The Free Radical Theory of Aging

Source: iStockphoto By: OpenStax Anatomy and Physiology The free radical theory on aging was originally proposed in the 1950s, and still remains under debate. Generally speaking, the free radical theory of aging suggests that accumulated cellular damage from oxidative stress contributes to the physiological and anatomical effects of aging. There are two significantly different versions … Continue reading The Free Radical Theory of Aging

Peroxisome and Detoxification

Peroxisomes are membrane-bound organelles that contain an abundance of enzymes for detoxifying harmful substances and lipid metabolism.Source: OpenStax Anatomy and Physiology By: OpenStax Anatomy and Physiology A peroxisome is a membrane-bound cellular organelle that contains mostly enzymes. Peroxisomes perform a couple of different functions, including lipid metabolism and chemical detoxification. In contrast to the digestive … Continue reading Peroxisome and Detoxification


By: OpenStax Anatomy and Physiology The mitochondria are the energy-conversion factories of the cell. (a) A mitochondrion is composed of two separate lipid bilayer membranes. Along the inner membrane are various molecules that work together to produce ATP, the cell’s major energy currency. (b) An electron micrograph of mitochondria. EM × 236,000. (Micrograph provided by … Continue reading Mitochondria

Cell Membrane Proteins

The cell membrane of the cell is a phospholipid bilayer containing many different molecular components, including proteins and cholesterol, some with carbohydrate groups attached. Source: OpenStax Anatomy and Physiology Cell Membrane Proteins (By: OpenStax Anatomy and Physiology) The lipid bilayer forms the basis of the cell membrane, but it is peppered throughout with various proteins. … Continue reading Cell Membrane Proteins

What are Nucleic Acids?

In the DNA double helix, two strands attach via hydrogen bonds between the bases of the component nucleotides. Source: OpenStax Anatomy and Physiology What are nucleic acids? (OpenStax Anatomy and Physiology) The nucleic acids differ in their type of pentose sugar. Deoxyribonucleic acid (DNA) is nucleotide that stores genetic information. DNA contains deoxyribose (so-called because … Continue reading What are Nucleic Acids?

How Proteins Function As Enzymes?

According to the induced-fit model, the active site of the enzyme undergoes conformational changes upon binding with the substrate. (a) Substrates approach active sites on enzyme. (b) Substrates bind to active sites, producing an enzyme–substrate complex. (c) Changes internal to the enzyme–substrate complex facilitate interaction of the substrates. (d) Products are released and the enzyme … Continue reading How Proteins Function As Enzymes?

Biology Photo: Toxoplasma gondii and Neurotoxoplasmosis

Source: Modification of work by USDA Neurotoxoplasmosis is an infection caused by Toxoplasma gondii parasite. The condition often affects AIDS patients who are immunocompromised resulting in the development of brain abscesses. The parasites are present almost everywhere and cats are the ultimate host. People can become infected by eating meat contaminated with cysts containing inactive … Continue reading Biology Photo: Toxoplasma gondii and Neurotoxoplasmosis