The Glycocalyx

This structure is an enormously diverse collection of glycoproteins and glycolipids that covers the surface of every cell, like trees on the surface of the Earth, and has many important functions. All eukaryotes originated from free-living cells that hunted bacteria for food. The glycoca-lyx evolved to meet the demands of this kind of lifestyle, providing a way for the cell to locate, capture, and ingest food molecules or prey organisms. Cell-surface glycoproteins also form transporters and ion...

Recombinant Technology Revolutionizes the Field

In 1973, Paul Berg, a professor of biochemistry at Stanford University, produced the first recombinant DNA molecule, consisting of a piece of mammalian DNA joined to a bacterial plasmid (a bacterial minichromosome). Bacteria have a natural tendency to take up plasmids from the medium they are growing in once they do, the plasmid DNA, with any insert it may contain, is replicated along with the bacterial chromosome each time the cell divides. This proliferation of a segment of DNA is called...

Hormone Imbalance Theory

Processing Resources Theory Aging

Coordination of an animal's physiology is the job of the endocrine system. This system consists of a command center located in a part of the brain called the hypothalamus a master endocrine gland called the pituitary, which is connected directly to the hypothalamus and a variety of secondary endocrine glands located in various parts of the body. The hypothalamus controls the pituitary by releasing hormone messengers that pass directly to the gland, where they stimulate or inhibit the release of...

Alzheimers Disease

Alzheimer's disease is a neurological disorder affecting the central nervous system (CNS) that leads to a progressive loss of memory, language, and the ability to recognize friends and family.The average course of the disease, from early symptoms to complete loss of cognitive ability, is 10 years. Alois Alzheimer first described AD in 1907, and it has since become the fourth-leading cause of death among the elderly. The incidence of this disease increases with age and is twice as common in...

Introduction To The Process Of Aging

It has been this way since multicellular creatures crawled out of the oceans more than 500 million years ago. Indeed, mortality and multicellularity seem to go hand in hand, for our unicellular ancestors, the protozoans and bacteria, have an indefinite life span. If we think of those ancestors as being a single lineage, it is a life form that has been alive for 3 billion years. There are those who think a human life span of 85 years is long enough, but compared...

Genes and Programmed Aging

Are we programmed to get old If we are, is it like the program that guides our development from a single fertilized egg to a multicellular organism Or is aging the unfortunate side effect of adaptations that make it possible for us to have and protect our offspring Many geron-tologists believe that aging is a matter of evolutionary neglect, rather than design. However life spans evolved, it is clear that our genes have the final say in how long we are going to be on the stage. Even though flies...

The Quest For Immortality

Concerns about human mortality date back at least 20,000 years when Cro-Magnons, the first Homo sapiens, prepared one of their own for burial. Cro-Magnon funerals are taken as evidence by anthropologists that those people thought like us. They knew about death, and in their sorrow, they adorned the corpse with prized possessions, possibly thinking they would be of use in a spiritual afterlife. In grieving for their lost loved ones, Cro-Magnons were drawn to a quest for immortality, but one that...

Fruit

The fruit fly Drosophila melanogaster is a popular research organism. During the 1980s, researchers managed to isolate long-lived Drosophila through selective breeding. These flies showed a greater metabolic capacity and enhanced resistance to stress initiated by heat, desiccation, and ethanol vapors. In addition, they have higher activities of antiox-idative enzymes, they are more efficient at utilizing nutrients, and they have enhanced stores of lipid and glycogen. Many of these features are...