PSY BEH 101D Lecture Notes - Lecture 5: Twin, Egg Cell, Chromosome
15 Jul 2018
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Document Summary
All living things are composed of cells that promote growth and sustain life according to instructions in their molecules of dna. Each molecule of dna is called a chromosome. Chromosomes contain units of instructions called genes, with each gene located on a particular chromosome. One of eight million possible sperm from the father interact with the genes on one of the eight million possible ova from the mother. Monozygotic twins (identical twins) originate from one zygote that splits apart very early in development; as a result, they have identical genetic makeup. Dizygotic twins (fraternal twins) are formed when two separate sperm fertilize two separate ova at roughly the same time. Share half of their genes and can look quite similar. Main difference between dizygotic twins and non twin siblings is whether or not they are in utero at the same time. If one of his parents is a carrier for that disease, he could inherit the disease.
