THE LEGUME FAMILY AND PULSE CROPS:
The garden pea, Pisum sativum of the legume family (Leguminosae) is a most widely grown vegetable for its high protein content. It is grown since Bronze Age. Humans cultivated peas for millennia. Its relatives are Black-eyed pea, the Chick-pea, and Lentils. The Lentil, Lens culinaris is among the most ancient of cultivated vegetables. India is by far the largest producer of lentils in the world. Lentils are grown for their seeds which are rich in protein, and for animal forage. They range in color from white to green, brown, orange, and violet blue. The grain legumes or pulse crops are a major source of dietary protein. Many legumes like soybean, and peanuts also supply fats and oils.
PROTEINS AND NUTRITION:
Proteins are nitrogen containing molecules essential to maintaining the structure and function of all living organisms. It is derived from the Greek word ‘proteios’- meaning “primary.” Proteins function in a variety of ways. For example, enzymes, hemoglobin, muscles, the collagen of bones, tendons, skin and polypeptide hormones like Insulin. Proteins play a role in virtually every cellular function. For instance, proteins regulate muscle contraction, antibody production, and dilatation and contraction of arterial blood vessels to maintain normal blood pressure. Generally, a lack of protein in the diet retards growth in children and causes a decrease in energy. The National Academy of Sciences in the United States recommends a daily protein intake of about 0.8 to 1.6 grams per kilogram of body weight. Excessive amounts of protein intake puts a burden on the liver and kidneys which excrete the excess nitrogen as urea and uric acid.
Proteins exist in diverse, complex structures that specify their particular function. Despite the variety of structures, all proteins comprise about 20 amino acids. A primary protein is simply a long chain of amino acids. The sequence of the amino acids in the chain varies with each type of protein. Protein is a critically important part of the diet. Plants synthesize all the amino acids required for building all the necessary proteins. Animals including humans cannot synthesize eight Essential Amino Acids and therefore depend upon animal or plant protein in their food to obtain them. Plants have the ability to combine ammonia, NH3 with the products of photosynthesis to form amino acids. Animals eat the plant proteins, break them down into amino acids during the process of digestion. These amino acids are absorbed into the blood stream, where they travel to tissues throughout the body. Cells build up new proteins from these amino acids in order to build tissues and organs of their bodies or to serve a specific function such as enzymes, hemoglobin, or hormones.
NITROGEN, NITROGEN FIXATION, AND NITROGEN CYCLE:
Nitrogen is a relatively inert, colorless, odorless gas. Nitorgen is the most abundant uncombined element. Air is 78.06 percent nitorgen gas by volume. It occurs as the diatomic molecule N2 which is very stable.
The production of a simple nitrogen compound from atmospheric nitrogen is known as Nitrogen Fixation. Several species of soil bacteria (Nitrosomonas, Nitrosococcus, Nitrobacter), some fungi, blue-green algae are involved in the process of Nitrogen Fixation. In nature, nitrogen from the air is converted to nitrates which is used by plants and the nitrogen is made available to all organisms through the Nitrogen Cycle. All living organisms participate in the Nitrogen Cycle which encompasses the processes and chemical reactions involved in producing organic nitogen compounds from inorganic nitrogen and subsequently breaking down organic nitrogen back to the inorganic form. An important genus of nitrogen-fixing bacteria is Rhizobium which forms nodules on the roots of legumes. The bacteria obtain food from the legume, and the legume obtains abundant usable nitrogen compounds from the bacteria. Because of this symbiotic relationship, legumes (alfalfa, beans, and peanuts) are excellent protein sources.
MENDEL’S LAWS OF HEREDITY AND GENETICS:
Genetics is the area of biology concerned with the study of inheritance, the process by which certain characteristics of organisms are handed down from parent to offspring.
Gregor Mendel, an Austrian monk, demonstrated the inheritance patterns of the garden pea through breeding experimentations in his monastery’s garden. He had discovered in 1866 hereditary factors or genes whose existence he deduced without actually seeing them. Mendel’s statistical analysis of his data provided the mathematical basis for modern genetics.
GENES AND GENETIC CODE:
Inside the nucleus of the cells of the higher organisms, the structures known as chromosomes are made up of units called genes. Each gene is responsible for a particular trait of the organism. Each gene is responsible for the manufacture of a particular protein that is involved in the expression of that trait. While genes are located inside the nucleus of the cell, the actual protein synthesis occurs in the structures known as ribosomes located in the cytoplasm outside the nucleus. The Genetic Code is the chemical equation by which hereditary information is translated from genes into proteins. The constancy of the Genetic Code in all past and present members of the species permit the genes to have the same effects on their carriers from generation to generation. Because of the constancy of the Genetic Code, we have the ability to identify the existence of individual species which maintain and display their species-specific traits.
Although the origin of the Genetic Code is unknown, since its formation more than 3 billion years ago, several organisms exist today with the same Genetic Code. The relationship between genes and the human sensory experiences of taste, flavor, and texture of plant and animal proteins is not yet studied in a systematic fashion. In higher organisms, the cells are differentiated to perform special functions. For example, the muscle cells have the ability to contract. Animals may use different modes of locomotion, the physiological function of the muscle cells which is contractility remains the same. While the key ingredients of muscle protein remain the same, man recognizes the existence of different varieties of animal muscle protein by his sensory experience of taste, flavor, and texture. Man applies his culinary skills to improve the palatability of the plant and animal proteins that he consumes as food.
MAN AND FOREIGN PROTEINS:
Man refuses to recognize any “evolutionary” connection between his body and other plant and animal proteins. The immune system of human body constantly defends itself from dangerous and sometimes even harmless foreign proteins. About 70 percent of body’s immune cells protect the gastro-intestinal tract. Several people are sensitive to foreign proteins found in milk, eggs, fish, wheat (Gluten), nuts and others.
While people tolerate ingested foreign proteins, the body very often rejects foreign proteins injected or inserted into the body. The proteins found in spider, scorpion, bee, or wasp stings and snake bites are very harmful. The Hypersensitivity reaction known as Anaphylaxis can cause shock and death. Extreme caution is used in the administration of blood transfusions and while using any serum or vaccine. The rejection of foreign substances poses serious problems in tissue and organ transplants.
THE PROOF OF PUDDING IS IN THE EATING:
The Magic of Creation is manifested in the taste sensation imparted by plant and animal proteins. Each has its distinctive species-specific taste. Organisms use similar mechanisms and metabolic processes to build the proteins with the same amino acids. If organisms are related to each other through “evolution”, we should be able to tolerate foreign proteins and our sensory experience should not perceive the variation in taste. When I eat, I taste the Power of Creation which has introduced this variation among all living entities.
Comment sent by Sri. R. Krishna Rao :
My favorite subject; Mendel’s Laws of Genetics remained buried in an obscure journal till discovered thirty years later by three scientists independently- a tribute to their integrity. Mendel’s simple experiments and deductions are a masterpiece of deductive logic.
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