Lesson 4: Lipids Flashcards
What elements do lipids contain?
C, H, and O
Lipids contain fewer oxygen atoms compared to carbohydrates.
What is the nature of lipids due to the abundance of C-H bonds?
Hydrophobic/largely non-polar
List the functions of lipids.
- Store energy
- Insulation
- Protection
- Functions in the cell membrane
What are the major types of lipids?
- Triglycerides
- Fatty acids
- Phospholipids
- Steroids
What is the structure of fatty acids?
Chain of usually 4 to 24 carbon atoms with a carboxyl group on one end and a methyl group on the other
What characterizes a saturated fatty acid?
Carbon atoms are saturated with hydrogen
What characterizes an unsaturated fatty acid?
Contains C=C bonds that could bond more hydrogen
What is a triglyceride composed of?
One glycerol molecule and three fatty acids
What is the bond between the hydroxyl group on glycerol and the carboxyl group on fatty acids called?
Ester linkage
What state are triglycerides containing saturated fatty acids typically at room temperature?
Solid (e.g., butter)
What state are triglycerides containing unsaturated fatty acids typically at room temperature?
Liquid (e.g., canola oil)
What happens to the human body if we consume too many saturated fatty acids?
Potential health risks such as heart disease
What are triglycerides also known as?
Neutral fats
Describe the composition of phospholipids.
Composed of fatty acid tails, a glycerol molecule, a phosphate functional group, and an ‘R’ group
What is the polarity of the ‘head’ and ‘tail’ of a phospholipid?
Head is polar; tail is non-polar
What structure do phospholipids form in aqueous environments?
Bilayer
What is lecithin?
A food additive with a mixture of various phospholipids used as an emulsifier or lubricant
What is the function of the lipid bilayer in cell membranes?
Keeps ions, proteins, etc., where needed and prevents them from diffusing out of the cell
What are steroids made of?
Four carbon rings
What is an example of a steroid and its functions?
Cholesterol; functions in the nervous system, part of the cell membrane, and as derivatives like testosterone & estrogen
What are waxes made of?
Long carbon chains
Give examples of waxes.
- Beeswax
- Earwax
- Covering in plants
What is fat?
A type of lipid used for energy storage
