNA.
B) They carry amino acids to the ribosome and match them to codons in mRNA.
C) They form the structure of ribosomes.
D) They regulate gene expression.
E) They are involved in DNA replication.

B) They carry amino acids to the ribosome and match them to codons in mRNA.
Explanation: tRNAs are responsible for bringing specific amino acids to the ribosome, where they recognize codons in mRNA through their anticodons.

p.4
Structure and Function of DNA

What is the base-pairing rule in DNA synthesis?
A) A binds to C, and T binds to G
B) A binds to T, and C binds to G
C) A binds to U, and C binds to T
D) A binds to G, and T binds to C
E) A binds to A, and T binds to T

B) A binds to T, and C binds to G
Explanation: The base-pairing rule states that adenine (A) pairs with thymine (T) and cytosine (C) pairs with guanine (G), which is crucial for the formation of complementary DNA strands during replication.

p.5
RNA and Protein Synthesis

What is the primary function of messenger RNA (mRNA)?
A) To store genetic information
B) To guide the synthesis of proteins
C) To catalyze chemical reactions
D) To replicate DNA
E) To transport nutrients

B) To guide the synthesis of proteins
Explanation: mRNA serves as an intermediary that carries genetic information from DNA to the ribosomes, where it guides the synthesis of proteins according to the genetic instructions.

p.5
RNA and Protein Synthesis

How do RNA molecules recognize and bind to other molecules?
A) By their size
B) Through their rigid structure
C) By forming weak bonds with complementary segments
D) By their color
E) Through electrical charges

C) By forming weak bonds with complementary segments
Explanation: RNA molecules can recognize and bind to other molecules by forming weak bonds with complementary segments of their own sequence, allowing for selective interactions.

p.1
Fundamental Units of Life: Cells

According to the text, what is a common feature of all living organisms?
A) They all have complex nervous systems
B) They all reproduce through sexual means
C) They all are made of cells
D) They all live in water
E) They all have a backbone

C) They all are made of cells
Explanation: The text states that despite their diversity, all living organisms share the common feature of being made of cells.

p.1
Fundamental Units of Life: Cells

What does the text suggest is necessary to understand the origins and diversity of life on Earth?
A) Studying nonliving matter
B) Understanding cell evolution
C) Focusing on individual organisms
D) Analyzing environmental factors
E) Exploring ancient civilizations

B) Understanding cell evolution
Explanation: The text indicates that a deeper understanding of cells and their evolution is crucial for tackling the grand historical problems of life on Earth.

p.2
Fundamental Units of Life: Cells

What is the primary function of a single cell in an organism?
A) To consume energy
B) To store water
C) To gather raw materials and replicate hereditary information
D) To produce waste
E) To communicate with other cells

C) To gather raw materials and replicate hereditary information
Explanation: A single cell serves as the vehicle for hereditary information and has the machinery to gather raw materials from the environment to construct new cells in its own image.

p.3
Structure and Function of DNA

What are the building blocks of DNA called?
A) Amino acids
B) Nucleotides
C) Fatty acids
D) Monosaccharides
E) Polypeptides

B) Nucleotides
Explanation: Nucleotides are the monomers that make up DNA, consisting of a sugar, a phosphate group, and a nitrogenous base.

p.3
Heredity and Genetic Information

What is the primary molecule that stores hereditary information in all living cells?
A) RNA
B) Protein
C) DNA
D) Lipids
E) Carbohydrates

C) DNA
Explanation: All living cells on Earth store their hereditary information in the form of double-stranded DNA, which is a fundamental characteristic of cellular biology.

p.4
Mechanisms of DNA Replication

What is the process called when DNA is copied to create a new strand?
A) Transcription
B) Translation
C) Replication
D) Polymerization
E) Transduction

C) Replication
Explanation: DNA replication is the process by which a double-stranded DNA molecule is copied to produce two identical DNA molecules, ensuring the hereditary information is preserved.

p.10
Fundamental Units of Life: Cells

What is the minimal self-reproducing unit of living matter?
A) Virus
B) Bacterium
C) Individual cell
D) Organism
E) Tissue

C) Individual cell
Explanation: The individual cell is defined as the minimal self-reproducing unit of living matter, emphasizing its fundamental role in life.

