Chapter 6:
The Chemistry of Life
Georgia Standards:
The learner will identify the structure & function
of the four major macromolecules (i.e.,
carbohydrates, proteins, lipids, nucleic acids).
Essential Questions:
How does the structure of a carbohydrate influence
its function?
What are the roles of carbohydrates in living things?
Why is Chemistry
important to Biology?
• Life depends on chemistry.
• The first job of a biologist is to
understand the chemistry of life.
Carbon Compounds &
Organic Chemistry
• What is organic chemistry?
• Organic chemistry is the study of all
compounds that contain bonds
between carbon atoms.
Properties of Carbon
Compounds
1.Carbon atoms have
four valence
electrons to make
4 bonds.
3. Carbon atoms can
bond to other
carbon atoms
4. Chains of carbon
2. Carbon can bond
atoms can even
with many elements
close upon
including hydrogen,
themselves to form
oxygen,
rings
phosphorus, sulfur,
and nitrogen
What is a Macromolecule?
• Many of the molecules in living cells
are so large that they are known as
macromolecules (large molecules)
• Monomers + Monomers = polymers
Polymerization - to form polymers.
Types of Macromolecules
in Living Systems
• Four groups of organic compounds
found in living things are
–
–
–
–
Carbohydrates
Lipids
Nucleic acids
Proteins
What are Carbohydrates?
• Carbohydrates are • Living things use
carbohydrates as
compounds made up
their main source of
of carbon,
energy.
hydrogen, and
oxygen atoms,
usually in a ratio of • Plants and some
animals also use
1 : 2 : 1.
carbohydrates for
structural purposes.
Carbohydrates
• Starches and
sugars are
examples of
carbohydrates
that are used by
living things as a
source of energy.
• Single sugar =
monosaccharides
(simple sugar)
– Glucose
– Galactose
– Fructose
Carbohydrates
• Polysaccharides
(complex sugar)
– Forms when
monosaccharides
link together
• Animals store
excess sugar as
glycogen.
• Plants store excess
sugar as starch.
– Cellulose
Starch
Glucose
Go to
Section:
Molecular Model Building
• Use the molecular model kit to build
glucose
–
–
–
–
Carbon = black
Oxygen = blue
Hydrogen = white
Electron bond = white plastic tube
#6 question to WS
• The structural arrangement of C, H, and O in
glucose, fructose, and galactose differs. This
helps explain why different model shapes are
used for each monosaccharide.
• Molucules of monosaccharides may have the same
molecular formula but differ in the 3D structure.
This is called isomerism. Using the three models
and structural formulas, describe isomerism in
your own words.
Ticket out the Door
Frayer Model on Carbohydrates
Warm-up:
1. What properties of carbon explain
carbon’s ability to form many
different macromolecules?
2. Why do living things need
carbohydrates?
Lipid Function:
• Lipids can be used
• Examples:
to
– store energy
– Body Fats
– Oils
– Form biological
– Waxes
membranes
– Steroids
– Form waterproof
– Testosterone
coverings
– Chlorophyll
– Steroid Hormones – Cell
membrane
– Pigments
Lipid Structure:
• Lipids are made mostly from:
– Carbon, hydrogen, & oxygen atoms
– Monomers of fatty acids &
Glycerol
• Many lipids are formed when a glycerol
molecule combines with compounds
called fatty acids.
Lipid Structure
Types of Lipids
• Saturated
– Carbon-carbon single
bonds
– All carbons are
completely surrounded
by hydrogen
– Solid at room temp
• Lard
• Unsaturated
– Carbon-carbon double
or triple bonds
– All carbons are not
completely
surrounded by
hydrogen.
– Liquid at room temp
• Olive oil
Fats in Foods Lab
• See Handout
Nucleic Acids
• Contain hydrogen,
oxygen, nitrogen,
carbon, and
phosphorus.
• Monomers of
nucleotides
– 5-carbon sugar
– Phosphate group
– Base
• Nucleic acids store
and transmit
hereditary, or
genetic, information.
• Ribonucleic acid
(RNA)
• Deoxyribonucleic acid
(DNA).
Nucleic Acid
Strawberry DNA
Extraction Lab
• See Handout
Proteins
• Proteins control the
rate of reactions
• Made of carbon,
hydrogen, nitrogen,
and oxygen.
• Monomers = amino
acids
– 20 different amino
acids
• Regulate cell
processes.
• Form bones and
muscles.
• Transport substances
into or out of cells
• Help to fight
diseases.
Amino Acids
Amino group
Carboxyl group
General structure
Alanine
Serine
Amino Acids (monomers) are linked by peptide bonds to
form proteins (polymers).
Go to
Section:
Levels of Proteins
• Proteins can have up
to four levels of
organization.
• Primary level is the
sequence of amino
acids in a protein
chain.
• Secondary level is the
amino acids within a
chain can be twisted
or folded.
• Tertiary level is
when the chain
itself is folded.
• Quaternary level is
when two or more
folded chains
interact.
