Chemistry lecture 21

BIOCHEMISTRY

Biochemistry, sometimes called biological chemistry, is the study of chemical processes in living organisms. Biochemistry governs all living organisms and living processes. By controlling information flow through biochemical signalling and the flow of chemical energy through metabolism, biochemical processes give rise to the incredible complexity of life. Much of biochemistry deals with the structures and functions of cellular components such as proteins, carbohydrates, lipids, nucleic acids and other biomolecules although increasingly processes rather than individual molecules are the main focus. Over the last 40 years biochemistry has become so successful at explaining living processes that now almost all areas of the life sciences from botany to medicine are engaged in biochemical research. Today the main focus of pure biochemistry is in understanding how biological molecules give rise to the processes that occur within living cells which in turn relates greatly to the study and understanding of whole organisms.

The four main classes of molecules in biochemistry are carbohydrates, lipids, proteins, and nucleic acids.

Carbohydrates are made from monomers called monosaccharides. Some of these monosaccharides include glucose (C₆H₁₂O₆), fructose (C₆H₁₂O₆), and deoxyribose (C₅H₁₀O₄). When two monosaccharides undergo dehydration synthesis, water is produced.

Lipids are usually made from one molecule of glycerol combined with other molecules. In triglycerides, the main group of bulk lipids, there is one molecule of glycerol and three fatty acids.

Proteins are very large molecules – macro-biopolymers – made from monomers called amino acids. There are 20 standard amino acids, each containing a carboxyl group, an amino group, and a side chain.

Nucleic acids are the molecules that make up DNA, an extremely important substance which all cellular organisms use to store their genetic information. The most common nucleic acids are deoxyribonucleic acid and ribonucleic acid. Their monomers are called nucleotides.

All cells require energy to maintain life. The energy to the cells come from the food humans and animals eat. Energy is used to synthesis body materials, transport substances, contract muscles, send electric impulses and maintain constant body temperature.  The chemical processes of cells are called cellular metabolism. The cell converts the chemical energy in food to that of chemical energy in the form that can be used for cellular metabolism.

Aging Process in Humans

The aging process in humans is a complex biochemical process which includes all the changes taking place socially, psychologically and physically. The process of aging in the human body is inevitable and there are many signs of aging occurring both within and outside the human body.

Normal Aging Process in Humans

Normally, the process of aging in the human body starts at middle age around 45. The process and its effects depend on both, the genetic as well as environmental factors. To understand the human aging process better, let us try and understand the cellular changes that occur along with the aging process. Aging causes some amount of reduction in the rate of human cell multiplication (cellular senescence) and also causes some of the cells to function inappropriately.

Aging Process in Women

Women undergoing a normal aging process tend to go through some major physical as well as psychological changes. Most women tend to put on some weight with the onset of menopause and also acquire some wrinkles and fine lines as signs of aging. Their skin tends to loose all the natural moisture, becomes dry and starts loosening out. There is also a substantial decrease in bone mass, body mass and muscle strength which makes them prone to a number of illnesses especially osteoporosis and arthritis. The process of aging in women also causes them to shrink or loose height due to loss of bone tissue from the vertebrae. Hormonal changes in aging women can bring about a lot of psychological and behavioral changes in them. Read more on wrinkles on face.

Aging Process in Men

Men too, go through a number of changes due to the process of aging, hormonal changes being the most important of all changes. This process of hormonal changes taking place in men is known as ‘andropause’ and can be identified by a marked change in the plasma levels of testosterone, melatonin and dehydroepiandrosterone. These changes lead to a decrease in the levels of libido, muscle and body mass, bone strength and also impotency in some males. Other changes that may be noticed in aging males include increased forgetfulness, insomnia and irritability. However, the aging process in men is far more easier than that in women and most men tend to age without facing any major physical aging problems. Aging men tend to face mental problems like Alzheimer’s disease and dementia and may also face prostrate related disorders and cardiovascular disorders.

The skin is made up of 3 main layers: the epidermis, dermis, and subcutaneous. The skin becomes damaged and shows signs of aging in each of the 3 layers.

As your skin ages, it changes in fundamental ways. The skin becomes thinner and weaker, and veins become more visible. Your face and body begin to lose their youthful tightness and as years of sun damage and gravity take effect sagging begins to pull and skin becomes flabby and droopy, especially in facial areas. Skin becomes much drier during the aging process as your body naturally begin to produce less oils, reduced levels of elastin and collagen, decreased hormone production levels, and decreased fat or lipid storage deep in the skin. The skin becomes discolored and age spots or sunspots appear on areas that have recieved a lot of UV exposure over the years. Another unfortunate sign of ageing, and one of the most unpleasant is wrinkles. Wrinkles can occur all over the body and are especially bothersome on the face. Typically wrinkles appear deepest and most pronounced around the eyes, mouth, neck, and forehead.