Download Chemical Bonds

Chemical Bonds
Bonding is FUN!
Remember: Compounds form
when elements are chemically
combined.
Chemical bond- the force that joins the
atoms of a compound; bonds contain
energy.
Atoms need to have their outer
energy level filled to be stable. In
order to do this, they bond with
other atoms.
(1st level: 2 electrons, 2nd level: 8
electrons, 3rd level: 8 electrons)
3 types of Bonds
1. Covalent Bond- two atoms share electrons so
that both atoms have full outer energy levels.
Write in the side column:
Strongest type of bond
A molecule is a group of atoms held together by
covalent bonds.
A) Carbon- can form 4
covalent bonds
Methane molecule
CH4
Why does Carbon
form 4 covalent
bonds?
B) Water
Oxygen can form 2
covalent bonds
H2O
2. Ionic Bonds
Electrons are transferred from one atom to
another so that both atoms have full outer
energy levels.
Ion- a charged atom
Write in the side column:
One atom loses electrons and becomes
positively (+) charged.
The other atom gains electrons and
becomes negatively (-) charged.
Ionic bonds break apart in water.
Example: NaCl
Na transfers one electron
to Cl, making Cl attracted
to Na.
Na has 11p+ 11n and 11e-
Cl has 17p+ 17n and 17e-
Safari
Video
WOOHOO!!
Remember: so far we have
talked about 2 types of
chemical bonds
Covalent bonds – electrons are shared
Ionic bonds – electrons are transferred
Hydrogen Bond
Links 2 polar molecules together (NOT atoms!!)
Hydrogen bonds are very weak.
Hydrogen bonds only form when molecules are very
close together.
Hydrogen bonds determine shapes of proteins and
DNA.
Polar Molecule
A molecule with unequal areas of charge.
Non-Polar Molecule
A molecule with equal areas of charge.
Example
In water, electrons are
shared unevenly, so
different parts of the
molecule have different
charges.
Oxygen pulls harder on the
electrons than hydrogen. The
electrons spend more time with the
oxygen, making that area negative
and the hydrogen area positive.
Water Molecules form hydrogen bonds
between each other.
Cohesion
Attraction between water
molecules. (creates surface
tension)
Example: surface tension
Example: water forms
drops
Adhesion
Attraction of water
molecules to another
polar molecule.
Example: water sticks to
glass
Example: capillary action
Water is called the universal solvent
Many things dissolve in water because it is a
polar molecule.
Solvent= a substance in which something can be
dissolved.
Water dissolves ionic compounds like
salt (NaCl)
Water is unique because its solid form (ice) is
less dense than the liquid form.
Question: Why is this property of water important to
aquatic plant an animal life?
Specific Heat
Water has a high specific heat.
It takes more energy to heat water than other
liquids, and also to cool water down.
Water acts as an insulator and helps maintain
homeostasis in plants during extreme heat
and cold.
Why is water so important to
biology?
NFL Body Building
Macromolecule
Large molecule. There are 4 main groups of biological
macromolecules (biomolecules)
Macromolecules are made by linking smaller
molecules called monomers.
Since macromolecules are made of many
monomers, they are called polymers.
Monomers are joined together through a process called
dehydration synthesis. (synthesis=to make) ** Can also
be called condensation**
A-H + B-OH --> A-B + H2O
Polymers can be broken down into their component
parts through a process called hydrolysis. (lysis= to
break)
A-B + H2O --> A-H + B-OH
Carbohydrate Structure
Atoms in a carbohydrate: carbon, hydrogen, and
oxygen.
Monomer: monosaccharide; they can be joined
together to form complex carbohydrates called
polysaccharides. (complex sugar)
The elements in a carbohydrate are combined in a
ratio of 1:2:1 (C:H:O)
Example: a carbohydrate with 6
carbons has the formula:
C6H12O6
What would the formula be for a carbohydrate with 5 carbons?
C5H10O5
Functions of Carbohydrates
Carbohydrates, especially glucose, are the main energy
source used in the body. (monosaccharide)
2 rings= disaccharide
In animals, excess sugar (glucose) is stored as glycogen.
(polysaccharide)
Plants store sugar in the form of starch. ( glycogen and
starch are polysaccharides)
Plants use the carbohydrate cellulose to strengthen
their cell walls.
What do humans use cellulose
for?
Humans can’t digest it, so it passes through the digestive system as
fiber.
