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 speed up 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. Protein Structures Primary Structures – it’s the amino acid sequence
Determined by the genetic code in the mRNA.
It is produced in the ribosome.

11. Protein Structures
Secondary Structures – form as a result from hydrogen bonds between peptide groups.
Planar or cylindrical

12. Protein Structures
Tertiary Structures – Its 3 dimensional formation as a result of protein folding.
Happens because of bonds between R groups of different amino acids.

13. Protein Structures
Quaternary Structures – 2 or more polypeptide chains associate and form a single protein.
Hemoglobin are 4 different amino acid chains.

14. 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

15. Enzymes
Catalyst –speeds up the rate of a chemical reaction
Enzymes – proteins that act as biological catalysts
Enzymes help lower the activation energy of a chemical reaction
the energy needed to get a reaction started

17. Substrates bind to a site on the enzyme called the active site
Enzymes
Substrates bind to a site on the enzyme called the active site
SHAPE MATTERS!!

18. Enzymes – Usually end in -ase
Enzyme Substrate Lactase Lactose Amylase Carbohydrate Sucrase Sucrose Maltase Maltose

19. ______________
___________
Substrate
Products
Active Site
Enzyme

20. Enzymes
The fit between the active site and substrates is so precise that it is often compared to a lock and key

21. Factors that affect enzyme activity
Temperature
Concentration pH
FGHGFH CONCENTRATION
LOW CONCENTRATION

22. Let’s EAT some Proteins!

23. 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