1. What is ssDNA Molecular Weight?

The molecular weight of single-stranded DNA (ssDNA) is the sum of the molecular weights of its nucleotides minus the weight of water molecules lost during polymerization. It's essential for molecular biology applications like PCR, sequencing, and hybridization.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( MW \) — Molecular weight (g/mol)
• \( MW_{nuc} \) — Molecular weight of individual nucleotides (g/mol)
• \( length \) — Number of bases in the sequence
• 18 — Molecular weight of water (g/mol)

Explanation: Each phosphodiester bond formation during polymerization results in the loss of one water molecule (18 g/mol).

3. Importance of Molecular Weight Calculation

Details: Knowing the molecular weight is crucial for determining DNA concentration, primer design, PCR optimization, and gel electrophoresis analysis.

4. Using the Calculator

Tips: Enter the DNA sequence in 5' to 3' direction (case insensitive). Only standard bases (A, T, C, G) are accepted. The calculator automatically sums nucleotide weights and subtracts water molecules.

5. Frequently Asked Questions (FAQ)

Q1: What are the molecular weights of individual nucleotides?
A: A=313.21, T=304.20, C=289.18, G=329.21 g/mol (as monophosphates).

Q2: Does this work for modified nucleotides?
A: No, this calculator only works for standard nucleotides. Modified bases require adjustment of their molecular weights.

Q3: How accurate is this calculation?
A: Very accurate for standard DNA sequences. The error is negligible for most practical purposes.

Q4: Can I use this for RNA sequences?
A: No, RNA has slightly different nucleotide weights (U instead of T). Use an RNA-specific calculator.

Q5: Why subtract water molecules?
A: Each phosphodiester bond formation during polymerization results in the loss of one water molecule.