Lessons in Biochemistry about Lipids.ppt

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1. Chapter 5 Section 3Chapter 5 Section 3
LipidsLipids
Mrs. KerstetterMrs. Kerstetter
BiologyBiology

2. LipidsLipids
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LipidsLipids
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Lipids are generally not soluble in water.Lipids are generally not soluble in water.
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Which means they are HYDROPHOBICWhich means they are HYDROPHOBIC
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Lipids Lipids are made mostly from carbon and hydrogen are made mostly from carbon and hydrogen
atoms.atoms.

3. Lipid structureLipid structure

4. LipidsLipids
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The common categories of lipids are:The common categories of lipids are:
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fatsfats
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oils oils
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waxeswaxes
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steroidssteroids

5. LipidsLipids
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What is the function of lipids?What is the function of lipids?

6. LipidsLipids
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Lipids can be used to store energy. Lipids can be used to store energy.
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Some lipids are important parts of biological Some lipids are important parts of biological
membranes and waterproof coverings. In other membranes and waterproof coverings. In other
words…BOUNDARIESwords…BOUNDARIES
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Some circulate in the body as chemical signals to Some circulate in the body as chemical signals to
other cellsother cells

7. LipidsLipids
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Many lipids are formed when a glycerol molecule Many lipids are formed when a glycerol molecule
combines with compounds called fatty acids. combines with compounds called fatty acids.
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If each carbon atom in a lipid’s fatty acid chains is If each carbon atom in a lipid’s fatty acid chains is
joined to another carbon atom by a single bond, the joined to another carbon atom by a single bond, the
lipid is said to be SATURATED.lipid is said to be SATURATED.
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The term The term saturatedsaturated is used because the fatty acids contain is used because the fatty acids contain
the maximum possible number of hydrogen atoms.the maximum possible number of hydrogen atoms.

8. LipidsLipids
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If there is at least one carbon-carbon double bond in If there is at least one carbon-carbon double bond in
a fatty acid, it is UNSATURATED.a fatty acid, it is UNSATURATED.
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Lipids whose fatty acids contain more than one Lipids whose fatty acids contain more than one
double bond are polyunsaturated.double bond are polyunsaturated.
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Lipids that contain unsaturated fatty acids tend to be Lipids that contain unsaturated fatty acids tend to be
liquid at room temperature.liquid at room temperature.
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Saturated fats are SOLIDS at room temperature.Saturated fats are SOLIDS at room temperature.

9. SteroidsSteroids
= a lipid molecule in which the C skeleton forms 4 = a lipid molecule in which the C skeleton forms 4
fused ringsfused rings
-all steroids have a core set of 4 fused rings, but -all steroids have a core set of 4 fused rings, but
they are different in the kinds and locations of they are different in the kinds and locations of
functional groups attached to the ringsfunctional groups attached to the rings

10. SteroidsSteroids
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Classified as lipids because they are Classified as lipids because they are
hydrophobichydrophobic
Functions:Functions:
1.1.Circulate in body as chemical signalsCirculate in body as chemical signals
2.2.Starting point for other steroidsStarting point for other steroids
Estrogen and testosterone are sex hormones cause Estrogen and testosterone are sex hormones cause
major differences in female and male sexual major differences in female and male sexual
characteristicscharacteristics

11. SteroidsSteroids

12. CholesterolCholesterol
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Best known steroidBest known steroid
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Found in molecules that surround your cellsFound in molecules that surround your cells
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Starting point for making other hormonesStarting point for making other hormones
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Bad Rep…Why?Bad Rep…Why?
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High levels of LDL and VLDL are linked to High levels of LDL and VLDL are linked to
increase risk of cardiovascular diseaseincrease risk of cardiovascular disease