Thursday, May 3, 2012

Gel filtration/Size-exclusion Chromatography

Principles of  Gel filtration chromatography

Gel filtration, also called size-exclusion chromatography, separates proteins according to their size. There are pores in the gel filtration matrix and these pores permit the buffer and smaller proteins to enter into it but reject larger proteins and protein complexes. Therefore, larger proteins move around the matrix particles and elute from the column first before smaller proteins. 

Tuesday, May 1, 2012

Textbooks available on the Internet

Biochemistry, 5th edition
Jeremy M Berg, John L Tymoczko, and Lubert Stryer.

Genomes, 2nd edition
Terence A Brown.

Immunobiology, 5th edition
The Immune System in Health and Disease
Charles A Janeway, Jr, Paul Travers, Mark Walport, and Mark J Shlomchik.

Bruce Alberts, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts, and Peter Walter.

Harvey Lodish, Arnold Berk, S Lawrence Zipursky, Paul Matsudaira, David Baltimore, and James Darnell.

More Textbooks

Sunday, April 29, 2012

Nutrients and Their Functions


Carbohydrates (sugar and starches) are the most efficient sources of energy and are known as the “fuel of life.”  They are abundantly found in most plant food sources. Complex  carbohydrates  (starches)  are  in breads,  cereals,  pasta,  rice,  dry  beans  and  peas,  and other vegetables, such as potatoes and corn. Simple carbohydrates are found in sugars, honey, syrup, jam, and many desserts. 

Thursday, April 26, 2012

Vitamins and Minerals: Their presence in adult DRI

The Dietary Reference Intakes (DRIs) are a set of scientifically based nutrient reference values for healthy populations. Vitamins and minerals are nutrients from our environment that we need for all the essential reactions in our cells to occur. Our bodies can make small amounts of certain vitamins, but we cannot manufacture minerals. Every mineral in our body must first come from outside our

Tuesday, April 24, 2012

DNA Cloning/ Recombinant DNA Technology/ Genetic Engineering

A clone is an identical copy. This term originally applied to cells of a single type, isolated and allowed to reproduce to create a population of identical cells. DNA cloning involves separating a specific gene or DNA segment from a larger chromosome, attaching it to a small molecule of carrier DNA, and then replicating this modified DNA thousands or millions of times through both an

Carbohydrate digestion begin in the mouth

Salivary gland produces saliva, which digests carbohydrate in mouth. This early step of digestion facilitates the absorption of glucose and thus facilitates getting energy from carbohydrate than other foodstuffs like protein, fat etc.

What does the thyroid gland do?

The thyroid gland controls how quickly the body uses energy, makes proteins, and controls how sensitive the body is to other hormones. It participates in these processes by producing thyroid hormones, the principal ones being triiodothyronine (T3) and thyroxine which can sometimes be referred to as tetraiodothyronine (T4). These hormones regulate the rate of metabolism and affect the growth and rate of function of many other systems in the body. T3 and T4 are synthesized from both iodine and tyrosine. The thyroid also produces calcitonin, which plays a role in calcium homeostasis.

Monday, April 23, 2012

General Transcription Factors

General transcription factors (GTF's) or basal transcription factors are protein transcription factors that have been shown to be important in the transcription of class II genes to mRNA templates.  Many of them are involved in the formation of a preinitiation complex, which, together with RNA polymerase II, bind to and read the single-stranded DNA gene template.

Why and how does salts precipitate proteins?

Salt dehydrates water around the protein molecules dissolved in solution. As a result, the solubility of protein molecules is reduced. This process brings the protein molecules close to interact each other. And thus the protein molecules settle down as precipitate.

Vitamins and minerals work together to maintain bone health

Vitamins and minerals have different functions in the body. Sometimes they may work together at times. Vitamins and minerals are needed to maintain the health of tissue, organs, muscles, bones and blood. Vinatim D is essential to absorb calcium. Actually, without vitamin D, the body can't form a hormone called calcitriol, which will contribute to insufficient dietary calcium absorption. If the body doesn't get enough calcium, it will extract it from the bones. This may cause Osteoporosis.

