Chapter 12 Test - Biology
Questions and Answers
- 1.
The following components make up a nucleotide: a sugar, ___________, and a nitrogenous base.
- A.
A phosphate
- B.
A ribose
- C.
A deoxyribose
- D.
A backbone
Correct Answer
A. A pHospHateExplanation
A nucleotide is composed of three components: a sugar, a phosphate, and a nitrogenous base. The sugar can be either ribose or deoxyribose, depending on whether it is found in RNA or DNA respectively. The phosphate group is responsible for linking the nucleotides together, forming the backbone of the nucleic acid molecule. The nitrogenous base can be adenine, thymine, cytosine, or guanine, and it pairs with a complementary base in the opposite strand to form the double helix structure of DNA. Therefore, the correct answer is a phosphate.Rate this question:
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- 2.
What are the four bases found in DNA?
- A.
G, C, A, U
- B.
G, C, A, T
- C.
A, U, G, C
- D.
A, T, G, U
Correct Answer
B. G, C, A, TExplanation
The four bases found in DNA are G, C, A, and T. These bases are the building blocks of DNA and they pair up to form the double helix structure of DNA. G (guanine) pairs with C (cytosine), and A (adenine) pairs with T (thymine). This pairing is crucial for DNA replication and protein synthesis.Rate this question:
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- 3.
The process by which one strain of bacterium is apparently changed into another strain is called _________.
- A.
Transcription
- B.
Transformation
- C.
Duplication
- D.
Replication
Correct Answer
B. TransformationExplanation
Transformation is the correct answer because it refers to the process by which one strain of bacterium is apparently changed into another strain. In transformation, bacteria can take up and incorporate foreign DNA from their surroundings, leading to genetic changes and the appearance of new traits in the transformed strain. Transcription, duplication, and replication are not accurate terms to describe this specific process of bacterial strain change.Rate this question:
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- 4.
Bacteriophages are _______.
- A.
A form of bacteria
- B.
Enzymes
- C.
Coils of DNA
- D.
Viruses
Correct Answer
D. VirusesExplanation
Bacteriophages are viruses that specifically infect bacteria. They are composed of genetic material, either DNA or RNA, enclosed in a protein coat. Bacteriophages attach to the surface of bacteria and inject their genetic material into the bacterial cell, taking over the cellular machinery to replicate themselves. Eventually, the bacteriophage particles are released, causing the bacterial cell to burst and release more phages to infect other bacteria. Therefore, the correct answer is viruses.Rate this question:
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- 5.
Which of the followng researchers used radioactive markers in experiments to show that DNA was the genetic material in cells?
- A.
Frederick Griffith
- B.
Oswald Avery
- C.
Alfred Hershey and Martha Chase
- D.
James Watson and Francis Crick
Correct Answer
C. Alfred Hershey and Martha ChaseExplanation
Alfred Hershey and Martha Chase used radioactive markers in their experiments to provide evidence that DNA was the genetic material in cells. They conducted an experiment with bacteriophages, viruses that infect bacteria. They labeled the DNA of the bacteriophages with radioactive phosphorus and the protein coat with radioactive sulfur. After infecting the bacteria, they found that the radioactive DNA was transferred into the bacterial cells, while the protein coat remained outside. This demonstrated that DNA, not protein, was responsible for transmitting genetic information, supporting the idea that DNA is the genetic material in cells.Rate this question:
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- 6.
Before DNA could be shown to be the genetic material in cells, scientists had to show that it could ___________.
- A.
Tolerate high temperatures
- B.
Carry and make copies of information
- C.
Be modified in response to environmental conditions
- D.
Be broken down into small subunits
Correct Answer
B. Carry and make copies of informationExplanation
Scientists had to show that DNA could carry and make copies of information in order to establish it as the genetic material in cells. This is because genetic material is responsible for storing and transmitting hereditary information, which requires the ability to carry and replicate genetic information accurately. This evidence was crucial in demonstrating that DNA possesses the necessary properties to serve as the genetic material.Rate this question:
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- 7.
A nucleotide does not contain ________.
- A.
A 5-carbon sugar
- B.
An amino acid
- C.
A nitrogen base
- D.
