Lipids Notes

​Lipids

By Christopher Powers

Types of Lipids

56

Multiple Choice

Which of the following is NOT a polymer?

• glucose
• starch
• cellulose
• DNA

Triglycerides

● Most common lipids are formed when glycerol

combines with 3 fatty acid chains to create a
triglyceride.

● These are the most common source of energy.
● Fatty acids are long chains of hydrogen and carbon

with a -COOH group attached.

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Triglycerides

● They are used as long-term energy storage,

cushioning of vital organs, and insulation.

● The monomer of lipids are fatty acids.

58

Types of Fatty Acids

59

Saturated Fatty Acids

● Saturated fatty acids are made of only

carbon-carbon single bonds and have the
maximum number of hydrogens present

● These are bad for you because they stack easily on

top of each other and are solid at room temp.
Ex: Meats, dairy products, and animals fats

60

Unsaturated Fatty Acids

● Unsaturated fatty acids have at least 1 double bond,

which creates a kink in the chain.

● This makes them harder to stack, so they are liquid at

room temperature and are better for you.

● Monounsaturated fatty acids have only 1

carbon-carbon double bond. Ex: nuts and fish oils

● Polyunsaturated fatty acids have more than 1

carbon-carbon double bond. Ex: peanut and corn oils

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Triglycerides

62

Phospholipids

● Phospholipids are a major component of cell

membranes.

● They are made of a phosphate head and 2 fatty

acid tails.

● The phosphate head is hydrophilic, or attracted to

water, which the fatty acid tails are hydrophobic,
or repelled by water.

63

Phospholipids

64

Waxes

● Waxes are lipids that repel water, are solid at

room temperature, and form waterproof
coatings for plants and animals.

● Ex: plants use waxes on their leaves to

prevent water loss

● Ex: some animals use waxes to clean and

protect their ears

● Ex: bees use wax to build honeycombs

65

Steroids

● Steroids are used to make some vitamins, sex

hormones, and cholesterol.

● Their structure consists of four fused rings.

67

Cholesterol

● Cholesterol is a key component of the cell

membrane.

● It is good in small quantities (keeps cell

membrane fluid), but can cause health
concerns in larger quantities
○ EX: can clog arteries and lead to heart

disease or stroke because of restricted
blood flow

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Lipid Facts

● Lipids are NOT soluble in water because they are

non-polar

● You receive 9 kCal/g of energy
● Used second after

carbohydrates for energy

● Major component of the

cell membrane

69

Multiple Choice

The picture indicates which macromolecule? 

• Carbohydrates
• Lipids
• Proteins
• Nucleic Acids