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Sickle cell disease (SCD), also simply called sickle cell, is a group of hemoglobin-related blood disorders typically inherited. [2] The most common type is known as sickle cell anemia. [2] It results in an abnormality in the oxygen-carrying protein haemoglobin found in red blood cells. [2] This leads to a rigid, sickle -like shape under ...
A strict but broad definition is an absolute decrease in red blood cell mass, [59] however, a broader definition is a lowered ability of the blood to carry oxygen. [60] An operational definition is a decrease in whole-blood hemoglobin concentration of more than 2 standard deviations below the mean of an age- and sex-matched reference range. [61]
Genetics is the study of genes, genetic variation, and heredity in organisms. [1][2][3] It is an important branch in biology because heredity is vital to organisms' evolution. Gregor Mendel, a Moravian Augustinian friar working in the 19th century in Brno, was the first to study genetics scientifically.
Stroke (also known as a cerebrovascular accident (CVA) or brain attack) is a medical condition in which poor blood flow to the brain causes cell death. [5] There are two main types of stroke: ischemic, due to lack of blood flow, and. hemorrhagic, due to bleeding.
Hemoglobin S (α 2 β S 2) – A variant form of hemoglobin found in people with sickle cell disease. There is a variation in the β-chain gene, causing a change in the properties of hemoglobin, which results in sickling of red blood cells.
A typical human cell contains about 150,000 bases that have suffered oxidative damage. [85] Of these oxidative lesions, the most dangerous are double-strand breaks, as these are difficult to repair and can produce point mutations , insertions , deletions from the DNA sequence, and chromosomal translocations . [ 86 ]
For other uses, see Mutation (disambiguation). Three major single-chromosome mutations: deletion (1), duplication (2) and inversion (3). In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. [ 1 ] Viral genomes contain either DNA or RNA.
Immune system. The immune system is a network of biological systems that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to parasitic worms, as well as cancer cells and objects such as wood splinters, distinguishing them from the organism's own healthy tissue.