1. General Chemistry
Review for the biological sciences

2. Why Chemistry???????
Hey…this is Biology! Why do we need to know about chemistry??
All living things are made up of
Atoms
Molecules
Chemicals
We need to know how chemicals interact to be able to understand biology!

3. Chemical Elements Each element consists of unique atoms
Represented by symbols—H, Na, Au, etc.
A total of 118 named elements
#’s 1 through 92 are naturally-occurring
93+ are synthetic

4. Chemical Elements 92 naturally occurring elements
About 25 are considered essential to life
4 make up > 95% of living matter
Carbon
Hydrogen
Oxygen
Nitrogen

5. Atoms
The smallest particle of an element that has the qualities of that element
Made up of smaller sub-atomic particles
Cannot be broken down into simpler substances by ordinary means

6. molecules
Atoms of two or more different types chemically combined in a fixed ratio
Chemically different than the atoms that make them up
Lots of molecules of the same kind are a compound
A molecule is the smallest part of a compound that acts like the compound

7. a water molecule H2O Hydrogen: a colorless, odorless gas; explosive!
water: a colorless, odorless liquid (at ordinary temps); necessary for life
H2O
Hydrogen: a colorless, odorless gas; explosive!
oxygen: a colorless, odorless gas; supports combustion

8. So…how are atoms held together in a molecule?
CHEMICAL BONDS!
Ionic: the giving and taking of electrons
Covalent: the sharing of electrons
Hydrogen: the attraction of + and -

9. Ionic Bonds Exchange of electrons Forms charged particles called ions
One atom takes electrons & the other donates them
Forms charged particles called ions
ex—sodium chloride

10. Covalent Bonds Sharing of electrons Between nonmetals Cl + Cl CH4
Non-polar
Polar

11. Covalent Bonds non-polar polar
Equal sharing of electrons between two or more atoms
Carbon, Hydrogen
CH4
C2H6
Unequal sharing of electrons between atoms
Forms polar molecules
Water, sugar, alcohol

12. Hydrogen bonds
The attraction between the +charged portion of one polar molecule and the –charged portion of another molecule
Found in water, proteins, DNA

13. Biomolecules or Macromolecules
Polymers produced by living things
Polymers are
Large molecules
made up of smaller, repeating units called monomers

14. Polymer Carbohydrates Lipids Proteins Nucleic acids monomers examples
Starches, cellulose,
Pasta, potatoes, etc.
Fats, oils, waxes
Meat, muscle tissue, enzymes, hair, etc.
DNA & RNA
Simple sugars
Glycerol & fatty acids
Amino acids
nucleotides
Carbohydrates
Lipids
Proteins
Nucleic acids

15. Glucose molecule
X 100’s
starch molecule

16. the awesomeness continues…
Enzymes!!
the awesomeness continues…

17. Classifying Enzymes
There are 4 major categories of macromolecules: carbohydrates, lipids, proteins, & nucleic acids

18. Almost all enzymes are proteins.
However, there are a few catalytic RNA molecules.
proteins
Image: Levels of protein structure, M Ruiz

19. Naming Enzymes
For many enzymes, take the name of the substrate the enzyme works on and add the suffix -ase
Example: Lactose  Lactase

20. Enzymes are Catalysts Enzymes speed up chemical reactions.
Enzymes allow reactions to happen that otherwise could not occur.
Enzymes are very specific!
Enzymes are catalysts to over 4000 biochemical reactions!

21. Enzymes change other molecules
Starch synthase (the enzyme) puts glucose molecules together into a chain = starch
Amylase (a different enzyme) breaks down starch into glucose molecules
These processes (using different enzymes) occur with all of the macromolecules

22. Enzymes are Reusable
enzymes are reusable molecules found in living things.
as a result, they do not get used up in the reaction

23. Enzyme Form and Function
Lock & key Model: The shape of an enzyme allows it to do a specific job much like a lock and key.

24. Induced Fit Model An enzyme can form to the shape of its substrate.

25. Why are enzymes so important?
Nearly all chemical reactions in biological cells require enzymes to make the reaction occur
in a reasonable amount of time
at biological temperatures
at biological pH’s

26. Enzymes are used all over your body!

27. THE END