1.
Which of the following statement is CORRECT concerning a genome?
Correct Answer
A. The totality of genetic information belonging to a cell or an organism
Explanation
The correct answer is "The totality of genetic information belonging to a cell or an organism." This statement accurately describes a genome as the complete set of genetic material, including all the genes and non-coding DNA, present in a cell or an organism. It encompasses all the hereditary information that determines the characteristics and functions of an individual.
2.
Which of the following is NOT a component of nucleotide of DNA?
Correct Answer
D. Ribose
Explanation
Ribose is not a component of a nucleotide of DNA. Nucleotides in DNA are composed of a phosphate group, a nitrogenous base, and a 2'-deoxyribose sugar. Ribose, on the other hand, is a sugar found in RNA, not DNA. RNA nucleotides contain ribose instead of 2'-deoxyribose.
3.
Which of the following is an accurate statement concerning the differences between DNA and RNA?
Correct Answer
D. RNA lacks the base thymine (which is found in DNA) and has uracil instead.
Explanation
RNA lacks the base thymine (which is found in DNA) and has uracil instead. This is because RNA and DNA are both nucleic acids, but they have slightly different structures. DNA contains the base thymine, while RNA replaces thymine with uracil. This difference in bases is important because it affects the pairing of nucleotides during DNA replication and RNA transcription. Thymine pairs with adenine in DNA, while uracil pairs with adenine in RNA. This distinction allows RNA to serve as a template for protein synthesis, while DNA remains as the genetic material.
4.
RNA polynucleotides contain 3′–5′ phosphodiester bonds, but these phosphodiester bonds are less stable than those in a DNA polynucleotide. This phenomenon is caused by the indirect effect of the hydroxyl group at _______
Correct Answer
B. The 2′-position of the sugar
Explanation
The 2'-position of the sugar in RNA polynucleotides contains a hydroxyl group. This hydroxyl group can participate in intramolecular interactions, such as hydrogen bonding, which can destabilize the phosphodiester bonds. As a result, the phosphodiester bonds in RNA are less stable than those in DNA, which lacks the hydroxyl group at the 2'-position of the sugar. This indirect effect of the hydroxyl group at the 2'-position of the sugar is responsible for the decreased stability of the phosphodiester bonds in RNA.
5.
Who carried out the base ratio studies of DNA?
Correct Answer
A. Erwin Chargaff
Explanation
Erwin Chargaff carried out the base ratio studies of DNA. He discovered that the amount of adenine is equal to the amount of thymine, and the amount of guanine is equal to the amount of cytosine in DNA. This finding became known as Chargaff's rules and provided important insights into the structure and composition of DNA.
6.
Which of the following is INCORRECT concerning the genome size?
Correct Answer
D. Saccharomyces cerevisiae genome is smaller than E. coli K12 genome
Explanation
The given statement is incorrect because Saccharomyces cerevisiae genome is actually larger than the E. coli K12 genome.
7.
Which of the following is INCORRECT concerning the gene categories in a eukaryotic genome?
Correct Answer
D. Th gene function classification can encompass a larger proportion of the set of genes in a genome.
Explanation
The incorrect statement is "Th gene function classification can encompass a larger proportion of the set of genes in a genome." This is incorrect because gene function classification does not necessarily encompass a larger proportion of the set of genes in a genome. The proportion of genes classified based on function can vary depending on the complexity and diversity of the organism's genome. Some genes may have unknown functions or multiple functions, making it difficult to classify them solely based on function. Other categorization methods, such as protein domain classification, can also be used to classify genes.
8.
Which of the following type of repetitive DNA have arisen by transposition?
Correct Answer
B. Interspersed repeats
Explanation
Interspersed repeats are a type of repetitive DNA that have arisen by transposition. Transposition refers to the movement of genetic material from one location in the genome to another. Interspersed repeats are scattered throughout the genome and can be found in multiple copies. They are often derived from transposable elements, which are DNA sequences that have the ability to move within the genome. This movement can lead to the duplication and spread of interspersed repeats throughout the genome.
9.
The mode of transposition that involves an RNA intermediate, is known as ___________
Correct Answer
A. Retrotransposition
Explanation
Retrotransposition is the mode of transposition that involves an RNA intermediate. In this process, a retrotransposon is transcribed into RNA, which is then reverse transcribed back into DNA and inserted into a new genomic location. This mechanism allows the retrotransposon to multiply and spread throughout the genome. Replicative transposition involves the duplication of the transposon during the insertion process, conservative transposition does not involve an intermediate RNA molecule, and replication slippage is a different mechanism that leads to DNA sequence duplications or deletions.
