1. What is DNA Copy Count?

DNA copy count refers to the number of molecules of a specific DNA fragment present in a given sample. It's essential for quantitative PCR (qPCR), next-generation sequencing library preparation, and other molecular biology applications.

2. How Does the Calculator Work?

The calculator uses the DNA copy count equation:

Where:

• \( \text{conc} \) — DNA concentration in ng/μL
• \( \text{vol} \) — Volume in μL
• \( N_A \) — Avogadro's number (6.022 × 10²³ molecules/mol)
• \( \text{MW} \) — Molecular weight in g/mol

Explanation: The equation converts mass concentration to molar concentration, then calculates the number of molecules using Avogadro's number.

3. Importance of DNA Copy Count

Details: Accurate DNA copy count is crucial for preparing standards in qPCR, normalizing inputs for sequencing, and ensuring reproducibility in molecular biology experiments.

4. Using the Calculator

Tips: Enter DNA concentration in ng/μL, volume in μL, and molecular weight in g/mol. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: How do I determine the molecular weight of my DNA?
A: For double-stranded DNA, MW ≈ (length in bp) × 650 g/mol/bp. For single-stranded DNA, MW ≈ (length in nt) × 330 g/mol/nt.

Q2: Why is copy count important in qPCR?
A: Knowing the exact copy number allows creation of standard curves for absolute quantification of unknown samples.

Q3: What's the difference between copy count and concentration?
A: Concentration measures mass per volume, while copy count measures the actual number of molecules present.

Q4: How accurate is this calculation?
A: The calculation is mathematically precise, but accuracy depends on precise measurement of concentration and accurate molecular weight.

Q5: Can this be used for RNA?
A: Yes, but use the appropriate molecular weight (RNA ≈ 340 g/mol/nt) and ensure concentration is measured by methods specific for RNA.