Genetics

New research uncovers biological drivers of heart disease risk

Over the past 15 years, researchers have identified hundreds of regions in the human genome associated with heart attack risk. However, researchers lack efficient ways to explore how these genetic variants are molecularly ...

Biomedical technology

Researchers use the eye as a window to study liver health

Researchers at Karolinska Institutet have developed a method to study liver function and disease without requiring invasive procedures. After transplanting liver cells into the eye of mice, the cornea can be used as a window ...

Alzheimer's disease & dementia

Re-energizing mitochondria to treat Alzheimer's disease

Nerve cells in the brain demand an enormous amount of energy to survive and maintain their connections for communicating with other nerve cells. In Alzheimer's disease, the ability to make energy is compromised, and the connections ...

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Metabolism

Metabolism is the set of chemical reactions that occur in living organisms to maintain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories. Catabolism breaks down organic matter, for example to harvest energy in cellular respiration. Anabolism, on the other hand, uses energy to construct components of cells such as proteins and nucleic acids.

The chemical reactions of metabolism are organized into metabolic pathways, in which one chemical is transformed into another by a sequence of enzymes. Enzymes are crucial to metabolism because they allow organisms to drive desirable but thermodynamically unfavorable reactions by coupling them to favorable ones, and because they act as catalysts to allow these reactions to proceed quickly and efficiently. Enzymes also allow the regulation of metabolic pathways in response to changes in the cell's environment or signals from other cells.

The metabolism of an organism determines which substances it will find nutritious and which it will find poisonous. For example, some prokaryotes use hydrogen sulfide as a nutrient, yet this gas is poisonous to animals. The speed of metabolism, the metabolic rate, also influences how much food an organism will require.

A striking feature of metabolism is the similarity of the basic metabolic pathways between even vastly different species. For example, the set of carboxylic acids that are best known as the intermediates in the citric acid cycle are present in all organisms, being found in species as diverse as the unicellular bacteria Escherichia coli and huge multicellular organisms like elephants. These striking similarities in metabolism are most likely the result of the high efficiency of these pathways, and of their early appearance in evolutionary history.

This text uses material from Wikipedia, licensed under CC BY-SA