DNA structure - watson and crick model

Question 1

DNA consists of

Answer 1

two right-handed helical polynucleotide chains, spiraling around a central axis.

Question 2

The two chains are ______

Answer 2

antiparallel

Question 3

Antiparallel

Answer 3

Their C-5’-to-C-3’ orientations run in opposite directions.

Question 4

Nitrogen bases are paired by

Answer 4

hydrogen bonds
(A + T) - 2
(C + G) - 3

Question 5

Nitrogen bases are ____ structures, stacked ________ to the axis

Answer 5

Flat

perpendicularly

Question 6

Nitrogen bases are separated from each other by a distance of

Answer 6

3.4Å (1nm = 10Å).

Question 7

Each complete turn of the helix contains ___ bases and is ____Å long

Answer 7

10

34Å

Question 8

The double helix has a diameter of

Answer 8

20Å.

Question 9

Larger ___________ alternate with smaller _______ throughout the total length of the DNA molecule.

Answer 9

“major grooves”

“minor grooves”

Question 10

Both right-handed and left-handed helixes exist, which is more common?

Answer 10

the right-handed form

Question 11

There are different types of DNA, name them and state which is the most important biological form.

Answer 11

A-DNA to E-DNA, as well as Z-DNA

B-DNA is the most important biological form

Question 12