Intro to Organic
Molecules
& Lipids
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
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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
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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
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3 fatty
acids
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
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unsaturated
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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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
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Waxes
 Solid at room temp
 Insoluble in water
 Function:
 Protective covering for
animals and plants
 Examples:



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Beeswax
Earwax
Cuticle of leaf (keeps water in)
Which of the following is an example
of a type of triglyceride?
1.
2.
3.
4.
A fat containing 3 saturated
fatty acids
A fat containing 2 saturated
fatty acids & 1 unsaturated
fatty acid
A fat containing 3 unsaturated
fatty acids
All of the above
eufic.org
AP Biology
aafp.org
mpkb.org
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3.
0%
4.
2 Which of the following types of fats (triglycerides) would
be an oil at room temperature and would be healthier to
eat since its bent carbon & hydrogen chains and don’t
stack well?
1.
2.
3.
4.
5.
Unsaturated fat WITHOUT any C to C
double bonds
Saturated fat WITHOUT any C to C
double bonds
Unsaturated fat containing C=C
Saturated fat containing C=C
Steroids like testosterone hormone or
cholesterol
eufic.org
AP Biology
aafp.org
mpkb.org
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1.
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2.
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3.
0%
4.
3 Which type of lipid makes up the
majority of the cell membrane?
1. phospholipids
2. waxes
3. steroids
4. triglycerides
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essortment.com
alevelnotes.com
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4.
4 Phospholipids contain:
1.
2.
A hydrophobic polar phosphate head & 2
hydrophilic nonpolar fatty acid tails
A hydrophilic polar phosphate head & 2
hydrophobic nonpolar fatty acid tails
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http://myhome.sunyocc.edu/~weiskirl/Alcamo_membra
ne.gif
5 Which is an example of a steroid?
Structure of triglycerides: fats
1. Fatty acids
& oils
2. Sex hormones
3. Phospholipids
4. Olive Oil
5. Triglycerides
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2.
3.
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5.
AP Biology
1.
Structure of
sex
hormones
6 What is the function of a
triglyceride?
1. Stores and transfers
genetic information
2. Long term energy storage,
as well as insulation &
protection
3. Control the rate of
reactions
4. Help to fight disease
AP Biology
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7 What is the function of hormones such as the steroid
hormones?
1. Communication &
cooperation between cells
2. Short term energy storage
3. Structural building
materials
4. Compose the bilayer cell
membrane
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AP Biology
1.
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2.
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3.
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4.
8 What is the cholesterol
considered a steroid?
1. They have a similar
hydrophobic structure
2. The both contain rings
made mostly of Carbon
and Hydrogen atoms
3. They are both nonpolar
covalent
4. All of the above
AP Biology
cholesterol
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2.
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4.