Chemistry of Life

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Transcript Chemistry of Life

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.
2.
3.
4.
•
These are the fundamental molecules of life that you will
be required to know.
•
•
Fats
Proteins
Sugars
Nucleic Acids.
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
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.
•
•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.
•
Quick check 
What are the parts of an atom?
B
C
A
D
•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?
•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.
•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
#
• # electrons
• # neutrons
= # protons
= # protons
= atomic mass - # protons.
Quick Check
Identify 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 protonelectron numbers don’t match.
•
•Formation of Ions: Count the p+ & ebefore & after the exchange…
Anion:
A negatively
charged ion.
Cation:
A positively
charged ion.
+
Na
Cl
Sodium
Before
After
Chlorine
Before
After
Protons
+11
+11
Protons
+17
+17
Electrons -11
-10
Electrons -17
-18
Total
+1
Total
-1
0
0
•The Numbers Really Matter
• The
numbers represent an atom’s proton,
neutron, and electron number when it is unbounded 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
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-
-
+++
+++
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+++
+++
-
-
-
-
-
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Different Orbits
Same 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 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.
•
•
•
•
•
•
•
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
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?