proteins on the surface of red blood cells
A virus has proteins on its capsid that bind to living host cell. Once the virus has attached it enters the cell or inserts DNA/RNA into the cell.
Antibodies.
receptors proteins
receptor proteins
check on Google, i don't like home work and i love that wiki lets you put random stuff that probably isn't right.
Receptor Proteins
Activators
cellular proteins have an specific site where ATP can bind
Receptor molecules, or called receptor proteins.
rRNA and associated proteins creates ribosomes.
transcription factor
carbohydrates