AP Biology Flashcards: Nucleic Acids
Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026
Review key ideas with interactive flashcards. This set includes 11 cards to help you master important concepts.
What does it mean that DNA forms an 'antiparallel double helix'?
DNA consists of two linear polymer strands that run in opposite directions to each other while wound into a helical shape.
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What does it mean that DNA forms an 'antiparallel double helix'?
DNA consists of two linear polymer strands that run in opposite directions to each other while wound into a helical shape.
Identify the three key structural differences between DNA and RNA.
The differences are the type of sugar (deoxyribose vs. ribose), one nitrogenous base (thymine vs. uracil), and strandedness (typically double-stranded vs. single-stranded).
How does base pairing in RNA differ from that in DNA?
In RNA, the nitrogenous base uracil is used instead of thymine, so adenine pairs with uracil (A-U).
What is the typical strandedness of DNA and RNA?
DNA is typically a double-stranded molecule, whereas RNA is typically single-stranded.
Describe the directionality of a nucleic acid polymer.
Nucleic acids are linear polymers with defined 3' hydroxyl and 5' phosphate ends.
What are the specific base pairing rules in DNA?
In DNA, adenine pairs specifically with thymine (A-T), and cytosine pairs specifically with guanine (C-G).
How is a nucleic acid chain synthesized or elongated?
During synthesis, new nucleotides are added to the 3' hydroxyl end of the growing polymer chain.
What sugar is found in DNA versus RNA?
DNA contains the five-carbon sugar deoxyribose, while RNA contains the sugar ribose.
What is the primary function of nucleic acids?
Nucleic acids encode biological information in sequences of nucleotide monomers.
What are the three components of a nucleotide monomer?
Each nucleotide contains a five-carbon sugar, a phosphate group, and a nitrogenous base.
A DNA sequence is 5'-ATGC-3'. Based on base pairing rules, what is the sequence of the complementary, antiparallel strand?
The complementary strand would be 3'-TACG-5'. Adenine pairs with thymine, and guanine pairs with cytosine.