1. Carbohydrates & Lipids
2.3

2. 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

3. 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

4. Disaccharides -2 mono saccharides joined together by a condensation reaction

5. 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

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

7. 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

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

9. 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

10. 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

11. 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)

12. 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)

13. 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)

14. 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)

15. 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

16. Carbs vs. Fats in Energy Storage
Water soluble = easy to transport around body, and cells with more carbs carry more water(2g/g of glycogen)
Water insoluble = more difficult to transport (requires use of energy)
1 g has about 4 calories of energy
(1/2 as much as fats)
1 g has about 9 calories of energy
(twice as much as carbs)
Large quantities would upset osmotic balance in cells (water would move into cells causing them to swell)
Large quantities do no impact osmotic balance (insoluble)
Glucose can be used in both aerobic and anaerobic, lipids only in aerobic

17. 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

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