Efficiency of Gross primary production Trophic-level transfer efficiency appears to average around 10%, though there is much variation. In some marine food chains, for example, it can exceed 30%.

#Id: 2777

#Unit 13. Methods in Biology

UV radiation is used to cause DNA breakage. UV reacts quickly hence helps to catch momentary protein binding and can be used in vivo as it penetrates cell membranes easily. But gels from such assays are difficult to interpret.

#Id: 2778

#Unit 13. Methods in Biology

If the sample is hydrophobic Organic solvent is used, then to separat

Differing molecular size - Molecular exclusion system.

Weakly ionic or polar - Reversed-phase partition system.

Strongly ionic - Ion-exchange system or Reversed-phase partition system with lon-pairing is used.

#Id: 2779

#Unit 13. Methods in Biology

General structure and component of a chromatographic system

A stationary phase – typically an aqueous buffer with sufficient ionic strength to maintain a soluble protein.

A column -

An injector system: To deliver test samples to the top of the column in a reproducible manner.

A detector with data acquisition - To give a continuous record of the presence of the analytes in the eluate as it emerges from the column.

A fraction collector: For collecting the separated analytes for further biochemical studies.

#Id: 2780

#Unit 13. Methods in Biology

The basis of all forms of chromatography is the distribution or partition coefficient (Kd), which describes the way in which a compound (the analyte) distributes between two immiscible phases.

#Id: 2781

#Unit 13. Methods in Biology

A chromatogram is a pictorial record of the detector response as a function of elution volume or retention time, It consists of a series of peaks or bands.

#Id: 2782

#Unit 13. Methods in Biology

The retention time tR for each analyte has two components

 i - dead time, tM. &

ii - adjusted retention time, t’R.