CHEMISTRY OF LIFE

Introduction to Biology 2

REVIEW: Think, pair, & share to complete the

“What Makes up an Atom” notes

Complete the “What Makes up an Atom” homework; Read & take notes on Chapter 2 from the book

ELECTROLYTES: WHAT ARE THEY?Is it more dangerous to swim in the ocean

or in a lake during a lightning storm?

Substances that release ions in water The electrically charged (either + or -)

ions can conduct an electric current+ ions are cations - ions are anions

For example, NaCl in H2O dissociates into Na+ and Cl-

HOW DOES THIS HAPPEN? Water is a polar molecule

Polar = electrons are not shared equally, thus the distribution of charges is uneven

Water has a unique shape due to its polarity and can form hydrogen bonds with other water molecules

The slightly charged ends of the water molecule cause the ions to separate and interact with water insteadNow that’s salty!

ELECTROLYTES IN YOUR BODY Na+ (sodium) is the major cation found

outside of cells & is necessary for the transmission of nerve impulses and muscle movement

Hypernatremia – too much sodium in the bloodstream Can simply drink more water!Usually due to dehydration

Hyponatremia – too little sodium in the bloodstream

Normal blood Na+ levels = 135-145 mmol/L

ELECTROLYTES IN YOUR BODY Potassium (K+) is the major cation

found inside cells & functions in transmission of nerve impulses and muscular function

Hyperkalemia - too much K+Kidneys may not be working properly to

secrete K+ Hypokalemia – too little K+

Kidney disease, poor diet, loss of electrolytes via excessive exercise/sweating

Normal K+ levels = 3.5 - 5.0 mmol/L

ELECTROLYTES & NERVE IMPULSES http://

brainu.org/files/movies/action_potential_cartoon.swf

http://highered.mheducation.com/sites/0072495855/student_view0/chapter14/animation__the_nerve_impulse.html

Let’s summarize this process!

ACIDS & BASES Strongest Acids:HCl, HNO3, H2SO4,

HBr, HI

Strongest Bases:

LiOH, NaOH, KOH, Ca(OH)2

What do you notice?

ACIDS ARE ELECTROLYTES …that release hydrogen ions (H+) in

water

HCl releases H+ and Cl- ions H+ donors

BASES ARE ELECTROLYTES… …that release ions that bond with

hydrogen ions called hydroxide ions (OH-)

NaOH is a base that dissociates to Na+ and OH- in water

H+ acceptors

PH & THE BODY pH measure the H+ concentration The concentration of H+ and OH- in

body fluids affect chemical reactions and bodily functions! (too acidic or too basic = very dangerous)

pH of 7 means there is an equal number of H+ and OH- ions (Neutral)

pH < 7 means there is a greater number of H+ (Acidic)

pH > 7 means there is more OH- (Basic)

BUFFERS: RESISTORS OF PH CHANGE Buffers keep the body’s pH in a safe

range Blood pH is normally at 7.4

Buffers combine with H+ ions when they are in excess (too acidic) OR they can donate H+ ions when there are too few (too basic)

If blood pH drops below 7.35, the person has acidosis

If blood pH rises above 7.45, the condition is alkalosis.

BICARBONATE BUFFER SYSTEM Bicarbonate ion HCO3- is a weak base,

accepting excess H+ ions

Carbonic acid H2CO3 is a weak acid that will donate extra H+

ORGANIC VS. INORGANIC Organic = chemicals that include both

carbon and hydrogen atoms (C and H)Macromolecules: lipids, carbohydrates,

proteins, nucleic acids

Inorganic = the chemicals that do not include both carbon and hydrogenWater, carbon dioxide, salts, oxygen, etc.

MACROMOLECULES Large molecules made up of smaller

building blocks or subunits

Define monomer

Define polymer

Make a model of a polymer, showing 3 monomers

MACROMOLECULE JOT CHART