Biochemistry

VOCAB Chapter 2: The chemistry of life All bold highlighted words and definitions

Matter Elements & Compounds Takes up space Has mass Atoms Basic unit of matter Protons, Neutrons, Electrons Element Can not be broken down by chemical rxns Examples ? Compound Two or more elements combine in fixed ratio

Elements and Compounds Sodium Chlorine chloride

Elemental Properties 2 Atomic number He Atomic mass 4.00 Element symbol Electron- distribution diagram Atomic mass 2 He 4.00

Bonds Covalent Bond Chemical bonds: Interactions between valance electrons Chemical bonds form molecules Covalent Bond Valance electrons shared Non polar covalent: equally shared e- Polar covalent: unequal sharing due to electronegativity  – O + +

Scientific Method Review Come up with TWO experimental scenarios. Write a paragraph describing each experimental situation. Under each paragraph identify and write out the following points. 1. Hypothesis (If…then…) 2. Independent variable (What is being manipulated) 3. Dependent variable (What is measured) 4. Control group 5. Experimental group 6. What are 5 things that would need to be kept constant 7. What are two possible conclusions for this experiment.

WATER

Structure of Water Structure key to special properties Polarity Uneven distribution of electrons between hydrogen and oxygen Allows water to dissolve many substances Hydrogen bonding Important to giving water its special properties Each molecule can form max 4 Common in water

H O H  –  +  –  +  –  +  –  + Hydrogen bond —— —— Fig. 3-2 Figure 3.2 Hydrogen bonds between water molecules  –  +

Properties of Water Versatility as a Solvent 4. Water as a solvent Solvent Solute Solution

Properties of Water Cohesive Behavior Cohesion Water linked to water Responsible for surface tension Partial charges make water “sticky” Adhesion Clinging of one substance to another Rainex Transpiration

Adhesion Water-conducting cells Direction Cohesion of water movement Fig. 3-3 Adhesion Water-conducting cells Direction of water movement Cohesion Figure 3.3 Water transport in plants 150 µm

Other uses of water to living things regulates body temperature maintains cell turgidity used to maintain shape of proteins transports nutrients provides environment for chemical reactions (most important for cells)