p.10
Biochemical Processes in Cells

What role do proteins play in the cell?
A) They store genetic information
B) They are the principal catalysts for chemical reactions
C) They provide structural support
D) They are involved in energy storage
E) They transport oxygen

B) They are the principal catalysts for chemical reactions
Explanation: Proteins serve as the principal catalysts for almost all chemical reactions in the cell, highlighting their essential role in cellular processes.

p.1
Diversity of Living Organisms

What is the relationship between the diversity of life and the fundamental mechanisms of biology as described in the text?
A) They are completely unrelated
B) There is astonishing variety in individual particulars and astonishing constancy in fundamental mechanisms
C) Diversity is more important than constancy
D) Fundamental mechanisms vary greatly among organisms
E) All organisms are identical in fundamental mechanisms

B) There is astonishing variety in individual particulars and astonishing constancy in fundamental mechanisms
Explanation: The text highlights a counterpoint in biology between the astonishing variety of individual organisms and the astonishing constancy of fundamental biological mechanisms.

p.12
Diversity of Living Organisms

What type of energy do organisms near hydrothermal vents primarily rely on?
A) Solar energy
B) Geochemical energy
C) Wind energy
D) Thermal energy
E) Kinetic energy

B) Geochemical energy
Explanation: Organisms living near hydrothermal vents thrive on geochemical energy derived from reactions between available chemicals, forming a unique ecosystem powered by this energy source instead of sunlight.

p.9
Cell Membrane Structure and Function

What is the primary function of the plasma membrane in a cell?
A) To store genetic information
B) To maintain the cell's integrity as a coordinated chemical system
C) To produce energy
D) To synthesize proteins
E) To facilitate cell division

B) To maintain the cell's integrity as a coordinated chemical system
Explanation: The plasma membrane is crucial for maintaining the integrity of the cell, allowing it to function as a coordinated chemical system by regulating what enters and exits.

p.5
Biochemical Processes in Cells

What role do proteins play in cells?
A) They store genetic information
B) They act as catalysts for chemical reactions
C) They provide structural support only
D) They transport RNA
E) They are solely for energy storage

B) They act as catalysts for chemical reactions
Explanation: Proteins function as catalysts in cells, facilitating various biochemical reactions, which is essential for maintaining cellular processes.

p.10
Diversity of Living Organisms

What is the significance of DNA sequences in understanding the diversity of organisms?
A) They determine the color of organisms
B) They provide a universal language for genetic information
C) They are used for energy production
D) They are responsible for cell division
E) They regulate temperature in organisms

B) They provide a universal language for genetic information
Explanation: DNA sequences serve as a universal language for genetic information, allowing for the characterization and comparison of living organisms.

p.2
Diversity of Living Organisms

What is the estimated number of living species on Earth today?
A) 1 million
B) 10 million
C) 100 million
D) 1 billion
E) 500 million

C) 100 million
Explanation: It is estimated that there are more than 10 million, perhaps up to 100 million living species on Earth today, highlighting the vast biodiversity present.

p.2
Structure and Function of DNA

What chemical code do all cells use to store their hereditary information?
A) RNA
B) Protein
C) DNA
D) Lipids
E) Carbohydrates

C) DNA
Explanation: All cells store their hereditary information in the same linear chemical code, which is DNA, making it a universal feature of life.

p.12
Heredity and Genetic Information

What is the role of nitrogen-fixing bacteria in the ecosystem?
A) They produce oxygen for plants
B) They convert nitrogen gas into usable nitrogen compounds
C) They decompose organic matter
D) They provide energy to plants
E) They fix carbon dioxide into organic compounds

B) They convert nitrogen gas into usable nitrogen compounds
Explanation: Nitrogen-fixing bacteria play a crucial role in converting atmospheric nitrogen (N2) into forms that can be utilized by plants, which cannot fix nitrogen on their own.

p.3
Mechanisms of DNA Replication

How do cells replicate their hereditary information?
A) By random polymerization
B) Through templated polymerization
C) By using RNA as a template
D) Through binary fission
E) By direct copying of proteins

B) Through templated polymerization
Explanation: Cells replicate their hereditary information by templated polymerization, where the sequence of nucleotides in an existing DNA strand guides the formation of a new strand.

