The Structure and Function of Large Biological Molecules

Page
5

Slide 39

Fats separate from water because water molecules form hydrogen bonds with each other and exclude the fats

In a fat, three fatty acids are joined to glycerol by an ester linkage, creating a triacylglycerol, or triglyceride

Slide 40

Fatty acids vary in length (number of carbons) and in the number and locations of double bonds

Saturated fatty acids have the maximum number of hydrogen atoms possible and no double bonds

Unsaturated fatty acids have one or more double bonds

Animation: Fats

Slide 41

Fig. 5-12

Structural

formula of a

saturated fat

molecule

Stearic acid, a

saturated fatty

acid

(a) Saturated fat

Structural formula

of an unsaturated

fat molecule

Oleic acid, an

unsaturated

fatty acid

(b) Unsaturated fat

cis double

bond causes

bending

Slide 42

Fig. 5-12a

(a)

Saturated fat

Structural

formula of a

saturated fat

molecule

Stearic acid, a

saturated fatty

acid

Slide 43

Fig. 5-12b

(b)

Unsaturated fat

Structural formula

of an unsaturated

fat molecule

Oleic acid, an

unsaturated

fatty acid

cis double

bond causes

bending

Slide 44

Fats made from saturated fatty acids are called saturated fats, and are solid at room temperature

Most animal fats are saturated

Fats made from unsaturated fatty acids are called unsaturated fats or oils, and are liquid at room temperature

Plant fats and fish fats are usually unsaturated

Slide 45

A diet rich in saturated fats may contribute to cardiovascular disease through plaque deposits

Hydrogenation is the process of converting unsaturated fats to saturated fats by adding hydrogen

Hydrogenating vegetable oils also creates unsaturated fats with trans double bonds

These trans fats may contribute more than saturated fats to cardiovascular disease

Slide 46

The major function of fats is energy storage

Humans and other mammals store their fat in adipose cells

Adipose tissue also cushions vital organs and insulates the body

Slide 47

Phospholipids

In a phospholipid, two fatty acids and a phosphate group are attached to glycerol