Promoters that do not contain a TATA element are called TATA-less promoters. Surveys of promoter sequences suggest that 50% or more of promoters may be TATA-less.

TLS Online TPP Program

#Id: 6353

#Unit 8. Inheritance Biology

TLS Online TPP Program

#Id: 3995

#Unit 2. Cellular Organization

When an ethidium ion intercalates between two base pairs, it causes the DNA to unwind by 260, reducing the normal rotation per base pair from 360 to 100. In other words, ethidium decreases the twist of DNA.

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#Id: 3980

#Unit 2. Cellular Organization

Eukaryotic cells also have type I and type II topoisomerases. The type I enzymes are topoisomerases I and III;

The eukaryotic type II topoisomerases cannot underwind DNA (introduce negative supercoils), but they can relax both positive and negative supercoils.

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#Id: 2852

#Unit 13. Methods in Biology

Stationary phases commonly used for exclusion chromatography

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#Id: 2568

#Unit 7. System Physiology – Animal

Secretion

A few substances (e.g., organic acids,

organic bases, K+) are secreted from peritubular capillary blood into tubular fluid for excreting substances in the urine.