Once you are done with this lesson you should be able to: 1  Identify the Abbasids. 2  Describe the roles of the caliphs and the viziers. 3  Explain how the caliphs' focus on trade led to the Golden Age of Islam. 4  Summarize the fall of the Abbasids.
Alleles are forms of the same gene with small differences in their sequence of DNA bases. These small differences contribute to each personâs unique physical features. Genes are made up of DNA.Each chromosome contains many genes. A gene is the basic physical and functional unit of heredity. Genes, which are made up of DNA, act as instructions to make molecules called proteins. In humans, genes vary in size from a few hundred DNA bases to more than 2 million bases.lleles are forms of the same gene with small differences in their sequence of DNA bases. These small differences contribute to each personâs unique physical features. Genes are made up of DNA.
Â­DNA carrÂ­ies all of the information for your physical characteristics, which are essentially determined by proteins. So, DNA contains the instructions for making a protein. In DNA, each protein is encoded by a gene (a specific sequence of DNA nucleotides that specify how a single protein is to be made).Specifically, the order of nucleotides within a gene specifies the order and types of amino acids that must be put together to make a protein.he particular sequence of amino acids in the chain is what makes one protein different from another. This sequence is encoded in the DNA where one gene encodes for one protein.