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!