human  metabolism : some facts and Information


Defining Metabolism

Metabolism is defined as the set of life-sustaining chemical transformations within the cells of living organisms. These enzyme-catalyzed reactions allow organisms to grow and reproduce, maintain their structures, and respond to their environments. The word metabolism can also refer to all chemical reactions that occur in living organisms, including digestion and the transport of substances into and between different cells, in which case the set of reactions within the cells is called intermediary metabolism or intermediate metabolism.

Metabolism is something that consists of both,' Catabolism,' and, 'Anabolism;' which are the buildup and breakdown of substances. In the field of Biology, Metabolism refers to all of the body's chemical processes, the digestion of food, and the elimination of waste.

Catabolism

The term, 'Catabolism,' comes from the Greek word, 'Cata,' which means, 'down.' Catabolism is a process consisting of all of the reactions during which larger molecules are broken down into smaller ones, releasing energy. An example of this process is the digestion of protein which is then broken down into amino acids that a person's body can absorb and use through the metabolic process, storing glycogen in their liver for energy. Chemically, this process is known as an, 'Oxidation Reaction.' Catabolism is the part of the metabolism responsible for breaking complex molecules down into smaller molecules. The other part of the metabolism, anabolism, builds simple molecules into more complex ones. During the catabolism energy is released from the bonds of the large molecules being broken down. Typically, that energy is then stored in the bonds of adenosine triphosphate (ATP). The catabolism increases the concentration of ATP in the cell as it breaks down nutrients and food. The ATP, in such high concentrations, becomes much more likely to give up its energy in the release of a phosphate. The anabolism then uses this energy to combine simple precursors into complex molecules that add to the cell and store energy for cell division.
protein catabolism 

All proteins in the known world are formed of the same 20 amino acids. That means that the proteins in plants, animals, and bacteria are all just different combinations of the 20 amino acids. When an organism consumes a smaller organism, all of the protein in that organism must be digested in the catabolism. Enzymes known as proteinases break the bonds between the amino acids in each protein, until the acids are completely separated. Once separated, the amino acids can be distributed to the cells of the body. According to the organism’s DNA, the amino acids will be recombined into new proteins.

Cell Metabolism:

Every living cell in a person's body has a metabolism, referred to as, Cell Metabolism. Multicellular organisms such as animals and plants do as well. People have an overall metabolism that differs from the metabolism of individual cells. There are metabolic pathways which form a two-part process; the first part is the one mentioned called, 'Catabolism,' during which the body processes food to use for energy. The other part is called, 'Anabolism,' where the person's body uses food in order to either repair or build cells. The metabolic process ceases only when a person dies.

Anabolism:

The term, 'Anabolism,' comes from the Greek word, 'Ana,' which means, 'up.' Anabolism is a process consisting of all of the reactions during which the assembly of small molecules are created into larger ones and then stored as energy in newly formed chemical bonds.The opposite of anabolism is catabolism the set of processes that breaks down larger molecules into smaller ones. Anabolism and catabolism are the two types of metabolic pathways. Metabolic pathways are series of chemical reactions that take place in the cell. Anabolic pathways use energy, while catabolic pathways release energy.

Function of Anabolism

Anabolic pathways in a cell lead to the formation of larger, more complex molecules from smaller ones. First, catabolic pathways are needed to break down nutrient molecules from food into small building blocks. These smaller molecules are then joined together to make different, bigger molecules called macromolecules. Anabolic pathways involve the input of energy, which is needed to form chemical bonds between smaller molecules to make macromolecules. Molecules built from anabolism are then used to build structures in the cell, or even to help build new cells. Anabolism and catabolism are controlled by circadian rhythms, and both are important for the development, growth, and maintenance of an organism’s cells.Two examples of anabolic hormones are testosterone and insulin. Hormones can also be produced artificially in the lab; this is how anabolic steroids are created.


Defining Metabolic Rate


The term, 'Metabolic Rate,' refers to the amount of chemical energy a person frees from their body per unit time. Chemical energy is something that is measured in calories, or the amount of energy that will heat one gram of water by one degree Celsius. It is easier to measure calories by kilo-calories, or, 'kcal's'. One kcal is 1,000 calories; something that both food labels and Dietitians refer to as a calorie with a capital, 'C.'. A person's metabolic rate is commonly expressed in terms of kcal's per hour or day. One way to measure someone's metabolic rate is through the use of a, 'Spirometer,' which is a device that measures their rate of oxygen consumption. For every liter of oxygen a person breathes, they use about 4.82 kcal's of energy from glycogen or fat.A person's metabolic rate is dependent on certain variables such as whether or not they have been fasting, their hormone levels, physical activity, their mental state, and their thyroid hormone in particular. A person's Total Metabolic Rate (TMR) involves their Basic Metabolic Rate (discussed below) in addition to their energy expenditures for other activities. Children have a higher TMR than adults. As people near middle-age they gain weight many times, even though they may not change their eating habits. People who pursue diets can become frustrated in part because initial weight lost is from water that is rapidly regained, but also because their TMR declines over time. As their diet process progresses, they burn fewer calories and begin to synthesize more fat, even with a stable intake of calories.

Interesting Metabolic Facts

1.
  • Contrary to common belief, a slow metabolism is rarely the cause of excess weight gain.

2. Anabolism is the set of constructive metabolic processes where the energy released by catabolism is used to synthesize complex molecules.

3. Metabolism involves a vast array of chemical reactions, but most fall under a few basic types of reactions that involve the transfer of functional groups of atoms and their bonds within molecules.

4. 
  • Most of the structures that make up animals, plants and microbes are made from three basic classes of molecule: amino acids, carbohydrates and lipids (often called fats).
5. 
  • Metabolism can vary greatly. A 5'2" woman weighing 130 lbs. may have a completely different metabolism than another woman who is the same height and weight.

6.One easy way to ramp up your metabolism is to build muscle through lifting weights.


7. Metabolism refers to all the physical and chemical processes in the body that convert or use energy.


8.
  • Carbohydrate catabolism is the breakdown of carbohydrates into smaller units.

9. 
  • Skinny individuals almost invariably have slower resting metabolisms; there is literally less of them to burn while at rest.

10. Temperature has a big impact on your metabolism.