Electrophoresis is the movement of particles dispersed in a fluid, under the influence of an electric field which has uniform spatial distribution. The electrophoresis is principally based on electrokinetic phenomenon which was observed for the first time by Ferdinand Frederic Reuss in 1807. It is the basis for a number of analytical techniques used in chemistry for separating molecules by size, charge, or binding affinity. Electrophoresis of positively charged particles (cations) is known as cataphoresis, while electrophoresis of negatively charged particles (anions) is known as anaphoresis. Electrophoresis is a technique used in laboratories in order to separate macromolecules based on size. The technique applies a negative charge so proteins move towards a positive charge. In electrophoresis molecules are separated on the basis of their charge and molecular weight. Infact, the charge is responsible for creating a pull and molecular weight creates a drag across the matrix that creates differences in the mobility of molecules. In broad terms, electrophoresis may be grouped into two sub types a. Zone electrophoresis and b. Moving Boundary electrophoresis DOWNLOAD FULLTEXT HERE
Analysis of CSIR-NET Biochemistry Questions (2011- 2016)
Dr. Aditya Arya*
Date of publication: 21 Mar 2017
Question paper has a very defined and set pattern of questions and weightage of each unit is well maintained in the paper. Part A has most of the aptitude questions involving basic Physics, Chemistry, Biology and mathematics. Section B and C has questions from the defined syllabus. It has been observed in the past years the questions are often arranged in the order of units prescribed in the syllabus. As Biochemistry is the first unit of the syllabus, the question from biochemistry section are found in the beginning of section B and Section C. Questions in section B are often memory based and require fewer efforts while questions of C part may involve technical details and experimental observations and therefore need a better comprehension. Biochemistry per se is equally important as other units and has defined set of questions that encompass, about 3-4 questions (generally, question no 21- 25) each year in part B and 4-5 question each year in part C (Generally Q 71- 76). However, some questions from the 13th Unit that involve techniques are often related to basic concepts of biochemistry and thereby increasing the questions from this subjects and causing variable trend across years.
Microarray is a hybridization of a nucleic acid sample (target) to a very large set of oligonucleotide probes, which are attached to a solid support, to determine the sequence or to detect variations in a gene sequence or expression or for gene mapping. Several competing technologies for microarray probe implementation have emerged. Affymetrix (name of the company) pioneered this field with by using in situ synthesized oligonucleotides as probes and by designing microarrays in silico, thereby obviating the need for the management of clone libraries. Later two more major companies named Agilent and Illumina begun their microarray platforms based on slightly different strategies. DNA microarrays can be used to detect DNA (as in comparative genomic hybridization), or detect RNA (most commonly as cDNA after reverse transcription) that may or may not be translated into proteins. The process of measuring gene expression via cDNA is called expression analysis or expression profiling. Microarray technology has two major applications: Gene Expression Analysis and Genetic Variation Analysis.
This Quick note provides a comprehensive understanding of microarray technique for especially for undergraduate students. However, for the researchers who intend to carry out actual microarray experiments, must consult further readings of this text.
Dr. Aditya Arya, Dr.
Amit Kumar and Ms Jayanti Jha
Date of publication: 30 Dec 2016
Polymerase chain reaction (PCR) is one of the most
important tools in molecular biology which allows amplification of nucleic acid
sequences in vitro through repetitive
cycles. PCR can replicate any specific region of DNA billions fold in few
hours. The PCR machine is also called as thermocycler. This Quick Note describes variants (including most modern classes of PCR called digital PCR)
techniques are critical to several research domains including biology, Physics and
Chemistry and even in clinical diagnosis. Apart from an essential tool in
research, microscopes have become a teaching a learning companion for both
students and teachers. Since the inventions of first microscope by Hans and Zacharias Janssen in 1590, microscopes
have evolved a lot both in terms of improved resolution and magnification. The
best microscopes today can have a resolution of less than 1 angstrom and a
magnification of over 1 million, while our eyes cannot resolve two dots at a
distance lesser than 0.2 mm. Increasing resolution and magnification has
created enormous opportunities in research and wider scope of application. Now,
microscopes are used in clinical diagnosis, molecular and cell biology studies,
nano-material research and even determination of structure of bio molecules.