Related Post

Nutrition: Some Definitions
Classification of Nutrients
Vitamins and Minerals: Their presence in adult DRI  

Principles of DEAE cellulose column method

Separation and purification of proteins using ion exchange chromatography is based primarily on differences in the ionic properties of surface of amino acid. Proteins bind to ion exchangers by electrostatic forces between the protein’s surface charges (mainly) and the dense clusters of charged groups on the exchangers. The charges are of course balanced by counterions such as metal ions, chloride ions, and sometimes buffer ions. A protein must displace the counterions and

Difference between Prokaryote and Eukaryote: Explanation

The differences between prokaryote and eukaryote range from size to intracellular movement. There are differences in many important points in-between. Unlike prokaryotic cells, typical eukaryotic cells are much larger with a thousand to a million times larger cell volumes than those of bacteria. The distinguishing characteristics of eukaryotes are the nucleus, which has a complex internal

Actin: Roles in Cell Division

Actin is a major component of the cytoarchitecture and plays significant roles in cell migration and cell division. It accomplishes its function over cell division in association with myosin. The most dramatic example of actin-myosin contraction in nonmuscle cells is provided by Cytokinesis—the division of a cell into two following mitosis. Toward the end of mitosis in animal cells, a contractile ring consisting of actin filaments and myosin II assembles just underneath the plasma membrane. Its contraction pulls the plasma membrane progressively inward, constricting the center of the cell and


Polymerase chain reaction (PCR) is a repetitive procedure that results in geometric amplification of a specific DNA sequence. In this method, two synthetic oligonucleotides are prepared, complementary to sequences on opposite strands of the target DNA at positions just beyond the ends of the segment to be amplified. The oligonucleotides serve as replication primers that can be extended by

Cell Cycle

Cell cycle is the period between the formation of a cell by division of its mother cell and the time when the cell itself divides to form two daughter cells. Cell division in eukaryotes occurs in four well-defined stages. In the S (synthesis) phase, the DNA is replicated to produce copies for both daughter cells. In the G2 phase (G indicates the gap between divisions), new proteins are synthesized and the cell approximately doubles in size. In the M phase (mitosis), the maternal

Sunday, April 22, 2012

What is the relevance of having two membranes in the mitochondria?

This is required to maintain the electrochemical potential in the space between two membranes. This electrochemical potential represents proton-motive force which is ultimately used to generate ATP by ATP synthase situated in the inner membrane.

What does the abstract mean in a scientific report?

It is a summary of scientific work. You may write 200-250 words to describe your work. Description may contain why the research has taken, how it has done, what things have considered and what are the major findings. The sum up of all these may construct an abstract of a scientific work

What's the main energy transfer during respiration?

ATP is formed due to transfer of electrons through respiratory chain located in the inner membrane of mitochondria. Actually, electrochemical gradient is formed in the intramembrane space simultaneously with electron transfer. And proton-motive force is subsequently is used to drive the synthesis of ATP. So, in human respiration the chemical energy is converted to heat and electric energy.

Salting Out Technique: Purpose

Salting out is a technique that has been using to separate desired substance from a solution. Adding of an appropriate percentage of salt to a solution causes the water molecules to be exhausted gradually from the surrounding of the desired molecules that are polar in the water. As a result, the desired substances/molecules come close together and are settled down.

It may be applicable to enzymes, proteins etc.

Prokaryotes and Eukaryotes: Difference

There are many parameters. Nonetheless, prokaryotic genome is nucleoid, not surrounded by memebrane and DNA is associated with nonhistone proteins. Conversely, DNA is complexed with histone and nonhistone proteins in eukaryotic chromosome and chromosome is in nucleolus, which has membranous envelope.

No membrane-bound organelles, mitochondrion and 
cytoskeleton are available in prokaryotic. On the other hand, eukaryote has many membrane-bound organelles, possesses oxidative enzymes and has complex cytoskeleton.

Heart and Circulatory System: Problems

The circulatory system is composed of the heart and blood vessels, including arteries, veins, and capillaries. Our bodies actually have two circulatory systems: The pulmonary circulation is a short loop from the heart to the lungs and back again, and the systemic circulation (the system we usually think of as our circulatory system) sends blood from the heart to all the other parts of our bodies and back again.

Problems of the Heart and Circulatory System

Heart and circulatory problems are grouped into two categories: congenital (problems present at birth) and acquired (problems developed some time after birth).