p.9
Cell Membrane Structure and Function

What property do amphiphilic molecules possess?
A) They are only hydrophobic
B) They are only hydrophilic
C) They consist of both hydrophobic and hydrophilic parts
D) They are water-soluble only
E) They are oil-soluble only

C) They consist of both hydrophobic and hydrophilic parts
Explanation: Amphiphilic molecules have both hydrophobic (water-insoluble) and hydrophilic (water-soluble) components, allowing them to form structures like bilayers in aqueous environments.

p.1
Fundamental Units of Life: Cells

What is the fundamental unit of life according to the text?
A) Molecule
B) Atom
C) Cell
D) Organism
E) Tissue

C) Cell
Explanation: The text emphasizes that all living things are made of cells, which are described as the fundamental units of life, capable of growing and dividing.

p.10
Energy Requirements for Life

How do living organisms obtain their free energy?
A) Only through photosynthesis
B) By feeding on other living things or organic chemicals
C) By absorbing sunlight
D) Through fermentation
E) By respiration alone

B) By feeding on other living things or organic chemicals
Explanation: Living organisms obtain their free energy in various ways, including feeding on other living things or the organic chemicals they produce.

p.7
RNA and Protein Synthesis

How many possible codons can be formed from four nucleotides?
A) 20
B) 64
C) 16
D) 256
E) 32

B) 64
Explanation: The number of distinct triplets (codons) that can be formed from four nucleotides is 4^3, which equals 64 possible codons.

p.7
Heredity and Genetic Information

How does the cell regulate gene expression?
A) By manufacturing all proteins at once.
B) By adjusting the rate of transcription and translation independently.
C) By eliminating non-coding DNA.
D) By increasing the number of genes.
E) By using only one type of RNA.

B) By adjusting the rate of transcription and translation independently.
Explanation: Cells regulate gene expression by controlling the transcription and translation rates of different genes based on their needs, rather than producing all proteins continuously.

p.4
RNA and Protein Synthesis

What is the role of RNA in the expression of genetic information?
A) To store genetic information
B) To replicate DNA
C) To guide the synthesis of proteins
D) To form the backbone of DNA
E) To bind to DNA directly

C) To guide the synthesis of proteins
Explanation: RNA plays a crucial role in expressing genetic information by guiding the synthesis of proteins through the processes of transcription and translation.

p.5
Structure and Function of DNA

What structural feature of RNA allows it to fold into specific shapes?
A) Double-stranded structure
B) Rigid backbone
C) Flexible single-stranded backbone
D) Circular form
E) Presence of ribosomes

C) Flexible single-stranded backbone
Explanation: The single-stranded nature of RNA, along with its flexible backbone, allows it to bend and fold into specific shapes, which can be crucial for its function.

p.1
Fundamental Units of Life: Cells

What does cell biology study?
A) The behavior of nonliving matter
B) The structure, function, and behavior of cells
C) The diversity of ecosystems
D) The evolution of species
E) The chemical composition of the Earth

B) The structure, function, and behavior of cells
Explanation: Cell biology is defined in the text as the study of the structure, function, and behavior of cells, which is essential for understanding life.

p.6
Structure and Function of DNA

How many types of amino acids are there?
A) 4
B) 10
C) 15
D) 20
E) 25

D) 20
Explanation: There are 20 different types of amino acids that can be linked together to form proteins, unlike DNA and RNA which have only 4 types of nucleotides.

p.2
Heredity and Genetic Information

What distinguishes life from non-living processes according to the text?
A) The ability to grow
B) The consumption of energy
C) The phenomenon of heredity
D) The formation of crystals
E) The ability to move

C) The phenomenon of heredity
Explanation: Heredity is central to the definition of life, distinguishing living organisms from non-living processes, as it involves the transmission of genetic information from parents to offspring.

p.4
RNA and Protein Synthesis

What is the first step in the process of gene expression?
A) Translation
B) Replication
C) Transcription
D) Polymerization
E) Duplication

C) Transcription
Explanation: Transcription is the first step in gene expression, where segments of DNA are used as templates to synthesize RNA molecules, which then guide protein synthesis.

p.10
Structure and Function of DNA

What form does every cell on Earth store its genetic information?
A) RNA
B) Protein
C) Double-stranded DNA
D) Single-stranded RNA
E) Chromatin

C) Double-stranded DNA
Explanation: Every cell on our planet stores its genetic information in the same chemical form, which is double-stranded DNA.

