16 Questions
What is the primary function of triacylglycerols in the body?
Energy storage
What is the difference between saturated and unsaturated fatty acids?
Saturated fatty acids have no double bonds, while unsaturated fatty acids have one or more double bonds
What is the function of bile acids in the body?
To facilitate the digestion of fats
What is the term for a fatty acid with more than one double bond?
Polyunsaturated fatty acid
What is the term for a fatty acid that cannot be synthesized by the human body and must be obtained through the diet?
Essential fatty acid
What is the term for the ester of glycerol and three fatty acids?
Triacylglycerol
What is the definition of a lipid?
A molecule that is insoluble in water but soluble in fat and organic solvents
What is the notation Δ9 in oleic acid (18:1 Δ9) indicating?
The location of a double bond between carbon 9 and 10
What is the effect of a double bond on the ability of fatty acids to pack together?
It reduces the ability of fatty acids to pack together
What is the main component of membranes?
Phospholipids
What is the hydrophilic part of phospholipids?
Glycerol and phosphate
What is the common name for phospholipids with choline as the head group?
Phosphatidylcholine
What is the characteristic of glycolipids?
They have a sugar-containing head group
What is the function of ceramide in lipids?
It replaces glycerol in some lipids
What is the characteristic of sphingomyelin?
It is a type of phospholipid with a ceramide backbone
What is the function of the terminal sugar in glycolipids?
It is often sialic acid
Study Notes
Lipid Structures
- Lipids are insoluble in water but soluble in fat and organic solvents.
- Biological functions of lipids include energy storage, precursors for vitamins and steroid hormones, bile acids, and membrane structure.
Fatty Acids (FA)
- Long-chain aliphatic carboxylic acids.
- Can be either saturated (e.g. myristic acid, palmitic acid, stearic acid) or unsaturated (e.g. oleic acid, polyunsaturated fatty acids (PUFA) with more than one double bond).
Triacylglycerols (TAG)
- Ester of three fatty acids and glycerol.
- Stored in adipose tissue.
- Function: energy storage.
Phospholipids
- Composed of glycerol, two fatty acids, and a phosphate-containing head group.
- Different classes of phospholipid depending on the nature of the head group.
- Major component of membranes.
- Head group and phosphate are hydrophilic, while fatty acids are hydrophobic.
- Examples: Phosphatidylcholine (PC), Phosphatidylserine (PS), Phosphatidylethanolamine (PE), and Phosphatidylinositol (PI).
Glycolipids
- Composed of glycerol, two fatty acids, and a head group containing sugars.
- Different classes of glycolipid depending on the sugars present.
- Specialized part of membranes.
- Often have monosaccharide or oligosaccharide chains, with terminal sugar often being sialic acid.
Sphingolipids
- Replace glycerol with sphingosine.
- Ceramide is formed when sphingosine is combined with a single fatty acyl chain.
- Found in some phospholipids (e.g. sphingomyelin) and glycolipids (e.g. GM1 ganglioside).
- Sphingomyelin is present in high amounts together with cholesterol in lipid rafts and in the membranes of myelin sheaths of neurons.
Recognize lipid structures, outline the 'fluid mosaic model' of membrane structure, and describe membrane components and proteins. Learn about the characteristics of integral, anchored, and peripheral membrane proteins.
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