Tutor profile: Arnab M.
Subject: Biomedical Science
What is DNA profiling or fingerprinting or typing?
The nucleotide forms the code, therefore the coded genetic information can be profiled to produce most authentic identity card of any organism. The molecular technology that facilities the identification of an individual based on the unique characteristics of their DNA, observed by the banding pattern of DNA fragments obtained by restriction enzyme digest and followed by southern blot hybridization using minisatellite probe is knowns DNA profiling or DNA fingerprinting or DNA typing.
Why proteins are the most important macromolecules?
Proteins are more important macromolecules that carbohydrate or lipid in following respects - GENE EXPRESSION: Among the organisms, the morphological or other differentiates are regulated by proteins that are again guided by a specific gene. Therefore genetic expression requires protein synthesis. This has been possible due to millions of combinations in number, arrangement, and nature of 20 different types of amino acids. FUNCTIONAL GROUP: Proteins have wide variety of functional groups (-NH2, -COOH, -OH, -CH3, -SH) not found in the other 2 macromolecules. This gives a functional diversification. INTERACTION OF OTHER MOLECULES: Proteins can interact with lipid or carbohydrates or other molecules which make them novel molecules. RIGIDITY AND FLEXIBILITY: Some proteins are rigid and some proteins are flexible which provide the functional and structural need of the cell or body which gives stability.
Write down the role of the spindle apparatus in anaphase separation of chromatids?
During a cell division, one of the most important phenomena is the separation of chromatids during the onset of anaphase. The chromatids during the metaphase stage remain attached to each other by the securin protein. This protein should be deactivated prior to the separation of chromatids. Cell division is controlled by several checkpoints of which the spindle assembly checkpoint is important. When the chromosomes are not assembled properly to spindle fiber or congressional of the chromosomes fails, anaphase is delayed. Anaphase promoting complex (APC) and a single cell factor (SCF) are 2 important components controlling the separation of the chromatids, SCF acts primarily but depleted during anaphase. 2 APC sets have been identified - APC^cdc20 and APC^cdh1. The first one is active during the metaphase - anaphase transition and inactivates the securin protein. It's inactivation causes activation of a protease called separase that separates the 2 chromatids of the chromosome through dissociation of cohesin protein. the APC^cdh1 is an association with APC and cleaves the mitotic cyclin and hence the cell leaves metaphase.
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