Essential Question:
What types of
molecules are in the
body?
Macromolecules
The food you eat, the
silk a spider uses to
make a web, the
muscles in your body –
all of these structures are
made of macromolecules.
Macromolecule is the term
that biologists use for
large molecules. There are
four types of
macromolecules that are
important in biology:
carbohydrates, lipids,
proteins, and nucleic acids.
Macromolecules
• Large organic molecules.
• Also called POLYMERS.
• Made up of smaller “building blocks” called
MONOMERS.
• Examples:
1. Carbohydrates
2. Lipids
3. Proteins
4. Nucleic acids (DNA and RNA)
4
Carbohydrates
Carbohydrates are a source of energy in our
diet. When we eat foods that contain
carbohydrates, the energy in them is changed
in our cells to a form that our bodies can use.
Carbohydrates also form building materials
like the chitin that covers the surface of insects
and cellulose that makes up plant cell walls.
Carbohydrates are
the group that
includes simple
sugars and more
complex molecules
made up of lots of
sugars bonded
together.
A carbohydrate
made of two
sugars is called a
disaccharide. An
example of this is
sucrose, which is
table sugar like
you may put on
your cereal or use
to make cookies.
Starch is an example of
a complex
carbohydrate made of
many linked sugars.
Plants often store
carbohydrates in the
form of starch. Eating
potatoes or grains is
the main source of
starch for
humans.
Carbohydrates
• Small sugar
molecules to large
sugar molecules.
• Examples:
A. monosaccharide
B. disaccharide
C. polysaccharide
9
Carbohydrates
Monosaccharide: one sugar unit
(from Greek: single, sacchar: sugar) are the
most basic units of biologically important
carbohydrates. They are the simplest form
of sugar and are usually colorless, watersoluble, crystalline solids. Some
monosaccharides have a sweet taste.
glucose
Examples:
glucose (C6H12O6)
deoxyribose
ribose
Fructose
Galactose
10
Carbohydrates
Disaccharide: two sugar unit
A disaccharide is the carbohydrate formed when
two monosaccharides undergo a condensation
reaction which involves the elimination of a small
molecule, such as water, from the functional
groups only. Like monosaccharides, disaccharides
also dissolve in water, taste sweet and are called
sugars.
Examples:
glucose
glucose
– Sucrose (glucose+fructose)
– Lactose (glucose+galactose)
– Maltose (glucose+glucose)
11
Fructose is a
naturally occurring
sweetener found in
fruit.
In diabetics who
have adequate
insulin available,
fructose
causes a slower rise
in blood glucose
levels than other
simple
sugars.
Maltose is a
disaccharide
with a
molecular
weight identical
to sucrose, but
it is only 30% as
sweet.
Carbohydrates
Polysaccharide: many sugar units
Examples:
starch (bread, potatoes)
glycogen (beef muscle)
cellulose (lettuce, corn)
glucose
glucose
glucose
glucose
cellulose
glucose
glucose
glucose
glucose
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The empirical or
simplest formula of
any carbohydrate is
(CH2O)n. This
formula looks like
carbon water just as
carbohydrate
suggests hydrated or
watered carbon. The
formula tells us that
all carbohydrates
are made of
carbon, hydrogen,
and oxygen atoms
in a 1:2:1 ratio.
Carbohydrate
Question:
How Are
Macromolecules
Formed?
Answer: Dehydration Synthesis
• Also called “condensation reaction”
• Forms polymers by combining
monomers by “removing water”.
HO
H
HO
H
H2O
HO
H
19
Question:
How are
Macromolecules
separated or
digested?
Answer: Hydrolysis
• Separates monomers by “adding
water”
HO
H
H2O
HO
H
HO
H
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Belgian Undertakers Want to Dissolve
& Flush Dead Into Sewers
Photo: Corbis A group of
undertakers in Belgium are
proposing a more ecological (but
perhaps creepier) alternative to
cremation: they hope to dissolve
corpses in a caustic solution and
flush the resulting liquid and
ashes down the drain, which will
be recycled at water treatment
plants. They contend that the
process - known as chemical
hydrolysis or resomation would use less energy than a
crematorium and emit no carbon
emissions. ...