Elements necessary for humans

At present there are 118 elements listed in the periodic table. Some of these elements are commonly found on the earth in the form of ores. Some are radioactive and have very short half lives. Many such elements have been synthesized in the laboratory and live for a very short time.

Human body like other things existing is made of compounds which are made from the elements. Out of these 118 only some elements are connected with the human body.

Although elements as such don’t make up the body it is the combined form that is molecules constitute the human body. But elemental composition is as follows by mass.

Oxygen: 65%

Carbon: 18%

Hydrogen: 10%

Nitrogen: 3%

Other elements: 4%

Other elements include Calcium, Potassium, Phosphorus, Sulphur, Sodium, Chlorine, Magnesium, Boron, Chromium, Cobalt, Copper,  Fluorine, Iodine, Iron, Manganese, Molybdenum, Selenium, Silicon, Tin, Vanadium and Zinc.

Although these elements are used in very minor amount, they are crucial to some body processes.

Elements can be divided into different groups according to the functions they perform.

Building Blocks

The main building blocks of the body are proteins which are synthesized from amino acids. For these elements used are Hydrogen, Carbon, Nitrogen, Oxygen, Phosphorus and Sulphur. DNA also contains these elements except Sulphur. DNA is the genetic code.

Enzymes

Enzymes are chemicals which are catalysts for carrying out chemical reactions like breakdown of sugars and other macro molecules. Such enzymes use some elements like Magnesium, Manganese, Copper, Zinc, Selenium and Molybdenum. Enzymes play role in respiration, digestion, metabolism and immune system.

Nerves and Control

Brain sends messages to different parts of the body and this is a two way communication. Electrical signals are carried through electrolytic solutions like brines. Sodium, Potassium and Calcium ions this play the role of transmitting the signals. Similarly Chloride ions regulate the water in and out of cells. Iodine is used to make hormones which regulate metabolism.

Bones and Teeth

Bones make the template on which our body is hoisted. Strong bones and teeth are essential for the healthy body.  Bones and Teeth are made of Calcium and phosphate. Phosphate contains Phosphorus and Oxygen. Manganese element makes more stronger and resistance to breaking.

Blood

Blood is the lifeline of the body. Blood carries oxygen to the cells and removes the carbon-dioxide gas which is the byproduct of combustion reaction. Oxygen is carried by blood due to the presence of iron which binds the Oxygen. Other elements which are constituents of blood are Carbon, Oxygen, Iron and Cobalt. Cobalt is essential to make red blood cells.

Respiration and Energy

Respiration is inhalation of Oxygen. Adinosine Triphosphate (ATP) is formed during respiration which is the compound used by body as energy. Main elements involved here are Carbon, Nitrogen, Phosphorus and Oxygen.

Source: c&en magazine of American Chemical Society (ACS)

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Why lobsters and crabs turn red on cooking

These two Sea foods are mouthwatering and popular all over the world. So much so that fairs are held to celebrate the lobster.  One such festival is held in Rockland, Maine which is attended by thousands.

lobster

When cooked these creatures turn coppery red. Although it is not necessary to become a chemist to become chefs but cooking is a science where chemistry takes place at each step. Some chemicals break down to get converted into edible and easily digestible. Similarly in many foods there are color changes when cooked which is also due to chemical modification of ingredients. Here also, chemistry is occurring.

Normal lobster is of muddy color when alive. But the final color is dependent on the amounts of a pigment called astaxanthin which is also the pigment responsible for the red color of carrots, pink of flamingos, salmon and crabs. This pigment is red in color when free. It’s chemical structure is given below.



due to the ketone and alcohol groups this compound is very active chemically easily binds other chemicals like proteins. pigment is a. powerful antioxidant. Lobsters ingest it keep stress of survival under control has been found be beneficial human beings.

What happens in the lobster is that this pigment binds to the proteins in its skin. Due to this binding, it is forced to change its geometric structure and gets twisted to fit in. Depending on the type of protein it bonds to, there’s either what’s called a bathochromic shift, which turns the pigment blue, or a hyspochromic shift, to yellow. When you’re looking at a lobster, you’re seeing light reflecting through different layers of free and bonded astaxanthin–a lot of colors mixed together, hence the muddy brown.

So the final color is a combination of many colors like red, blue and amount and type  of proteins present in the body of lobster and the age . The muddy color is good for camouflaging from the predator because it becomes indistinguishable from the muddy water.

When the lobster is cooked the proteins are denatured and release the astaxanthin pigment turning the cooked meat into coppery red.

Eggs: A concoction of Chemicals

Chicken eggs are convenient food item. It is easy to make a number of recipes. They can be scrambled, boiled, fried, or poached. Eggs are used in custards and cakes and so many other confectioneries. The versatility of eggs is a reflection of their intricate chemical makeup. Eggs contain a big list of chemicals including proteins, fats, vitamins, minerals, and water.

We wrongly think that eggshells are impervious. Eggs do have holes. A single eggshell is perforated by 9,000 pores, on average. The shell forms the egg’s container, protecting it and acting as a permeable membrane for air and moisture to pass through.

