1. What is DNA Molar Mass?

DNA molar mass is the mass of one mole of a DNA molecule, calculated by summing the masses of its constituent nucleotides and subtracting the mass of water molecules lost during polymerization.

2. How Does the Calculator Work?

The calculator uses the DNA molar mass formula:

Where:

• \( MW \) — Molar mass of DNA (g/mol)
• \( \sum(base\_masses) \) — Sum of masses of individual bases (g/mol)
• \( n \) — Number of bases in the DNA strand
• \( water\_mass \) — Mass of water molecule (typically 18 g/mol)

Explanation: For each phosphodiester bond formed between nucleotides, one water molecule is lost. The formula accounts for these lost water molecules in the total mass calculation.

3. Importance of DNA Molar Mass Calculation

Details: Accurate DNA molar mass calculation is essential for molecular biology applications including PCR setup, DNA quantification, and stoichiometric calculations in cloning experiments.

4. Using the Calculator

Tips: Enter the sum of base masses in g/mol, number of bases in the DNA strand, and water mass (default is 18 g/mol). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: How do I determine the sum of base masses?
A: Sum the molecular weights of each nucleotide in the sequence. Standard nucleotide weights are: dAMP (331.22), dTMP (322.21), dGMP (347.22), dCMP (307.20).

Q2: Why subtract water mass?
A: During DNA polymerization, a water molecule is lost for each phosphodiester bond formed between nucleotides (n-1 bonds in n-length DNA).

Q3: Does this work for RNA?
A: Yes, but use RNA nucleotide masses instead: AMP (347.22), UMP (324.18), GMP (363.22), CMP (323.19).

Q4: What about modified bases?
A: For modified bases, use their specific molecular weights in the base mass sum calculation.

Q5: How accurate is this calculation?
A: It provides theoretical molecular weight. For precise work, consider isotopic distribution and actual sequence composition.