metabolism

Examples of metabolism in the following topics:

• Metabolic Pathways

  • A metabolic pathway is a step-by-step series of interconnected biochemical reactions that convert a substrate molecule or molecules through a series of metabolic intermediates, eventually yielding a final product or products.
  • For example, one metabolic pathway for carbohydrates breaks large molecules down into glucose.
  • Another metabolic pathway might build glucose into large carbohydrate molecules for storage.
  • Consequently, metabolism is composed of these two opposite pathways:
  • Chemical reactions in metabolic pathways rarely take place spontaneously.

• Metabolic Changes

  • Protein and carbohydrate metabolism are affected during pregnancy and maternal insulin resistance can lead to gestational diabetes.
  • During pregnancy, both protein metabolism and carbohydrate metabolism are affected.
  • Increased liver metabolism is also seen, with increased gluconeogenesis leading to increased maternal glucose levels.

• Human Metabolism

  • Metabolism in humans is the conversion of food into energy, which is then used by the body to perform activities.
  • The body metabolizes all the food we consume.
  • The body stores fat or metabolizes it only if energy intake changes for a period of several days.
  • The body adjusts its basal metabolic rate to compensate (partially) for over-eating or under-eating.
  • (a) The first law of thermodynamics applied to metabolism.

• Alkalosis

  • Alkalosis can refer to respiratory alkalosis or metabolic alkalosis.
  • Metabolic alkalosis is a metabolic condition in which the pH of tissue is elevated beyond the normal range (7.35-7.45 ).
  • Metabolic alkalosis can be caused by prolonged vomiting, resulting in a loss of hydrochloric acid with the stomach content.
  • Compensatory mechanism for metabolic alkalosis involves slowed breathing by the lungs to increase serum carbon dioxide, a condition leaning toward respiratory acidosis.
  • As respiratory acidosis often accompanies the compensation for metabolic alkalosis, and vice versa, a delicate balance is created between these two conditions.

• Organic Acid Metabolism

  • Microbes can harness energy and carbon derived from organic acids by using a variety of dedicated metabolic enzymes.
  • Many types of carboxylic acids can be metabolized by microbes, including:
  • Formate metabolism is important in methylotrophic organisms.
  • The ability to metabolize formate is also critical in bacterial anaerobic metabolism, in which case formate is also oxidized by an FDH enzyme but the electrons are donated to cytochromes (proteins involved in electron transport).
  • Give examples of types of organic acid metabolism that are used by microorganisms for a sole source of energy

• The Role of Energy and Metabolism

  • All organisms require energy to complete tasks; metabolism is the set of the chemical reactions that release energy for cellular processes.
  • Metabolism is the set of life-sustaining chemical processes that enables organisms transform the chemical energy stored in molecules into energy that can be used for cellular processes.
  • Animals consume food to replenish energy; their metabolism breaks down the carbohydrates, lipids, proteins, and nucleic acids to provide chemical energy for these processes.
  • All of the chemical reactions that take place inside cells, including those that use energy and those that release energy, are the cell's metabolism.
  • Many cellular process require a steady supply of energy provided by the cell's metabolism.

• Cell Signaling and Cellular Metabolism

  • The rush of adrenaline that leads to greater glucose availability is an example of an increase in metabolism.
  • As the environments of most organisms are constantly changing, the reactions of metabolism must be finely regulated to maintain a constant set of conditions within cells.
  • Metabolic regulation also allows organisms to respond to signals and interact actively with their environments.
  • Two closely-linked concepts are important for understanding how metabolic pathways are controlled.
  • The result of one such signaling pathway affects muscle cells and is a good example of an increase in cellular metabolism.

• Chemical Composition of Bone

  • Acid-base imbalances including metabolic acidosis and alkalosis, can produce severe, even life-threatening medical conditions.
  • Metabolic alkalosis is a metabolic condition in which the pH of tissue is elevated beyond the normal range (7.35-7.45).
  • The causes of metabolic alkalosis can be divided into two categories, depending upon urine chloride levels.
  • Excess sodium increases extracellular volume and the loss of hydrogen ions creates a metabolic alkalosis.
  • Differentiate among the acid-base disorders: metabolic acidosis, metabolic alkalosis, respiratory acidosis, and respiratory alkalosis

• Acidosis

  • Metabolic acidosis may result from increased production of metabolic acids or disturbances in the ability to excrete acid via the kidneys.
  • Metabolic acidosis is compensated for in the lungs, as increased exhalation of carbon dioxide promptly shifts the buffering equation to reduce metabolic acid.
  • The amount of metabolic acid accumulating can also be quantitated by using buffer base deviation, a derivative estimate of the metabolic as opposed to the respiratory component.
  • It can also occur as a compensatory response to chronic metabolic alkalosis.
  • These symptoms usually accompany symptoms of another primary defect (respiratory or metabolic).

• Energy Requirements

  • Cardiac muscle tissue has among the highest energy requirements in the human body (along with the brain) and has a high level of mitochondria and a constant, rich, blood supply to support its metabolic activity.
  • Aerobic metabolism is a necessary component to support the metabolic function of the heart.
  • Coronary circulation branches from the aorta soon after it leaves the heart, and supplies the heart with the nutrients and oxygen needed to sustain aerobic metabolism.
  • Myoglobin transfers oxygen from the blood to the muscle cell and also stores reserve oxygen for aerobic metabolic function in the muscle cell.
  • Lactate, created from lactic acid fermentation, accounts for the anaerobic component of cardiac metabolism.