antibody a protein produced by a B lymphocyte that protects the organism against an antigen. A protein(immunoglobulin) molecule, produced by the immune system, that recognizes a particular foreign antigen and binds to it, if the antigen is on the surface of a cell, this binding leads to cell aggregation and subsequent destruction anticoding strand The DNA strand that forms the template for both the transcribed mRNa and the coding DNA Strand antinode The three-base sequence in tRNA complementary to a codon on mRNA. A nucleotide in a trna mole with a RNA nfluence of the ribosome, so that the amino acid carried by the trNa is added to a antigen A molecule whose shape triggers the production of antibodies (immunoglobulins) that will bind to the antigen. A foreign substance capable of triggering an immune response in antimorpl A mutant expressing some agent that antagonizes a normal gene product antimutator mutation mutation of dNa polymerase that decreases the overall mutation rate antiparallel a term used to describe the opposite orientations of the two strands of a DNA double helix; the 5 end of one strand aligns with the 3'end of the other strand antisense RNA RNA product of mic(mRNA-interfering complementary RNA) genes that regulates antisense strand antiterI Itor protein A protein that, when bound at its normal attachment sites in DNA, lets RNa polymera AP endonucleaseantibody A protein produced by a B lymphocyte that protects the organism against an antigen. A protein (immunoglobulin) molecule, produced by the immune system, that recognizes a particular foreign antigen and binds to it; if the antigen is on the surface of a cell, this binding leads to cell aggregation and subsequent destruction. anticoding strand The DNA strand that forms the template for both the transcribed mRNA and the coding DNA strand. anticodon The three-base sequence in tRNA complementary to a codon on mRNA. A nucleotide triplet in a tRNA molecule that aligns with a particular codon in mRNA under the influence of the ribosome, so that the amino acid carried by the tRNA is added to a growing protein chain. antigen A molecule whose shape triggers the production of antibodies (immunoglobulins) that will bind to the antigen. A foreign substance capable of triggering an immune response in an organism. antimorph A mutant expressing some agent that antagonizes a normal gene product. antimutator mutation mutation of DNA polymerase that decreases the overall mutation rate. antiparallel A term used to describe the opposite orientations of the two strands of a DNA double helix; the 5' end of one strand aligns with the 3' end of the other strand. antisense RNA RNA product of mic (mRNA-interfering complementary RNA) genes that regulates another gene by base pairing with and thus preventing translation from its mRNA. antisense strand See anticoding strand. antiterminator protein A protein that, when bound at its normal attachment sites in DNA, lets RNA polymerase read through normal terminator sequences (eg the N- and Q-gene products of phage lambda). AP endonuclease