Congenital heart defects

These abnormalities in the heart's structure are present at birth and these defects occur while the fetus is developing in the mother's uterus and it's not usually known why they occur. Some congenital heart defects are caused by genetic disorders, but most are not. What all congenital heart defects have in common, however, is that they involve abnormal or incomplete development of the heart.
A common sign of a congenital heart defect is a heart murmur — an abnormal sound (like a blowing or whooshing sound) that's heard when listening to the heart. Usually a heart murmur is detected by a doctor who's listening to the heart with a stethoscope during a routine exam. Murmurs are very common in children and can be caused by congenital heart defects or other heart conditions.

Biochem Blog and Info: Retrovirus and Bacteriophage

Biochem Blog and Info: Retrovirus and Bacteriophage: A  retrovirus  is an RNA virus that is duplicated in a host cell using the reverse transcriptase enzyme to produce DNA from its RNA g...

Synthases and Synthetases; Ligases and Lyases; Kinases, Phosphatases, and Phosphorylases

Synthases catalyze condensation reactions in which no nucleoside triphosphate (ATP, GTP, and so forth) is required as an energy source. e.g. Citrate synthase  

Synthetases catalyze condensations that do use ATP or another nucleoside triphosphate as a source of energy for the synthetic reaction. Succinyl-CoA synthetase is such an enzyme.

Ligases are enzymes that catalyze condensation reactions in which two atoms are joined using ATP or another energy source. (Thus synthetases are ligases.) DNA ligase, for example, closes breaks in DNA molecules, using energy supplied by either ATP or NAD+; it is widely used in joining DNA pieces for genetic engineering.

Saturday, April 21, 2012

Classification of Nutrients

According to their chemical nature

Nutrients are organic and inorganic compounds in foods and, according to their chemical nature, are classified into the following types of substances:

*       Protein
*       Carbohydrates
*       Lipids
*       Vitamins
*       Mineral salts
*       Water

Nutrients are normally obtained by the ingestion of foods. Organic nutrients include carbohydrates, proteins or amino acids, lipids, and vitamins. Inorganic nutrients include minerals. Water is sometimes included in a listing of nutrients

Nutritional Classification of Foods

The different groups of foods may be broadly classified under three heads from the nutritional point of view.

*       Energy-yielding foods;
*       Body- building foods and
*       Protective foods.

Energy Yielding Foods

The group includes foods rich in carbohydrates and also fats. They may be broadly divided into two groups:
*       Cereals, roots and tubers and
*       Carbohydrates and Fats.

Cereals provide, in addition to energy the greater part of the proteins, certain minerals and vitamins in the deits of the low income groups in the developing countries. Roots and tubers also provide some amounts of proteins, minerals and vitamins while pure carbohydrates and fats provide only energy.

Body Building Foods

Foods rich in proteins are called body building foods. These may be broadly divided into two groups:

*       Milk, egg and fish rich in proteins of high biological value and
*       Pulses, oilseeds and nuts and low fat oilseed flours rich in proteins of medium nutritive   value.

Protective Foods

Foods rich in proteins, vitamins and minerals are termed protective foods. Protective foods are broadly classified into two groups:

*       Foods rich in vitamins, minerals and proteins of high biological value e.g.., milk, egg, fish and liver and
*       Foods rich in certain vitamins and minerals only e.g., green leafy vegetables and some fruits.

Depending on the importance

In terms of participation in metabolic reactions of the organism as a whole, the nutrients can be:

*       Nonessential Nutrients: Nonessential Nutrients which are not vital to the body and that, under certain conditions, are synthesized via precursor molecules (usually essential nutrients). Therefore, the body does not need regular intake of such a condition to obtain the precursors of their environment. These are produced by the body's metabolism.

*       Essential nutrients: Essential nutrients are those that are vital to the agency as you can not synthesize. That is, are substances that are so indispensable to obtain the environment. For humans, these include essential fatty acids, essential amino acids, some vitamins and certain minerals. Oxygen and water are also essential for human survival, but usually not considered as nutrients when consumed in isolation.

Humans can get energy from a variety of fats, carbohydrates, proteins and ethanol and other compounds can be synthesized (eg, certain amino acids) from essential nutrients.

The nutrients have a significant role on health, whether beneficial or toxic. For example, sodium is a nutrient that is involved in water balance processes when provided in adequate amounts. But his excessive intake in the diet can promote hypertension.

According to its mass

Depending on the quantity necessary for cells and organisms are classified as:

*  Macronutrients are required in large quantities daily (usually in the order of grams). These nutrients are involved as substrates in metabolic processes for energy. These include proteins,  carbohydrates and fats and are the basis of any diet.