10.
What is the initial product of genome expression?
Correct Answer
A. Transcriptome
Explanation
The initial product of genome expression is the transcriptome. This refers to the complete set of RNA molecules transcribed from the DNA of an organism. It includes messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA), among others. The transcriptome represents the first step in the process of gene expression, where the genetic information encoded in the DNA is transcribed into RNA molecules. These RNA molecules can then be further processed and translated into proteins, forming the proteome.
11.
All of the following statements about the genetic content of organelle genomes are true, EXCEPT
Correct Answer
C. Organelle genomes specify all of the proteins found in the organelle
12.
Which of the following is ‘satellite' DNA that formed by clusters up to 20 kb in length, with repeat units up to 25 bp?
Correct Answer
A. Minisatellite
Explanation
Minisatellite DNA refers to short segments of DNA that are repeated multiple times in tandem, forming clusters up to 20 kilobases (kb) in length. These repeated units are typically around 25 base pairs (bp) in length. Therefore, the correct answer is Minisatellite.
13.
Which of the following is NOT an correct reason concerning the importance of the Human Genome Project?
Correct Answer
D. To deduce the double helix structure
Explanation
The Human Genome Project was not conducted to deduce the double helix structure of DNA. The double helix structure of DNA was already discovered by James Watson and Francis Crick in 1953, before the Human Genome Project began. The main goals of the Human Genome Project were to create a human gene catalog, understand how the information in the genome is used by cells, and study the organization of intergenic DNA in human genomes.
14.
Powerful molecular biology techniques now allow us to amplify, analyze, and compare genes. Review these methods by matching each phrase on the left with a term on the right. Terms may be used MORE THAN ONCE or NOT AT ALL.
16
This plasmid carries genes coding for enzymes that enable the host bacterium to withstand the growth-inhibitory effects of two antibiotics: ampicillin and tetracycline
A. Alkaline phosphatase
B. DNA polymerases
C. pBR322
D. PCR
E. Chemical degradation sequencing
F. Primer
G. Cloning vector
H. Sequencing
I. Ligases
J. Restriction endonuclease
K. Sticky or cohesive ends
L. Nucleases
M. Chain termination method
N. Selectable markers
O.Template
17
An enzyme that cuts DNA molecules at a limited number of specific nucleotide sequences.
18
Enzymes that join DNA molecules together by synthesizing phosphodiester bonds between nucleotides
19
A technique that results in exponential amplification of a selected region of a DNA molecule
20
A oligonucleotides that is used in a polymerization reaction to produce a complementary DNA or RNA strand
21
The linear ends of a dsDNA molecule that have some single-stranded bases on their ends
22
A gene carried by a vector and conferring a recognizable characteristic on a cell containing the vector or a recombinant DNA molecule derived from the vector.
23
A DNA molecule that is able to replicate inside a host cell and therefore can be used to clone other fragments of DNA
24
The methods for sequencing DNA that was developed by Fred Sanger
25
A DNA sequencing method that involves enzymatic synthesis of polynucleotide chains that terminate at specific nucleotide positions.
Correct Answer
C
pBR322
C. pBR322
Explanation
pBR322 is a plasmid that carries genes coding for enzymes that allow the host bacterium to resist the inhibitory effects of ampicillin and tetracycline. It is a cloning vector, which means it can be used to replicate and clone other fragments of DNA. pBR322 also contains selectable markers, which are genes that confer a recognizable characteristic on cells containing the vector or recombinant DNA derived from the vector. Therefore, the correct answer is C, pBR322.
15.
Powerful molecular biology techniques now allow us to amplify, analyze, and compare genes. Review these methods by matching each phrase on the left with a term on the right. Terms may be used MORE THAN ONCE or NOT AT ALL.
16
This plasmid carries genes coding for enzymes that enable the host bacterium to withstand the growth-inhibitory effects of two antibiotics: ampicillin and tetracycline
A. Alkaline phosphatase
B. DNA polymerases
C. pBR322
D. PCR
E. Chemical degradation sequencing
F. Primer
G. Cloning vector
H. Sequencing
I. Ligases
J. Restriction endonuclease
K. Sticky or cohesive ends
L. Nucleases
M. Chain termination method
N. Selectable markers
O.Template
17
An enzyme that cuts DNA molecules at a limited number of specific nucleotide sequences.
