AP BIOLOGY

THE MOLECULAR BASIS OF INHERITANCE

DNA MAKES RNA MAKES PROTEIN

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
If one side of the helix is CACTGG, the complementary side would be
A
CACTGG
B
GGTCAC
C
GTGACC
D
GTGUCC
Explanation: 

Detailed explanation-1: -The DNA strands have the opposite orientation: one strand is in the 5′ to 3′ direction with respect to the carbon atoms on the sugar (deoxyribose) and the complementary strand is in the 3′ to 5′ direction (Figure 1(a)).

Detailed explanation-2: -Henceforth, for AAGCT, the complementary sequence is TTCGA.

Detailed explanation-3: -Complementary sequence: Nucleic acid sequence of bases that can form a double-stranded structure by matching base pairs. For example, the complementary sequence to C-A-T-G (where each letter stands for one of the bases in DNA) is G-T-A-C.

Detailed explanation-4: -Because one side of each sugar molecule is always connected to the opposite side of the next sugar molecule, each strand of DNA has polarity: these are called the 5’ (5-prime) end and the 3’ (3-prime) end, in accordance with the nomenclature of the carbons in the sugars.

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