A phosphate group
Correct Answer
B. An amino acidExplanation
A nucleotide is composed of three main components: a 5-carbon sugar, a nitrogen base, and a phosphate group. These components are essential for the structure and function of nucleotides. However, an amino acid is not a part of a nucleotide. Amino acids are the building blocks of proteins and are not involved in the structure of nucleotides. Therefore, the correct answer is "an amino acid".Rate this question:
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- 8.
According to Chargoff's rule of base pairing, which of the following is true about DNA?
- A.
A = T, C = G
- B.
A = C, T = G
- C.
A = G, T = C
- D.
A = T = C = G
Correct Answer
A. A = T, C = GExplanation
Chargaff's rule of base pairing states that in DNA, the amount of adenine (A) is equal to the amount of thymine (T), and the amount of cytosine (C) is equal to the amount of guanine (G). This means that A pairs with T and C pairs with G in DNA. Therefore, the correct answer is A = T, C = G.Rate this question:
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- 9.
The bonds that hold the two strands of DNA together come from ___________.
- A.
The attraction of phosphate groups for each other
- B.
Strong bonds between nitrogenous bases and the sugar-phosphate backbone
- C.
Weak hydrogen bonds between nitrogenous bases
- D.
Carbon-to-carbon bonds in the sugar portion of the nucleotides
Correct Answer
C. Weak hydrogen bonds between nitrogenous basesExplanation
The correct answer is weak hydrogen bonds between nitrogenous bases. The two strands of DNA are held together by hydrogen bonds formed between the nitrogenous bases. These bases, adenine (A), thymine (T), cytosine (C), and guanine (G), pair specifically with each other (A with T and C with G) through these weak hydrogen bonds. This bonding allows for the complementary base pairing that is essential for DNA replication and transcription.Rate this question:
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- 10.
In prokaryotes, DNA molecules are located in the _____.
- A.
Nucleus
- B.
Nucleoid region
- C.
Ribosomes
- D.
Histones
Correct Answer
B. Nucleoid regionExplanation
In prokaryotes, DNA molecules are located in the nucleoid region. Unlike eukaryotic cells, prokaryotes do not have a true nucleus. Instead, the DNA is found in a region called the nucleoid, which is a concentrated area within the cell where the genetic material is located. The nucleoid region is not surrounded by a membrane like a nucleus, but it is still the site where DNA replication, transcription, and other genetic processes take place in prokaryotic cells.Rate this question:
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- 11.
In eukaryotes, all the DNA (except for mitochondria and chloroplasts) is found in the _____.
- A.
Nucleus
- B.
Nucleoid region
- C.
Ribosomes
- D.
Histones
Correct Answer
A. NucleusExplanation
In eukaryotes, the DNA is found in the nucleus. The nucleus is a membrane-bound organelle that contains the genetic material of the cell, which includes the DNA. This DNA carries the instructions for the cell's functions and is responsible for the inheritance of traits. The nucleus also regulates the activities of the cell and protects the DNA from damage. Therefore, it is correct to say that all the DNA (except for mitochondria and chloroplasts) is found in the nucleus in eukaryotes.Rate this question:
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- 12.
The main enzyme responsible for linking individual nucleotides into DNA molecules is ______.
- A.
DNA protease
- B.
Ribose
- C.
Carbohydrase
- D.
DNA polymerase
Correct Answer
D. DNA polymeraseExplanation
DNA polymerase is the correct answer because it is the main enzyme responsible for linking individual nucleotides into DNA molecules. DNA polymerase catalyzes the formation of phosphodiester bonds between adjacent nucleotides, creating the sugar-phosphate backbone of the DNA molecule. This enzyme is essential for DNA replication, repair, and synthesis during various cellular processes. DNA protease, ribose, and carbohydrase are not directly involved in the synthesis of DNA molecules and do not play a role in linking nucleotides together.Rate this question:
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- 13.
During replication, which sequence of nucleotides would bond with the DNA sequence TATGA?
- A.
TATGA
- B.
ATACT
- C.
CACTA
- D.
AGTAT
Correct Answer
B. ATACTExplanation
During replication, the nucleotide sequence that would bond with the DNA sequence TATGA is ATACT. This is because in DNA replication, adenine (A) always pairs with thymine (T), and cytosine (C) always pairs with guanine (G). Therefore, the complementary sequence to TATGA would be ATACT, where A pairs with T, T pairs with A, G pairs with C, and A pairs with T.Rate this question:
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- 14.
