There are RNA polymerase crystal structures that provide considerable insight into how the enzyme retains contact with its substrate while breaking and remaking bonds in the process of the nucleotide addition cycle and undergoing translocation by a Brownian ratchet mechanism.

TLS Online TPP Program

#Id: 1359

#Unit 4. Cell Communication and Cell Signaling

All cytokines have a similar tertiary structure consisting of four long conserved α helices folded together.

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#Id: 7333

#Unit 11. Evolution and Behavior

When a population is in Hardy-Weinberg equilibrium, the genotypic frequencies are determined by the allelic  frequencies.

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#Id: 492

#Unit 2. Cellular Organization

The metaphase scaffold consists of a dense network of fibers. Threads of DNA emanate from the scaffold, apparently as loops of average length 30 to 90 kb.

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#Id: 8034

#Unit 1. Molecules and their Interaction Relevant to Biology

Nonpolar amino acids have three ionisations zones

1. 1--------pK1 – charge +1

2. pK1---------pK2 charge 0

3. pK2---------14 charge -1

TLS Online TPP Program

#Id: 8979

#Unit 11. Evolution and Behavior