Unit 1: Chemistry of Life Unit 1: Biochemistry and Digestion Unit 1: Chemistry of Life Topic 1: Nature of Matter Topic 2: Bonding and Properties of Water

Unit 1: Biochemistry and Digestion Topic 1 The Nature of Matter

What are your cells made of? Levels of Organization in Biology Biochemistry Anatomy Ecology

SPONCH What are your cells made of? 80% Water! 20% Organic compounds Unit 1: Biochemistry and Digestion OBJ 1, 2 What are your cells made of? 80% Water! 20% Organic compounds Carbon Hydrogen Oxygen Nitrogen Phosphorus Sulfur Trace Elements Iron, iodine, fluoride….. SPONCH

What makes atoms of different elements different? OBJ 3, 4 What makes atoms of different elements different? Differing numbers of Protons, Electrons and Neutrons Atomic number and mass number (atoms) (Molecules)

Ions and Isotopes Ion - charged atom Obj 5 Ion - charged atom Cation - positive, electrons lost Anion - negative, electrons gained Isotope - atoms of the same element but different mass Neutron numbers different Ex. Carbon-12 and Carbon 14

Bohr model of the Atom and Structural Formulas Bohr model of Atom Structural Formulas of Molecules Alanine (Compound) Chlorine (Element) Molecules are 3D Specific shape Remember VSEPR Glucose (Compound)

Topic 2 Bonding and Properties of Water Unit 1: Biochemistry and Digestion Topic 2 Bonding and Properties of Water

Bonding Ionic Bonds Electron transfer to fill valance shell Unit 1: Biochemistry and Digestion OBJ 6 Bonding Ionic Bonds Electron transfer to fill valance shell Ions - charged atoms Covalent Bonding Electrons are shared to fill valance shells Sharing is not always equal - Electronegativitiy EN difference between 0 and 2 = polar covalent EN difference 2.0 or greater = ionic

Unit 1: Biochemistry and Digestion OBJ 6 Polar Molecules Molecule acts like a magnet with positive and negative poles Polar molecules form hydrogen bonds with each other, giving special properties Water is involved in as many as 4 H-bonds

Properties of Water Polarity (within each molecule of water) Unit 1: Biochemistry and Digestion OBJ 7 Properties of Water Polarity (within each molecule of water) Uneven distribution of electrons Greater chance of finding electrons at one end of the molecule Due to large differences in electronegativity between the atoms ENOxygen = 3.5 ENHydrogen = 2.1 Difference = 1.5 (strong polar covalent) One of the few naturally occurring compounds that is liquid at the Earth’s surface

Obj 8/9

Unit 1: Biochemistry and Digestion OBJ 8 Cohesion Attraction between molecules of the same substance, often water Cause molecules on surface to be drawn inward, forming a bead

Cohesion Surface tension allows insects and spiders walk on surface Unit 1: Biochemistry and Digestion OBJ 8 Cohesion Surface tension allows insects and spiders walk on surface Spread their weight over a large area

Basilisk lizard! Surface tension and rapid movement OBJ 8 Unit 1: Biochemistry and Digestion OBJ 8 Basilisk lizard! Surface tension and rapid movement We would need to grow feet the size of open umbrellas and take 20 steps per second

Water conducting cells Unit 1: Biochemistry and Digestion Adhesion OBJ 8 Attraction between molecules of different substances Capillary action - causes water to rise in a narrow tube against force of gravity Water conducting cells Figure 3.3 100 µm

Water has a High Specific Heat OBJ 8 Water has a High Specific Heat 4.186 J/gC Absorbs a lot of heat Keeps coastal climates moderate (heat sink)

Water has a high heat of vaporization OBJ 8 Water has a high heat of vaporization Sweat cools your body as it turns to vapor

Ice! Ice is less dense than liquid water It floats! Unit 1: Biochemistry and Digestion OBJ 8 Ice! Ice is less dense than liquid water It floats! Density = Mass/Volume

Why does ice float? OBJ 8 Hydrogen bond Liquid water Ice Unit 1: Biochemistry and Digestion OBJ 8 Why does ice float? Liquid water Hydrogen bonds constantly break and re-form Ice Hydrogen bonds are stable Hydrogen bond

“Universal solvent” Obj 9 Substance that can dissolve many different solutes. Water - highly polar which means it can dissolve many things solute solvent solution

Obj 9

Obj 8/9

Unit 1: Biochemistry and Digestion Topic 3 Basic Chemistry

Acids and Bases Acid – produces H+ in solution Unit 1: Biochemistry and Digestion OBJ 10 Acids and Bases Acid – produces H+ in solution Ex HCl Base – produces OH- in solution Ex NaOH

7.4 pH scale Measure of the concentration of H+ compared to OH- Unit 1: Biochemistry and Digestion OBJ 10 pH scale Measure of the concentration of H+ compared to OH- Human blood = ?? 7.4

pH in Biology Ecology– Acid rain Biochemistry – acid and bases can be highly reactive with organic compounds Anatomy Blood is a buffer Stomach pH

Activity D – Mini pH Lab Groups of 2 3 separate experiments – water, buffer, milk 10 mL of substance into beaker Add drops NaOH Check pH with test strips Add your data to class data table Record class averages Sketch graph using class data Clean up Waste beaker on front table Rinse equipment Throw away trash

Chemical Reactions in Biology Obj 11 Chemical Reactions in Biology C6H12O6 + 6O2  6CO2 + 6H2O Products Reactants Reversible reactions – Equilibrium H+ + HCO3- H2CO3 H2O + CO2 Dehydration synthesis and Degradation Hydrolysis