p.9
Cell Membrane Structure and Function

What is the significance of phospholipids in the formation of cell membranes?
A) They are the only type of lipid in the cell
B) They spontaneously aggregate to form bilayers
C) They are responsible for energy production
D) They are involved in genetic information transfer
E) They prevent all substances from entering the cell

B) They spontaneously aggregate to form bilayers
Explanation: Phospholipids, due to their amphiphilic nature, spontaneously aggregate in water to form bilayers, which are fundamental to the structure of cell membranes.

p.6
Biochemical Processes in Cells

What is the significance of the feedback loop connecting proteins and polynucleotides?
A) It allows for energy production
B) It facilitates cell division
C) It forms the basis for self-replicating behavior in living organisms
D) It helps in nutrient absorption
E) It regulates gene expression

C) It forms the basis for self-replicating behavior in living organisms
Explanation: The feedback loop between proteins and polynucleotides is crucial for the autocatalytic and self-reproducing nature of living cells.

p.7
RNA and Protein Synthesis

What is the function of a codon in messenger RNA (mRNA)?
A) It serves as a structural component of the ribosome.
B) It specifies a single amino acid in a protein.
C) It acts as a regulatory sequence in DNA.
D) It is a type of transfer RNA (tRNA).
E) It is a nucleotide that does not code for proteins.

B) It specifies a single amino acid in a protein.
Explanation: Each triplet of nucleotides, or codon, in mRNA codes for a specific amino acid, which is essential for protein synthesis.

p.12
Biochemical Processes in Cells

Which elements are the primary components of DNA, RNA, and proteins?
A) Iron, Calcium, Magnesium
B) Hydrogen, Carbon, Nitrogen, Oxygen, Sulfur, Phosphorus
C) Sodium, Potassium, Chlorine
D) Gold, Silver, Copper
E) Carbon, Hydrogen, Oxygen, Nitrogen

B) Hydrogen, Carbon, Nitrogen, Oxygen, Sulfur, Phosphorus
Explanation: DNA, RNA, and proteins are composed of six essential elements: hydrogen, carbon, nitrogen, oxygen, sulfur, and phosphorus, which are abundant in the nonliving environment.

p.4
Structure and Function of DNA

What structure is formed by the twisting of two complementary DNA strands?
A) RNA helix
B) Protein complex
C) DNA double helix
D) Single-stranded DNA
E) RNA duplex

C) DNA double helix
Explanation: The two strands of DNA twist around each other to form a double helix, which is a fundamental structure of DNA that allows for its stability and function.

p.3
Structure and Function of DNA

What is the role of hydrogen bonds in DNA structure?
A) They link nucleotides within a single strand
B) They hold the two strands of DNA together
C) They provide energy for DNA replication
D) They stabilize the sugar-phosphate backbone
E) They are responsible for the directionality of the strands

B) They hold the two strands of DNA together
Explanation: Hydrogen bonds form between complementary bases on opposite strands of DNA, holding the two strands together in a double helix structure.

p.8
Energy Requirements for Life

How do plants obtain their free energy?
A) From chemical bonds in food molecules
B) From sunlight
C) From other living organisms
D) From the soil
E) From the air

B) From sunlight
Explanation: Plants harness energy from sunlight to create their own small organic molecules, distinguishing their energy acquisition method from that of animals, which consume other living things.

p.2
Biochemical Processes in Cells

How do living organisms utilize free energy according to the text?
A) To grow larger
B) To drive complex chemical processes specified by hereditary information
C) To reproduce quickly
D) To maintain a constant temperature
E) To create waste products

B) To drive complex chemical processes specified by hereditary information
Explanation: Living organisms consume free energy to maintain their organization and to drive complex chemical processes that are dictated by their hereditary information.

p.3
Structure and Function of DNA

Which of the following correctly describes the structure of DNA?
A) Single-stranded with no directionality
B) Double-stranded with a sugar-phosphate backbone
C) Circular and unbranched
D) Composed only of ribose sugars
E) Lacks a defined structure

B) Double-stranded with a sugar-phosphate backbone
Explanation: DNA is characterized by its double-stranded structure and a sugar-phosphate backbone, which provides stability and directionality.

