1. Chapter 2 The Chemistry of Life

2. Chemistry Vocabulary Element 12. Chemical energy Atom 13. Water
Organization Polar
Electron Non-polar
Isotope Solvent
Chemical Bonds Cohesion
Covalent Bond Capillary Action
Ionic Bond Transpiration
Hydrogen Bond pH Scale
Enzyme Acid
Chemical Compound Base

3. Composition of an Atom
The subatomic particles that make up atoms are protons(+) neutrons, and electrons (-).
Atoms  molecules  cells  tissues  organs  organ systems

5. In this space-filling model, glucose (center molecule) is a polar molecule with unequal sharing of electrons.  It dissolves easily in water because the positive regions of a water molecule are attracted to glucose's negative regions and the negative regions of a water molecule are attracted to glucose's positive regions --so they "get along." The dashed lines represent hydrogen bonds, which which are weak electrochemical attractions that form and reform in a liquid solution.
From

6. Electrons The flow of electrons produces current or electricity.
Electricity is pure energy.
Cells contain current. Your body has an electrical system.

7. Movement of Electrons
Electrons move through the chloroplast and the mitochondria in the Electron Transport Chain.

8. Isotopes
Isotope - one of two or more atoms with the same atomic number that contain different numbers of neutrons

9. The main types of chemical bonds.
Covalent bonds – two atoms share (e-).
Ionic bonds – one atom gains an (e-), and the other atom loses an (e-).
Hydrogen bond – a weak bond between two hydrogen or other atoms. The sharing of an (e-) with a hydrogen atom.

11. Bonds are like Firecrackers!
Firecrackers contain Potential Energy (gunpowder). Chemical Bonds contain Chemical Energy.
How do you get the energy out of the firecracker? Out of the chemical bond?

12. You BREAK them!
“Answer”
With ENZYMES

13. Enzymes and pH Enzymes work within Narrow pH ranges.
What pH does pepsin work
best in?
What pH does trypsin work
Will pepsin work at pH 9?
Will trypsin work at pH 7?

14. A chemical compound is a substance formed by the chemical combination of two or more elements in definite proportions

15. Chemical energy is the energy that’s stored in the bonds and atoms that make up molecules.
If different chemicals are allowed to react, these bonds can rearrange themselves.
Sometimes they need extra energy to do this, so they soak up some from their surroundings. These reactions are called ’endothermic’. 
But sometimes they’ll release some extra energy into the environment, heating it up. These are called ’exothermic’ reactions.
Exothermic example –
combustion
Endothermic example –
Melting of ice

16. Where does all energy originally come from?

17. Why study about water? All life occurs in water
Inside and outside the cell

18. - + + Chemistry of Water Water is a polar molecule Rule:
_____________________________ -
Rule:
Polar dissolves Polar
non-polar dissolves
non-polar

19. Water is the universal solvent of life
Polar – molecule that is asymmetrical charged
(-) charge at one end and (+) charge at the other
Solute + Solvent  Solution
(substance being dissolved) (doing the dissolving) (Mixture of both)
Sugar Water  sugar water
Salt water  salt water
Kool aid water  kool aid solution
Grease (non-polar) water 

20. The special case of ice Most (all?) substances are more dense
when they are solid
But not water…
Ice floats!
(Hydrogen bonds are represented
by dotted lines).

21. Why is “ice floats” important?
Oceans and lakes don’t freeze solid
Surface ice insulates water below
allowing life to survive the winter
Seasonal turnover of lakes (cycling
nutrients)

22. Cohesion (Surface Tension)
Like molecules attract
H bonding between
H2O creates cohesion
examples:
* meniscus
* thin membrane-
like film across
water
* beading up

23. Adhesion Adhesion- unlike molecules attract to each other. Example
water and glass, water and
pastic, water and paper towel.

24. How does water get to the top of trees?
Adhesion or
Capillary action

25. Acids, Bases, and pH
The pH scale Chemists devised a measurement system called the pH scale to indicate the concentration of H+ ions in solution.
Acidic solutions contain higher concentrations of H+ ions than pure water and have pH values below 7.

27. Acids Have a pH of 0 to 6.9 Taste sour Feel oily
-releases (H+) hydrogen ions when placed in water
Have a pH of 0 to 6.9
Taste sour
Feel oily
Corrosive and poisonous

28. The effects of Acid Rain.
Acid rain damages the tissues of plants.
Acid rain leaches nutrients from soil.
Changes the pH in pond, lakes, and rivers killing wildlife.

29. BASE pH values ranging from 7.1 to 14.
Bases is a compound that produces hydroxide ions (OH− ions) in solution.
Basic or alkaline, solutions contain lower concentrations of H+ ions than pure water and have pH values above 7.
pH values ranging from 7.1 to 14.

30. Neutral pH 7 Neither an acid or base Salt Contains equal
Numbers of OH-
And H+
Acid Base  Salt water

31. Buffers
Buffer: system of molecules that absorb or release H+ —maintaining a relatively stable pH

32. Macromolecules (basic structure)
Macromolecule - giant molecules (many atoms, not just a few)
Monomers (one unit) – monomers make up polymers
Polymers are assembled by dehydration synthesis
Polymers are disassembled by hydrolysis

33. Carbohydrate Examples of function: fuel, fuel storage
Saccharides (C6H12O6)—sugar groups that make up many carbohydrates
Monosaccharides—just one saccharide group
Examples: glucose, fructose, galactose
Also called "simple sugars" or "single sugars”
Disaccharides—have two saccharide groups
Examples: sucrose, maltose, lactose
Also called "double sugars"
Polysaccharides—have many saccharide groups
Example: glycogen
Examples of function: fuel, fuel storage