3. Consider a diploid liver cell that is about to enter S phase, in which all DN

Question

3. Consider a diploid liver cell that is about to enter S phase, in which all DNA is copied. The cell has a cellular concentration of dGTP of 100 M (small molecules has the same concentration in the cytoplasm and nucleus). If all new dGTP synthesis were stopped, what part (or how many copies) of the genome could be replicated? Show the details of your calculation. You will have to make several assumptions: state these as you use them (e.g. a liver cell is assumed to be a cube X cm on each side). Keeping track of units is essential What is the importance of this result to cancer chemotherapy? (Hint: cancer chemotherapy attacks cancer cells because they have the most DNA synthesis going on in the body.)

Explanation / Answer

In general, a diploid somatic cell (here, liver cell) usually have '2n' number of chromosome and '2X' amount of DNA.

But after the cell enters and completes the S-phase, the DNA content becomes double.However, the number of chromosomes remain the same.

Hence, the liver cell will have twice the number of chromosome (2n) and four times the DNA content (4X).

This result has its importance to cancer chemotherapy as DNA synthesis represents the primary target for a large number of cancer chemotherapeutics, and a common feature of many of these drugs is their ability to either directly or indirectly damage DNA.

Related Questions

Navigate

• Browse (All)
• Browse 3
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.