
In a double helix DNA molecule normally found in all plants and animal, each successive base pair in the stack turns
A)36 ͦ in a clockwise direction.
B)36 ͦ in an anticlockwise direction.
C)360 ͦ in a clockwise direction.
D)360 ͦ in an anticlockwise direction.
Answer
495.9k+ views
Hint: The Double helical structure of DNA was proposed by Watson and Crick. DNA is composed of two straight chains which run opposite to each other and are twisted in the form of Helix. The chain is made up of nucleotides. Both the chains are bound together by the hydrogen bond between the nucleotide bases.
Complete answer:
To solve this question, we must know about the structure of DNA.
The structure of DNA looks like a twisted staircase. The DNA helix is made up of phosphate, sugar and nucleotide bases Adenine, guanine, cytosine, thymine. According to Watson and Crick model, the structure of DNA is as follows-
1.The DNA Helix is right handed.
2.The two strands of DNA are held together by hydrogen bonds between the nucleotides- A=T, C forms three hydrogen bonds with guanine.
3.The width of each turn is around 34 Angstrom and has around 10 base pairs per turn.
4.The frequency of twist depends on the stacking forces. Each successive turn in the stacking base pair is around 36 ͦ in a clockwise direction.
Hence, the correct answer is option (A)
Note: There are mainly three forms of DNA- A-form, B-form, Z-form. The double stranded right handed helix exists in the B-form which is the most common form of DNA. Z-DNA is a left handed helix. The main function of DNA is to carry the genetic material.
Complete answer:
To solve this question, we must know about the structure of DNA.
The structure of DNA looks like a twisted staircase. The DNA helix is made up of phosphate, sugar and nucleotide bases Adenine, guanine, cytosine, thymine. According to Watson and Crick model, the structure of DNA is as follows-
1.The DNA Helix is right handed.
2.The two strands of DNA are held together by hydrogen bonds between the nucleotides- A=T, C forms three hydrogen bonds with guanine.
3.The width of each turn is around 34 Angstrom and has around 10 base pairs per turn.
4.The frequency of twist depends on the stacking forces. Each successive turn in the stacking base pair is around 36 ͦ in a clockwise direction.
Hence, the correct answer is option (A)
Note: There are mainly three forms of DNA- A-form, B-form, Z-form. The double stranded right handed helix exists in the B-form which is the most common form of DNA. Z-DNA is a left handed helix. The main function of DNA is to carry the genetic material.
Recently Updated Pages
Master Class 12 Biology: Engaging Questions & Answers for Success

Master Class 12 Physics: Engaging Questions & Answers for Success

Master Class 12 Economics: Engaging Questions & Answers for Success

Master Class 12 Maths: Engaging Questions & Answers for Success

Master Class 12 Business Studies: Engaging Questions & Answers for Success

Master Class 12 English: Engaging Questions & Answers for Success

Trending doubts
What is the Full Form of PVC, PET, HDPE, LDPE, PP and PS ?

Number of planes of symmetry in the above molecule class 12 chemistry CBSE

How many muscles are there in the human body A 320 class 12 biology CBSE

Bacterial cell wall is made up of A Cellulose B Hemicellulose class 12 biology CBSE

Centrosome is found only in A Animal cells B Plant class 12 biology CBSE

According to Lewis concept an acid is AProton donor class 12 chemistry CBSE
