A long carbon and hydrogen chain and a carboxyl group.
In images of fatty acids (the monomers of Lipids), it is depicted as a long carbon chain with hydrogen on the ends and connected to them as well, yet on the clear side is the carboxyl group.
Hope this helps!
"An organism in which the two copies of the gene are identical — that is, have the same allele — is called homozygous for that gene. An organism which has two different alleles of the gene is called heterozygous."