18
Enzymes that join DNA molecules together by synthesizing phosphodiester bonds between nucleotides
19
A technique that results in exponential amplification of a selected region of a DNA molecule
20
A oligonucleotides that is used in a polymerization reaction to produce a complementary DNA or RNA strand
21
The linear ends of a dsDNA molecule that have some single-stranded bases on their ends
22
A gene carried by a vector and conferring a recognizable characteristic on a cell containing the vector or a recombinant DNA molecule derived from the vector.
23
A DNA molecule that is able to replicate inside a host cell and therefore can be used to clone other fragments of DNA
24
The methods for sequencing DNA that was developed by Fred Sanger
25
A DNA sequencing method that involves enzymatic synthesis of polynucleotide chains that terminate at specific nucleotide positions.
Correct Answer
J.
Restriction endonuclease
J. Restriction endonuclease
Explanation
Restriction endonucleases are enzymes that cut DNA molecules at specific nucleotide sequences. They are used in molecular biology techniques to create fragments of DNA for analysis or manipulation. In this question, the phrase "An enzyme that cuts DNA molecules at a limited number of specific nucleotide sequences" matches with the term "Restriction endonuclease" (option J). The repetition of option J in the answer indicates that this term is used more than once in the matching exercise.
16.
Powerful molecular biology techniques now allow us to amplify, analyze, and compare genes. Review these methods by matching each phrase on the left with a term on the right. Terms may be used MORE THAN ONCE or NOT AT ALL.
16
This plasmid carries genes coding for enzymes that enable the host bacterium to withstand the growth-inhibitory effects of two antibiotics: ampicillin and tetracycline
A. Alkaline phosphatase
B. DNA polymerases
C. pBR322
D. PCR
E. Chemical degradation sequencing
F. Primer
G. Cloning vector
H. Sequencing
I. Ligases
J. Restriction endonuclease
K. Sticky or cohesive ends
L. Nucleases
M. Chain termination method
N. Selectable markers
O.Template
17
An enzyme that cuts DNA molecules at a limited number of specific nucleotide sequences.
18
Enzymes that join DNA molecules together by synthesizing phosphodiester bonds between nucleotides
19
A technique that results in exponential amplification of a selected region of a DNA molecule
20
A oligonucleotides that is used in a polymerization reaction to produce a complementary DNA or RNA strand
21
The linear ends of a dsDNA molecule that have some single-stranded bases on their ends
22
A gene carried by a vector and conferring a recognizable characteristic on a cell containing the vector or a recombinant DNA molecule derived from the vector.
23
A DNA molecule that is able to replicate inside a host cell and therefore can be used to clone other fragments of DNA
24
The methods for sequencing DNA that was developed by Fred Sanger
25
A DNA sequencing method that involves enzymatic synthesis of polynucleotide chains that terminate at specific nucleotide positions.
Correct Answer
I
Ligases
I. Ligases
Explanation
Ligases are enzymes that join DNA molecules together by synthesizing phosphodiester bonds between nucleotides. In this case, the plasmid carries genes coding for enzymes that enable the host bacterium to withstand the growth-inhibitory effects of two antibiotics. Therefore, ligases are needed to join the DNA fragments together to create the plasmid. The use of ligases is essential in molecular biology techniques for cloning and creating recombinant DNA molecules.
17.
Powerful molecular biology techniques now allow us to amplify, analyze, and compare genes. Review these methods by matching each phrase on the left with a term on the right. Terms may be used MORE THAN ONCE or NOT AT ALL.
16
This plasmid carries genes coding for enzymes that enable the host bacterium to withstand the growth-inhibitory effects of two antibiotics: ampicillin and tetracycline
A. Alkaline phosphatase
B. DNA polymerases
C. pBR322
D. PCR
E. Chemical degradation sequencing
F. Primer
G. Cloning vector
H. Sequencing
I. Ligases
J. Restriction endonuclease
K. Sticky or cohesive ends
L. Nucleases
M. Chain termination method
N. Selectable markers
O.Template
17
An enzyme that cuts DNA molecules at a limited number of specific nucleotide sequences.
