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816 Chapter 26
Copyright © 2017 Pearson Education, Inc.
17.
B
is the only sequence that has a chance of being recognized by a restriction endonuclease because it is the
only one that has the same sequence of bases in the 5
S
3 direction that the complementary strand has in
the 5
S
3 direction.
A—C—G—C—G—T
T—G—C—G—C—A
5
3
5
3
18.
Lys-Val-Gly-Tyr-Pro-Gly-Met-Val-Val
19.
5
¬
GAC
¬
CAC
¬
CAT
¬
TCC
¬
GGG
¬
GTA
¬
GCC
¬
AAC
¬
TTT
¬
3
20.
5
¬
AAA
¬
GTT
¬
GGC
¬
TAC
¬
CCC
¬
GGA
¬
ATG
¬
GTG
¬
GTC
¬
3
21.
A segment of DNA with 18 base pairs has 36 bases. If there are 7 cytosines, then there are 7 guanines. This
accounts for 14 bases. Therefore, 22 (36
-
14
=
22) are adenines and thymines.
a.
11 thymines
b.
7 guanines
22.
a.
guanosine 3 -monophosphate
c.
2 -deoxyadenosine 5 -monophosphate
b.
cytidine 5 -diphosphate
d.
thymidine
23.
The third base in each codon has some variability.
mRNA
5 -GG(UCA or G)UC(UCA or G)CG(UCA or G)GU(UCA or G)CA(U or C)GA(A or G)-3
or
AG(U or C) AG(A or G)
DNA
3 -CC(AGT or C)AG(AGT or C)GC(AGT or C)CA(AGT or C)GT(A or G)CT(T or C)-5
template
or
TC(A or G) TC(T or C)
sense 5 -GG(TCA or G)TC(TCA or G)CG(TCA or G)GT(TCA or G)CA(T or C)GA(A or G)-3
or
AG(T or C) AG(A or G)
Notice that Ser and Arg are two of three amino acids that can be specified by six different codons.