The scientist(s) responsible for the discovery of bacterial transformation is (are) ___________.
- A.
Watson and Crick
- B.
Avery
- C.
Griffith
- D.
Franklin
Correct Answer
C. GriffithExplanation
Griffith is the correct answer because he was the scientist responsible for the discovery of bacterial transformation. In his experiment, Griffith observed that a harmless strain of bacteria could be transformed into a deadly strain when exposed to heat-killed bacteria of the deadly strain. This transformation suggested that there was a transfer of genetic material between the two strains, which laid the foundation for further research on DNA and genetic transformation. Watson and Crick are known for their discovery of the structure of DNA, Avery for his work on DNA as the genetic material, and Franklin for her contributions to understanding DNA structure through X-ray crystallography.Rate this question:
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- 15.
Which of the following does not describe the structure of DNA?
- A.
Double helix
- B.
Nucleotide polymer
- C.
Contains adenine-guanine pairs
- D.
Sugar-phosphate backbone
Correct Answer
D. Sugar-pHospHate backboneExplanation
The sugar-phosphate backbone is a description of the structure of DNA, as it refers to the alternating sugar and phosphate molecules that form the backbone of the DNA molecule. The other options, including double helix, nucleotide polymer, and adenine-guanine pairs, all accurately describe aspects of the structure of DNA.Rate this question:
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- 16.
What Hershey and Chase's work show?
- A.
Genes are probably made of DNA.
- B.
Genes are probably made of protein.
- C.
Viruses contain DNA but not protein.
- D.
Bacteria contain DNA but not protein.
Correct Answer
A. Genes are probably made of DNA.Explanation
Hershey and Chase's work showed that genes are probably made of DNA. This conclusion was based on their experiments with bacteriophages, which are viruses that infect bacteria. They labeled the DNA of the bacteriophages with radioactive phosphorus and the protein coat with radioactive sulfur. After infecting the bacteria, they found that the radioactive phosphorus was transferred to the bacterial cells, indicating that DNA was the genetic material being passed on. This experiment provided strong evidence that DNA, not protein, is the carrier of genetic information in organisms.Rate this question:
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- 17.
The two "backbones" of the DNA molecule consist of _____.
- A.
Adenines and sugars
- B.
Phosphates and sugars
- C.
Adenines and thymines
- D.
Thymines and sugars
Correct Answer
B. pHospHates and sugarsExplanation
The two "backbones" of the DNA molecule consist of phosphates and sugars. The phosphate groups and deoxyribose sugars form a repeating pattern along the length of the DNA molecule. The phosphate groups provide a negative charge, while the sugars provide a backbone structure. These two components alternate to form the sturdy and stable structure of the DNA molecule. Adenines, thymines, guanines, and cytosines are the nitrogenous bases that are attached to the sugars and project inward, forming the rungs of the DNA ladder through hydrogen bonding.Rate this question:
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- 18.
In eukaryotic chromosomes, DNA is tightly coiled around proteins called ________.
- A.
DNA polymerase
- B.
Chromatin
- C.
Histones
- D.
Nucleotides
Correct Answer
C. HistonesExplanation
In eukaryotic chromosomes, DNA is tightly coiled around proteins called histones. Histones play a crucial role in organizing and compacting DNA within the nucleus. They help to maintain the structure and stability of chromosomes by forming a complex called chromatin. This coiling and packaging of DNA allow for efficient storage and replication of genetic information. DNA polymerase is an enzyme involved in DNA replication, nucleotides are the building blocks of DNA, but neither of them specifically refers to the proteins that DNA is coiled around in eukaryotic chromosomes.Rate this question:
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- 19.
Compared to eukaryotic cells, prokaryotic cells contain ________.
- A.
About 1000 times more DNA
- B.
About 1/1000 as much
- C.
Twice as much
- D.
