Download 1-3 macromolec-digestion

Macromolecules, Food and
What’s in food?
Digestion
Carbohydrates
Protein
Lipids (Fat)
Macromolecules
Many small molecules connect to form
Carbohydrates
Macromolecules
Monomers – Small Molecules (Building Blocks)

Range in size from single sugars to long
sugar chains (polysaccharides)
Polymers – Large Molecules
Carbohydrates

Polysaccharides are longer sugar chains

Glycogen is a polysaccharide stored in animal
tissue
Proteins
Polymers constructed from amino
acid monomers
Polymers – long chains of simple sugars
Proteins = polymers of amino acids
Polypeptides
Protein Monomers
The millions of different
proteins are all formed
from just 20 building
blocks, called amino
acids
Amino acids
come in 20 Different Flavors!
(Lysine, Valine, Tryptophan, Proline, etc.)
Lipids (or fats)
Functions of proteins

Macromolecules that are not soluble in
water



Body structures
Regulate body functions



OH
CH3
Enzymes
Hormones
Triglycerides
Saturated fats have no double bonds



The Carbon chain is completely saturated with hydrogens
solid at room temperature
O
Lipids

liquid at room temperature

HC
Steroids

Unsaturated fats have at least one double bond

CH3
Steroids
Seldom used for energy
Lipids

X
Hydrophobic or “water-fearing”
large molecules with a
four-ring structure
Examples

cholesterol –

sex hormones –
CH3
3
H3C
CH3
CH3
HO
a. Cholesterol
an integral
part of cell membranes
responsible for the enormous
changes of puberty
OH
CH3
OH
CH3
CH3
O
b. Testosterone
HO
c. Estrogen
Why we eat




What is a Nutrient?
Water
Energy (calories)
“Building blocks”
Essential nutrients


Any substance that the body uses to:



Primarily vitamins and minerals

provide energy (calories)
regulate body processes
contribute to cell and body structure
Is alcohol a nutrient?
Alcohol provides energy (7 Cal/g)
But it has no necessary function in the body
Toxic when consumed in large amounts
What are the 6 types of
nutrients?
Water is critical for body
functions

Vitamins
Minerals
Carbohydrates


Protein
The body is about 70%
water
Found both inside and
outside the cells
Functions


Fats

Water
Nutrients supply energy

Protein
Carbohydrates
Fats
These nutrients
supply energy
(calories) to power
muscle contraction,
maintain body temp
and other cell
functions
Helps regulate body
temperature
Transports nutrients
Excretes waste products
Food as Fuel

Cells


Break down food
macromolecules in
cellular respiration.
Generate many
molecules of ATP.
Some nutrients help regulate
body processes
Energy (Calories) from Nutrients
Nutrient

Energy
Carbohydrate 4 cal/g
Protein
4 cal/g
Fat
9 cal/g
Vitamins and minerals
(the micronutrients) and
water

Vision

Metabolism


Which is the most energy-rich nutrient?


Food as Building Material
Nutrients contribute to cell and body structure
Proteins, minerals and water provide structure to
bone, muscle and other tissues


Bone
Muscle



Simple sugars

Polysaccharides
Table sugar, soft drinks
Long starch molecules
Why do we need Fats?
Metabolized to provide Energy


Blood pressure
Primary source of energy
for living organisms

carbohydrates?
Iodine is a component of
thyroid hormone
Iron helps transport O2
Carbohydrates

How does the body use
Vitamin A
Primary source of energy for the body
and brain
Provide Fiber


Dietary fats provide

A complex carbohydrate that humans
can’t digest



Energy for the body
Fat-soluble vitamins (vitamins A, D, E and K)
Essential fatty acids (omega-3 and omega-6)
Long-term energy storage in adipose
tissue
Kinds of Fats
Cholesterol
Saturated Fatty Acids
(All Single Bonds C-C)
Heighten Heart
Disease Risk
Unsaturated Fatty Acids
(Some Double Bonds C=C)
Reduce Heart
Disease Risk
Trans-Fatty Acids (Hydrogenated)
Heighten Heart
Disease Risk
Not Found Naturally!
LDL and HDL cholesterol

HDL or “Healthy” cholesterol





Helps build and maintain body tissues

Regulates body functions

Protects you from illness

Removes excess cholesterol
from cells
Protects against heart disease

LDL or “Lousy” cholesterol


Protein –
an all important nutrient
Transports cholesterol to the
cells; sticks to artery walls
Contributes to plaque build-up

High levels of LDL
cholesterol raise the risk of
heart disease

Must be obtained from
the diet – the body
can’t synthesize them.

Different foods contain
different essential amino
acids.
Many hormones are proteins
Antibodies are protein

Sometimes used for energy

Sources:

Essential Amino Acids
Main job is to build muscle, bone, skin
and hair
meat, eggs, beans, nuts
The Micronutrients



Essential (can’t be made by body)
Required in small amounts (‘micro’)
for normal growth and health
Vitamins



Fat-soluble: A, D, E and K
Water-soluble: C, B-vitamins
Minerals

Calcium, iron, iodine, zinc and others
Is alcohol a nutrient?



Alcohol provides energy (7 Cal/g)
But it has no necessary function in
the body
Toxic when consumed in large
amounts
Alcohol - the good, the bad
and the ugly


People drink to relax,
celebrate and socialize
Harmful effects




carrying protein in red blood cells




Cardiovascular disease
Certain types of cancer
Type 2 diabetes
What is “good nutrition”?
Getting the right nutrients

Foods that provide energy
Essential nutrients that the body can’t
make
Basic advice for good nutrition

Eat a variety of
foods


Getting the correct amount of food
energy (cal)


Fruits, vegetables
and whole grains
Eat less


the oxygen-
Results from regular
intake of excess energy
Major risk factor for
chronic diseases


Alcoholism
Iron is part of hemoglobin,
Obesity

Weight gain
Damage to the digestive
system, heart and liver
Puts a healthy pregnancy at
risk
don’t overeat
Avoid too much junk
food
Exercise more