Proteins (bio test 3)

reaction:

dehydration synthesis - water removed

dipeptides

two amino acids joined together by a peptide bond

polypeptide

chains of many amino acids joined together by a peptide bond

essential amino acids

cannot be made by the body, must be obtained by the food a person eats. 9/20

proteins have a ___ shape

3D

proteins involve:

more than one polypeptide chain joined together

diversity comes from:

having many different shapes that let them carry out different functions

digestive enzymes

• help to break down food molecules in the digestive system so that they can be absorbed in the small intestine

• examples: lactase, lipase, amylase, pepsin (-ase)

contractile

• allow animals to move

• filaments that slide over each other creating flexibility

• examples: actin and myosin

transport

• help move substances around the body in the blood stream

• examples: hemoglobin binds oxygen in red blood cells to transport it to tissues

defense

• if pathogens (harmful microogrganisms) enter the body, white blood cells produce defense proteins called antibodies. these neutralize it or mark it for destruction

hormones

• these regulate many functions in the body by traveling through the blood to target organs

• tells organs “what to do”/”work!”

• example: insulin and glucose control glucose levels by interacting with the liver

structure

• these build different structures in cells, such as the cytoskeleton

• examples: actin, keratin, tubulin

storge

• some provide a source of food for developing embryos in some animals, i.e. chickens, and for seedlings in some plants

• example: albumin in eggs