Zvikonzero zvekunyora (transcription factors) mapuroteni anodzora anosunga kuDNA, kana kusimudzira kana kudzora kunyora kwegene. Mukati me genome yeEscherichia coli bacteria, semuenzaniso, pane akateedzana ejenasi anodiwa ekugadzirwa kweamino acid tryptophan. Zvisinei, kana tryptophan yatovepo kusero, aya majini ekugadzira tryptophan haachadiwe. Kuvapo kwe tryptophan kunokanganisa zvakananga chiitiko chejenasi yemamolekyumu e tryptophan kudzvinyirira (a repressor), nekudaro ichivharira maitiro e tryptophan, nekudaro ichivharira maitiro e tryptophan. Mubvunzo: Maitiro ekudzvinyirira ari mukati me tryptophan anovhara sei maitiro e tryptophan?
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