adjective. Of or relating to two adjacent molecules whose sequences of atoms or other elements run in opposite directions.

Running parallel but in a contrary direction.

noun. In geometry, one of two or more lines which make equal angles with two other lines, but in contrary order.

adjective. Running in a contrary direction.

adjective. of vectors, parallel but of opposite direction

adjective. describing the orientations of the two strands of DNA

adjective. describing two beta strands comprising a protein's secondary structure that are aligned and hydrogen bonded but the vector describing the amino- and carboxy-terminal ends of each strand are oriented 180° relative to one another.

noun. A line that forms equal angles with two other lines, but in opposite directions.

adjective. (especially of vectors) parallel but oppositely directed

"In most organisms, DNA is formed as a very long and very narrow double-helix formation of two DNA strands coiled around each other in a head-to-toe "antiparallel" orientation."

parallel  

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