Genetic Disorders and Birth Defects

Amino acid sequence is the arrangement of amino acids in a protein. Proteins can be made from 20 different kinds of amino acids, and the structure and function of each protein are determined by the kinds of amino acids used to make it and how they are... Full Answer

Alpha-fetoprotein, also called AFP, is a protein normally produced by a fetus. AFP levels are usually undetectable in the blood of healthy adult men or women (who are not pregnant). An elevated level of AFP suggests the presence of either a primary liver... Full Answer

An antibody is a protein made by plasma cells (a type of white blood cell) in response to an antigen (a substance that causes the body to make a specific immune response). Each antibody can bind to only one specific antigen. The purpose of this binding... Full Answer

DNA contains the biological and genetic instructions that control the day-to-day function of your cells. DNA is like a blueprint, containing the directions necessary to construct other components of cells, such as proteins and RNA (ribonucleic... Full Answer

Telomerase is a cell protein that scientists involved in aging research are studying to determine if it can be used to extend a cell's natural lifespan. All cells contain telomerase, but this protein is inactive except in abnormal cells like tumors and... Full Answer

First, a quick anatomy lesson: Whether "youth" is defined as physical strength, appearance, or the sharpness of one's mental facilities, it all begins on a cellular level. Telomeres are located on the cell's DNA and play a crucial role in the creation of... Full Answer

Named after Pennsylvania biologist Leonard Hayflick, the Hayflick limit is the end of a cell's lifespan. Hayflick discovered that cells produce only a limited number of copies of themselves before they die. The implications are that immortality is... Full Answer

Evidence and studies on this issue seem to point both ways. It is not clear whether there is a connection between longevity and height. Japanese women, with a life span of 86 years old, live the longest worldwide, according to a report in the Washington... Full Answer

Researchers have discovered that some people have a genetic mutation that decreases their cells' use of a particular growth hormone, called IGF1, which stands for insulin-like growth factor 1. As a result, they tend to be smaller and live longer than an... Full Answer

The appendix appears to be a hold over from the days when our ancestors ate plants. In other vertebrates, the appendix is larger than it is in humans and it is used to break down cellulose in plants. In humans, the appendix is a small, withered pouch -... Full Answer