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You Are What You Eat:
A look at food and the digestive system
Today’s Lecture:
FOOD
Text Ref: Sec 6.1
In this section, you
will:
•describe the
chemical nature of
carbohydrates,
lipids, and proteins
•explain, in general
terms, how
carbohydrates,
lipids, and proteins
are synthesized and
how they are broken
down (hydrolyzed)
You Are What You Eat:
A look at food and the digestive system
Thought Web:
A blood test analysis
can tell us what an
individual’s diet is like.
What kind of things do
you expect to find in
blood?
How do we classify
them?
You Are What You Eat:
A look at food and the digestive system
Classifying the food we eat: Macromolecules
Macromolecules are large, complex assemblies of organic
molecules.
The four categories are:
Carbohydrates
Proteins
Lipids
Nucleic Acid
You Are What You Eat:
A look at food and the digestive system
Let’s Learn A little More about Macromolecules.
Time to digest some food and find out what’s inside!
You Are What You Eat:
A look at food and the digestive system
Questions Answered:
1. Examples of foods containing your macromolecule.
2. Main function of your macromolecule
3. Subunits of your macromolecule
4. Interesting Facts
You Are What You Eat:
A look at food and the digestive system
Carbohydrates:
1. Examples of foods containing your macromolecule.
2. Main function of your macromolecule
3. Subunits of your macromolecule
4. Interesting Facts
You Are What You Eat:
A look at food and the digestive system
Proteins:
1. Examples of foods containing your macromolecule.
2. Main function of your macromolecule
3. Subunits of your macromolecule
4. Interesting Facts
You Are What You Eat:
A look at food and the digestive system
Lipids:
1. Examples of foods containing your macromolecule.
2. Main function of your macromolecule
3. Subunits of your macromolecule
4. Interesting Facts
You Are What You Eat:
A look at food and the digestive system
Nucleic Acids:
1. Examples of foods containing your macromolecule.
2. Main function of your macromolecule
3. Subunits of your macromolecule
4. Interesting Facts
You Are What You Eat:
A look at food and the digestive system
Macromolecule
Example(s) of
subunits
Main functions
Examples of
macromolecules
carbohydrates
monosaccharides
energy storage
sugars, starches, and
Let’s Learn
A little More about
Macromolecules.
(such as glucose) and
glycogen
polymers of glucose
lipidsTime
glycerol and
three fatty
energy
storage
and
cellwhat’s
fats, oils,
and
to digest
some
food
and
find
out
inside!
acids or glycerol and
membranes
phospholipids
two fatty acids
proteins
polymers of amino
transport, blood clotting,
hemoglobin, fibrin,
Mrs. Baker
will
let
you
know
how
this
will
work!
acids
support, immunity,
collagen, antibodies,
nucleic acids
polymers of
nucleotides
catalysis, and muscle
action
enzymes, actin, and
myosin
transfer and expression
of genetic information
DNA and RNA
You Are What You Eat:
A look at food and the digestive system
The Making and The Breaking of Macromolecules
• Even though the macromolecules look different, they
are all made and broken down in the same way:
1. Anabolic reaction – synthesis of macromolecules
• Occurs through the removal of water
2. Catabolic reaction – breakdown of macromolecules
• Occurs through the addition of water
You Are What You Eat:
A look at food and the digestive system
1. Anabolic reaction – synthesis of macromolecules
• Occurs through the removal of water (called
dehydration synthesis):
2. Catabolic reaction – breakdown of macromolecules
• Occurs through the addition of water (called
hydrolysis):
In our cells, large molecules are
built by dehydration synthesis
and broken down by hydrolysis.
• Starch, a carbohydrate
polymer, is made of many
glucose monomers linked
together in long chains.
• Proteins or polypeptides are
polymers of many amino acid
monomers linked together.
• Polymers like fats and nucleic
acids (DNA and RNA) follow
the same rule.
• All of these large molecules
are made of small building
blocks called monomers.
You Are What You Eat:
A look at food and the digestive system
The Making and The Breaking of Carbohydrates
You Are What You Eat:
A look at food and the digestive system
The Making and The Breaking of Carbohydrates
The branching of
glucose molecules is
the main difference
between different types
of carbohydrates.
You Are What You Eat:
A look at food and the digestive system
The Making and The Breaking of Lipids (Fats)
You Are What You Eat:
A look at food and the digestive system
The Making and The Breaking of Proteins
You Are What You Eat:
A look at food and the digestive system
Task Review
You will be assigned one of the following molecules:
1. Disaccharide from two molecules of glucose
2. Triglyceride from one molecule of glycerol and three
fatty acid molecules
3. Dipeptide from two amino acid molecules
You will have to sketch a representation of the
dehydration synthesis and hydrolysis of the
molecule on an index card (use textbook sec 6.1).
Each table should end up with a complete set of review
cards.
You Are What You Eat:
A look at food and the digestive system
Preserving our Macromolecules
• Most food in raw form spoils very quickly in one of
two ways:
1. Growth of microorganisms (bacteria, fungus)
2. Breakdown of fats (rancid food)
• There are a wide variety of methods for preserving
food to increase the shelf life.
You Are What You Eat:
A look at food and the digestive system
Methods of Preservation
1. Chilling/freezing to prevent bacterial growth
2. Heating/cooking at high temperature to kill growth
3. Sealing food from air to prevent microorganisms
4. Use of trans-fats to prevent food from going rancid
5. Putting large amounts of salt to dehydrate food
6. Change pH (make foods more acidic or basic)
7. Expose food to ionizing radiation
8. Addition of preservative chemicals
You Are What You Eat:
A look at food and the digestive system
Your Task:
1. Check out the packaging on the food items I give
you.
2. Look for clues to see how these foods are preserved
for a long shelf life (check ingredient list, examine
packaging, and read directions for clues).
3. Come up with your best inference (guess) on how
your item is preserved.
CHECK OUT THE HISTORY OF FOOD PRESERVATION (Takes a few
Minutes to load)