Macromolecules: An Introduction to Cell Products - School Web Sites

Macromolecules: An
Introduction to Cell Products
9-11 PS 2F: All forms of life are composed of large
Molecules that contain carbon. Carbon atoms bond
To each other and other elements by sharing electrons,
Forming covalent bonds. Stable molecules of carbon
Have four covalent bonds per carbon atom.

Nutrients: The Matter of Life
In order for organisms to grow, function and
reproduce, certain raw materials are
required.
These raw materials provide:
1. Energy: For movement, work, cellular
processes, growth and reproduction.
2. Building materials: To make the raw
materials to make cells and tissues (skin,
muscle).

ORGANIC COMPOUNDS
• These raw materials have many names and
titles, but because they are manufactured by
living cells these macromolecules are
referred to as ORGANIC COMPOUNDS
All of these compounds come from our diet,
the foods we eat and are broken down by our
digestive system, and then reassembled into
the building blocks to make our cells and
tissues.

ORGANIC COMPOUNDS
• There are three categories of organic compounds:
1. Carbohydrates: Primarily used as the fuel to
make our cells and bodies function. “Glucose” is
the molecule that serves as the primary cellular
fuel.
2. Proteins: Primarily used as the building materials
for our cells and tissues.
a. Enzymes: Used to speed up the chemical
reactions in our cells.
3. Lipids: Primarily used as a building material for
our cells and tissues.

How are organic compounds
manufactured by our cells?
• Our cells are actually complex working
machines. Inside these “machines” are
small structures called ORGANELLES, that
have specific functions and responsibilities.
• The organelles take the raw materials to
break down and reassemble them into
specific products that end up being
carbohydrates, proteins, lipids or enzymes.

Take It From the Top
• This is where the
creation of the
organic compounds
begins.
The foods you eat are the source of the raw materials that
will eventually become the carbohydrates to fuel your
activities, proteins to make muscle and skin, enzymes
to make your metabolism function and lipids to create cells.

Digestion
Digestion is the process where our bodies take
large, complex molecular mixtures and break
them down into their individual organic
building blocks.
There are two types of digestion:
1. Mechanical Digestion: Your teeth grinding
and crushing food, as well as the stomach
squeezing the food you have swallowed.
2. Chemical Digestion: Enzymes and digestive
juices in your saliva and digestive tract that
break apart the chemical bonds that hold the
molecules together.

The Digestive System
The digestive system is
a series of glands and
organs that are
responsible for
taking the food you
eat and breaking it
down into it’s
individual molecular
components.

Organs of the Digestive System
1. Mouth: site where both
mechanical (chewing)
and chemical
(saliva)digestion begin.
2. Salivary Glands: Produce
saliva for chemical
digestion (starch/carbs).
3. Esophagus: Muscular
tube that squeezes food
into the stomach.
3b. Stomach: Site of
mechanical and chemical
digestion (stomach acids
and enzymes).

Organs of the Digestive System
4. Small Intestine:
Digestion finishes here,
then the newly broken
down nutrient molecules
are absorbed into the
bloodstream to be carried
to the cells.
5. Large Intestine: Site
where water is absorbed
from the remains of the
digested waste.

Organs of the Digestive System
6. Liver: Produces bile to
break down fats (lipids)
and converts extra
glucose into glycogen.
7. Gall Bladder: Stores
extra bile.
8. Pancreas: Regulates
the level of glucose in
the bloodstream.
9. Rectum: Site where all
the leftover waste (feces)
is stored until you are
ready to get rid of it.

Overview
A. Step 1: Food is eaten, then broken down by
digestive system into the individual building
blocks of carbs, proteins and lipids that made
up the food.
B. Step 2: The nutrients are absorbed into the
bloodstream and transported to the cells.
C. Step 3: The cells take these building blocks
and reassemble them into new combinations
to create the carbs, proteins and lipids our
bodies need.

