AP Biology

Life is based on Carbon
 Carbon atoms are versatile building blocks
 Special bonding properties
 Has 4 valence electrons so it can form
4 stable covalent bonds with other carbon atoms or atoms of other elements
 Bonds with
CHNOPS
– the elements that make up living things;
Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, and Sulfur
H
H
C
H

Lipids
 Lipids are organic molecules essential for life that are composed mostly of C, H, O
 4 types of lipids
 fats (triglycerides)
 phospholipids

 steroids waxes
AP Biology

Triglycerides
 Fat molecules



Structure = 3 fatty acids chains linked to glycerol
Functions = long term energy storage and insulation for animals
Can be saturated or unsaturated
Glycerol
3 fatty acids
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Saturated fats


All C bonded to H
No C=C double bonds

 long, straight chain most animal fats and butter
 solid at room temperature
 contributes to cardiovascular disease
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Unsaturated fats
 At least one C=C double bond in the fatty acids
 plant & fish fats

 vegetable oils liquid at room temperature
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Saturated vs. unsaturated saturated unsaturated
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
Phospholipids
Structure: 2 fatty acids chains + phosphate head


Fatty acid chains = non-polar = hydrophobic “water fearing”
Phosphate head = polar = hydrophillic “water loving”
 Function: make up cell membranes
(phospholipid bilayer)
AP Biology

Steroids


Structure: 4 fused Carbon rings examples:



cholesterol – Function =control the fluidity of the cell membrane
hormones – Function = regulate processes in the body (such as pregnancy)
vitamins (A, B, D) – Function = supports metabolism and cell processes
AP Biology

Waxes




Solid at room temp
Insoluble in water
Function:
 Protective covering for animals and plants
Examples:



Beeswax
Earwax
Cuticle of leaf (keeps water in)
AP Biology

What is the function of a triglyceride?
1.
2.
3.
4.
Stores and transfers genetic information
Long term energy storage
Control the rate of reactions
Help to fight disease
10%
75%
15%
3
0%
4
AP Biology
1 2

1.
2.
3.
4.
Which type of lipid makes up the majority of the cell membrane?
phospholipids waxes steroids triglycerides
79%
1
5%
11%
5%
2 3 4
AP Biology

Fats that have at least one double bond between Carbon atoms are called
3.
4.
1.
2.
Unsaturated
Saturated
Glycerol
Fatty Acids
65%
20%
10%
5%
1 2 3 4
AP Biology

Phospholipids have a
1.
2.
hydrophobic head and hydrophilic tail hydrophilic head and hydrophobic tail
16%
1
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84%
2

Which of the following is an example of a steroid
1.
2.
3.
4.
Fatty acids
Sex hormones
Phospholipids
Olive Oil
88%
12%
1 2
0%
3
0%
4
AP Biology