Question:
A DNA strand has a length with 12 full turns. Then identify the number of Nitrogen bases in total
A DNA strand has a length with 12 full turns. Then identify the number of Nitrogen bases in total
Show Hint
Always distinguish between "base pairs" and "individual nitrogen bases".
Total nitrogen bases = \( 2 \times \text{number of base pairs} \).
Total nitrogen bases = \( 2 \times \text{number of base pairs} \).
Updated On: Jul 22, 2026
- 120
- 200
- 240
- 480
Show Solution
Verified By Collegedunia
The Correct Option is C
Solution and Explanation
Step 1: Understanding the Question:
The question asks us to calculate the total number of nitrogenous bases in a double-stranded DNA molecule that contains exactly 12 complete helical turns.
Step 2: Key Formula or Approach:
We use the structural parameters of standard B-DNA:
1 complete helical turn contains exactly 10 base pairs (bp).
Each base pair consists of 2 nitrogenous bases.
Therefore, the number of nitrogenous bases per turn is: \[ \text{Bases per turn} = 10 \times 2 = 20 \]
Step 3: Detailed Explanation:
• Standard double-helical DNA (B-DNA) described by Watson and Crick contains 10 nucleotide base pairs per complete pitch/turn of the helix.
• Since a base pair involves two complementary bases (one on each strand, e.g., Adenine-Thymine or Guanine-Cytosine), a single base pair consists of 2 individual nitrogenous bases.
• Therefore, 1 turn of the DNA contains: \[ 10 \text{ base pairs} \times 2 = 20 \text{ nitrogenous bases} \]
• Given that the DNA strand has 12 full turns, we calculate the total number of nitrogenous bases as follows: \[ \text{Total bases} = 12 \text{ turns} \times 20 \text{ bases per turn} \] \[ \text{Total bases} = 240 \]
Step 4: Final Answer:
The total number of nitrogenous bases in a DNA strand with 12 full turns is 240.
The question asks us to calculate the total number of nitrogenous bases in a double-stranded DNA molecule that contains exactly 12 complete helical turns.
Step 2: Key Formula or Approach:
We use the structural parameters of standard B-DNA:
1 complete helical turn contains exactly 10 base pairs (bp).
Each base pair consists of 2 nitrogenous bases.
Therefore, the number of nitrogenous bases per turn is: \[ \text{Bases per turn} = 10 \times 2 = 20 \]
Step 3: Detailed Explanation:
• Standard double-helical DNA (B-DNA) described by Watson and Crick contains 10 nucleotide base pairs per complete pitch/turn of the helix.
• Since a base pair involves two complementary bases (one on each strand, e.g., Adenine-Thymine or Guanine-Cytosine), a single base pair consists of 2 individual nitrogenous bases.
• Therefore, 1 turn of the DNA contains: \[ 10 \text{ base pairs} \times 2 = 20 \text{ nitrogenous bases} \]
• Given that the DNA strand has 12 full turns, we calculate the total number of nitrogenous bases as follows: \[ \text{Total bases} = 12 \text{ turns} \times 20 \text{ bases per turn} \] \[ \text{Total bases} = 240 \]
Step 4: Final Answer:
The total number of nitrogenous bases in a DNA strand with 12 full turns is 240.
Was this answer helpful?
0
0
Top AP EAPCET Botany Questions
- Plant that possess characters like ramenta, archegonia, circinate
- Identify the correct pair from the following
A. Golden algae - diatoms
B. Trichodesmium erythrium - Red Sea
C. Kieselguhr - Chrysophytes
D. Red tides of Mediterranean sea - Dinoflagellates - Assertion (A): Fertilization in Cycas is called siphonogamy and zooidogamy.
Reason (R): Male gametes are multiciliate and carried by pollen tube. - Identify the organisms based on their cell wall characteristics such as pseudomurein, mycolic acid, stiff cellulose plates, chitin.
- Find the correct matching
A) Carrot -- Flowers appear from the same point of peduncle
B) Cocos -- Flowers protected by the modified bract
C) Achyranthes -- Flowers appear in the varied lengths of pedicels
D) Cassia -- Flowers appear on the flattened peduncle
View More Questions
Top AP EAPCET Structure of DNA and RNA Questions
Top AP EAPCET Questions
- A body is projected from the ground at an angle of $\tan^{-1} \left( \frac{8}{7}\right)$ with the horizontal. The ratio of the maximum height attained by it to its range is
- The four quantum numbers of the valence electron of potassium are :
- A lens forms real and virtual images of an object, when the object is at $u_{1}$ and $u_{2}$ distances respectively. If the size of the virtual image is double that of the real image, then the focal length of the lens is (take, the magnification of the real image as $m$ )
- Two spheres $P$ and $Q$, each of mass $200\, g$ are attached to a string of length one metre as shown in the figure. The string and the spheres are then whirled in a horizontal circle about $O$ at a constant angular speed. The ratio of the tension in the string between $P$ and $Q$ to that of between $P$ and $O$ is $(P$ is at mid-point of the line joining $O$ and $Q$ )
- The volume of $0.02\, M$ acidified permanganate solution required for complete reaction of $60\, mL$ of $0.01\, MI^{-}$ ion solution to form $I_2$ in $mL$ is
View More Questions