1. 2.3 – Carbohydrates and Lipids

2. Essential Idea: Compounds of carbon, hydrogen, and oxygen are used to supply and store energy.

3. Fatty acids can be saturated, monounsaturated or polyunsaturated
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

4. I. Carbohydrates
A. Monosaccharides 1. Contain C, H, O in a 1:2:1 ratio 2. Names usually end in –ose 3. Immediate source of energy for cells

5. Isomers of glucose

6. Disaccharides
1. Two monosaccharides joined together by a condensation reaction
2. Good for transporting sugars throughout an organism

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

8. 4. Cellulose
a. Polymer of beta glucose, no branching
b. 2nd glucose 180 compared to 1st
c. Component of plant cell walls to give support

9. b. Linkage of alpha glucose molecules
5. Starch
a. Used to store glucose in plants (in leaves when photosynthesis is working faster than export to rest of plant)
b. Linkage of alpha glucose molecules
c. Composed of two types of alpha glucose polymers
amylopectin which branches
amylose which does not branch
d. Hydrophilic but too large to dissolve

10. Glycogen
a. Alpha glucose with mainly 1,4 linkages, 1,6 linkages for branching
b. Used to store glucose in animals (mostly in liver and muscle) and fungi
c. Lots of branching

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

13. B. Triglycerides 1. Fats – liquid at body temp but solid at room temp 2. Oils – liquid at both room and body temp 3. Combine 3 fatty acids on a glycerol backbone by a condensation reaction - forms 3 water molecules and 3 ester bonds 4. Long – term energy storage, insulation, shock absorption

14. C. Saturated Fatty Acids 1
C. Saturated Fatty Acids 1. All single bonds between the carbons of the hydrocarbon chain (saturated with hydrogen) 2. Pack together tightly 3. Usually solid at room temperature 4. Ex. butter, bacon grease, Crisco (animal fats)

15. D. Unsaturated Fatty Acids 1
D. Unsaturated Fatty Acids 1. Contain one (monounsaturated) or more (polyunsaturated) double bonds between the carbons in the hydrocarbon chain 2. Causes “kinking” of the chain 3. Can’t pack as tightly together 4. Usually liquid at room temperature 5. Ex. Vegetable oil, olive oil (plant fats)

16. E. Hydrogenated fatty acids 1
E. Hydrogenated fatty acids 1. Take an unsaturated fatty acid and artificially add hydrogens to the double bonds creating a saturated fatty acid 2. Used to turn plant oils into substances that are solid at room temperature (margarine, oreo filling)

17. Cis Unsaturated Fatty Acids Trans Unsaturated Fatty Acids
F. 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)

18. Carbohydrates (Glycogen)
III. Energy Storage
Carbohydrates (Glycogen)
Lipid (triglyceride)
Short-term energy storage
Long-term energy storage
More readily digested –used for aerobic or anaerobic respiration
Less easily digested- can only be used for aerobic respiration
Stores half as much ATP per gram (4 cal/g)
Stores twice as much ATP per gram (9 cal/g)
Water soluble as monomers/dimers –easier to transport
Not water soluble (hydrophobic) –more difficult to transport (requires energy)

20. IV. Health risks associated with various lipids
A. Consuming fats in excess may cause adverse health effects because fats in the diet influence the level of cholesterol in the blood stream. 1. Saturated fats and trans fats raise blood cholesterol, while cis unsaturated fats lower blood cholesterol levels.

21. B. Coronary heart disease (CHD) – coronary arteries partially blocked by deposits of fat – linked to high blood cholesterol levels

22. 1. There is a correlation between trans & saturated fat intake and CHD
a. Diets high in cis unsaturated fats (Mediterranean) tend to have low levels of CHD
b. Not all cultures fit - ex. Maasai of Kenya – diet includes lots of meat, fat, milk (high in sat. fat), but low incidence of CHD

23. V. Body Mass Index (BMI)
A. Indicates amount of weight per amount of height

24. Nomogram