The same amount of DNA
Correct Answer
B. About 1/1000 as muchExplanation
Prokaryotic cells are single-celled organisms that lack a nucleus and other membrane-bound organelles. They have a simpler structure compared to eukaryotic cells. One major difference is that prokaryotic cells have a much smaller amount of DNA. This is because they lack a nucleus where the DNA is stored and instead have a single circular chromosome located in the cytoplasm. In contrast, eukaryotic cells have a nucleus and multiple linear chromosomes, resulting in about 1/1000 times more DNA compared to prokaryotic cells.Rate this question:
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- 20.
In the Hershey-Chase experiment, components on phages were tagged with radioactive elements. Proteins were tagged with ________, while DNA was tagged with _______.
- A.
Sulfur-35, phosphorus-37
- B.
Phosphorus-37, sulfur-35
- C.
Deoxyribose, ribose
- D.
Ribose, deoxyribose
Correct Answer
A. Sulfur-35, pHospHorus-37Explanation
In the Hershey-Chase experiment, sulfur-35 was used to tag proteins while phosphorus-37 was used to tag DNA. This choice of radioactive elements allowed the researchers to track the location and transfer of these components within the phages. By using different tags for proteins and DNA, the experimenters were able to determine that DNA, not proteins, is the genetic material that is passed on during phage infection.Rate this question:
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- 21.
E.C. DNA replication _______.
- A.
Occurs in the same direction on both strands
- B.
Occurs using only one half of the double helix
- C.
Happens smoothly on one strand, but is more complicated on the other strand
- D.
Does not require any enzymes
Correct Answer
C. Happens smoothly on one strand, but is more complicated on the other strandExplanation
DNA replication is a process where a new DNA molecule is synthesized using an existing DNA molecule as a template. It occurs in both directions on both strands of the double helix. However, the replication process is more straightforward on one strand, known as the leading strand, where DNA synthesis occurs continuously. On the other strand, known as the lagging strand, DNA synthesis occurs discontinuously in small fragments called Okazaki fragments. These fragments are later joined together by enzymes to form a complete DNA strand. Therefore, DNA replication happens smoothly on one strand but is more complicated on the other strand.Rate this question:
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- 22.
The sugar-phosphate backbone is held together with _____ bonds.
- A.
Hydrogen
- B.
Covalent
- C.
Ionic
- D.
Van der Waals
Correct Answer
B. CovalentExplanation
The sugar-phosphate backbone is held together with covalent bonds. Covalent bonds involve the sharing of electrons between atoms, which creates a strong and stable connection. In the case of the sugar-phosphate backbone, the covalent bonds form between the phosphate group of one nucleotide and the sugar molecule of the adjacent nucleotide. This bond is essential for maintaining the integrity and stability of the DNA molecule, as it allows for the formation of a continuous chain of nucleotides.Rate this question:
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- 23.
In Griffith's experiment, mice were injected with two strains of bacteria, S (deadly) and R (harmless). Which of the four groups of mice produced a conclusive result?
- A.
The living S group
- B.
The dead S group
- C.
The living R group
- D.
The dead S, living R group
Correct Answer
D. The dead S, living R groupExplanation
The dead S, living R group produced a conclusive result in Griffith's experiment. This is because when the living R bacteria were injected into the mice along with the heat-killed S bacteria, the mice in this group still died. This showed that the genetic material from the dead S bacteria was able to transform the harmless R bacteria into a deadly form. Therefore, the dead S, living R group provided conclusive evidence of bacterial transformation.Rate this question:
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- 24.
Whose work on X-ray diffraction on DNA provided important clues to developing a model of DNA'?
- A.
Rosalind Franklin
- B.
Oswald Avery
- C.
Alfred Hershey
- D.
Martha Chase
Correct Answer
A. Rosalind FranklinExplanation
Rosalind Franklin's work on X-ray diffraction on DNA provided important clues to developing a model of DNA. X-ray diffraction is a technique used to study the structure of materials by analyzing how X-rays interact with them. Franklin's X-ray diffraction images of DNA provided crucial information about its helical structure and dimensions. Her work was instrumental in the discovery of the double helix structure of DNA by James Watson and Francis Crick.Rate this question:
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- 25.
The two strands of DNA run ___________ one another.
- A.
Parallel to
- B.
Antiparallel to
- C.
On top of
- D.
