Biotechnology questionz!!

Today's SET 1 questions are:

1. What do you understand by endosperm culture? What is its significance? How it can help combat the problem of deforestation?

Q1. Endosperm is the tissue produced under the seeds of most flowering plants during fertilization. It surrounds the embryo and provides nutrition in the form of starch, oils and protein. Tissue culture methods used for culturing endosperm are known as endosperm culture, the basic steps involved in tissue culture are:

1. The immature seeds are dissected under aseptic conditions and endosperms along with embryos, are excised;
2. The excised endosperms are cultured on a suitable medium and embryos are removed after initial growth;
3. The initial callus phase is followed by 'embryogenesis' or 'shoot bud differentiation'
4. The shoots and roots may subsequently develop and complete triploid plants can be established for further use.

Significance:

1. Endosperm culture has been used to produce triploid plants as they are useful for production of seedless fruits (apple, banana, watermelon)
2. Endosperm culture has been used for the production of of trisomics for cytogenetic studies
3. Triploid plants produced by endosperm culture were found to be more vigorous than the parents for e.g. Petunia axillaris
4. Endosperm provides an experimental system for studying biosynthesis and metabolism of natural products e.g. Endosperm of coffee was shown to sysnthesize caffine
5. Triploid production by conventional method is laborious and may be unsuccesful. In such cases, endosperm culture is the only feasible technique

Deforestation refers to the cutting, clearing, and removal of rainforest or related ecosystems into less bio-diverse ecosystems such as pasture, cropland, or plantations. Endoperm culture can combat the problem of deforestation in the following ways:

1. Generally for afforestation seedling are planted but it may happen that the seeds may be destroyed by the insects rodents etc. Using Endosperm culture afforestation can be achieved without seeds ensuring 100 percent accuracy.
2. The time period for growth of plants is shortned using endosperm culture
3. Propagation of species which are on the verge of extinction can be brought about by the endosperm culture.

1. How the overexpression of a transgene be enhanced in a transformed cell?

Q2. A transgene is a gene that is introduced into a cell or animal from an external source.The over expression of transgene can be achieved by two ways:

1. Using inducible promoters: The transgene is placed is under the control of a inducible promoter for its experssion. These inducible promoters used to control transgene expression respond to chemicals. These chemical are added in the culture medium of the transfected cell. The chemical stimulation brings about activation and expression of the transgene. Thus more the amount of chemical more expression of the transgene will occur.

2. Using regulatory transcription factor: For the activation of the transgene certain transcription factors are required. Thus the trangene is said to be regulated by that transcription factor. Transcription factor's activity is controlled by the external stimulus or chemical. Since the chemical stimulus can activate only a particlar transcription factor which is required by that transgene no coincidental activation of other genes can occur. Thus when the concentration of the chemical or the stimulus increases in the surrounding overexpression of the transgene can be achieved.