Examples:
• Structural:
• Functional:
– enzymes
– Collagen, Keratin,
myosin,
Figure 2-17 A Protein
Amino
acids
Go to
Section:
Concept Map
Carbon
Compounds
include
Carbohydrates
Lipids
Nucleic acids
Proteins
Monomers of
Monomers of
Monomers of
Monomers of
Sugars and
starches
Fats and oils
Nucleotides
Amino Acids
which contain
which contain
Carbon,
hydrogen,
oxygen
Go to
Section:
Carbon,
hydrogen,
oxygen
which contain
which contain
Carbon,hydrogen,
oxygen, nitrogen,
phosphorus
Carbon,
hydrogen,oxygen,
nitrogen,
Checkpoint!!!
1.
Name four groups of organic compounds found in
living things.
2. Describe at least one function of each group of
organic compounds.
3. What properties of carbon explain carbon’s
ability to form many different macromolecules?
4. Explain why proteins are polymers but lipids are
not.
Chapter 6:
The Chemistry of Life
Georgia Standards:
•Explain how enzymes (functional proteins)
function as biological catalysts.
Essential Questions:
• How does the enzyme-substrate complex work?
•Why are enzymes important to living things?
Chemical Reactions & Enzymes
• A chemical
reaction is a
process that
changes one set of
chemicals into
another set of
chemicals.
• Chemical reactions
always involve the
breaking of bonds
in reactants and
the formation of
new bonds in
products.
Chapter 6
Chemistry in Biology
6.2 Chemical Reactions
Chemical Equations
 Chemical formulas describe the substances in
the reaction and arrows indicate the process of
change.
 Reactants are the starting substances, on the
left side of the arrow.
 Products are the substances formed during the
reaction, on the right side of the arrow.
Chapter 6
Chemistry in Biology
6.2 Chemical Reactions
 Glucose and oxygen react to form carbon
dioxide and water.
Chapter 6
Chemistry in Biology
6.2 Chemical Reactions
Balanced Equations
 The law of conservation of mass states matter
cannot be created or destroyed.
 The number of atoms of each element on the
reactant side must equal the number of atoms
of the same element on the product side.
Chapter 6
Chemistry in Biology
6.2 Chemical Reactions
Energy of Reactions
 The activation
energy is the
minimum amount of
energy needed for
reactants to form
products in a
chemical reaction.
Chapter 6
Chemistry in Biology
6.2 Chemical Reactions
 This reaction is
exothermic and
released heat
energy.
 The energy of the
product is lower than
the energy of the
reactants.
Chapter 6
Chemistry in Biology
6.2 Chemical Reactions
 This reaction is
endothermic and
absorbed heat
energy.
 The energy of the
products is higher
than the energy of
the reactants.
Energy in Reactions
• Chemical reactions
that release
energy often occur
spontaneously
– Exothermic
– Feels warm to the
touch
• Chemical reactions
that absorb energy
will not occur
without a source of
energy.
– Endothermic
– Feels cools to the
touch
Enzymes
• Enzymes are
proteins that act
as biological
catalysts
– Functional protein
• Cells use enzymes
to speed up
chemical reactions
that take place in
cells, by lowering
the activation
energy (energy
needed to start a
reaction)
Chapter 6
Chemistry in Biology
6.2 Chemical Reactions
Enzymes
 A catalyst is a substance that
lowers the activation energy
needed to start a chemical
reaction.
 It does not increase how
much product is made and it does not get used
up in the reaction.
Section 2-4
Effect of Enzymes
Reaction pathway
without enzyme
Activation energy
without enzyme
Reactants
Reaction pathway
with enzyme
Activation
energy
with enzyme
Products
Go to
Section:
Chapter 6
Chemistry in Biology
6.2 Chemical Reactions
 The reactants that bind to the enzyme are called
substrates.
 The specific location where a substrate binds on an
enzyme is called the active site.
Chapter 6
Chemistry in Biology
6.2 Chemical Reactions
 The active site changes shape and forms
the enzyme-substrate complex, which helps
chemical bonds in the reactants to be
broken and new bonds to form.
 Factors such as pH, temperature, and other
substances affect enzyme activity.
Enzyme Action: How do enzymes
do their job?
• Enzymes are very
specific.
• Enzymes must collide
with enough energy so
that old bonds can be
broken and new bonds
can be formed.
• Enzymes have an
active site where the
substrate (reactant)
will bind.
• Activation energy is
reduced
Section 2-4
Enzyme Action
Enzyme
(hexokinase)
Glucose
Substrates
Products
ADP
Glucose-6phosphate
Products
are released
ATP
Active site
Enzyme-substrate
complex
Substrates
are converted
into products
Go to
Section:
Substrates
bind to
enzyme
Chapter 6
Chemistry in Biology
Classwork:
Complete the Regulation of
Enzyme Handout
• pH
• Temperature
• Other proteins turn enzymes “on” and
“off”
Checkpoint!!!
1. What happens to chemical bonds during chemical
reactions?
2. Describe the role of energy in chemical
reactions.
3. What are enzymes, and how are they important
to living things?
4. Describe how enzymes work, including the role of
the enzyme-substrate complex.
5. A change in pH can change the shape of a
protein. How might a change in pH affect the
function of an enzyme such as hexokinase?
Enzyme Lab
• See Handout