Distinguish between DNA in form A, form B and form Z, matching the following cha
ID: 271408 • Letter: D
Question
Distinguish between DNA in form A, form B and form Z, matching the following characteristics provided in the following list with the respective form. (Some may or may not correspond to more than one of the DNA forms.)
1. Double helix with right direction.
2. Conformation of sugar is always ? conformation.
3. The base inclination is much higher compared to the other two forms.
4. Double helix with left direction.
5. The "greatest groove" is deeper.
6. Conformation that results in regions rich in cytosines and guanines.
7. It tends to occur under dehydrating conditions (when removing H2O).
8. Its structure is the most enlightened.
Alternatives for DNA in form A: ______________________________________
Alternatives for DNA in form B: ______________________________________
Alternatives for DNA in Z form: ______________________________________
Explanation / Answer
This form of DNA is the most enlightened form of DNA. It was given by Watson and Crick. It has a right handed double helix with antiparallel strands. The 2 strands are held by the hydrogen bonding between the base pairs as per complementary base pairing rule. It follows Chargaff's rule. There are 10 base pairs per turn, 0 34 nm apart. 2 nm in diameter.
This was discovered by Rosalind Franklin, it is also a right-handed double helix. Found mostly in the dehydrating conditions in our body, with C3 endoconformation of sugars. Rise of each helical turn is 2.86 nm, 11 base pairs per turn with 0.26 nm apart.
It is the zig zag form of DNA, which is left-handed and rich in GC bases. Due to stacking of GC bases in anti-syn conformation, it acquires zig zag shape. 12 base pairs per turn, 0.37 nm apart and diameter is 1.8 nm. Purines and pyrimidines in anti-syn conformation.