The Chemistry of Life

What makes up an atom?

An atom is made of two main areas:

-Nucleus

-The nucleus contains Protons and Neutrons.

Proton is positively charged

Neutron has no charge

-Electron Energy Levels

-hold the electrons.

Electron is negatively charged

PARTICLES CONT.

• THE NUMBER OF PROTONS IN THE NUCLEUS OF AN ATOM IS EQUAL TO THE ATOMIC NUMBER

• EACH ELEMENT IS DIFFERENT

ELECTRON CLOUD

• ELECTRONS MOVE AROUND THE NUCLEUS IN A CLOUD

• THEY OCCUR IN DIFFERENT ENERGY LEVELS

More on electrons….

• An atom is said to be stable when its outermost energy level is full.

• We know how many electrons an element has by looking at the Periodic Table…

How to figure out atomic particles

• The atomic number = # of Protons and under normal circumstance, the

• # of Protons = the # of Electrons.

• We can tell how an atom will bond with other atoms by looking at how many electrons are in the outermost energy level (valence electrons)

Combining of elements

• There are several different types of bonds. The first two are called Ionic and Covalent.

• Covalent bonds occur when two or more atoms will SHARE their electrons to complete their outermost energy levels

Bonding continued…

• Ionic Bonds however, do not share.

• One of the atoms will give up an electron and the other will take it away…leaving the two atoms electrically charged.

• This charge holds them together… remember opposites attract.

• Like Sodium and Chlorine

Mixtures Vs. Solutions

• A mixture is when you have a combination of more than one substance, but are not combined chemically…

• You can still see each of the different substances (like a salad)

• -A solution is when one or more substances are distributed evenly with one another…

• You cannot see each substance (like Chocolate Milk)

Water

• Water is called a polar molecule

• Polar Molecule: when there is an unequal distribution of charge in a molecule

• Water is polar because the oxygen pulls the electrons from hydrogen more than the hydrogen pulls…

• This gives water some pretty strange properties…

Water Continued…

• Water resists temperature changes

• Water expands when it freezes

• Water is “sticky”

• Because it is polar, the molecules are electrically attracted

• This means that they can hang onto one another.

Diffusion

• The movement of molecules from areas of high concentration to low concentration

• Diffusion is a slow process and only works really well over short distances…

• (With enough time it can work over long distances though…lots of time…)

• Diffusion will continue until

• Dynamic Equilibrium occurs

• -This is when there is no difference in concentration.

• Remember: An atom is unstable unless its outermost energy level is full.

• To make an energy level full, most atoms need 8 electrons in the outer level.

• The element carbon has 4 valence electrons (outer most electrons).

• This means that carbon can bond with many different types of element to create a full energy level.

• In fact carbon is so great at making bonds that every known living thing uses carbon as its main ingredient. Even humans are carbon-based.

Types of compounds

• Polymers

Remember Legos? Small pieces that came together to create one large object…

That’s a polymer. A polymer is when smaller molecules come together to make one large molecule.

Carbohydrates:

• A carbon-based (organic) compound made from hydrogen, oxygen and carbon.

• “Carbs” are used to store and release energy.

• Carbohydrates come in many forms, the smallest it the monosaccharide.

• Two monosaccharides can combine to create a disaccharide…

• Or many monosaccharides could come together to form a polysaccharide.

• Lipids

• (A.K.A. Fats)

• Cells use lipids for energy storage, insulation, and protective coatings.

Proteins

• A protein is a type of polymer that is made up of Amino Acids.

• Proteins are the building blocks for most of the structures in an organism.

• (Muscles, chemical reactions, regulation of the body systems)

• Enzymes are special proteins that can change the rate of reactions in the body.

• Enzymes are involved in almost every body process…from digestion to breathing

Nucleic Acids:

• Type of polymer made up of small units called nucleotides.

• Used to store vital cell information.

• DNA and RNA are types of nucleic acids