Eggshell is made mainly of calcium carbonate which is chemical insoluble in water and is also major constituent of limestone. Calcium carbonate content is about 95% and rest  5% is a mix of other minerals, such as calcium phosphate and magnesium carbonate, as well as soluble and insoluble proteins. These components strongly influence the strength of the shell. A hen on a diet low in calcium or vitamin D, for example, lays eggs having thin, soft shells, or no shells at all.

Generally the shell of egg is white or brown but chickens lay eggs of other colors, from pink to green to blue. The colors of eggs come from pigments that are secreted by the hen and deposited on the eggshell’s outer layers during formation in the chicken’s oviduct, the canal that eggs travel through from the ovaries to the outside world. Egg color is a genetic trait, so colors vary from breed to breed. Brown eggshells contain the pigment protoporphyrin, a breakdown product of hemoglobin. Found only on the shell’s surface, the brown pigment can be dissolved by vinegar or rubbed off with sandpaper. Blue and green hues are caused by the pigment oocyanin, a by-product of bile formation. White eggshells are devoid of these pigments.

Surrounded by the eggshell, the slimy, clear fluid of the egg is the albumen, or egg white—the egg’s cytoplasm. It consists of 90% water, seven major proteins, and no fat. Main protein present in the albumen is called ovalbumin and it accounts for 54% of the white.

In a fresh egg, the albumen contains carbon dioxide, which diffuses out of the egg as it ages. With the loss of CO2, the egg white becomes more alkaline and thins. Because of CO2 loss through the shell pores, an egg a few weeks old will be easier to peel after boiling than a fresh egg with a higher CO2 concentration, although the cause of this phenomenon isn’t completely understood.

Yolk makes up one-third of the egg’s weight,  is the near-opposite of albumen in chemical composition. It contains all of the egg’s fat and cholesterol, half of its protein, and four times the calories of the white. A yolk’s golden yellow color is due to the diet of the hen. A diet rich in the yellow and orange plant pigments called xanthophylls leads to a yellow yolk. If the hen’s diet is low in these pigments, the yolk can be almost colorless.

Yolks contain all of the vitamin content in the egg, including six B vitamins, as well as vitamins A, D, and E. The yolk also contains the antioxidants lutein and zeaxanthin and trace amounts of β-carotene, phosphorus, iron, magnesium, and other metals.

The freshness of an egg can be determined from the appearance of its yolk. A fresh egg has a round, firm yolk and a tight surrounding membrane, called the vitelline membrane. As the egg ages, the yolk absorbs water from the albumen, which distends the membrane and results in a looser, flattened yolk.

The greenish gray ring that can form around the yolk of a boiled egg comes from overcooking. The iron and sulfur in the yolk form ferrous sulfides, creating the green ring at the yolk’s surface. Although the color is unappealing, the research proves that the ring does not affect an egg’s flavor and nutritional content.

Contributing to an egg’s normal odor are a number of volatile constituents, including hydrocarbons, phenols, indans, indoles, pyrroles, pyrazines, and sulfides, including hydrogen sulfide. Dimethyl sulfide and dimethyl trisulfide in small amounts contribute to the characteristic odor and flavor of eggs, even fresh ones.

A truly rotten egg is formed when bacteria penetrate the shell and produce foul-smelling hydrogen sulfide.

The complexity of eggs puts them in the spotlight of health debates. Although eggs are high in protein and vitamins and low in fat and sugar, they’re heavy on cholesterol, which could raise a person’s risk of heart disease. An egg can contain up to 250 mg of cholesterol, which is 83% of the U.S. recommended daily allowance of 300 mg.

Raktika: The bright seed of Gunja

Raktika or Rati, seed of Gunja vine, was used in ancient India as a unit of weight for weighing the precious metals like Gold. The seeds have the quality of having almost identical weights. It is generally taken as 0.118 grams but the consistency over the different times is doubtful. The standard varied from time to time and place.

Gunja is also the name of girls in India. Remember, Actress Sadhana Singh was called by this name in the super hit Hindi movie called “Nadia Ke Paar“.

The botanical name of Gunja is Arbus Precatorious. It is vine which spirals on the trunks of the trees. The seed is bright red with black spots like ladybirds. The seeds contain a potent toxin called which is called abrin and consists of proteins which are dimers and called abrin A and abrin B respectively. It is very lethal. The unit B attaches itself to the cell. Once inside the cell, the A chain deactivates the 26S subunit of Ribosome. One moelcule is enough to deactivate up to 1,500 ribosome.

Manu defined the weight units in ancient India as follows:

5 Raktikas = 1 masa

16 masas = 1 tola or suvarna.

4 tolas =1 pala

10 palas =1 dharana.

Thus Raktika or Ratti was the smallest weight unit.

Besides, the Raktikas were used to make beads and ornaments.

The seed is also known as Jequirity, Crab’s Eye, Rosary Pea, John Crow Bead, Precatory bean, Indian Licorice, Akar Saga, Giddee Giddee or Jumbie  Bead in different parts of the world. It is, as one of its names suggests, used as rosary beads. The seeds are used in Andhra and Tamil Nadu in the medicine called Siddha medicine. For this purpose, the toxin arbin has to be deactivated. It is done by boiling the seeds with milk which helps in peptization of the proteins.