ZOL2602 Assignment 1 (100% COMPLETE
ANSWERS) Semester 1 2025 - DUE 14 March 2025
Institution
University Of South Africa
Book
Textbook of Clinical Embryology
QUESTION 1
QUESTION 1 [15] Discuss, with the aid of diagrams, how these nucleotides (2'-
deoxyguanosine-5'-triphosphate; 2'-deoxycytidine-5'-triphosphate and 2'-
deoxythymidine-5'-triphosphate) are linked together to form a polynucleotide
during the polymerisation process
Answer:Polymerization of DNA Nucleotides DNA polymerization occurs
through a condensation reaction that forms phosphodiester bonds between
nucleotides. The three nucleotides in question—2'-deoxyguanosine-5'-
triphosphate (dGTP), 2'-deoxycytidine-5'-triphosphate (dCTP), and 2'-
, deoxythymidine-5'-triphosphate (dTTP)—are deoxyribonucleotides, which serve as
monomers in DNA synthesis.
1. Structure of the Nucleotides Each nucleotide consists of three key
components:
A nitrogenous base (Guanine, Cytosine, or Thymine) A deoxyribose sugar (lacking
an -OH group at the 2' position) A triphosphate group at the 5' carbon The
structure of these nucleotides is critical to their polymerization.
2. Formation of the Phosphodiester Bond During DNA polymerization:
DNA polymerase catalyzes the reaction. The 3'-OH of the growing DNA strand
attacks the α-phosphate of the incoming nucleotide's 5'-triphosphate group. A
phosphodiester bond forms between the 3'-OH of one nucleotide and the 5'-
phosphate of another. This reaction releases pyrophosphate (PPi), which is later
hydrolyzed to drive the reaction forward. 3. Step-by-Step Process Initiation: A free
3'-OH group from an existing DNA strand or primer is required. Nucleophilic
Attack: The 3'-OH of the last nucleotide in the strand attacks the α-phosphate of
the incoming dNTP. Bond Formation: A phosphodiester bond is created between
the nucleotides. Pyrophosphate Release: The remaining pyrophosphate (PPi) is
hydrolyzed into two inorganic phosphates, ensuring that the reaction is
irreversible. 4. Diagram Representation To fully explain this process, you need
diagrams illustrating:
The structure of dGTP, dCTP, and dTTP. The nucleophilic attack mechanism by the
3'-OH group. The formation of the phosphodiester bond. The elongation of the
DNA strand.
Detailed Explanation of DNA Polymerization Using dGTP, dCTP, and dTTP DNA
polymerization is a process in which individual deoxyribonucleotides are linked
together by phosphodiester bonds to form a growing DNA strand. Below is a
detailed breakdown of the process, including the role of 2'-deoxyguanosine-5'-
triphosphate (dGTP), 2'-deoxycytidine-5'-triphosphate (dCTP), and 2'-
deoxythymidine-5'-triphosphate (dTTP).
1. Structure of the Nucleotides Each nucleotide consists of three key
components:
Nitrogenous Base: dGTP (Guanine) – Purine dCTP (Cytosine) – Pyrimidine dTTP
(Thymine) – Pyrimidine Deoxyribose Sugar: A five-carbon sugar with no hydroxyl (-
OH) group at the 2' carbon. Triphosphate Group: Attached to the 5' carbon of the
ANSWERS) Semester 1 2025 - DUE 14 March 2025
Institution
University Of South Africa
Book
Textbook of Clinical Embryology
QUESTION 1
QUESTION 1 [15] Discuss, with the aid of diagrams, how these nucleotides (2'-
deoxyguanosine-5'-triphosphate; 2'-deoxycytidine-5'-triphosphate and 2'-
deoxythymidine-5'-triphosphate) are linked together to form a polynucleotide
during the polymerisation process
Answer:Polymerization of DNA Nucleotides DNA polymerization occurs
through a condensation reaction that forms phosphodiester bonds between
nucleotides. The three nucleotides in question—2'-deoxyguanosine-5'-
triphosphate (dGTP), 2'-deoxycytidine-5'-triphosphate (dCTP), and 2'-
, deoxythymidine-5'-triphosphate (dTTP)—are deoxyribonucleotides, which serve as
monomers in DNA synthesis.
1. Structure of the Nucleotides Each nucleotide consists of three key
components:
A nitrogenous base (Guanine, Cytosine, or Thymine) A deoxyribose sugar (lacking
an -OH group at the 2' position) A triphosphate group at the 5' carbon The
structure of these nucleotides is critical to their polymerization.
2. Formation of the Phosphodiester Bond During DNA polymerization:
DNA polymerase catalyzes the reaction. The 3'-OH of the growing DNA strand
attacks the α-phosphate of the incoming nucleotide's 5'-triphosphate group. A
phosphodiester bond forms between the 3'-OH of one nucleotide and the 5'-
phosphate of another. This reaction releases pyrophosphate (PPi), which is later
hydrolyzed to drive the reaction forward. 3. Step-by-Step Process Initiation: A free
3'-OH group from an existing DNA strand or primer is required. Nucleophilic
Attack: The 3'-OH of the last nucleotide in the strand attacks the α-phosphate of
the incoming dNTP. Bond Formation: A phosphodiester bond is created between
the nucleotides. Pyrophosphate Release: The remaining pyrophosphate (PPi) is
hydrolyzed into two inorganic phosphates, ensuring that the reaction is
irreversible. 4. Diagram Representation To fully explain this process, you need
diagrams illustrating:
The structure of dGTP, dCTP, and dTTP. The nucleophilic attack mechanism by the
3'-OH group. The formation of the phosphodiester bond. The elongation of the
DNA strand.
Detailed Explanation of DNA Polymerization Using dGTP, dCTP, and dTTP DNA
polymerization is a process in which individual deoxyribonucleotides are linked
together by phosphodiester bonds to form a growing DNA strand. Below is a
detailed breakdown of the process, including the role of 2'-deoxyguanosine-5'-
triphosphate (dGTP), 2'-deoxycytidine-5'-triphosphate (dCTP), and 2'-
deoxythymidine-5'-triphosphate (dTTP).
1. Structure of the Nucleotides Each nucleotide consists of three key
components:
Nitrogenous Base: dGTP (Guanine) – Purine dCTP (Cytosine) – Pyrimidine dTTP
(Thymine) – Pyrimidine Deoxyribose Sugar: A five-carbon sugar with no hydroxyl (-
OH) group at the 2' carbon. Triphosphate Group: Attached to the 5' carbon of the
