A LITTLE LIGHTBULB MOMENT
Biology
DNA base pairs
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Apples in Tuxedos. Cats in Goggles.
The idea behind the cue
In the usual double-stranded DNA structure, adenine pairs with thymine and cytosine pairs with guanine. Each strand can therefore provide the pairing information for a complementary strand.
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Short & simple
Apples in Tuxedos. Cats in Goggles.
Acronym
AT / CG: Apples in Tuxedos; Cats in Goggles. A–T, C–G.
Story
An Apple arrives in a Tuxedo. A Cat wears enormous Goggles. The DNA party has exactly these pairs: A–T and C–G.
Connect the pieces
- A → adenine
- T → thymine
- C → cytosine
- G → guanine
Know the limits
This cue covers base pairing. Strand direction, replication and gene regulation need separate explanations.
MedlinePlus Genetics · DNA ↗Check your understanding
A position on a DNA strand contains cytosine. Which base belongs opposite it in the complementary strand?
A. Adenine
B. Thymine
C. Guanine
D. Cytosine
Reveal explanation
Guanine
Cytosine pairs with guanine; adenine pairs with thymine.