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.
Heterozygous is a term that describes the genotype and just means that there are two alleles of different types. If you're heterozygous, you're Mm. You can't be heterozygous dominant or heterozygous recessive because by definition if you're heterozygous you have one of each allele.You only specify dominant or recessive when it's homozygous. So, in short, it's neither, it's just plain heterozygous.f you're heterozygous, you're Mm. You can't be heterozygous dominant or heterozygous recessive because by definition if you're heterozygous you have one of each allele. You only specify dominant or recessive when it's homozygous.