18
Enzymes that join DNA molecules together by synthesizing phosphodiester bonds between nucleotides
19
A technique that results in exponential amplification of a selected region of a DNA molecule
20
A oligonucleotides that is used in a polymerization reaction to produce a complementary DNA or RNA strand
21
The linear ends of a dsDNA molecule that have some single-stranded bases on their ends
22
A gene carried by a vector and conferring a recognizable characteristic on a cell containing the vector or a recombinant DNA molecule derived from the vector.
23
A DNA molecule that is able to replicate inside a host cell and therefore can be used to clone other fragments of DNA
24
The methods for sequencing DNA that was developed by Fred Sanger
25
A DNA sequencing method that involves enzymatic synthesis of polynucleotide chains that terminate at specific nucleotide positions.
Correct Answer
D
PCR
D. PCR
Explanation
PCR stands for polymerase chain reaction, which is a technique used to amplify a specific region of DNA. It involves multiple cycles of DNA denaturation, primer annealing, and DNA synthesis using a DNA polymerase enzyme. This allows for the exponential amplification of the targeted DNA sequence. PCR is a powerful tool in molecular biology and is widely used in various applications such as gene cloning, DNA sequencing, and diagnostic testing. It is an essential method for studying genes and their functions.
18.
Powerful molecular biology techniques now allow us to amplify, analyze, and compare genes. Review these methods by matching each phrase on the left with a term on the right. Terms may be used MORE THAN ONCE or NOT AT ALL.
16
This plasmid carries genes coding for enzymes that enable the host bacterium to withstand the growth-inhibitory effects of two antibiotics: ampicillin and tetracycline
A. Alkaline phosphatase
B. DNA polymerases
C. pBR322
D. PCR
E. Chemical degradation sequencing
F. Primer
G. Cloning vector
H. Sequencing
I. Ligases
J. Restriction endonuclease
K. Sticky or cohesive ends
L. Nucleases
M. Chain termination method
N. Selectable markers
O.Template
17
An enzyme that cuts DNA molecules at a limited number of specific nucleotide sequences.
18
Enzymes that join DNA molecules together by synthesizing phosphodiester bonds between nucleotides
19
A technique that results in exponential amplification of a selected region of a DNA molecule
20
A oligonucleotides that is used in a polymerization reaction to produce a complementary DNA or RNA strand
21
The linear ends of a dsDNA molecule that have some single-stranded bases on their ends
22
A gene carried by a vector and conferring a recognizable characteristic on a cell containing the vector or a recombinant DNA molecule derived from the vector.
23
A DNA molecule that is able to replicate inside a host cell and therefore can be used to clone other fragments of DNA
24
The methods for sequencing DNA that was developed by Fred Sanger
25
A DNA sequencing method that involves enzymatic synthesis of polynucleotide chains that terminate at specific nucleotide positions.
Correct Answer
F
Primer
F. Primer
Explanation
A primer is an oligonucleotide that is used in a polymerization reaction to produce a complementary DNA or RNA strand. In molecular biology techniques such as PCR, a primer is necessary to initiate the synthesis of new DNA strands. It provides a starting point for DNA polymerase to bind and begin copying the target DNA sequence. Therefore, in the context of the given statement, the primer is needed to amplify the genes coding for enzymes that enable the host bacterium to withstand the growth-inhibitory effects of antibiotics.
19.
Powerful molecular biology techniques now allow us to amplify, analyze, and compare genes. Review these methods by matching each phrase on the left with a term on the right. Terms may be used MORE THAN ONCE or NOT AT ALL.
16
This plasmid carries genes coding for enzymes that enable the host bacterium to withstand the growth-inhibitory effects of two antibiotics: ampicillin and tetracycline
A. Alkaline phosphatase
B. DNA polymerases
C. pBR322
D. PCR
E. Chemical degradation sequencing
F. Primer
G. Cloning vector
H. Sequencing
I. Ligases
J. Restriction endonuclease
K. Sticky or cohesive ends
L. Nucleases
M. Chain termination method
N. Selectable markers
O.Template
17
An enzyme that cuts DNA molecules at a limited number of specific nucleotide sequences.