Micronutrients are needed in small quantities (usually in amounts less than milligrams). These nutrients are involved in regulating metabolism and energy processes, but not as substrates. These include vitamins and minerals. 

Related Post

Nutrition: Some Definitions

Vitamins and Minerals: Their presence in adult DRI

Nutrients and Their Functions

Friday, April 20, 2012

Nutrition: Some Definitions

Food: Food is the prime necessity of life. The food we eat is digested and assimilated in the body and used for its maintenance and growth. Food also provides energy for doing work. So,
food is that which nourishes the body.

Nutrients: Nutrients are those organic and inorganic compounds that a living organism must acquire from the environment to support essential life processes, including 1basal metabolism, growth and maintenance of body tissues, activity, reproduction, and maintenance of general health.

Saturday, April 14, 2012

Biochemistry: Has a wide range of applications

Biochemistry is a hub of life science. This knowledge of biochemistry has been applying to medicine, dentistry, and veterinary medicine since long. In food science, this branch of biology is involved in the development of abundant and cheap sources of nutritious foods, determination of the chemical composition of foods and development of methods to extract nutrients from waste products.  Biochemistry is also engaged in the invention the ways to prolong the shelf life food products.

Biochemistry and Agriculture

Agricultural biochemistry is not only the chemistry of living things; it's a part and parcel of modern life science. It is a combination of mathematics, chemistry, physics, biochemistry, genetics, molecular cell biology, and research. In agriculture, biochemists involve in the study of interaction between herbicides and plants. They explore the structure-activity relationships of compounds, determine their ability to inhibit growth, and evaluate the toxicological effects on surrounding life.

Living Matter: Identifying Characteristics

There are some unique characteristics that make difference the living organism from non-living world. The distinguishing features of living organisms are as follows:

1) High level of chemical complexity and minute organization

Living organism is very complex. Hundreds of thousands of different molecules make up a cell’s complicated internal structures. Distinguishing sequence of subunits, unique three-dimensional structure, and its highly specific selection of binding partners in the cell are some features of every molecule.

Saturday, April 7, 2012

Biochemistry and Medicine

Two fields of life science-biochemistry and medicine are closely related. Understanding and maintenance of health and the understanding and effective treatment of diseases are the two major concerns for workers involved in health sciences. Biochemistry has much impact on both of these fundamental concerns of medicine. Actually, a broad interrelationship exists between biochemistry and medicine. Biochemical studies have lighted up many aspects of health and disease. In other words, the study of various aspects of health and disease has opened up new areas of biochemistry.

Tuesday, April 3, 2012

Biochemistry and Nutrition

Many disciplines have emerged from Biochemistry . Nutritional biochemistry is a branch of biochemistry and is made up of the core knowledge, concepts, and methodology related to the chemical properties of nutrients and other dietary constituents and to their biochemical, metabolic, physiological, and epigenetic functions. This discipline has influence on mammalian physiology, health, and behavior.

Thursday, March 29, 2012

Molecular Biology: Relationship with Biochemistry and Genetics

Molecular biology is a discipline of biology and it deals with the molecular basis of biological activity. This stem interconnects other areas of biology and chemistry, mainly genetics  and biochemistry. Molecular biology largely concerns itself with understanding the interactions between the various systems of a cell, including the interactions between the different types of macromolecules e.g., DNA, RNA and protein biosynthesis as well as learning how these interactions are regulated.

Wednesday, March 28, 2012

Universe and Life Arising

About fifteen to twenty billion years ago, the universe arose as a cataclysmic eruption of hot, energy-rich subatomic particles.The simplest elements (hydrogen and helium) were formed shortly. In the early stage, the universe was very hot. As it expanded and cooled, material condensed under the influence of gravity to form stars. Some stars became enormous and then exploded as supernovae.


Take a close look at the living organisms. Actually, they are the collection of thousands of different lifeless biomolecules. Biochemistry asks how the amazing properties of living organisms arise  from these different lifeless biomolecules. When these molecules are isolated and examined individually, they follow all the physical and chemical laws that describe the behavior of lifeless matter. Notably all the processes occurring in living organisms follow these laws. The study of biochemistry give you an idea about how the collections of inanimate molecules that constitute living organisms interact to maintain and continue life animated solely by these laws (physical and chemical laws) that govern the nonliving universe.