Oncology & Cancer

Blood lipids linked to cancer, along with family history

Fat biomolecules in the blood, called 'serum lipids,' are necessary evils. They play important roles in the lipid metabolism and are integral for the normal functioning of the body. However, they have a darker side; according ...

Cardiology

Sleep apnea worsens heart disease, yet often untreated

Health care experts urge increased awareness of obstructive sleep apnea among people with cardiovascular disease or risk factors such as high blood pressure, according to a new scientific statement from the American Heart ...

Health

Low-fiber, high-fat diets adversely impact the gut

Changes to the gut microbiome are known to affect metabolic health. Physiologists at Laval University in Canada have discovered that diets containing low fiber and high fat cause significant shifts in the composition of the ...

Oncology & Cancer

'Bad fat' suppresses killer T cells from attacking cancer

In order for cancer to grow and spread, it has to evade detection by our immune cells, particularly specialized "killer" T cells. Salk researchers led by Professor Susan Kaech have found that the environment inside tumors ...

Diseases, Conditions, Syndromes

Malaria parasite's partiality for the spleen

The malaria parasite Plasmodium vivax may accumulate in the spleen soon after infection to a greater extent than its better-known relative P. falciparum, according to new research published by John Woodford of the University ...

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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.

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