CHEM 109C – Zhang
Nucleic Acids - KEY
CLAS, F10
1.
Ch 27 #2 Write the full name and draw the structure for the following. Indicate whether they are nucleosides or nucleotides. a.
dCDP
2’-deoxycytidine 5’-diphosphate is a nucleotide (nucleoside = base + sugar & nucleotide = base + sugar + 5’-phosphate(s)) b.
dTTP
2’-deoxythymidine 5’-triphosphate is a nucleotide
2.
Ch 27 #21 Name the following. guanosine 3’-monophosphate is a nucleoside
2’-deoxythymidine is a nucleoside
3.
Ch 27 #4 Indicate whether each functional group of each heterocyclic base is an
H-bond acceptor, an H-bond donor or both. Draw the H-bonds between complementary base pairs.
H-bond acceptors (A): X: where X is N, O (or F), groups the have the lone pairs to “accept” an H in an H-bonding interaction.
Ex. N: in a ring or as –NH
2
, O in carbonyl group
H-bond donor (D): X-H where X is N, O (or F), groups that have the H to
“donate” to an H-bonding interaction.
Ex. –O-H, or –NH
2
NH
2
N
N
A = Adenine N
H
N ring N is A, amino group is D
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CHEM 109C – Zhang
Nucleic Acids - KEY
CLAS, F10
O
N
G = Guanine N
H
NH
2
N
N
NH
NH
2
ring NH and amino grp are D, carbonyl O is A
C = Cytosine
N
H
O
O ring N and carbonyl O are A, amino group is D
NH
T = Thymine
O
N
H
O ring NH is D, carbonyl O is A
NH
U = Uracil
N
H
O ring NH is D, carbonyl O is A
(#10 Why do both T and U specify the incorporation of A? B/c T and U are the same in their interaction with their base pair A, maximum number of Hbonds)
2 H-bonds between A & T or A & U 3 H-bond between G & C
4.
I also recommend problems like # 7, 11-14, 23-28 and will go questions on these types of problems when we get back from Thanksgiving.
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