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.
Homozygous â having identical alleles for a single trait. Heterozygous â having two different alleles for a single trait. genotype â genetic structure of a cell or organism. Phenotype â physical or biochemical characteristics of an organism.eply. Homozygous-when the 2 alleles are the same. Heterozygous-when the 2 alleles are different. Phenotype-what the alleles physically look like. Genotype-the alleles as letters eg bb Bb BB etc. Reply. Homozygous â genes that are the same.