MACROMOLECULES LIPIDS Which lunch is better Carbohydraterich 1

MACROMOLECULES LIPIDS

Which lunch is better? Carbohydrate-rich • • 1 low-fat muffin 1 banana 2 oz carrot sticks 8 oz fruit yoghurt Calories = 550 Weight (g) = 500 Fat-rich • 6 butter style crackers • 1 ½ oz cheddar cheese • 2 oz trail mix with candy Calories = 550 Weight (g) = 115

Okay……… What is a CALORIE? • A unit of ENERGY. Why is energy important? • Needed for all biological processes. • Eg. Heart beating, brain working, muscles moving, breathing, etc. CARBOHYDRATES vs. FATS • Carbohydrates are MUCH EASIER for your body to use for ENERGY. • Therefore, carbs are much easier for your body to “BURN. ” • Fats are usually stored for a while without being used. Imagine that you have an important presentation. For breakfast, should you have: a) Cereal & fruit b) A Bacon’n Egg Mc. Muffin c) Nothing (You’re trying to lose weight) Not eating for a while?

If fats are so “bad, ” then why do we need them? What are they good for? Let’s learn about fats!

. THE FUNCTIONS OF LIPIDS 1) LONG-TERM ENERGY STORAGE • twice as much energy as carbohydrates, but harder to use 2) INSULATION • helps keep heat in & cold out 3) CUSHIONS • Layer of fat around organs protects them from damage 4) VITAMIN ABSORBANCE • fats help your body absorb other hydrophobic substances • vitamins A, D, E, and K are hydrophobic. 5) CELL MEMBRANE • The cell membrane is mostly made of LIPIDS.

. 4 TYPES OF LIPIDS Waxes Phospholipids Triglycerides Sterols

1. TRIGLYCERIDES • Hydrophobic – insoluble in water but soluble in other nonpolar substances. • Monomers: 1) Glycerol, 2) Fatty Acids • Made of 1 glycerol (C 3 H 8 O 3) molecule and 3 fatty acid (hydrocarbon with COOH) chains. • Linked together via Condensation Reaction

FATTY ACIDS UNSATURATED • • • Maximum amount of hydrogen atoms No double bonds Straight Solid at room temperature (straight F. A. chains can stack) Sources: animal fat (bacon, butter) Dangers: cholesterol, arteriosclerosis (arteries harden), atherosclerosis (arteries get clogged) • • • Missing hydrogen atoms Contains double bonds Bent at double bonds Liquid at room temperature (bent F. A chains can’t stack easily) Sources: plant fat (olive oil) Dangers: Obesity, heart attack glycerol & fatty acids All fats are digested into ____________ before they can enter the bloodstream.

TRANS FATS & CHOLESTEROL (PARTIALLY HYDROGENATED OILS) • Created by adding hydrogen to liquid vegetable oil (hydrogenation) • Makes plant fats more solid, lengthens shelf life, makes more suitable for frying and other uses. • Eg. Margarine BAD CHOLESTEROL GOOD CHOLESTEROL - HDL – highdensity lipoproteins - Pick up excess cholesterol and transport to liver for processing. - Consuming trans fats lowers HDL levels. - LDL – low-density lipoproteins - Transports cholesterol through blood - Cholesterol in blood builds up, narrowing and hardening the arteries – reduces blood flow and increased chance of heart attack and stroke. - Consuming trans fats increases LDL levels.

2. PHOSPHOLIPIDS Bipolar – Hydrophilic head and Hydrophobic tail. – Head: Choline group, Phosphate group, and Glycerol (attracted to water) – Tail: Two hydrocarbon fatty acid (attracted to other hydrophobic substances) • F. A. chains linked to head by condensation reaction

BIPOLAR NATURE OF PHOSPHOLIPIDS • Acts as an Emulsifier: helps keep hydrophobic and hydrophilic substances from separating from each other. • Eg. Lecithin, a phospholipid, is found in egg yolk. It is use as an emulsifier in salad dressings, holondaise sauce, mayonnaise, baked goods, etc. • Micelles • When added to water, phospholipids orient their hydrophobic tails towards each other and their hydrophilic heads outward towards water. • Cell Membrane • Membrane is mostly made of a phospholipid bilayer. • Separates extracellular (outside) fluid from intracellular (inside) fluid • Hydrophillic heads face out towards fluid, and hydrophobic tails face each other. • Is not solid – remains fluid and moving.

3. STEROLS • Consists of interconnected rings of carbon and side chains. • Cholesterol • Helps make bile – produced by the liver and aids in digestion of lipids. • Component of the cell membrane – helps it remain fluid • High cholesterol in blood can lead to fatty deposit buildup • Vitamin D • Found in very few foods • Sun exposure changes a special cholesterol molecule in the skin to vitamin D. • Helps with calcium and phosphorous absorbance – maintance of healthy bones and teeth. • Steroid Hormones • Important for growth and development • Eg. Testosterone

4. WAXES Many different types and structures, usually contain single Fatty Acid • 3 main types: A) Animal Waxes • Beeswax: • Secreted by bees to make honecombs • lip balm, moisturizer, candles, cooking, etc. • Spermaceti (Sperm Whale): • Function in whales unknown • Candles, ointments, cosmetics. • Ear Wax (Mammals) • Secreted in the ear canal: Acts as a sticky reside that captures bacteria, fungi, insects and water before entering the inner ear.

B) Plant Waxes • Epicuticular Waxes • Plants secrete waxes onto their cuticles (outside of leaves and stems) – keeps plant from being water logged and from becoming dehydrated • Food coatings, car and furniture polish, floss coating, surfboard wax.

C) Petroleum Wax • Parrafin wax • Deprived from fossil fuels from ancient marine mammals between layers of rock • Electrical insulator, candles, waxed paper, shiny coating on candy (indigestible), coating on hard cheese, sealant for jars and bottles, chewing gum, crayons, surfwax…

Now you know what some of the substances are on food labels!