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  2. Base pair - Wikipedia

    en.wikipedia.org/wiki/Base_pair

    An unnatural base pair (UBP) is a designed subunit (or nucleobase) of DNA which is created in a laboratory and does not occur in nature. DNA sequences have been described which use newly created nucleobases to form a third base pair, in addition to the two base pairs found in nature, A-T (adenine – thymine) and G-C (guanine – cytosine).

  3. Nucleotide base - Wikipedia

    en.wikipedia.org/wiki/Nucleotide_base

    Each of the base pairs in a typical double-helix DNA comprises a purine and a pyrimidine: either an A paired with a T or a C paired with a G. These purine-pyrimidine pairs, which are called base complements, connect the two strands of the helix and are often compared to the rungs of a ladder. Only pairing purine with pyrimidine ensures a ...

  4. Lewis acids and bases - Wikipedia

    en.wikipedia.org/wiki/Lewis_acids_and_bases

    A Lewis base is often a Brønsted–Lowry base as it can donate a pair of electrons to H +; [11] the proton is a Lewis acid as it can accept a pair of electrons. The conjugate base of a Brønsted–Lowry acid is also a Lewis base as loss of H + from the acid leaves those electrons which were used for the A—H bond as a lone pair on the ...

  5. Hoogsteen base pair - Wikipedia

    en.wikipedia.org/wiki/Hoogsteen_base_pair

    Chemical structures for Watson–Crick and Hoogsteen A•T and G•C+ base pairs. The Hoogsteen geometry can be achieved by purine rotation around the glycosidic bond (χ) and base-flipping (θ), affecting simultaneously C8 and C1 ′ (yellow). [1] A Hoogsteen base pair is a variation of base-pairing in nucleic acids such as the A

  6. Common base - Wikipedia

    en.wikipedia.org/wiki/Common_base

    In this circuit the emitter terminal of the transistor serves as the input, the collector as the output, and the base is connected to ground, or "common", hence its name. The analogous field-effect transistor circuit is the common-gate amplifier.

  7. Basis of a matroid - Wikipedia

    en.wikipedia.org/wiki/Basis_of_a_matroid

    The bases of a matroid characterize the matroid completely: a set is independent if and only if it is a subset of a basis. Moreover, one may define a matroid to be a pair (,), where is the ground-set and is a collection of subsets of , called "bases", with the following properties: [7] [8]

  8. Negative base - Wikipedia

    en.wikipedia.org/wiki/Negative_base

    The base −r expansion of a is then given by the string d n d n−1...d 1 d 0. Negative-base systems may thus be compared to signed-digit representations, such as balanced ternary, where the radix is positive but the digits are taken from a partially negative range. (In the table below the digit of value −1 is written as the single character T.)

  9. Non-canonical base pairing - Wikipedia

    en.wikipedia.org/wiki/Non-canonical_base_pairing

    Since base pairs are mediated through hydrogen bonding interactions based on hydrogen bond donor-acceptor complementarity, this, in turn, provides a convenient bottoms-up approach towards classifying base pair geometries in terms of respective interacting edges of the participating bases.