18
Enzymes that join DNA molecules together by synthesizing phosphodiester bonds between nucleotides
19
A technique that results in exponential amplification of a selected region of a DNA molecule
20
A oligonucleotides that is used in a polymerization reaction to produce a complementary DNA or RNA strand
21
The linear ends of a dsDNA molecule that have some single-stranded bases on their ends
22
A gene carried by a vector and conferring a recognizable characteristic on a cell containing the vector or a recombinant DNA molecule derived from the vector.
23
A DNA molecule that is able to replicate inside a host cell and therefore can be used to clone other fragments of DNA
24
The methods for sequencing DNA that was developed by Fred Sanger
25
A DNA sequencing method that involves enzymatic synthesis of polynucleotide chains that terminate at specific nucleotide positions.
Correct Answer
K
Sticky end
cohesive end
K. Sticky or cohesive end
Explanation
Sticky ends, also known as cohesive ends, are single-stranded overhangs at the ends of a DNA molecule. They are produced by restriction endonucleases, which cut DNA at specific nucleotide sequences. The complementary sticky ends of two DNA molecules can easily bind together, allowing for the joining of different DNA fragments. This is important in molecular biology techniques such as cloning, where DNA fragments are inserted into a vector, and PCR, where specific regions of DNA are amplified. Sticky ends play a crucial role in these processes by facilitating the precise and efficient manipulation of DNA molecules.
20.
Powerful molecular biology techniques now allow us to amplify, analyze, and compare genes. Review these methods by matching each phrase on the left with a term on the right. Terms may be used MORE THAN ONCE or NOT AT ALL.
16
This plasmid carries genes coding for enzymes that enable the host bacterium to withstand the growth-inhibitory effects of two antibiotics: ampicillin and tetracycline
A. Alkaline phosphatase
B. DNA polymerases
C. pBR322
D. PCR
E. Chemical degradation sequencing
F. Primer
G. Cloning vector
H. Sequencing
I. Ligases
J. Restriction endonuclease
K. Sticky or cohesive ends
L. Nucleases
M. Chain termination method
N. Selectable markers
O.Template
17
Correct Answer
N
Selectable marker
N. Selectable marker
Explanation
The correct answer for question 17 is N, Selectable marker. A selectable marker is a gene or DNA sequence that is used to identify and select cells that have successfully taken up a specific gene or DNA fragment during genetic engineering experiments. It allows researchers to distinguish between cells that have incorporated the desired genetic material and those that have not. This is an important tool in molecular biology techniques such as gene cloning and gene expression studies.
21.
Powerful molecular biology techniques now allow us to amplify, analyze, and compare genes. Review these methods by matching each phrase on the left with a term on the right. Terms may be used MORE THAN ONCE or NOT AT ALL.
16
This plasmid carries genes coding for enzymes that enable the host bacterium to withstand the growth-inhibitory effects of two antibiotics: ampicillin and tetracycline
A. Alkaline phosphatase
B. DNA polymerases
C. pBR322
D. PCR
E. Chemical degradation sequencing
F. Primer
G. Cloning vector
H. Sequencing
I. Ligases
J. Restriction endonuclease
K. Sticky or cohesive ends
L. Nucleases
M. Chain termination method
N. Selectable markers
O.Template
17
An enzyme that cuts DNA molecules at a limited number of specific nucleotide sequences.
18
Enzymes that join DNA molecules together by synthesizing phosphodiester bonds between nucleotides
19
A technique that results in exponential amplification of a selected region of a DNA molecule
20
A oligonucleotides that is used in a polymerization reaction to produce a complementary DNA or RNA strand
21
The linear ends of a dsDNA molecule that have some single-stranded bases on their ends
22
A gene carried by a vector and conferring a recognizable characteristic on a cell containing the vector or a recombinant DNA molecule derived from the vector.
23
A DNA molecule that is able to replicate inside a host cell and therefore can be used to clone other fragments of DNA
24
The methods for sequencing DNA that was developed by Fred Sanger
25
A DNA sequencing method that involves enzymatic synthesis of polynucleotide chains that terminate at specific nucleotide positions.
Correct Answer
G
Cloning vector
G. Cloning vector
Explanation
A cloning vector is a DNA molecule that is able to replicate inside a host cell and can be used to clone other fragments of DNA. In this context, the plasmid carrying genes coding for enzymes that enable the host bacterium to withstand the growth-inhibitory effects of two antibiotics (ampicillin and tetracycline) is acting as a cloning vector. The genes on the plasmid serve as selectable markers, allowing for the identification of cells that have taken up the plasmid. Therefore, the correct answer is G, Cloning vector.
