You can tell that this is an image of a DNA nucleotide and not an RNA nucleotide because you see a _____.

Question

A chemical compound consisting of three parts. The first (from left to right) part contains a phosphorus atom with four oxygen atoms attached. Two oxygen atoms have a negative charge. The second part is represented by a five-membered carbon ring, where one carbon is replaced with an oxygen atom. The third part is a six-membered carbon ring, where the second (clockwise starting from the top) and the fourth carbons are replaced with nitrogen.

double-stranded molecule, not a single-stranded molecule
phosphate group, not a uracil
sugar with two, and not three, oxygen atoms
uracil nitrogenous base, not a thymine nitrogenous base
thymine nitrogenous base, not a uracil nitrogenous base
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Part G
Which of these nitrogenous bases is found in DNA but not in RNA?

thymine
adenine
guanine
uracil
cytosine
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Part H
Which of these is(are) pyrimidines?

Structures of nitrogenous bases. Structures A and B consist of two fused rings, whereas structures C through E contain only one ring. Rings of all bases are represented by five-membered carbon rings or six-membered ones. The second (clockwise, starting from the top) and the fourth carbons of the six-membered rings are replaced with nitrogen; the same is true for the first and the fourth carbons of the five-membered rings. Rings of structures A and B are a five-membered and a six-membered one, whereas structures C through E are represented by six-membered rings only.

B, C, and D
A, B, and C
B and C
C, D, and E
A and B
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Part I
In a nucleotide, the nitrogenous base is attached to the sugar's _____ carbon and the phosphate group is attached to the sugar's _____ carbon.

1' ... 3'
2' ... 3'
1' ... 5'
1' ... 2'
2' ... 1'
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Part J
Nucleic acids are assembled in the _____ direction.

1' to 5'
4' to 5'
5' to 3'
5' to 1'
2' to 3'
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Part K
In a DNA double helix an adenine of one strand always pairs with a(n) _____ of the complementary strand, and a guanine of one strand always pairs with a(n) _____ of the complementary strand.

thymine ... cytosine
guanine ... adenine
cytosine ... uracil
uracil ... cytosine
cytosine ... thymine

Answer 1

Here are the answers to each part:

Part G: You can tell that this is an image of a DNA nucleotide and not an RNA nucleotide because you see a thymine nitrogenous base, not a uracil nitrogenous base.

Part H: The nitrogenous base that is found in DNA but not in RNA is thymine.

Part I: In a nucleotide, the nitrogenous base is attached to the sugar's 1' carbon, and the phosphate group is attached to the sugar's 5' carbon.

Part J: Nucleic acids are assembled in the 5' to 3' direction.

Part K: In a DNA double helix, an adenine of one strand always pairs with a(n) thymine of the complementary strand, and a guanine of one strand always pairs with a(n) cytosine of the complementary strand.