p.12
Fundamental Units of Life: Cells

What distinguishes prokaryotic cells from eukaryotic cells?
A) Prokaryotic cells have a nucleus
B) Eukaryotic cells are smaller
C) Prokaryotic cells lack membrane-bound organelles
D) Eukaryotic cells can only be unicellular
E) Prokaryotic cells are always multicellular

C) Prokaryotic cells lack membrane-bound organelles
Explanation: Prokaryotic cells are characterized by their lack of membrane-bound organelles and a nucleus, distinguishing them from eukaryotic cells, which have these structures.

p.9
Heredity and Genetic Information

What is the minimum number of genes required for a viable cell in today's environments?
A) 100
B) 300
C) 500
D) 600
E) 800

B) 300
Explanation: The minimum number of genes for a viable cell in contemporary environments is estimated to be around 300, indicating the complexity and essential functions required for life.

p.11
Diversity of Living Organisms

Where are lithotrophic organisms typically found?
A) In the atmosphere
B) In human habitats
C) In deep ocean and inhospitable environments
D) In freshwater lakes
E) On the surface of the Earth

C) In deep ocean and inhospitable environments
Explanation: Lithotrophic organisms are mostly microscopic and inhabit extreme environments such as deep ocean floors and other areas that humans do not frequent.

p.8
Biochemical Processes in Cells

What is the role of ATP in cells?
A) It is a waste product
B) It serves as a building block for DNA and RNA
C) It is only used for energy storage
D) It is a structural component of the cell membrane
E) It is a type of protein

B) It serves as a building block for DNA and RNA
Explanation: ATP (adenosine triphosphate) is crucial not only as a building block for DNA and RNA synthesis but also as a carrier of free energy needed for numerous chemical reactions in the cell.

p.10
RNA and Protein Synthesis

What is the role of ribosomes in the cell?
A) They store genetic information
B) They synthesize proteins
C) They replicate DNA
D) They transport molecules across membranes
E) They provide structural support

B) They synthesize proteins
Explanation: Ribosomes are complex molecular machines that guide the synthesis of protein molecules, playing a crucial role in translation.

p.6
Heredity and Genetic Information

What role do polynucleotides play in relation to proteins?
A) They provide energy for protein synthesis
B) They specify the amino acid sequences of proteins
C) They act as catalysts for protein folding
D) They transport proteins within the cell
E) They degrade proteins after use

B) They specify the amino acid sequences of proteins
Explanation: Polynucleotides, such as DNA and RNA, contain the genetic information that dictates the sequence of amino acids in proteins.

p.9
Heredity and Genetic Information

Which organism has one of the smallest known genomes?
A) Escherichia coli
B) Mycoplasma genitalium
C) Saccharomyces cerevisiae
D) Homo sapiens
E) Caenorhabditis elegans

B) Mycoplasma genitalium
Explanation: Mycoplasma genitalium is noted for having one of the smallest known genomes, with about 530 genes, and it serves as a model for understanding the minimal requirements for cellular life.

p.5
Structure and Function of DNA

What is a key feature of RNA that distinguishes it from DNA?
A) RNA is double-stranded
B) RNA contains uracil instead of thymine
C) RNA is more stable than DNA
D) RNA is only found in the nucleus
E) RNA does not carry genetic information

B) RNA contains uracil instead of thymine
Explanation: One of the distinguishing features of RNA is that it contains uracil (U) in place of thymine (T), which is found in DNA, affecting its structure and function.

p.11
Energy Requirements for Life

What type of reactions do aerobic lithotrophs utilize?
A) Anaerobic reactions
B) Fermentation
C) Photosynthesis
D) Aerobic reactions
E) Chemosynthesis

D) Aerobic reactions
Explanation: Aerobic lithotrophs use molecular oxygen from the environment to derive energy, linking them to the products of past life, as atmospheric oxygen is a result of living organisms.

p.10
Heredity and Genetic Information

What is the simplest known number of genes required for a cell to survive?
A) 100 genes
B) 200 genes
C) 300 genes
D) 400 genes
E) 500 genes

D) 400 genes
Explanation: The simplest known cells can survive with about 400 genes, indicating the minimal genetic requirements for life.

p.8
Cell Membrane Structure and Function

What is a universal feature of all cells?
A) They all have a nucleus
B) They are enclosed by a plasma membrane
C) They all contain chloroplasts
D) They can photosynthesize
E) They all have a rigid cell wall