Structure of Proteins
Atoms in a protein: carbon, oxygen, hydrogen, and
nitrogen.
Monomer: amino acids
Amino acids join to make long chains that are folded
into 3-D structures. The shape of the protein
determines its function.
Function of Proteins
Proteins form bone and muscle.
Antibodies help fight off disease and are made of
proteins.
Proteins called enzymes speed up chemical reactions in
the body. (catalyst)
Hemoglobin is a protein that helps red blood cells
carry oxygen.
When you eat meat, beans, eggs, and rice you get
protein from these foods.
video clip
Gatorade/H2O
In the movie “The Water Boy”, Adam Sandler is told that Gatorade is better than
water.
After reading the information with your group, do you agree or disagree? Share with
your group, and then your group should be ready to share with the class.
Structure of Lipids
Lipids are not soluble in water. This is because water is
polar and most lipids are nonpolar.
Lipids are made mostly from carbon and hydrogen
atoms.
There are 3 categories of lipids: fats, oils, and waxes.
Fats and oils are made of smaller units (monomers) call
triglycerides.
Function of Lipids
Lipids can be used to store energy.
Lipids are important parts of biological
membranes and waterproof coverings.
Lipids also form steroids which serve as
chemical messengers in the body.
Structure of Nucleic Acids
Nucleic Acids are made of carbon,
hydrogen, oxygen, nitrogen, and
phosphorous.
Nucleic Acids are polymers made from
monomers called nucleotides.
Function of Nucleotides
Nucleic Acids store and transmit hereditary or
genetic information.
There are 2 kinds of nucleic acids: Ribonucleic
acid (RNA) and Deoxribonucleic acid (DNA)
Energy in Living Things
ATP and Metabolism
What is energy?
The ability to do work (measured in joules or
calories)
Why do cells need energy?
To move, digest, make proteins, get rid of waste
Law of Conservation of
Energy
Energy cannot be created or destroyed.
How do consumers obtain
energy? By eating other things
All molecules store energy in
bonds between atoms. The
energy in molecules is released
by breaking the bonds between
atoms. When bonds are
created between atoms, energy
is stored.
The major energy
source for all cells is a
carbohydrate called
amylose starch. To do
work, cells must
convert starch into
glucose.
How do producers obtain useable
energy?
They produce “food” through
photosynthesis with energy from the sun.
Why do lipids have more energy
per gram than carbohydrates?
Lipids have higher energy bonds and
more bonds. More bonds = more energy
stored.
ATP – Adenosine Triphosphate
– the primary source of energy
used by cells.
3 PHOSPHATES
ADENOSINE
When the last phosphate is
removed, energy is released.
+℗
ATP
ADP + Phosphate
Where does the energy in ATP
come from?
Energy from food/light is stored in chemical bonds in
ATP.
ADP + ℗ ATP
Enzymes
Objectives 6-8
Enzymes - A protein that acts as a catalyst
(speeds up chemical reactions)
Why are enzymes needed?
So reactions happen fast enough to sustain life
functions
How do enzymes work?
Enzymes lower the activation energy of a chemical
reaction. Activation Energy is the energy needed to
______
start a chemical reaction.
No enzyme
With enzyme
Finish
shape based on how
Each enzyme has a specific ________
the ________
protein is folded.
Substrate – Substance that the enzyme acts on
Each enzyme binds only to certain substrates. In
order for the substrate to bind to the enzyme it must
shape
be the right ________.
The place where the substrate binds to the enzyme is
called the active
_______ site
______
Once the enzyme and substrate bind, a reaction
occurs.
Draw a picture explaining
how an enzyme works in the
space below.
Active
site
-substrate
products
ENZYME
Example: The reaction shown below helps convert
CO2 into a form that is more easily carried through
the bloodstream. Without enzymes this reaction
wouldn’t happen fast enough and dangerous levels of
CO2 would build up in the bloodstream. The
enzyme carbonic anhydrase allows this reaction to
happen 10 million times faster.
CO2 + H2O
ENZYME
H2CO3
Video
Controlling Enzymes
Enzymes don’t always need to be “ON.” There are 2
ways to turn an enzyme “OFF.”
Competitive Inhibition –
Inhibitor
A substance other than the
substrate blocks the active site
Substrate
Non- Competitive Inhibition –
A molecule binds to a location
other than the active site and
changes the shape of the enzyme
Substrate
Inhibitor
V ideo