Microscopy is the
technical field of using microscopes to view objects and areas of objects that
cannot be seen with the naked eye (objects that are not within the resolution
range of the normal eye). There are three well-known branches of microscopy:
optical, electron, and scanning probe microscopy.
In this Quick note,
we will be discussing about basic principles and types of common microscopic
techniques and their application in Life Science Research.
In situ Hybridization Techniques from Ish… to
Date of publication: 6 Nov 2016
Among various other biochemical and molecular techniques,
in situ hybridization techniques have their own importance especially due to
its ability to detect a molecular change directly at its site of occurrence. In
situ hybridization was developed by Joseph G. Gall and Mary-Lou Pardue in 1969.
In situ hybridization is a type of
hybridization of target DNA or RNA with a labeled complementary DNA, RNA or modified
nucleic acids strand (commonly known as probe) to localize a specific DNA or
RNA sequence in a portion or section of tissue (in situ), or, if the tissue is
small enough (e.g., plant seeds, Drosophila embryos), in the entire tissue
(whole mount ISH), in cells, and in circulating tumor cells (CTCs) etc.
Originally, the detection of hybridization was based on radioactive nucleotides
and detection of radioactivity, however the with the advent of highly specific
and sensitive fluorophore it is now possible to tag probes with fluorophore and
therefore the technique is now popular as Florescent in situ hybridization of
FISH. In this Quick note a description
about the principle, its variants and applications are provided.
A GuideforChoosing M.Sc. program in Life Sciences is finally released..
Must read for all B.Sc. life Science students aspiring to do M.Sc. in Life Sciences
book is intended for many students who wonder what next after their BSc in
biological sciences. As a stepwise guide, this will also serve as a self counselling tool to the students. In the past decade, It was common tradition
in Indian education system that most of the student and of course their parents
train their students to prepare for medical or engineering exams, and in case
not selected in medical exams they often seek the basic biology courses such as
BSc followed by MSc, without even known the scope and opportunities in this
segment of educational qualification. The trends are however changing and
students as well as parents are become aware by emerging trends in print and
digital media and students are orienting themselves towards non-conventional
vocational courses or conventional non-tradition courses for MSc. The lack of awareness of suitable courses or
the opportunities prevents the young talent from being groomed and thus results
in poor employability. A prospective doctor becomes a teacher, a prospective
teacher joins a marketing expert in industries and in neither of the cases
individuals becomes successful. This book is an attempt to guide young students
to groom their talent by reaching the suitable place and also knowing the
prospective path of their professional life.
book contain several chapters which describe about the importance of MSc course
and guide students to make a choice between various programs. Also, this book
provides comprehensive details about a number of courses and institutions
offering MSc programs in biological sciences. A separate chapter has been added
on how to prepare for MSc entrance exams and opportunities outside India,
Research proposals and
write up are very important for entrance in some of the premiere Institutes of
India such as TIFR (Tata Institute of Fundamental research) as well as for
various MS programs abroad. As a matter of fact most of the students in Indian universities
(except premiere Institutes) are not exposed to hardcore research and have
hands on learning experience on limited techniques and seldom perform a
research based project. Some of the summer training programs such as Indian
Academies Summer Fellowship (IAS) provides opportunity to Masters Students to
undergo research oriented training and experience scientific procedures.
Usually, the purpose of asking for such research proposals or write ups from
the students, is to determine the scientific aptitude, level of technical
skills and interest of the candidate to determine the suitability for specific
position or course. Based on the increasing demand from the students and several queries, this articles was prepared, Any comments or suggestions may be made at the comment option below or further queries may be sent to email@example.com EXTENDED and UPDATED on Oct 3, 2016
Dr. Aditya Arya 20 Sep 2016 [last updated on 16 March 2017]
I am glad to share with you scanned copy of my handwritten notes (made during undergraduate /Postgraduate studies) on various topics (1000+ pages). Based on the request from various students (5000+ students used the photocopies of these notes in Jiwaji University colleges in last 10 years). I am now making them available publicly for academic purpose. These may be helpful for both, MSc. entrance exams as well as university exams. These notes are very basic and you may need to add more to this if preparing higher exams like CSIR-NET JRF etc. Please note that, these notes are being distributed free of cost, anyone making commercial use of this content shall be treated under law.
