Different types of peanuts. Not every peanut is the same! There are thousands of different types of peanuts, these are known as different cultivars. We can distinguish four popular different types of peanuts: the Runner peanut, the Virginia peanut, the Valencia peanut and the Spanish peanut. All these peanuts differ in size, color, flavor and oil content and are often used for very different purposes.
For a signal molecule to bind with an intracellular receptor it must be able to pass through the cellular membrane. Generally signal molecules that enter the cell are nonpolar and fat soluble. These signal molecules can pass through the lipid bilayer of the cell membrane.
Whether a hormone binds to a receptor inside or outside a cell depends on the chemical nature of the hormone and its compatibility with the cellâs fatty outer membrane. The membraneâs fat layers impede water-friendly hormones from passing through but allow fat-derived hormones to readily enter the cell. A ligand is any molecule that binds to a specific site on a protein or other molecule. 2  In this case, the estrogen hormone 17-beta-estradiol is the ligand, and the estrogen receptor is the protein.