The Chemistry of Life

Unit Objective:• To identify the carbon-based organic molecules of life and

understand the roles they play in life processes.

What do YOU need today? • white board• marker• your notebook

•The Basic Compounds of Life.• Regardless of the amount, most organisms are

composed of and use several important molecules.1. Fats

2. Proteins

3. Sugars

4. Nucleic Acids.

• These are the fundamental molecules of life that you will be required to know.

• These carbon-based molecules are known as Organic Compounds.

• Another molecule you will learn about in this unit is water.

•Before You Learn About the Organic Macromolecules…• You must understand that all bigger molecules are built of smaller pieces.

• Everything of atoms…• Sometimes arranged into basic molecules.

• These smaller pieces are called…

• These will sometimes be called…

• What is a subunit?• Something that is combined with other subunits to build

something bigger.

Quick check Let’s test you..

Place the following in order from smallest to biggest

• Element• Macromolecule• Atom• Compound

•Atoms

• All matter is made of very small particles called atoms.

• These are the most basic subunit of everything, including life.

• An atom is the smallest unit of matter that cannot be broken down by chemical means.

• Every living and nonliving thing is made of matter. • Matter is anything that has mass and takes up space.

•Atoms• The atom is composed of three main types of smaller particles.

• Protons: positively charged particles.

• Neutrons: particles with no charge.

• Electrons: negatively charged particles.

•Atoms• The particles are in two specific areas:

• The nucleus.• The electron cloud.

• Protons and neutrons are in the nucleus.• Electrons are in various energy levels contained in the electron cloud around the nucleus.

•Atoms, continued• 99+% of the atom’s mass is made up

of the protons and neutrons found in the nucleus.

• The other <1% of the atom’s mass is found by adding up all the individual electrons.

• The nucleus takes up less than 1% of the atom’s physical space

• 99+% of the atoms actual space is the electron cloud where the electrons are zooming around at nearly the speed of light.

• Technically, we are 99% empty space!

Electron Cloud

Nucleus

•Quick Facts. Put an atom into perspective.• If you used a stadium to model and atom…

• The Houston Astrodome (Home of the Houston Astros…a baseball team) seats 60,000 fans, covers 9 acres and the dome rises to a height of 200ft.

• If you could blow up an atom to the size of this stadium a basketball could represent the volume of an atom's nucleus.

• The rest of the open area is the volume of where the electrons, maybe the size of tiny BB’s, would be constantly flying around at speeds approaching the speed of light through the electron cloud in their orbitals.

++

+++

+

B

C

D

A

What are the parts of an atom?

Quick check

•Why Do Things Feel Solid?

We actually feel very little that is solid.What we feel is the interpretation of what solid is because of the electron clouds pushing away from one another.Which segues into the next part of the lesson.

•How Is an Atom Built?• Find carbon on the periodic table.• This is the information for the element CARBON• Notice its row and column.

• Every box represents a different element.• An element is any quantity of a substance that is 100%

the same type of atom.• Being the same type means they have the same # of

protons. • Ex: Diamonds are always the element carbon, regardless of the

size, because every atom has 6 protons.

• Quick check

What is the difference between an atom and an element?

• The six highlighted below are the most abundant elements in the bodies of most biological organisms.

• Take out the periodic tables & Mark these in your Periodic Table.

•CHNOPS: What are the Most Abundant Elements in Biology?

•Reading the Periodic Table• Atomic Number• Symbol• Name• Atomic Mass

•Atomic Numbers, Mass, Electrons…• The boxes give a lot of information.• How do you know how many protons, electrons, and neutrons an element has?

• It’s all based upon the atomic number found in the periodic table.

• Atomic # = # protons • # electrons = # protons• # neutrons = atomic mass - # protons.

Quick CheckIdentify the atomic number for the 6 most abundant elements in living organisms.

•What Happens When an Atom Gains or loses an Electron is Ionic.• Rarely are atoms completely happy.• They like to be in relationships.• They are usually flying around or bouncing off on another

interacting with each other.• When this happens electron clouds interact.• Sometimes electrons will transfer between atoms in this

interaction.• When than happens is the electron-proton numbers don’t

match anymore. • This forms ions.• Ions are atoms that have a charge because the proton-

electron numbers don’t match.

•Formation of Ions: Count the p+ & e- before & after the exchange…

Sodium Before After Chlorine Before After

Protons +11 +11 Protons +17 +17

Electrons -11 -10 Electrons -17 -18

Total 0 +1 Total 0 -1

Na+ Cl-

Cation:A positively charged ion.

Anion:A negatively charged ion.

•The Numbers Really Matter• The numbers represent an atom’s proton, neutron, and electron number when it is un-bounded and electrically neutral.

• Atoms are rarely like this, stable, in nature.• Mainly because the electrons are always flying around.

electron

•Bohr’s V. Rutherford’s

++

+++

+

-

-

--

-

-

-

-

++

+++

+

-

-

--

-

-

-

-

Different OrbitsSame Orbit

++

+++

+

•Where electrons actually are…Schrödinger• Q: Can you

identify where the electron is?

• A: No! because the electrons never stop moving!

•The Outer Ring… The Valence Shell• Remember, electrons are orbiting the nucleus in the

region called the electron cloud... In different energy levels (orbitals).

• The outer ring is the important one. • It is the valence shell• This shows you the valence shell electrons.• In the valence shell bonding happens.

•The Outer Ring

• The column determines the valence shell electrons.• Group 1A (hydrogen, etc.) has one valence electron.• Group 2A (beryllium, etc.) has two.• This rule only applies to A groups though.• How many valence electrons does phosphorus have?• A: 5

• The outer most edges of this cloud is called the valence shell.

• There is a strict rule for how many electrons are in this valence shell.

• For most groups of atoms, you can determine the # of valence shell electrons from the column it’s in.

Quick Check

Can you demonstrate how to show electrons on a diagram like this?

Try demonstrating CARBON. GO!

Quick Write

On your own piece of paper, answer the following and turn into the box:

1. Explain the basic structure of an atom.

2. If we are 99.9% empty space, explain how it is we “appear” solid.

3. Identify 3 things that the periodic table of elements can show you?

4. Explain the significance of the valance shell?