Bachelor's Notes: Prepared as per the prescribed syllabus of the Jiwaji University, Gwalior (MP) from 2006- 2008.
The Protein Folding Problem: Anfinsen
hypothesis and Levinthal paradox
Arya, Dr. Amit Kumar
of publication: 21 Aug 2016
We all know that proteins fold
spontaneously on keeping them in suitable aqueous environment. However, there
are some deeper questions which we must know about protein folding that, what
are the models of proteins folding? Which route does a protein follow while
folding? And how protein folding does not defy the second law of thermodynamics
despite of the fact the randomness of protein itself is reduced on folding? We
would also understand two famous hypothesis put forth by Levinthal and Anfinsen
and various probability based question arising about the protein structure. .
Infact the work of Anfinsen was recognized globally and he was awarded Nobel
Prize in chemistry in the year 1972. Finally this note will end with a few
practice MCQs based on the two key concepts.
There have been a number of questions in MSc entrances including JNU, IISc and TIFR on anfinsen hypothesis and levinthal paradox.
Metabolic processes are so complicated and it is difficult to understand them especially when we observe the individualistic approach. In biochemistry, It is equally important to have a bird eye's view on overall metabolism of various bio molecules to get a clear idea of what is happening to food that we eat. How it is digested, transported and utilised in the body. Liver is central to all metabolic processes and the functions of liver are regulated under the tight control of nervous system and hormonal system. Here in this post I present you an illustrated view of the overall process. This is a PDF (non-printable) documents only intended for digital reading. These illustrations are closely related to classroom lectures, so students may also visit the you tube channel to view some of the related classroom lectures on Biochemistry to recall the content (click to visit channel)., This content is adopted from Concise Biochemistry - by Aditya Arya. Hope this will help in enhancing the understanding of the topic.
Proteolytic Enzyme: Basic information and cleavage rules
of publication: 10 June 2016
Cleavage pattern obtained from proteolytic enzymes are commonly used to
determine the sequence of small proteins or peptides. Most of the proteolytic enzymes are capable
of cleaving the protein at specific positions. Cleaving a protein with specific
enzyme and then analysing the fragments may help in the determination of the
order of amino acids by simple logical reasoning. In this quick note we will understand how to
solve such questions and also a detailed view cleavage rules. Additionally, we will also understand the problem solving skills based on the cleavage rules. Concluding remarks include commercial applications of proteases. This note has
been prepared by content provided by global experts in the field of proteins
(European Molecular Biology Laboratory and Swiss Bioinformatics
NOTE: Past years trends of CSIR-NET exam and other nationwide competitive exams have shown frequent usage of these rule in questions. The question might appear very difficult and cannot be solved if we do not know the cleavage rules. Most of books and online solved papers have not provided any details or solutions of such questions and this is Exclusive content prepared by us. Hope this will help in your preparation.
LAST MINUTE ENZYMOLOGY PREPARATION for CSIR -NET ASPIRANTS
Understanding the fact that enzymology is one the key areas of many competitive exams and there is a lot of confusion over various type of regulation, we are providing you free access to one of the chapter (a few pages deleted) of our brand new "Concise Biochemistry" book which is further supported by a video lecture by author on the same topic. All the previously asked questions have been solved at the end of the chapter.
Hope it will help in your last minute preparation. Good Luck.
Flow cytometry is one of the most powerful technique for the research as well as clinical diagnosis that simultaneously measures and then analyzes multiple physical characteristics of single particles (often cells) by forcing them to flow in a fluid stream and analysing through a beam of light. The properties measured include a particle’s relative size, relative granularity or internal complexity and relative fluorescence intensity. These characteristics are determined using an orchestered optical and electronic system that records how the cell or particle scatters incident laser light and emits fluorescence. This technology has applications in a number of fields, including molecular biology, pathology, immunology, plant biology and marine biology. It has broad application in medicine (especially in transplantation, hematology, tumor immunology and chemotherapy, prenatal diagnosis, genetics and sperm sorting for sex preselection). Also, it is extensively used in research for the detection of DNA damage, caspase cleavage and apoptosis. The articles will provide a basic information on principle and data representation in flow cytometry.