DNA Topology Parameters
This section calculates the Linking Number (Lk) and Base Pairs per Turn (BPT) for the given DNA molecule based on its topological properties.
Linking Number Calculation
The Linking Number (Lk) represents the total number of times one DNA strand winds around the other. It is determined by the sum of the Topological Winding Number (Tw) and the Writhing Number (Wr).
Formula: $ Lk = Tw + Wr $
Given Values:
- Topological Winding Number ($Tw$) = $191$
- Writhing Number ($Wr$) = $-4$
Calculation:
$ Lk = 191 + (-4) $
$ Lk = 191 - 4 $
$ Lk = 187 $
The calculated Linking Number is $187$.
Base Pairs per Turn Calculation
The Number of Base Pairs per Turn (BPT) indicates the helical pitch of the DNA under specific conditions. It is calculated by dividing the total number of base pairs in the DNA molecule by its Linking Number.
Formula: $ BPT = \frac{\text{Total Base Pairs}}{\text{Linking Number}} $
Given Values:
- Total Base Pairs = $2.0 \text{ kb} = 2000$
- Linking Number ($Lk$) = $187$
Calculation:
$ BPT = \frac{2000}{187} $
$ BPT \approx 10.695187... $
Rounding to two decimal places, the calculated Number of Base Pairs per Turn is $10.69$.
Important Questions from Molecular Structure of Genes and Chromosomes
- All pseudogenes DO NOT code for a __________.
- C-value paradox refers to
- DNA sample collected from an unidentified bacterial species (Y) contains 13% of adenine. The G+C content (in percentage) of Y is ________
The contour length of a B-DNA molecule that encodes a bacterial protein of 33 kDa is _________ nm.
Consider the average molecular weight of an amino acid as 110 Da and helix rise per base pair for B-DNA as 0.34 nm.
(Round off to the nearest integer)
- Which of the following methods is/are used for identifying histone modifications?
