1. Proteins

2. Multipurpose molecules
Proteins:
Multipurpose molecules

3. Proteins Examples muscle skin, hair, fingernails, claws pepsin insulin
collagen, keratin
pepsin
digestive enzyme in stomach
insulin
hormone that controls blood sugar levels
pepsin
collagen (skin)

4. Proteins Function: many, many functions hormones movement
signals from one body system to another
insulin
movement
muscle
immune system
protect against germs
enzymes
help chemical reactions

5. Proteins —N— H | —C— C—OH || O Building block = amino acids –
20 different amino acids
There’s 20 of us…
like 20 different letters in an alphabet! Can make lots of different words
—N— H |
—C—
C—OH || O
variable group

6. Amino acid chains Proteins Each amino acid is different
amino acids chained into a polymer
amino acid
Each amino acid is different
some “like” water & dissolve in it
some “fear” water & separate from it

7. Water-fearing amino acids
Hydrophobic
“water fearing” amino acids
try to get away from water in cell
the protein folds

8. Water-loving amino acids
Hydrophillic
“water loving” amino acids
try to stay in water in cell
the protein folds

9. For proteins: SHAPE matters!
Proteins fold & twist into 3-D shape
that’s what happens in the cell!
Different shapes = different jobs
growth hormone
hemoglobin
pepsin
collagen

10. 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)
unfolded “denatured”
In Biology,
it’s not the size,
it’s the SHAPE that matters!
folded

11. Let’s EAT some Proteins!

12. Activities demo raw egg vs. cooked egg
drop raw egg into boiling water, like egg drop soup
compare raw egg to hard-boiled egg
demo cheese-making with heated milk & vinegar
make yogurt