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. Information molecules
Nucleic acids:
Information molecules

12. Nucleic Acids Examples DNA RNA DeoxyriboNucleic Acid RiboNucleic Acid

13. Nucleic Acids Function: genetic material stores information
genes
blueprint for building proteins
DNA  RNA  proteins
transfers information
blueprint for new cells
blueprint for next generation
DNA
proteins

14. Genes (DNA) are needed to run bodies every day…C G
Genes (DNA) are needed to run bodies every day…
to make you and me… to make new cells…
to make babies!

15. Nucleic acids 5 different nucleotides Building block = nucleotides
nucleotide – nucleotide – nucleotide – nucleotide
5 different nucleotides
different nitrogen bases
A, T, C, G, U
Nitrogen bases I’m the A,T,C,G or U part!
phosphate
sugar
N base

16. Nucleotide chains Nucleic acids nucleotides chained into a polymer DNA
phosphate
sugar
N base
Nucleotide chains
Nucleic acids
nucleotides chained into a polymer
DNA
double-sided
double helix
A, C, G, T
RNA
single-sided
A, C, G, U
phosphate
sugar
N base
strong bonds
phosphate
sugar
N base
phosphate
sugar
N base
RNA

17. DNA Double strand twists into a double helix
weak bonds between nitrogen bases join the 2 strands
A pairs with T
A :: T
C pairs with G
C :: G
the two strands can separate when our cells need to make copies of it
weak bonds
It’s a helix or B sheet within a single region. Can have both in one protein but a specific region is one or another

18. Copying DNA Replication copy DNA
2 strands of DNA helix are complementary
they are matching
have one, can build other
have one, can rebuild the whole
when cells divide, they must duplicate DNA exactly for the new “daughter” cells
Why is this a good system?

19. Newly copied strands of DNA
DNA replication
Copying DNA
pairing of the bases allows each strand to serve as a pattern for a new strand
The greatest understatement in biology!
Newly copied strands of DNA

20. Watson and Crick … and others…
1953 | 1962
Watson and Crick … and others…

21. HELIXHELIX
Let’s build some
DNA!