Regents Biology

Proteins

Regents Biology 2006-2007

Proteins:

Multipurpose Molecules

Regents Biology collagen (skin)

Proteins

insulin

Examples muscle skin, hair, fingernails, claws

collagen, keratin

pepsin digestive enzyme

in stomach

insulin hormone that controls blood

sugar levels

pepsin

Regents Biology

Proteins Function:

many, many functions hormones

signals from one body system to anotherinsulin

movementmuscle

immune systemprotect against germs

enzymeshelp chemical reactions

Regents Biology

Proteins

Building block =

aminoacid

aminoacid–

aminoacid–

aminoacid–

aminoacid–

—N—H

H

H|

—C—|

C—OH

||O

variable group

amino acids

20 different amino acidsThere’s

20 of us…like 20 different

letters in analphabet!

Can make lots of different

words

Regents Biology

Dipeptide = two amino acids bonded by a condensation reaction

Covalent bond called a

Peptide Bond shown in lavender (?)

Regents Biology

Proteins = Polypeptides Polypeptide = Long amino acid

chains… composed mainly of carbon, hydrogen, oxygen, and nitrogen

Regents Biology

Amino acid chains Proteins = amino acids chained into a

polymer

Each amino acid is different some “like” water & dissolve in it

some “fear” water & separate from it

amino acid amino acid amino acid amino acid amino acid

Regents Biology

Water-fearing amino acids Hydrophobic

“water fearing” amino acids try to get away from water in cell

the protein folds

Regents Biology

Water-loving amino acids Hydrophillic

“water loving” amino acids try to stay in water in cell

the protein folds

Regents Biology pepsin

For proteins: SHAPE matters!

collagen

Proteins fold & twist into 3-D shape that’s what happens in the cell!

Different shapes = different jobs

hemoglobingrowth

hormone

Regents Biology

It’s SHAPE that matters! Proteins do their jobs, because

of their shape Unfolding a protein destroys its shape

wrong shape = can’t do its job unfolding proteins = “denature”

temperature pH (acidity)

folded

unfolded“denatured”

In Biology,it’s not the size,it’s the SHAPEthat matters!

Regents Biology

Regents Biology 2006-2007

Let’s EAT some

Proteins!