Carbohydrates & Lipids 2.3

Essential Idea: Compounds of carbon, hydrogen, and oxygen are used to supply and store energy. 2.3 Carbohydrates and Lipids Understandings: Monosaccharide monomers are linked together by condensation reactions to form disaccharides and polysaccharide polymers   Fatty acids can be saturated, monounsaturated or polyunsaturated Unsaturated fatty acids can by cis or trans isomers Triglycerides are formed by condensation from three fatty acids and one glycerol Application: Structure and function of cellulose and starch in plants and glycogen in humans Scientific evidence for health risks of trans fat and saturated fatty acids Lipids are more suitable for long-term energy storage in humans than carbohydrates Evaluation of evidence and the methods used to obtain the evidence for health claims about lipids Skills: Use molecular visualization software to compare cellulose, starch and glycogen Determination of body mass index by calculation or use of a nomogram

Monosaccharides -Contain C, H, O in a 1:2:1 ratio -Names usually end in –ose -Immediate source of energy for cells Alpha v beta glucose – OH on C1 pointing down v up

Isomers of glucose

Disaccharides -2 mono saccharides joined together by a condensation reaction

Polysaccharides - Long chains of monosaccharides -Great for short-term energy storage (easily built by condensation reactions, can easily pop off monosacchrides by hydrolysis to use for energy) -Most often made from glucose, most often linking C1-C4, C6 used for branching

Cellulose -polymer of beta glucose, no branching -2nd glucose 180 compared to 1st -component of plant cell walls to give support

Starch -used to store glucose in plants (in leaves when photosynthesis is working faster than export to rest of plant) -linkage of alpha glucose molecules -composed of two types of glucose polymers -amylopectin which branches -amylose which does not branch -hydrophilic but too large to dissolve

Glycogen -used to store glucose in animals (mostly in liver and muscle) and fungi -lots of branching

Discuss Have each person at your table state one new thing they learned about carbs (no repeats).

Fatty Acids -Carboxyl group (-COOH), long hydrocarbon chain, and a methyl (CH3-) -Hydrocarbon usually 12 – 24 carbons long (including the C from the methyl) Methyl Hydrocarbon chain Carboxyl

Triglycerides Fats – liquid at body temp but solid at room temp Oils – liquid at both room and body temp Combine 3 fatty acids on a glycerol backbone by a condensation reaction - forms 3 water molecules and 3 ester bonds Long – term energy storage, insulation, shock absorption

Saturated Fatty Acids -All single bonds between the carbons of the hydrocarbon chain (saturated with hydrogen) -Pack together tightly -Usually solid at room temperature -Ex. butter, bacon grease, Crisco (animal fats)

Unsaturated Fatty Acids Contain one (monounsaturated) or more (polyunsaturated) double bonds between the carbons in the hydrocarbon chain Causes “kinking” of the chain Can’t pack as tightly together Usually liquid at room temperature Ex. Vegetable oil, olive oil (plant fats)

Hydrogenated fatty acids -Take an unsaturated fatty acid and artificially add hydrogens to the double bonds creating a saturated fatty acid -Used to turn plant oils into substances that are solid at room temperature (margarine, oreo filling)

Cis Unsaturated Fatty Acids Trans Unsaturated Fatty Acids Unsaturated Fatty Acid Isomers Cis Unsaturated Fatty Acids Trans Unsaturated Fatty Acids Both hydrogens are on the same side of the molecule causing kink Hydrogens are on opposite sides of the molecule, no kinking Natural Formation Lab-created formation – referred to as “partially hydrogenated” Oil at room temp Solid at room temp Much more healthful for consumption More like saturated fat (not so healthful)

Long Term Energy Storage -Body uses triglycerides for long term storage -Store triglycerides in adipose cells (aka adipocytes, fat cells) -Most prevalent just beneath skin and around internal organs -6x more efficient at energy storage than carbs

Storage: Carbohydrates vs. Lipids Carbohydrates (Glycogen) Lipid (triglyceride) Short-term energy storage Storage Long-term energy storage More effect on osmotic pressure (causes water to move into cells) Osmolality Less effect on osmotic pressure More readily digested –used for aerobic or anaerobic respiration Digestion Less easily digested- can only be used for aerobic respiration Stores has as much ATP per gram (4 cal/g) ATP Yield Stores twice as much ATP per gram (9 cal/g) Water soluble as monomers/dimers –easier to transport Solubility Not water soluble (hydrophobic) –more difficult to transport (requires energy)

Health Risks Scientific evidence for health risks of trans fats and saturated fatty acids. (A.2) All types of fats are consumed, consuming in excess may cause adverse health effects. Fats in the diet influence the level of cholesterol in the blood stream. Saturated fats and trans fats raise blood cholesterol, while cis unsaturated fats lower blood cholesterol levels.

Health risks and fats Coronary heart disease (CHD) – coronary arteries partially blocked by deposits of fat There is a correlation between trans & saturated fat intake and CHD Not all cultures fit Maasai of Kenya – diet includes lots of meat, fat, milk (high in sat. fat), but low incidence of CHD Diets high in cis unsaturated fats (Mediterrainean) tend to have low levels of CHD

Artherosclerosis – build-up of plaque in the arteries Plaque is composed of lipids, cholesterol, cell debris, calcium Occlusion – when blood flow in an artery is obstructed by plaque

BMI (Body Mass Index) -Indicates amount of weight per amount of height

Nomogram

Discuss Do you think BMI is an accurate measurement of a persons health?? Should there be more restrictions on a persons food intake? No more “biggie” size at McDonalds No soda over a certain size. No soda/junk food at schools.

Brainstorm As a table come up with at least one clarifying question you would like to ask