Chapter 3 Section 1 Chemistry of life

AtomsEverything in the universe is made of tiny

particles called ATOMSStars in the skyAir you breathWater you drinkThe paper in your notebookThe atoms are so small that you cannot see them

without microscopes. If you lined up 3 million atoms side by side they would only reach across the period at the end of this sentence.

100 Different Types of ElementsEach type of atom is called an ELEMENTYou have seen them in the Periodic Table of

Elements in every Science Book at the backScientists use one or two letter abbreviations

to symbolize each element. The first letter is always capitalizedThe second letter is always lowercase

Common Elements & their symbols you need to knowHydrogen HCarbon CNitrogen NOxygen OSodium NaPhosphorus PSulfur SChlorine ClPotassium K

Calcium CaIron Fe

MoleculesMost of the substances you see are not made

of only one type of atom.Atoms bind together to form larger particles

called moleculesSome molecules have only a few atoms for ex: the air you breath has two molecules

of oxygen ex: water is made of one oxygen & two

hydrogen

Abbreviations & NumbersScientists use abbreviations and numbers to

symbolize moleculesEx; water is H20 The small 2 written below

the line after the H means that water has two hydrogen atoms

There is not a number after the O, so that means there is only one oxygen atom

GlucoseA sugar that is the major source of energy in

plants and animalsC6H12O6

It has six carbon atomsIt has twelve hydrogen atomsIt has six oxygen atomsGET IT?

QuantityIf you are dealing with more than one of the

same kind of molecule, you write the number of molecules before the symbol of the molecule

602

What do you think this means?It means we have six molecules of oxygen

WaterYour body is 70 percent water!!!It transports substances throughout your

bodyIt is VERY important for chemical reactions

to take place in your body

Water MoleculeThe atoms in a water molecule do not form a

straight lineInstead, they form a triangle

Water serves as a solvent for many other molecules. Salts and sugars can dissolve easily in water. Oils do not dissolve easily in water.

Molecules of LifeLiving things are made up of many types of

chemicalsThere are four groups that are unique to all

living thingsCarbohydratesLipidsProteinsNucleic acidsCARBON ATOMS FROM THE BACKBONE OF ALL

FOUR! THEREFORE WE CALL THEM ORGANIC MOLECULES

CarbohydratesSugarsStarchesCelluloseThe store energy

LipidsMolecules that make up fats and oilsPlants & Animals use them as fat reservesLayers of fat could insulate an animal from

extremely cold temperaturesThey are in your nerve cells, hormones & cell

membranesLipids do not dissolve in water

Heard of good fats & bad fats?Good fats are called polyunsauturated and

are liquid at room temperature. You can find them in fruits and vegetables.

Bad fats, are called saturated fats, and they cause heart disease. They are solid at room temperature and found in meats and dairy products

Saturated fat in meats- bad fats

Unsaturated fats- Good fats

ProteinsHold your skin togetherGive your bones strengthHelp you fight diseasesAre an excellent source of energyMost importantly- they control chemical

reactions in your bodyProteins are composed of long strings of units

called Amino Acids. There are 20 types of amino acids. Think of amino acids as letters and proteins as words

…proteins continuedHeat and chemicals, such as acids, can

disrupt the weak bonds between amino acidsThe protein my partially unravelIt can never again regain it’s original shapeThis happens with a fried egg. The egg white

(which is made of protein) turns from a clear liquid to a white solid. No matter how much you cool the egg it will never go back

It can never regain the shape

EnzymesEnzymes are some of the most important

proteins in all living thingsThey break down foodRepair tissueManufacture chemicalsWithout enzymes, all chemical activity would

stop in your body

Enzymes continued…All chemical reactions need energy to get

going. A tsp of sugar will eventually break down into

carbon dioxide and water but could take millions of years

Your body cannot wait that long to break down sugars for your energy

Instead they use ENZYMES

What do enzymes do?Enzymes are proteins that speed up reactions

by reducing the amount of energy needed for these reactions to take place

Each enzyme can trigger only one type of reaction. Much like one key only fits into a certain lock. One type of molecule can bind to one type of enzyme