Nucleic Acids_KEY

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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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