1. Lipids
Biology I

2. Lipids Lipids – macromolecules made mostly of carbon and hydrogen.
These are not the only elements found in lipids, just the majority.
Another name for lipids is fats!

3. Lipids
Lipids are made by joining a glycerol molecule with fatty acids (typically 2-3).
The glycerol is bonded to the fatty acids using dehydration synthesis!
dehydration synthesis

4. Dehydration Synthesis

5. Lipids Lipids have three uses: Store energy (fat!).
Waterproof coverings.
Biological membrane parts.
Lipid behavior was found in the first cells

6. Lipids There are three types of fats that occur naturally:
Saturated
Unsaturated/Monounsaturated
Polyunsaturated
Industrially, unsaturated fats are manipulated to make trans fats.
Can you name some foods with trans fats?
Answer: fast foods, donuts, cookies and cakes, yum!

7. Saturated Fat

8. Unsaturated Fat

9. Lipids
Saturated Fats
Each carbon atom in the fatty acid is joined to the next carbon atom by a single covalent bond.
These are called “saturated” because they contain as many hydrogen atoms as possible (i.e. they are “saturated” with hydrogen).
Solid at room temperature.
Saturated fats are bad for you.

10. Lipids Saturated Fats A good way to remember:
Saturated fats have straight fatty acid tails attached to a glycerol molecule.
A good way to remember:
Single, Solid, Straight

11. Lipids Unsaturated Fats
Contain at least one carbon-carbon double covalent bond (not as much hydrogen as possible).
If there is only one carbon-carbon double covalent bond, the lipid is unsaturated/monounsaturated.
If there is more than one, the lipid is polyunsaturated.
Liquids at room temperature.
Better for you than saturated fats.

12. Lipids Unsaturated Fats
Unsaturated fats have kinks in their fatty acid tails.
Each kink is where a double bond occurs.

13. Unsaturated

14. Lipids Is this lipid saturated, unsaturated, or polyunsaturated?
How do you know?
More than one kink, representing more than one carbon-carbon double covalent bond.

15. Lipids Is this lipid saturated, unsaturated, or polyunsaturated?
How do you know?
The chains are straight, meaning it has only single covalent bonds.

16. Lipids
Why are unsaturated fats good for you, but saturated fats are not?
Saturated fats are straight. They clump close together, which makes them solid. It also makes it harder for your body to break the molecules apart, meaning they are more likely to be stored than digested.
Unsaturated fats are kinked, making it hard for them to stick to one another. This looseness makes them a liquid, and also makes it easier for your body to digest them.

17. Compare Unsaturated and Saturated

18. Lipids
Trans Fats
Trans fats are produced by chemically forcing more hydrogen atoms into unsaturated fats to make them closer to being saturated.
This causes the fatty acid chains to become straight.
Doing this increases their melting point, making them ideal for baking, and also gives them a longer shelf life.
Because these are not essential or naturally occurring, they are incredibly bad for the body because of how difficult they are to break down.