DNA Conformations

Q. Which of the following is not applicable to single stranded DNA?

1. Chargaff's rule
2. Absence of uracil
3. 5' phosphoryl and 3' hydroxyl ends
4. Heterocyclic nitrogenous bases

Q. If the distance between two consecutive base pairs is 0.34 nm and the total number of base pairs of a DNA double helix in a E.coli cell is $4.6\times {10}^6$ bp, then the length of the DNA is approximately

1. 2.2 mm
2. 1.13 mm
3. 1.56 mm
4. 2.5 mm

Q. Z – DNA is characterized by

1. Left handed helix
2. Right handed helix
3. Bending of nitrogen bases to helix axis at an angle other than perpendicular
4. Both A and B

Q. In B-DNA, the distance between two base pairs is

1. 3.4 Å
2. 34 Å
3. 0.34 Å
4. 20 Å

Q. In B-DNA, the distance between two base pairs is

1. 3.4 Å
2. 34 Å
3. 0.34 Å
4. 20 Å

Q. In B-DNA, the distance between two base pairs is

1. 3.4 Å
2. 34 Å
3. 0.34 Å
4. 20 Å

Q. In B-DNA, the distance between two base pairs is

1. 20 Å
2. 34 Å
3. 0.34 Å
4. 3.4 Å

Q. If the length of E. coli DNA is 1.36 mm, then how many base pairs are present in E. coli?

1. $3.6\times {10}^4$
2. $3.6\times {10}^6$
3. $4.6\times {10}^6$
4. $4.0\times {10}^6$

Q.

Which of the following statement(s) about A and Z DNA structure are correct?

1. Z-form DNA is a right-handed helix; A-form DNA is a left-handed helix

2. A-form DNA is a right-handed helix; Z-form DNA is a left-handed helix

3. In A-form, the bases occupy the interior of the helix; In Z-form, guanosine rotates around the glycosidic bond

4. In A-form, the bases rotate around the glycosidic bond; In Z-form, the bases occupy the interior of the helix

Q. what is the diameter of the double helix of DNA ?How? Explain it with a diagram

Q.

Which of the following arrangements in the DNA helix is not correct?

1. A = T

2. G = C

3. T = A

4. A = C

Q.

Which of the following statement(s) about A and Z DNA structure are correct?

1. Z-form DNA is a right-handed helix; A-form DNA is a left-handed helix

2. A-form DNA is a right-handed helix; Z-form DNA is a left-handed helix

3. In A-form, the bases occupy the interior of the helix; In Z-form, guanosine rotates around the glycosidic bond

4. In A-form, the bases rotate around the glycosidic bond; In Z-form, the bases occupy the interior of the helix

Q.

Which of the following statement(s) about A and Z DNA structure are correct?

1. Z-form DNA is a right-handed helix; A-form DNA is a left-handed helix.

2. A-form DNA is a right-handed helix; Z-form DNA is a left-handed helix.

3. In A-form, the bases occupy the interior of the helix; In Z-form, the bases rotate around the phosphodiester bond.

4. In A-form, the bases rotate around the phosphodiester bond; In Z-form, the bases occupy the interior of the helix.