Lipids Flashcards
Lipids are a group of organic compounds that share what one property?
Insoluble in water due to non-polar C—H bonds in lipid molecules
What is the chemical composition of lipids?
Composed of carbon, hydrogen, and oxygen with less oxygen than that found in carbs. They may also contain phosphorous and nitrogen
What are the main functions of lipids?
Insulation to keep the body warm during the cold, it is a structural component in all cell membranes (phospholipid bilayer), has 2.5x the energy storage per gram than carbs, fat layers around organs protect them from damage
Describe fatty acids
The simplest type of lipid, composed of long hydrocarbon chains with carboxyl groups at one end. These chains always contain an even number of carbons (14-22 carbons long)
Give two examples of fatty acids
Palmitic acid and oleic acid
What term is given to a molecule which possesses both polar and non polar ends?
Amphipathic
Describe the polarity of fatty acids
The carboxyl end is polar therefore hydrophilic. The hydrocarbon end is non-polar, therefore hydrophobic
Which type of lipid is composed of long hydrocarbon chains with a carboxyl group at one end?
Fatty acid
What is the simplest type of lipid?
Fatty acid
What molecule is formed when a fatty acid and carbohydrate combine?
Glycolipid
What molecule is formed when a fatty acid and protein combine?
Lipoprotein
What are the types of lipoproteins?
High-density lipoprotein (HDL) (good), low-density lipoprotein (LDL) (bad), very low-density lipoprotein (VLDL) (very bad)
Describe the chemical composition of triglyceride molecules
Composed of three fatty acid molecules (same or different) joined to a glycerol molecule by ester linkages
What type of chemical reaction connects fatty acids to glycerol molecules in triglycerides?
Dehydration synthesis ester formation linkage (three water molecules removed)
Draw a general triglyceride molecule
H O H H H H H
| ‖ | | | | |
H — C — O — C — C — C — C — C — C — H
| | | | | | |
| H H H H H H
| O H H H H H
| ‖ | | | | |
H — C — O — C — C — C — C — C — C — H
| | | | | | |
| H H H H H H
| O H H H H H
| ‖ | | | | |
H — C — O — C — C — C — C — C — C — H
| | | | | | |
H H H H H H H
Describe animal fat triglycerides
Saturated, solid at room temperature, cause of cardiovascular disease
Describe plant oil triglycerides
Unsaturated, liquid at room temperature
Describe the function of waxes
Waterproof coating on the surface of organisms such as fruit, fur, and feathers
Describe the chemical composition of waxes
An ester formed from a very long fatty acid chain and an alcohol chain with only one hydroxyl group. Both the alcohol and fatty acid will have 24-36 carbons each
Describe a physical property of waxes
Very soluble with high melting points
What term is given to the waxy coating on plants, such as the outside of an aloe vera plant?
Cuticle (cutin)
Describe steroids
Ringed fats that act as chemical messengers in the body. They are derived from cholesterol and contain four fused hydrocarbon rings
What is the function of vitamin D (steroid)?
Strengthens bone structure which improves your immune system
What is the function of cholesterol?
Provides cell membrane flexibility
