In E. coli., DNA polymerase I (coded by polA) is involved in the repair of damaged DNA and, in a subsidiary role, in semiconservative replication.

TLS Online TPP Program

#Id: 6417

#Unit 2. Cellular Organization

The trp operon is controlled by repression and attenuation, providing a two-stage response to progressively more stringent tryptophan starvation. But attenuation alone can provide robust regulation: other amino acid operons such as leu and his rely entirely on attenuation for their control. In the case of the leucine operon, its leader peptide has four adjacent leucine codons, and the histidine operon leader peptide has seven histidine codons in a row.

TLS Online TPP Program

#Id: 537

#Unit 2. Cellular Organization

The shape of a bacterium is governed by its rigid cell wall.

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#Id: 3880

#Unit 5. Developmental Biology

Slug migrates to the top layer of the soil, where it proceeds to build the fruiting structure.

TLS Online TPP Program

#Id: 10159

#Unit 6. System Physiology – Plant

Direct application of cytokinin to axillary buds stimulates

their growth but strigolactone suppresses axillary bud growth. Besides activating BRC1, strigolactone also inhibits cytokinin biosynthesis by negatively regulating the IPT genes.

TLS Online TPP Program

#Id: 7560

#Unit 6. System Physiology – Plant

Cytokinin Primary site of synthesis -- root tips. High concentrations -- immature seeds and developing fruits