
The number of bases in each turn of Z-DNA and B-DNA helices respectively is
A. 9 and 11
B. 12 and 10
C. 10 and 13
D. 12 and 11
Answer
516.3k+ views
Hint: DNA molecule exists in different forms in different conditions. The DNA exists in three different forms- A-DNA, B-DNA, Z-DNA. Under ordinary conditions, B- DNA exists in the cell predominantly. In human cells a huge volume of DNA is twisted and stored in a very small volume.
Complete Answer:
- DNA occurs as a double helical structure. A, B, Z DNA are the forms of DNA in which the nucleotides(A, G, C, T) are linked together in a long chain and form amino acids. The bond between the two chains is formed by the complementary bases.
- Adenine bonds with Thymine and Cytosine bonds with Guanine and forms a double helix.
- B-DNA: In this the nitrogenous base is perpendicular to the axis of helix and the base twists at 36 degrees with the adjacent bases. Each complete turn has around 10 base pairs.
- Z-DNA: Z DNA is a left handed helical structure with 4.4nm turn length and 12 bases in each turn. The presence of Z-DNA occurs in some enhancers.
Thus the correct answer is (B). The number of bases in each turn of Z-DNA and B-DNA helices respectively is 12 and 10.
Additional Information: A DNA is the most stable form of DNA as it has an additional –OH group in the ribose. It occurs during the transcription.
Note: Generally under the ordinary condition, DNA exists in the B form. Under low humidity and presence of certain salts the B DNA gets converted to Z form.
Complete Answer:
- DNA occurs as a double helical structure. A, B, Z DNA are the forms of DNA in which the nucleotides(A, G, C, T) are linked together in a long chain and form amino acids. The bond between the two chains is formed by the complementary bases.
- Adenine bonds with Thymine and Cytosine bonds with Guanine and forms a double helix.
- B-DNA: In this the nitrogenous base is perpendicular to the axis of helix and the base twists at 36 degrees with the adjacent bases. Each complete turn has around 10 base pairs.
- Z-DNA: Z DNA is a left handed helical structure with 4.4nm turn length and 12 bases in each turn. The presence of Z-DNA occurs in some enhancers.
Thus the correct answer is (B). The number of bases in each turn of Z-DNA and B-DNA helices respectively is 12 and 10.
Additional Information: A DNA is the most stable form of DNA as it has an additional –OH group in the ribose. It occurs during the transcription.
Note: Generally under the ordinary condition, DNA exists in the B form. Under low humidity and presence of certain salts the B DNA gets converted to Z form.
Recently Updated Pages
Master Class 11 Economics: Engaging Questions & Answers for Success

Master Class 11 Accountancy: Engaging Questions & Answers for Success

Master Class 11 English: Engaging Questions & Answers for Success

Master Class 11 Social Science: Engaging Questions & Answers for Success

Master Class 11 Biology: Engaging Questions & Answers for Success

Master Class 11 Physics: Engaging Questions & Answers for Success

Trending doubts
1 ton equals to A 100 kg B 1000 kg C 10 kg D 10000 class 11 physics CBSE

Difference Between Prokaryotic Cells and Eukaryotic Cells

One Metric ton is equal to kg A 10000 B 1000 C 100 class 11 physics CBSE

1 Quintal is equal to a 110 kg b 10 kg c 100kg d 1000 class 11 physics CBSE

Draw a diagram of nephron and explain its structur class 11 biology CBSE

Explain zero factorial class 11 maths CBSE
