DNA Structure And Replication Quiz Questions
DNA replication is the biological process of producing one identical replica of DNA from one original DNA molecule. Take this quiz and learn more about it!
Questions and Answers
- 1.
What does DNA stand for?
- A.
Deoxyribonucleic Acid
- B.
Deoxyrinonucleic Acid
- C.
Deoxyribonucleic Antacid
- D.
Deoxyrinonucleic Antacid
Correct Answer
A. Deoxyribonucleic AcidExplanation
DNA stands for Deoxyribonucleic Acid. It is a molecule that contains the genetic instructions used in the development and functioning of all known living organisms. DNA is composed of two long chains of nucleotides twisted into a double helix structure. It carries the genetic information that determines the traits and characteristics of an organism.Rate this question:
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- 2.
Where is DNA NOT found
- A.
In humans
- B.
In bacteria
- C.
In red blood cells
- D.
In brain cells
Correct Answer
C. In red blood cellsExplanation
Red blood cells do not contain DNA. Unlike other cells in the body, red blood cells lose their nucleus during development and therefore do not have DNA. This allows them to have more space to carry oxygen and carbon dioxide.Rate this question:
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- 3.
Over 99% of our DNA is the same as other humans
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Humans share a remarkably high percentage of their DNA with each other. The statement suggests that over 99% of our DNA is identical to that of other humans. This is supported by scientific research, which has shown that humans share a common genetic code and have many similar genes. While there may be minor variations in DNA sequences among individuals, the overall genetic makeup of humans is highly similar. Therefore, the statement is true.Rate this question:
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- 4.
DNA is a single helical strucutre
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
DNA is not a single helical structure, but rather a double helix. It consists of two strands that are twisted around each other in a helical shape. Each strand is made up of a long chain of nucleotides, and the two strands are held together by hydrogen bonds between complementary nucleotides. This double helical structure is a key feature of DNA and allows for its replication and transmission of genetic information. Therefore, the correct answer is False.Rate this question:
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- 5.
What makes up the nucleotides of DNA?
- A.
Sugar, Phosphate and Nitrogenous base
- B.
Ribose Sugar, Phosphate and Nitrogenous base
- C.
Sugar, Phosphate and Nickle base
- D.
Deoxyribose Sugar, Phosphorus and Nitrogenous base
- E.
Deoxyribose Sugar, Phosphate and Nitrogenous base
- F.
Cytosine, Thymine, Adenine and Guanine
Correct Answer
E. Deoxyribose Sugar, Phosphate and Nitrogenous baseExplanation
The nucleotides of DNA are made up of deoxyribose sugar, phosphate, and a nitrogenous base. Deoxyribose is a type of sugar that forms the backbone of the DNA molecule, while phosphate molecules connect the sugar molecules together. The nitrogenous base, which includes adenine, thymine, cytosine, and guanine, is attached to the sugar molecule and forms the "rungs" of the DNA ladder through base pairing. This combination of deoxyribose sugar, phosphate, and nitrogenous base forms the basic building blocks of DNA.Rate this question:
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- 6.
Which of the following are pyrimidines?
- A.
Adenine and cytosine
- B.
Adenine and guanine
- C.
Adenine and thymine
- D.
Cytosine and guanine
- E.
Cytosine and thymine
- F.
Guanine and thymine
Correct Answer
E. Cytosine and thymineExplanation
Cytosine and thymine are pyrimidines. Pyrimidines are one of the two types of nitrogenous bases found in DNA and RNA, the other being purines. They are characterized by a single-ring structure. Adenine and guanine, on the other hand, are purines, which have a double-ring structure. Therefore, the correct answer is cytosine and thymine.Rate this question:
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- 7.
Which of the following are purines?
- A.
Adenine and cytosine
- B.
Adenine and guanine
- C.
Adenine and thymine
- D.
Cytosine and guanine
- E.
Cytosine and thymine
- F.
Guanine and thymine
Correct Answer
B. Adenine and guanineExplanation
Adenine and guanine are both purines. Purines are one of the two types of nitrogenous bases found in DNA and RNA, the other being pyrimidines. Purines are characterized by a double-ring structure, while pyrimidines have a single-ring structure. Adenine and guanine both have a double-ring structure, making them purines. Cytosine and thymine, on the other hand, are pyrimidines.Rate this question:
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- 8.
What does Chargraff's Rule mean?
- A.
Whatever Chargraff's says is correct
- B.
Guanine always binds with Cytosine and Adenine always binds with Thymine
- C.
Guanine always binds with Adenine and Cytosine always binds with Thymine
- D.
Guanine always binds with Thymine and Adenine always binds with Cytosine
- E.
