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
