TLS Online TPP Program

#Id: 4631

#Unit 13. Methods in Biology

Competitive ELISA. In this technique, antibody is first incubated in solution with a sample containing antigen. The antigen-antibody mixture is then added to an antigen coated microtiter well.
The more antigen present in the sample, the less free antibody will be available to bind to the antigen-coated well. 
Addition of an enzyme-conjugated secondary antibody (Ab2) specific for the isotype of the primary antibody can be used to determine the amount of primary antibody bound to the well as in an indirect ELISA. 
In the competitive assay, however, the higher the concentration of antigen in the original sample, the lower the absorbance.

TLS Online TPP Program

#Id: 3508

#Unit 2. Cellular Organization

Genes that share a common ancestry have similar organizations with conservation of the positions of the introns.

TLS Online TPP Program

#Id: 7818

#Unit 10. Ecological Principles

In many endotherms, shivering occurs in cold conditions whereby the body undergoes rapid muscle contractions without any locomotion.

When the body temperature falls, brown fat cells increase their metabolic rate, and hence heat production.

TLS Online TPP Program

#Id: 2845

#Unit 13. Methods in Biology

Affinity chromatography fraction can be analyzed by two ways

Absorption or UV visible spectrophotometry which analyzes the concentration of protein in the fraction by using Beer lamberts law.

Polyacrylamide gel electrophoresis to fractionize the protein sample on the basis of their molecular weight.

TLS Online TPP Program

#Id: 2151

#Unit 9. Diversity of Life Forms

Only four possible states of a particular site in a DNA sequence. A single base pair difference among species provides little reliable evidence about their phylogeny