Guanine always binds with Guanine and Adenine always binds with Adenine
Correct Answer
B. Guanine always binds with Cytosine and Adenine always binds with ThymineExplanation
Chargraff's Rule states that in DNA, the amount of adenine is equal to the amount of thymine, and the amount of guanine is equal to the amount of cytosine. This means that guanine always binds with cytosine and adenine always binds with thymine. This rule is fundamental in understanding the structure and replication of DNA.Rate this question:
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- 9.
In the Meselson-Stahl experiment, which model of DNA replication was eliminated by the analysis of DNA isolated from bacteria one replication cycle after shifting from 15N to 14N medium?
- A.
Semi-conservative
- B.
Conservative
- C.
Dispersive
Correct Answer
B. ConservativeExplanation
The Meselson-Stahl experiment involved labeling DNA with heavy nitrogen (15N) and then switching to a lighter nitrogen (14N) medium to observe DNA replication. The analysis of DNA isolated after one replication cycle showed that the DNA had a mixture of both heavy and light strands, which ruled out the conservative model of DNA replication. In the conservative model, one strand of the original DNA molecule is completely conserved and used as a template for the synthesis of a new complementary strand. Since the experiment showed a mixture of heavy and light strands, it supported the semi-conservative model of DNA replication, where each new DNA molecule consists of one original strand and one newly synthesized strand. Therefore, the conservative model was eliminated as the correct answer.Rate this question:
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- 10.
DNA replicates through what process?
- A.
Semi-conservative replication
- B.
Conservative replication
- C.
Dispersive replication
Correct Answer
A. Semi-conservative replicationExplanation
DNA replicates through semi-conservative replication. In this process, the double-stranded DNA molecule separates into two strands, and each strand serves as a template for the synthesis of a new complementary strand. As a result, each new DNA molecule formed consists of one original (conserved) strand and one newly synthesized strand. This ensures the preservation of the original genetic information while allowing for the production of identical copies of DNA during cell division. Conservative replication involves the synthesis of two completely new DNA molecules, while dispersive replication results in the random distribution of original and newly synthesized DNA segments.Rate this question:
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- 11.
What is the function of DNA Polymerase III?
- A.
It adds nucleotide pairs to the growing DNA strand
- B.
It adds single nucleotides to the growing DNA strand
- C.
It unwinds DNA
- D.
It attaches the RNA primers to the DNA strand
Correct Answer
B. It adds single nucleotides to the growing DNA strandExplanation
DNA Polymerase III is responsible for adding single nucleotides to the growing DNA strand. It does this by catalyzing the formation of phosphodiester bonds between the incoming nucleotide and the existing DNA strand. This process is essential for DNA replication, as it ensures that the new DNA strand is complementary to the template strand.Rate this question:
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- 12.
How many RNA primers are needed on the leading strand?
- A.
1
- B.
2
- C.
3
- D.
Depends on the length of the DNA
- E.
Infinity
Correct Answer
A. 1Explanation
Only one RNA primer is needed on the leading strand during DNA replication. The RNA primer provides a starting point for DNA polymerase to begin synthesizing new DNA strands. The leading strand is continuously synthesized in the 5' to 3' direction, so only one RNA primer is required to initiate replication. In contrast, the lagging strand is synthesized in short fragments called Okazaki fragments, and each fragment requires its own RNA primer. Therefore, the number of RNA primers needed depends on the length of the lagging strand, not the leading strand.Rate this question:
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- 13.
DNA always replicates from ___ to ____?
- A.
3' to 5'
- B.
2' to 4'
- C.
4' to 2'
- D.
5' to 3'
- E.
North to South
- F.
South to North
- G.
On end to the other end
Correct Answer
D. 5' to 3'Explanation
DNA always replicates from 5' to 3'. This is because DNA is composed of two strands that run in opposite directions, with one strand running from 5' to 3' and the other running from 3' to 5'. During replication, the enzyme DNA polymerase can only add nucleotides to the 3' end of the growing strand. Therefore, the new DNA strand is synthesized in the 5' to 3' direction, complementary to the original template strand. This process ensures that the genetic information is accurately copied during DNA replication.Rate this question:
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- 14.
DNA Ligase will glue the Okazaki fragments together using a glycosyl bond
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
DNA Ligase does indeed play a role in the replication of DNA by joining together the Okazaki fragments on the lagging strand. However, it does not use a glycosyl bond to do so. Instead, DNA Ligase forms a phosphodiester bond between the adjacent nucleotides, which helps to create a continuous DNA strand. Therefore, the correct answer is False.Rate this question:
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Current Version
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Apr 28, 2023Quiz Edited by
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Mar 17, 2011Quiz Created by
Danylodd
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