B) They are enclosed by a plasma membrane
Explanation: All cells are enclosed by a plasma membrane, which acts as a selective barrier, allowing the concentration of nutrients and retention of products, a fundamental characteristic of cellular structure.

p.6
Structure and Function of DNA

What are the building blocks of proteins called?
A) Nucleotides
B) Fatty acids
C) Amino acids
D) Monosaccharides
E) Polysaccharides

C) Amino acids
Explanation: Amino acids are the monomers of proteins, differing from the monomers of DNA and RNA, which are nucleotides.

p.6
Biochemical Processes in Cells

What is the primary function of proteins in cells?
A) Store genetic information
B) Provide energy
C) Catalyze chemical reactions
D) Transport oxygen
E) Form cell membranes

C) Catalyze chemical reactions
Explanation: Proteins act as enzymes to catalyze reactions, directing the majority of chemical processes in the cell.

p.11
Energy Requirements for Life

What term describes organisms that derive energy from sunlight?
A) Organotrophic
B) Lithotrophic
C) Phototrophic
D) Anaerobic
E) Aerobic

C) Phototrophic
Explanation: Phototrophic organisms are those that harvest energy from sunlight, playing a crucial role in the ecosystem and contributing to the oxygen in the Earth's atmosphere.

p.11
Biochemical Processes in Cells

What is a significant by-product of phototrophic organisms' biosynthetic activities?
A) Carbon dioxide
B) Nitrogen
C) Oxygen
D) Methane
E) Sulfur

C) Oxygen
Explanation: The oxygen in the Earth's atmosphere is a by-product of the biosynthetic activities of phototrophic organisms, which include bacteria, algae, and plants.

p.6
Structure and Function of DNA

What is a polypeptide?
A) A type of carbohydrate
B) A chain of nucleotides
C) A sequence of amino acids
D) A lipid molecule
E) A type of RNA

C) A sequence of amino acids
Explanation: A polypeptide is created by joining amino acids in a specific sequence, forming the structure of proteins.

p.11
Energy Requirements for Life

Which type of organisms are known to feed on inorganic chemicals?
A) Organotrophic
B) Lithotrophic
C) Phototrophic
D) Heterotrophic
E) Autotrophic

B) Lithotrophic
Explanation: Lithotrophic organisms capture energy from energy-rich inorganic chemicals in their environment, making them essential for certain ecosystems, especially in extreme habitats.

p.6
Heredity and Genetic Information

What was a major mystery regarding DNA in the 1950s?
A) Its structure was unknown
B) Its role in energy production
C) How it specifies protein production
D) Its ability to replicate
E) Its composition of nucleotides

C) How it specifies protein production
Explanation: In the 1950s, the mechanisms by which DNA translates genetic information into proteins were not understood, marking a significant area of scientific inquiry.

p.8
Energy Requirements for Life

What happens to a cell when it stops consuming free energy?
A) It grows larger
B) It becomes more efficient
C) It decays toward chemical equilibrium and dies
D) It starts producing more energy
E) It transforms into another cell type

C) It decays toward chemical equilibrium and dies
Explanation: When a cell ceases to consume free energy, it begins to decay toward chemical equilibrium, ultimately leading to its death, emphasizing the critical role of energy in cellular life.

p.11
Diversity of Living Organisms

What is a characteristic feature of hot hydrothermal vents?
A) They are located in freshwater lakes.
B) They have a temperature gradient from 2-3°C to over 350°C.
C) They are found in the atmosphere.
D) They are devoid of minerals.
E) They are only found in the Arctic region.

B) They have a temperature gradient from 2-3°C to over 350°C.
Explanation: Hot hydrothermal vents exhibit a significant temperature gradient, with extreme temperatures near the core and cooler temperatures in the surrounding ocean, creating unique habitats for various organisms.

p.8
Energy Requirements for Life

What is required for a cell to grow or replicate itself?
A) Only water
B) Free energy and raw materials
C) Only genetic information
D) Oxygen and sunlight
E) Carbon dioxide and minerals

B) Free energy and raw materials
Explanation: A living cell requires free energy from the environment and raw materials to drive the synthetic reactions necessary for growth and replication, highlighting the fundamental energy requirements for life.

Study Smarter, Not Harder
Study Smarter, Not Harder