The Chemistry of Life

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Anchoring Phenomenon: Why Did Sailors Get Scurvy?

2.1 The Nature of Matter


-protons (positive)
-electrons (negative)
- neutrons (no charge)

atomic structure


-consist of only one type of atom
- Examples: Carbon, Hydrogen, Oxygen


-consist of two or more elements
- Examples: Water, table salt

The Periodic Table

- shows elements arranged by their atomich number

Chemical Bonds

- ionic (transferring of electrons)
- covalent (sharing electrons)

Interactions between atoms and molecules

- hydrogen bonds (water)
- van der Waals forces (gecko feet)


2.2 Properties of Water

Video: Why Water Striders Make Terrible Lifeguards

1. Polarity

- water has a partial positive and partial negative charge
- it is a polar molecule
- forms hydrogen bonds (weak)

2. Cohesion

- surface tension (water is "sticky")
- allows some insects to walk on water

3. Adhesion

- water sticks to other things
- capillary action

4. Heat Capacity

- the amount of energy needed to change temperature
- water absorbs heat
- the surface of water can freeze, leaving liquid water underneath (for fish)

5. Universal Solvent

- many substances dissolve in water
- solutes are things that dissolve (like salt)
- creates a solution

6. Occurs in Three States

- gas (water vapor)
- liquid (pond, oceans)
- solid (ice)

* Frozen water is less dense than liquid water, so ice floats!

Water in Living Things

- organisms are mostly water
- the body's chemical reactions are dependent on water

Investigation: Water and Surface Tension

hydrogen bond

2.3 Carbon Compounds

- organic compounds (chains of carbon)
- macromolecules (large molecules)


- monosaccharides (simple sugars)
- polysaccharides (complex, multi chain sugars)

- glycogen for energy storage in animals
- starch for energy storage in plants
- cellulose for plant structure

Nucleic Acids

- information storage


- made of amino acids
- joined by peptide bonds
- example: hemoglobin

2.4 Enzymes

- speed chemical reactions that take place in cells
- Lactase is an enzyme that helps us digest milk (Lactose)

Example of Enzyme Reaction

Enzymes interact with substrates, resulting in products

enzyme reaction

Catalase + Hydrogen Peroxide --> Water and Oxygen

Oxygen creates bubbles!

Enzymes work best at OPTIMAL temperatures

Enzymes also have an OPTIMAL pH (measure of acidity)

Investigation: Enzymes