22.
Powerful molecular biology techniques now allow us to amplify, analyze, and compare genes. Review these methods by matching each phrase on the left with a term on the right. Terms may be used MORE THAN ONCE or NOT AT ALL.
16
This plasmid carries genes coding for enzymes that enable the host bacterium to withstand the growth-inhibitory effects of two antibiotics: ampicillin and tetracycline
A. Alkaline phosphatase
B. DNA polymerases
C. pBR322
D. PCR
E. Chemical degradation sequencing
F. Primer
G. Cloning vector
H. Sequencing
I. Ligases
J. Restriction endonuclease
K. Sticky or cohesive ends
L. Nucleases
M. Chain termination method
N. Selectable markers
O.Template
17
An enzyme that cuts DNA molecules at a limited number of specific nucleotide sequences.
18
Enzymes that join DNA molecules together by synthesizing phosphodiester bonds between nucleotides
19
A technique that results in exponential amplification of a selected region of a DNA molecule
20
A oligonucleotides that is used in a polymerization reaction to produce a complementary DNA or RNA strand
21
The linear ends of a dsDNA molecule that have some single-stranded bases on their ends
22
A gene carried by a vector and conferring a recognizable characteristic on a cell containing the vector or a recombinant DNA molecule derived from the vector.
23
A DNA molecule that is able to replicate inside a host cell and therefore can be used to clone other fragments of DNA
24
The methods for sequencing DNA that was developed by Fred Sanger
25
A DNA sequencing method that involves enzymatic synthesis of polynucleotide chains that terminate at specific nucleotide positions.
Correct Answer
M
Chain termination method
M. Chain termination method
Explanation
The correct answer is M, Chain termination method. This refers to the method of DNA sequencing developed by Fred Sanger. It involves enzymatic synthesis of polynucleotide chains that terminate at specific nucleotide positions. This method uses modified nucleotides that lack a 3' hydroxyl group, preventing further chain elongation. The terminated fragments are then separated by size using gel electrophoresis, allowing the determination of the DNA sequence.
23.
Powerful molecular biology techniques now allow us to amplify, analyze, and compare genes. Review these methods by matching each phrase on the left with a term on the right. Terms may be used MORE THAN ONCE or NOT AT ALL.
16
This plasmid carries genes coding for enzymes that enable the host bacterium to withstand the growth-inhibitory effects of two antibiotics: ampicillin and tetracycline
A. Alkaline phosphatase
B. DNA polymerases
C. pBR322
D. PCR
E. Chemical degradation sequencing
F. Primer
G. Cloning vector
H. Sequencing
I. Ligases
J. Restriction endonuclease
K. Sticky or cohesive ends
L. Nucleases
M. Chain termination method
N. Selectable markers
O.Template
17
An enzyme that cuts DNA molecules at a limited number of specific nucleotide sequences.
18
Enzymes that join DNA molecules together by synthesizing phosphodiester bonds between nucleotides
19
A technique that results in exponential amplification of a selected region of a DNA molecule
20
A oligonucleotides that is used in a polymerization reaction to produce a complementary DNA or RNA strand
21
The linear ends of a dsDNA molecule that have some single-stranded bases on their ends
22
A gene carried by a vector and conferring a recognizable characteristic on a cell containing the vector or a recombinant DNA molecule derived from the vector.
23
A DNA molecule that is able to replicate inside a host cell and therefore can be used to clone other fragments of DNA
24
The methods for sequencing DNA that was developed by Fred Sanger
25
A DNA sequencing method that involves enzymatic synthesis of polynucleotide chains that terminate at specific nucleotide positions.
Correct Answer
M
Chain termination method
M. Chain termination method
Explanation
The correct answer is M, Chain termination method. This refers to the method of DNA sequencing developed by Fred Sanger. In this method, DNA is synthesized using DNA polymerase and a mixture of normal deoxynucleotides (dNTPs) and modified dideoxynucleotides (ddNTPs) that lack a 3' hydroxyl group. The incorporation of a ddNTP into the growing DNA chain terminates synthesis, resulting in a series of DNA fragments of different lengths. These fragments are then separated by size using gel electrophoresis, and the sequence can be determined by reading the positions of the terminated fragments.