Carbohydrates
1. Used primarily as the first source of cellular
energy (glucose).
2. The primary building block of carbs is a
“saccharide” (a single sugar molecule/unit).
3. There are two types of carbohydrates:
a. Simple carbohydrates: made of a single sugar
molecule.
b. Complex carbohydrates: made of more than
one sugar unit.
4. Carbohydrates are also used as a structural
building material in plants (cellulose in plants –
used to make paper and clothes).
5. Most carbohydrates are produced by plants
through the process of photosynthesis.

Classes of Carbohydrates
There are three classes of carbohydrates. The
number of sugar units (saccharides) in the
molecule determines which class the
carbohydrate belongs to.
1. Monosaccharides: Made up of only one
sugar unit.
2. Disaccharides: Made up of two sugar
molecules bonded together.
3. Polysaccharides: Made up of at least 3 sugar
molecules bonded together.

Monosaccharides
• These are the simple sugars. They are composed
of a single sugar unit called a saccharide.
1. These molecules are ready to provide energy for
the cell.
2. Examples: Glucose, Fructose (fruit sugars) and
galactose (a type of dairy sugar).
3. Dietary Sources: Fruits, honey, juices, corn
syrup and vegetables.

Disaccharides
• These are a type of complex carbohydrate.
They are composed of two monosaccharides
chemically bonded together.
1. In order to be used to produce energy, they
need to be split apart into the two sugars.
2. Examples: Sucrose (table sugar), lactose
(milk sugar) and maltose (grain sugar).
3. Dietary sources: Sweets/candy, milk,
dairy products and syrup.

Polysaccharides
• Complex carbohydrate composed of at least
three mono’s bonded together. Typically LONG
chains.
1. This is a storage form of energy for cells and
tissue.
2. Must also be broken into individual sugar units
to be able to serve as a source of cellular energy.
3. These tend to come from the “storage” parts of
plants: roots and seeds.

Polysaccharides
4. Dietary Sources: Rice, grains, starches, potatoes.
5. Examples
a. Starch: primary storage form of energy in
plants. Usually found in seeds and roots.
b. Cellulose: primary component in the cell wall
of plant cells. Wood pulp (for paper and
cardboard) and cotton are examples of cellulose.
c. Glycogen: This is the storage form of energy in
animals (our version of starch).
i: When our cells have absorbed all the glucose
they can, the extra is converted into glycogen and
stored in the liver and muscle tissue.
ii: Glycogen is used as an “emergency reserve”.

Carbohydrate Deficiency
• What happens if your body is not able to get
the carbohydrates it needs?
A. Your cells will not be able to provide the
energy you need for work/activity.
B. You will become tired due to a lack of energy.
C. The body will begin to break down fat, then
protein in order to get the energy it needs.
1. Eventually, if it doesn’t change, the fat and muscle
will be consumed by the body (anorexia).

Carbohydrate Summary
• ALL carbohydrates are manufactured by
plants through the process of photosynthesis.
• The only exception are lactose (milk sugar)
and glycogen.
– These take the monosaccharides from foods that
were consumed and released through digestion,
then rearranged by the cells into their final
product (lactose, galactose or glycogen).

Proteins
Protein is an important component of every cell
in the body. If you remove the water from our
bodies, we are 75% protein.
A. Your body uses protein to build and repair
cells & tissues.
B. Proteins are also used to make enzymes and
hormones to regulate the chemical reactions
in your cells.
C. Proteins are an important building block in
bones, muscle, skin and blood.
D. Proteins can also be used as a source of energy
if there are no carbohydrates or fats available.

Proteins
• When foods containing protein are
digested in your body, the protein is
broken down into the individual units that
make up the protein.
• These “units” or building blocks are called
amino acids.
• Amino acids are linked together in
different lengths or chains depending on
what needs to be manufactured. Each
protein has a different length and
sequence.

Proteins
Amino acids are the building blocks of
proteins.
1. A protein is formed when aa’s are linked
together into chains of varying lengths and
sequences.
2. There are 20 amino acids, our
body produces 12
of them. The other 8
we
get from the foods.
we eat.

