The Chemistry of Life

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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

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The Basic Compounds of Life.

• Regardless of the amount, most organisms are
  composed of and use several important molecules.
• Fats
• Proteins
• Sugars
• 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.

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Objectives

• Essential Questions

• How does hydrogen, carbon, and oxygen combine to
  form molecules that participate in living
  systems?
• What do these molecules do to support life?

• To review/identify what makes up matter.
• To know the elements that form most organic
  molecules.
• To review/understand why atoms form bonds.
• To understand how and why these bonds are
  essential for life by forming the carbon-based
  organic molecules of life.
• This information will help you soon be able to
  explain how these molecules participate in
  important processes in living things.

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Vocabulary

• Atoms
• Element
• Valence electrons
• Compound
• Molecule
• Ion

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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.

BUILDING BLOCKS
SUBUNITS
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Quick check ?

• Lets test you..
• Place the following in order from smallest to
  biggest
• Element
• Macromolecule
• Atom
• Compound

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Atoms

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

• 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.

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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.

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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.

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Atoms, continued
Electron Cloud

• 99 of the atoms mass is made up of the protons
  and neutrons found in the nucleus.
• The other lt1 of the atoms mass is found by
  adding up all the individual electrons.
• The nucleus takes up less than 1 of the atoms
  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!

Nucleus
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Quick Facts. Put an atom into perspective.

• If you used a stadium to model and atom
• The Houston Astrodome (Home of the Houston
  Astrosa 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 BBs, would
  be constantly flying around at speeds approaching
  the speed of light through the electron cloud in
  their orbitals.

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Quick check ?
B
What are the parts of an atom?
C
A
D
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Technically, We Are 99.9 Empty Space?

• Why do we appear solid?

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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.
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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.

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• Quick check ?
• What is the difference between an atom and an
  element?

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CHNOPS What are the Most Abundant Elements in
Biology?

• 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.

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Reading the Periodic Table

• Atomic Number
• Symbol
• Name
• Atomic Mass

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Atomic Numbers, Mass, Electrons

• The boxes give a lot of information.
• How do you know how many protons, electrons, and
  neutrons an element has?
• Its all based upon the atomic number found in
  the periodic table.
• Atomic protons
• electrons protons
• neutrons atomic mass - protons.

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Quick Check?

• Identify the atomic number for the 6 most
  abundant elements in living organisms.

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

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Formation of Ions Count the p e- before
after the exchange
Anion A negatively charged ion.
Cation A positively charged ion.
Sodium Before After Chlorine Before After
Protons 11 11 Protons 17 17
Electrons -11 -10 Electrons -17 -18
Total 0 1 Total 0 -1
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The Numbers Really Matter

• The numbers represent an atoms 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
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Bohrs V. Rutherfords
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Same Orbit
Different Orbits
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Where electrons actually areSchrödinger

• Q Can you identify where the electron is?

• A No! because the electrons never stop moving!

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The Energy Levels

• Atoms are usually represented as a nucleus
  surrounded by rings.
• The rings are energy levels.
• The row (going from top to bottom) tells you how
  many rings the atom has.
• Hydrogen is in the 1st row one ring
• Nitrogen is in the 2nd row two rings
• Shown to the right.
• How many rings does iodine have?
• These are the atoms energy levels.

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Reading the Periodic Table

• The Column tells you how many electrons in the
  outer shell (valence electrons).
• The Row tells you how many rings (Energy levels)

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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.

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The Outer Ring

• 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 its
  in.

• 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

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Concept Check

• On your handouts (back side of the periodic
  table), complete the blank atom for the element
  carbon.
• Draw the
• Correct of electrons
• Correct of electron in the valence shell
• Correct of protons
• Correct of neutrons
• Put them in the correct places.

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Quick Check ?
Can you demonstrate how to show electrons on a
diagram like this? Try demonstrating CARBON. GO!
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Quick Write

• On your own piece of paper, answer the following
  and turn into the box
• Explain the basic structure of an atom.
• If we are 99.9 empty space, explain how it is we
  appear solid.
• Identify 3 things that the periodic table of
  elements can show you?
• Explain the significance of the valance shell?