A stroke occurs when blood flow to a part of the brain stops. A stroke is sometimes called a brain attack.. If blood flow is cut off for longer than a few seconds, the brain cannot get nutrients and oxygen. Brain cells can die, causing lasting damage.
A cell is said to be homozygous for a particular gene when identical alleles of the gene are present on both homologous chromosomes. The cell or organism in question is called a homozygote. True breeding organisms are always homozygous for the traits that are to be held constant.
Heterozygote. Definition. noun, plural: heterozygotes. A nucleus, cell or organism possessing two different alleles for a particular gene. Supplement. An example is a zygote having one dominant allele and one recessive allele for a particular gene.Word origin: hetero (different) + zygote. Related forms: heterozygous (adjective). Compare: homozygote. See also: zygote. Related term: 1  Compound heterozygote.n example is a zygote having one dominant allele and one recessive allele for a particular gene. Word origin: hetero (different) + zygote. Related forms: heterozygous (adjective). Compare: homozygote. See also: zygote. Related term: 1  Compound heterozygote.