Question

When the helix axis of a closed circular duplex DNA of 2310 bp is constrained to lie in a plane, the DNA has a twist (T) of 207. When released, the DNA takes up its normal twist of 10.5 bp per turn. Indicate the values of the linking number (L), writhing number (W), and twist for both the constrained and unconstrained conformational states of this DNA circle. What is the superhelix density, σ = W/T, of both the constrained and unconstrained DNA circles?

Name: when the helix axis of a closed circular duplex dna of 2310 bp is constrained to lie in a plane the dna has a twist t of 207 when released the dna takes up its normal twist of 105 bp per tur 34707
Uploaded: 2022-12-09T15:10:02-08:00
Duration: 2 min 28 s
Channel: Sri K
Description: when the helix axis of a closed circular duplex dna of 2310 bp is constrained to lie in a plane the dna has a twist t of 207 when released the dna takes up its normal twist of 105 bp per tur 34707

          When the helix axis of a closed circular duplex DNA of 2310 bp is constrained to lie in a plane, the DNA has a twist (T) of 207. When released, the DNA takes up its normal twist of 10.5 bp per turn. Indicate the values of the linking number (L), writhing number (W), and twist for both the constrained and unconstrained conformational states of this DNA circle. What is the superhelix density, σ = W/T, of both the constrained and unconstrained DNA circles?

Added by Amanda T.

Biology for AP Courses

Julianne Zedalis, John Eggebrecht

Instant Answer

Solved by Expert Sri K

12/09/2022

Step 1

The linking number (L) is the sum of the twist (T) and the writhing number (W). For the constrained state, the DNA is lying in a plane, so the writhing number (W) is 0. \[ L = T + W \] \[ L = 207 + 0 \] \[ L = 207 \] Show more…

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When the helix axis of a closed circular duplex DNA of 2310 bp is constrained to lie in a plane, the DNA has a twist (T) of 207. When released, the DNA takes up its normal twist of 10.5 bp per turn. Indicate the values of the linking number (L), writhing number (W), and twist for both the constrained and unconstrained conformational states of this DNA circle. What is the superhelix density, σ = W/T, of both the constrained and unconstrained DNA circles?