Abound to
Correct Answer
B. Antiparallel toExplanation
The two strands of DNA run antiparallel to one another because they are oriented in opposite directions. In DNA, one strand runs in the 5' to 3' direction, while the other runs in the 3' to 5' direction. This antiparallel arrangement allows for the complementary base pairing between the strands, where adenine pairs with thymine and guanine pairs with cytosine. This arrangement is crucial for DNA replication and transcription processes.Rate this question:
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- 26.
What is the name of base abbreviated "C"?
- A.
Cytosine
- B.
Chlorine
- C.
Clueless
- D.
Carbon
Correct Answer
A. CytosineExplanation
Cytosine is the correct answer because it is the base abbreviated as "C". Cytosine is one of the four bases found in DNA and RNA, along with adenine, guanine, and thymine (in DNA) or uracil (in RNA). It is a pyrimidine base, meaning it has a single-ring structure, and it pairs with guanine through hydrogen bonding in DNA and RNA molecules. Cytosine is crucial for the genetic code and plays a significant role in protein synthesis and gene expression.Rate this question:
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- 27.
What is the name of the base abbreviated "G"?
- A.
Guanine
- B.
Guava
- C.
Grovelling
- D.
Glycine
Correct Answer
A. GuanineExplanation
Guanine is the correct answer because it is the base that is abbreviated as "G". Guanine is one of the four main bases found in DNA and RNA, along with adenine, cytosine, and thymine (in DNA) or uracil (in RNA). It plays a crucial role in the structure and function of nucleic acids, as it forms base pairs with cytosine. Guanine is also involved in various biological processes, such as protein synthesis and cell signaling.Rate this question:
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- 28.
What is the name of the base abbreviated "A"?
- A.
Asparin
- B.
Aponine
- C.
Adenine
- D.
Aggravating
Correct Answer
C. AdenineExplanation
Adenine is the correct answer because it is the base abbreviated as "A". Adenine is one of the four nucleobases in the nucleic acids DNA and RNA. It pairs with thymine in DNA and with uracil in RNA. Adenine is an important component of genetic material and plays a crucial role in the functioning of DNA and RNA molecules.Rate this question:
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- 29.
What is the name of the base abbreviated "T"?
- A.
Tyrosine
- B.
Thymine
- C.
Tetramine
- D.
Terrifying
Correct Answer
B. ThymineExplanation
The name of the base abbreviated "T" is thymine. Thymine is one of the four nucleotide bases found in DNA and RNA, along with adenine, cytosine, and guanine. It pairs with adenine in DNA and uracil in RNA. Thymine is essential for the proper functioning and replication of genetic material.Rate this question:
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- 30.
E.C. During DNA replication, the two strands are called ______ and ________.
- A.
Leading, lagging
- B.
Misleading, bragging
- C.
Open, closed
- D.
Same, complimentary
Correct Answer
A. Leading, laggingExplanation
During DNA replication, the two strands are called leading and lagging. The leading strand is synthesized continuously in the 5' to 3' direction, while the lagging strand is synthesized discontinuously in the opposite direction, creating short fragments called Okazaki fragments. This occurs because DNA polymerase can only add nucleotides in the 5' to 3' direction. The leading and lagging strands work together to ensure the accurate and efficient replication of the DNA molecule.Rate this question:
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- 31.
Bases that are placed in specific pairings are said to be ______ to each other in DNA.
- A.
Complimentary
- B.
Opposite
- C.
Rival
- D.
Competitive
Correct Answer
A. ComplimentaryExplanation
Bases that are placed in specific pairings in DNA are said to be complimentary to each other. This means that they have a specific relationship where they can bind together in a specific way. In DNA, the bases adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G). These pairings are essential for the structure and function of DNA, as they allow for the accurate replication and transcription of genetic information.Rate this question:
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- 32.
How many copies of DNA are produced after DNA replication is completed?
- A.
2
- B.
4
- C.
8
- D.
46
Correct Answer
A. 2Explanation
After DNA replication is completed, two copies of DNA are produced. This is because DNA replication is a process in which the DNA molecule unwinds and each strand serves as a template for the synthesis of a new complementary strand. As a result, two identical copies of the original DNA molecule are formed, each consisting of one original strand and one newly synthesized strand.Rate this question:
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