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.
To make a muscle contract, the acetylcholine produced in the presynaptic neuron of the neuromuscular junction must bind to the nicotinic receptors on the postsynaptic side. Each of these receptors consists of 5 subunits that form a pentagonal structure around a central channel.
Acetylcholine is an organic chemical that functions in the brain and body of many types of animals as a neurotransmitter âa chemical released by nerve cells to send signals to other cells. Its name derives from its chemical structure: it is an ester of acetic acid and choline.4) Acetylcholine binds to postsynaptic receptors. (5) This binding causes ion channels to open and allows sodium ions to flow into the muscle cell. (6) The flow of sodium ions across the membrane into the muscle cell generates an action potential which induces muscle contraction.