Chemistry Reference
In-Depth Information
(b)
C
2
H
4
will not form hydrogen bonds because the carbon atoms have no
lone pairs to bond with hydrogen atoms from other molecules.
(c)
HBr will not form hydrogen bonds because the bromine atom is too large
and not electronegative enough.
NH
4
(d)
by itself cannot form hydrogen bonds because it has no lone pairs.
Hydrogen bond
H
GC
N
H
O
N
N
AT
N
H
N
N
GC
N
O
H
N
CG
H
TA
Guanine
(G)
Cytosine
(C)
CG
GC
Hydrogen bond
AT
H
GC
CH
3
O
H
N
N
TA
N
N
H
N
CG
N
N
AT
O
Thymine
(T)
Adenine
(A)
Figure 13.13
Hydrogen Bonding in the DNA Double Helix
The hydrogen bonding is indicated by the blue shading in the structural formulas. The base groups detailed on the left are
represented by their initials in the double helix on the right. Other than those occupied by a nitrogen atom, each corner of
each hexagon or pentagon is occupied by a carbon atom.
