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
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
(a) The Golgi apparatus manipulates products from the rough ER, and also produces new organelles called lysosomes. Proteins and other products of the ER are sent to the Golgi apparatus, which organizes, modifies, packages, and tags them. Some of these products are transported to other areas of the cell and some are exported from the … Continue reading What is Golgi Apparatus?
(a) The ER is a winding network of thin membranous sacs found in close association with the cell nucleus. The smooth and rough endoplasmic reticula are very different in appearance and function (source: mouse tissue). (b) Rough ER is studded with numerous ribosomes, which are sites of protein synthesis (source: mouse tissue). EM × 110,000. … Continue reading Endoplasmic Reticulum and Ribosome
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
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?
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?
Triglycerides are composed of glycerol attached to three fatty acids via dehydration synthesis. Notice that glycerol gives up a hydrogen atom, and the carboxyl groups on the fatty acids each give up a hydroxyl group. Source: OpenStax Anatomy and Physiology OpenStax Anatomy and Physiology A triglyceride is one of the most common dietary lipid groups, … Continue reading What is Triglyceride?
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