Proteins
• Dietary sources of proteins are:
a. beef
b. poultry
c. fish
d. eggs & dairy products
e. nuts & seeds
f. legumes (lentils and black beans)

Enzymes
1. Enzymes are a special form of a protein.
2. They are classified as being “catalysts”.
3. Catalysts are substances that speed up the rate of
chemical reactions, and are not changed by that
reaction.
4. Without enzymes, the chemical reactions in most
organisms would not occur fast enough to sustain
life. Our metabolism won’t work without them.
5. Enzymes are temperature dependent:
work slower in colder
temperatures,
faster in warmer
temperatures.

Protein Deficiencies
• What if your body does not get the amount of
protein it needs?
A. This is a risk in vegetarian based diets.
Eating non-animal sources of protein will
take care of any problems.
B. Without enough protein, the body will:
1. Not grow and develop as it should.
2. You will become weaker due to muscle wasting.
3. Your immune system will become weak.

Lipids
• You know lipids as “fats”. However, in the
scientific world, they are also called
“triglycerides”.
• Lipids are a molecule made up of a glycerol
group and fatty acids.
A. Lipids are used primarily as a structural
component in the cell membrane.
B. Lipids are also used to insulate nerve cell
fibers.
C. Lipids are also used as a source of energy
if there are no available carbohydrates.

Two Classes of Lipids
1. Saturated Fats
a. These are the “bad fats”, as their molecular
structure makes it difficult for the body to
break down and they tend to build up in the
blood vessels.
b. Dietary sources: whole milk products (ice
cream, butter, whole milk), lard, red meats,
coconut oil. Mostly “animal sources”.

Two Classes of Lipids
2. Unsaturated Fats
a. These are the “good fats”.
b. Their molecular structure allows them to
dissolve more easily in our body.
c. These are liquid at room temp, whereas the
saturated fats are solid at room temps.
d. Dietary sources: cooking oils (safflower,
canola, olive & corn), avocados, nuts and
fish.

What About Trans-fats?
Trans-fats are chemically altered “unsaturated
fats” that are turned into “saturated fats”.
A. This is done to make the fat more stable at
room temperature.
B. These tend to be unhealthy, like saturated
fats.
C. They have been linked to cancer.
D. Examples: anything that contains
“hydrogenated” or “partially hydrogenated”
fats.

Lipid Deficiencies
• What happens if we do not get enough lipids
in our diet?
1. Nutritionists estimate that 20% of our daily
calories should be from healthy sources of
lipids.
2. Your skin, hair & nails become dry/brittle.
3. Stiff joints.
4. Excessive menstrual/pre-menstrual cramps.

Lipids: The Summary
• Fats/lipids have a great deal of energy
stored in their bonds. This is why the
human body converts excess glucose to fat
to store it.
• When your body needs the extra fuel, it
breaks down the fat and uses that energy.
• Fats contain more than twice the energy of
a molecule of glucose.
– One pound of fat produces 4320 Kcal of
energy, enough to raise the temperature of
more than 10 gallons of water from the
freezing point to the boiling point.

The Wrap-Up
1. Our bodies require the three nutrient
groups for energy and building materials.
2. The function of the digestive system is to
take the complex foods we eat and break
them down into their smallest unit.
3. Those are then absorbed into the
bloodstream, carried to cells and put to use
(see #1).
4. Carbohydrates are the primary cellular
fuel. There are three different types.

5. Polysaccharides provide the greatest amount of
energy. They are a complex carb.
6. Proteins are used primarily as a building
material in our cells & tissues.
7. When proteins are digested, they are broken
down into amino acids.
8. Amino acids are reorganized into thousands of
different protein combinations.
9. An enzyme is a special type of protein that is
required for our metabolism to occur.

10. Lipids are also used as a structural
component (like proteins). They also
insulate our nervous system.