AP Biology

Intro to Organic

Molecules & Lipids

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Life is based on CarbonCarbon atoms are versatile building blocks

Special bonding propertiesHas 4 valence electrons so it can form 4 stable covalent bonds with other carbon atoms

or atoms of other elementsBonds with CHNOPS – the elements that make up

living things; Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, and Sulfur

HH C

H

H

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Lipids Lipids are organic molecules essential for

life that are composed mostly of C, H, O

4 types of lipidsfats (triglycerides)phospholipidssteroidswaxes

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TriglyceridesFat molecules

Structure = 3 fatty acids chains linked to glycerolFunctions = long term energy storage and insulation

for animalsCan be saturated or unsaturated

Glycerol3 fatty acids

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Saturated fatsAll C bonded to HNo C=C double bonds

long, straight chainmost animal fats and butter solid at room temperature

contributes to cardiovascular disease

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Unsaturated fatsAt least one C=C double bond in

the fatty acidsplant & fish fats vegetable oils liquid at room temperature

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Saturated vs. unsaturatedsaturated 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)

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SteroidsStructure: 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

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WaxesSolid at room tempInsoluble in waterFunction:

Protective covering for animals and plants

Examples:BeeswaxEarwaxCuticle of leaf (keeps water in)

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What is the function of a triglyceride?

1 2 3 4

10%

0%

15%

75%1. Stores and transfers genetic information

2. Long term energy storage

3. Control the rate of reactions

4. Help to fight disease

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Which type of lipid makes up the majority of the cell membrane?

1 2 3 4

79%

5%11%

5%

1. phospholipids2. waxes3. steroids4. triglycerides

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Fats that have at least one double bond between Carbon atoms are called

1 2 3 4

65%

10%5%

20%

1. Unsaturated2. Saturated3. Glycerol4. Fatty Acids

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Phospholipids have a

1 2

84%

16%

1. hydrophobic head and hydrophilic tail

2. hydrophilic head and hydrophobic tail

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Which of the following is an example of a steroid

1 2 3 4

12%

0%0%

88%1. Fatty acids2. Sex hormones3. Phospholipids4. Olive Oil