Monday 15 April 2013

Rosalind Elsie Franklin

Rosalind Franklin
Rosalind Elsie Franklin (25 July 1920 – 16 April 1958) is probably the most famous yet controversial female scientist in terms of the critical contributions to the understanding of molecular structure of DNA. Apart from her most known work, she also dedicate her life to the investigation of viruses, coal and graphite.

Franklin was educated at a private school in London where she studied physics and chemistry from an early age, at an advanced level, especially so for a woman at that time. An excellent and dedicated student, she earned a Ph.D. in physical chemistry in 1945 from Cambridge University. Early in her career, it was Rosalind Franklin who painstakingly conceived of and captured "Photograph 51" of the "B" form of DNA in 1952 while at King's College in London. It is this photograph, acquired through 100 hours of X-ray exposure from a machine Dr. Franklin herself refined, that revealed the structure of deoxyribonucleic acid, DNA.

The discovery of the structure of DNA was the most important advance of modern biology. Quite simply, it changed the future of healthcare forever. James Watson and Francis Crick, working at Cambridge University, used Photograph 51 as the basis for their famous model of DNA which culminated in their Nobel Prize in 1962. 


Photo 51
Franklin was responsible for much of the research and discovery work that led to the understanding of the structure of DNA. The story of DNA is a tale of competition and intrigue, told one way in James Watson's book The Double Helix, and quite another in Anne Sayre's study, Rosalind Franklin and DNA. James Watson, Francis Crick, and Maurice Wilkins received a Nobel Prize for the double-helix model of DNA in 1962.
In the summer of 1956, while on a work-related trip to the United States, Franklin found she could no longer do up her skirt because of a lump around her abdomen. It was too much exposure to X-ray radiation when she was working with in order to get the photo of DNA caused the illness. She fell ill again and again afterwards, and she died on April 16, 1958, in Chelsea, London.

Sunday 14 April 2013

Things About Triglyceride

Triglycerides are the chemical form in which most fat exists in food as well as in the our bodies. They're also present in blood plasma and, in association with cholesterol, form the plasma lipids. We eat lipid on a daily basis. When we eat, our body converts calories it doesn't need to use into triglycerides. The triglycerides are then stored in fat cells, which can be used  as an energy source when there's no enough food ingested later on. So, if one regularly eat more calories  than one burn, particularly "easy" calories like carbohydrates and fats, one may have high triglycerides. 

Triglycerides in plasma are derived from fats eaten in foods or made in the body from other energy sources like carbohydrates. They help enable the bidirectional transference of adipose fat and blood glucose from the liver. Calories ingested in a meal and not used immediately by tissues are converted to triglycerides and transported to fat cells to be stored. Hormones regulate the release of triglycerides from fat tissue so they meet the body's needs for energy between meals.

Structure of tryglyceride
From a chemical respective of view, triglyceride is an ester composed of glycerol and three fatty acids connected by ester bonds. Triglycerides are different from other biological macromolecules because they do not fit the monomer-polymer relationship based on their basic structure. Triglycerides vary each other from the three fatty acids bonded the glycerol. There are different lengths and bonding of three fatty acids. When the bonding between carbon atoms are all single bonds (C-C), they are called saturated compounds. If there is(are) double bond(s)  between carbon atoms(C=C), they are refer as unsaturated compounds.

Unsaturated fats have a lower boiling point than saturated fats. Also, unsaturated fats are usually liquids under room temperature whereas saturated fats are usually solid. Animal fats are typically saturated while vegetable oil are typically unsaturated, which unsaturated fats are known as more healthier than saturated ones. In addition, triglycerides are the main components of human skin oils. 

One of the very important functions of triglycerides and, even more so, the related phospholipids is that they contribute to the structure of membranes by forming a lipid bilayer. The membranes serve as a barrier to keep the inside of a cell from the outside. The triglycerides and the phospholipids help to achieve this by having the polar head facing the outside which is hydrophilic, and the non-polar fatty acids tails facing inside of the cell membrane which is hydrophobic. Because the non-polar tails tend to dissolve into one another and form a layer that is resistant to water, thus keeping the solution outside the cell from the inside. Cell membranes made in this way is not rigis, but quite fluid and flexible, which is a considerable value to cells. 
Structure of bilayer