this is the most diverse group of proteins, as cells can make huge numbers of different antibodies
histones are associated with DNA in eukaryotes and help chromosomes to condense during mitosis
binding sites in membranes and cytoplasm for hormones, neurotransmitters, tastes and smells, and also receptors for light in the eye and in plants
some such as insulin, FSH and LH are proteins, but hormones are chemically very divers
membrane proteins are used for facilitated diffusion and active transport, and also for electron transport during cell respiration and photosynthesis
membrane proteins cause adjacent animal cells to stick to each other within tissues
Transport of nutrients and gases
proteins in blood help transport oxygen, carbon dioxide, iron and lipids
plasma proteins act as clotting factors that cause blood to turn from a liquid to a gel in wounds
fibrous proteins give tensile strength needed in skin, tendons, ligaments and blood vessel walls
tubulin is the subunit of microtubules
that gives animals cells their shape and pull on chromosomes during mitosis
actin and myosin together cause the muscle contractions used in locomotion and transport around the body
there are thousands of different enzymes to catalyse specific chemical reactions within the cell or outside it