How many base pairs are present in 1 μm long dsDNA?
The Correct Answer and Explanation is :
To determine the number of base pairs in a 1 μm long double-stranded DNA (dsDNA) molecule, we need to know the average length of a base pair. The distance between adjacent base pairs in DNA is approximately 0.34 nanometers (nm) or 0.00034 micrometers (μm).
Calculation
- Length of DNA segment: 1 μm
- Length per base pair: 0.34 nm = 0.00034 μm
Now, we can calculate the number of base pairs (bp) in 1 μm of dsDNA:
[
\text{Number of base pairs} = \frac{\text{Length of DNA}}{\text{Length per base pair}} = \frac{1 \, \mu m}{0.00034 \, \mu m} \approx 2941.18
]
Since the number of base pairs must be a whole number, we round it to approximately 2941 base pairs.
Explanation
Double-stranded DNA is composed of two strands that run in opposite directions, with pairs of nitrogenous bases (adenine with thymine and guanine with cytosine) holding the strands together through hydrogen bonds. The structure is often described as a double helix, resembling a twisted ladder, where the rungs of the ladder represent the base pairs.
The base pair length of 0.34 nm is critical because it is a result of the precise geometry of DNA. This uniform spacing is crucial for the stability of the DNA structure, allowing for the replication and transcription processes essential for cellular functions.
Understanding the number of base pairs in a given length of DNA is fundamental in molecular biology, genetics, and biotechnology. It helps researchers estimate gene lengths, analyze genetic variations, and design experiments involving DNA manipulation, such as PCR (Polymerase Chain Reaction) and sequencing.
In summary, a 1 μm long dsDNA molecule contains approximately 2941 base pairs, a number that reflects the intricate and uniform structure of DNA, allowing it to serve as the blueprint for life.