1. What is Oligonucleotide Molecular Weight?

The molecular weight (MW) of an oligonucleotide is the sum of the molecular weights of its constituent nucleotides. It's essential for preparing accurate concentrations in molecular biology experiments.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( MW \) — Molecular weight of oligonucleotide (g/mol)
• \( MW_{nuc} \) — Molecular weight of individual nucleotides (g/mol)

Standard nucleotide molecular weights:

• Adenine (A): 313.21 g/mol
• Thymine (T): 304.20 g/mol
• Cytosine (C): 289.18 g/mol
• Guanine (G): 329.21 g/mol
• Uracil (U): 290.17 g/mol

3. Importance of Molecular Weight Calculation

Details: Accurate molecular weight calculation is crucial for preparing solutions with precise molar concentrations, which is essential for PCR, sequencing, and other molecular biology applications.

4. Using the Calculator

Tips: Enter the oligonucleotide sequence in 5' to 3' direction using standard nucleotide codes (A, T, C, G, U). The calculator is case-insensitive.

5. Frequently Asked Questions (FAQ)

Q1: Does this calculator account for modified nucleotides?
A: No, this is a basic calculator that only handles standard nucleotides. For modified nucleotides, specialized calculators are needed.

Q2: Does it include the molecular weight of water?
A: No, this calculates the molecular weight of the oligonucleotide itself without terminal hydroxyl groups.

Q3: Can I use lowercase letters in the sequence?
A: Yes, the calculator automatically converts input to uppercase.

Q4: What about phosphates in the backbone?
A: The molecular weights already include the phosphate groups between nucleotides.

Q5: How accurate is this calculation?
A: It provides theoretical molecular weight based on average nucleotide masses. For exact mass, consider isotopic distribution.