1. Review
Each small organic molecule can be a unit of a large organic molecule called a macromolecule.
Small organic molecules can serve as monomers, the subunits of polymers.

2. There are four types of biological macromolecules
Carbohydrates
Lipids
Proteins
Nucleic acids

3. What Are Lipids?
All lipids contain large chains of nonpolar hydrocarbons (chains of carbon and hydrogen)
Most lipids are therefore hydrophobic and water insoluble

4. What Are Lipids?
Lipids are diverse in structure and serve in a variety of functions
Energy storage
Waterproofing
Membranes in cells
Hormones

5. Types of Lipids
Triglycerides
Waxes
Phospholipids
Sterols

7. Page 21: Triglycerides Fats and oils Formed by condensation reactions
3 fatty acids + glycerol  triglyceride

8. A fatty acid is a long chain of mostly carbon and hydrogen atoms with a –COOH group (“carboxyl”) at one end.

9. The hydrocarbon chain can vary in length …
from 4 to about 24 carbons long,
depending on the type of fatty acid.
(in humans, 16 and 18 are the most common)

10. Fats and oils used for long-term energy storage
Fats and oils possess a high density of stored chemical energy

11. Saturated Fatty Acids
Saturated fatty acids have mostly single C-C bonds in the fatty acid chains
Saturated fats are typically solid at room temperature
Saturated fats are often from animal sources

13. Unsaturated Fatty Acids
Unsaturated fats have one or more C=C double bond in the fatty acid chain
Unsaturated fats are typically liquid at room temperature, because kinks in the tails prevent tight packing
Unsaturated fats are often from plant sources

15. Cis-unsaturated fatty acids
Page 22
Most naturally occurring unsaturated fatty acids occur in the cis- confirmation
Cis is a Latin word meaning "on the same side”
Causes a kink in the fatty acid chain

16. Trans-unsaturated fatty acids
Most fatty acids in the trans configuration (trans fats) are not found in nature and are the result of human processing
Trans is a Latin word meaning "across", "on the opposite side"
Causes a straight fatty acid chain (even though it is unsaturated)

18. What's the problem with trans fatty acids?
Trans fatty acids increase LDL cholesterol levels, and reduce HDL cholesterol levels.
In other words, trans fatty acids are detrimental to cardiac health.

19. Which foods contain trans fatty acids?
Margarines
High-fat baked goods
Any product for which the label says "partially hydrogenated vegetable oils" (which, it sadly appears, includes virtually all processed foods.)

22. Types of Lipids
Fatty Acids
Fats
Phospholipids
Waxes
Sterols

28. Glucose Glycogen Fat Page 23: Carbs vs. fats
Our body uses three main sources of energy:
Glucose
Glycogen
Fat
Can’t be
stored
Carbohydrates
Long term
storage

29. Types of Lipids
Fatty Acids
Fats
Phospholipids
Waxes
Sterols

30. Phospholipids
They are formed by attachment of two fatty acids plus a phosphate group to a glycerol.
They are the main structural components of membranes.

32. Types of Lipids
Fatty Acids
Fats
Phospholipids
Waxes
Sterols

33. Waxes
Waxes are composed of long hydrocarbon chains and are strongly hydrophobic
Waxes are highly saturated and solid at room temperature
Waxes form waterproof coatings
Leaves and stems of plants
Fur in mammals
Insect exoskeletons
Used to build honeycomb structures
Figure: 19-2 part a
Title:
Viral structure and replication part a
Caption:
(a) A cross section of the virus that causes AIDS. Inside, genetic material is surrounded by a protein coat and molecules of reverse transcriptase, an enzyme that catalyzes the transcription of DNA from the viral RNA template after the virus enters the host cell. This virus is among those that also have an outer envelope that is formed from the host cell's plasma membrane. Spikes made of glycoprotein (protein and carbohydrate) project from the envelope and help the virus attach to its host cell.

34. The frozen ropes in this image represent the wax on the surface of Asparagus!
The tube-like structures are called stomatal chimneys. They are composed of wax.

35. Types of Lipids
Fatty Acids
Fats
Phospholipids
Waxes
Sterols

36. Sterols Sterols have a backbone of four carbon rings
Cholesterol is a component of cell membranes and can be modified to form sex hormones (testosterone and estrogen).

38. Cholesterol: a steroid