Exam 1: Lipids, membranes, and cells Flashcards
What is the polarity of lipids?
Non-polar
What are the three types of lipids?
Fats, Steroids, Phospholipids
How do lipids form?
Dehydration reactions (remove a water)
What is a fatty acid? What does it look like?
A simple lipid
Hydrocarbon chain bonded to polar carboxyl functional group (-COOH)
What is the difference between a saturated fatty acid and an unsaturated fatty acid?
Unsaturated fatty acids have double bonds
What is the effect of a double bond on the structure of a fatty acid?
There is a kink
Do saturated fatty acids or unsaturated fatty acids have a higher boiling point?
Saturated fatty acids
What is a glycerol?
3 carbon chain; each carbon bonded to a hydroxyl
What is the structure of a fat?
A glycerol linked to three fatty acids
How are fats formed?
Ester linkages; dehydration synthesis b/t hydroxyl group of GLYCEROL and carboxyl group of free FATTY ACID
What is the structure of steroids?
Four carbon rings with a hydroxyl group
What are steroids derived from?
Cholesterol
Why are steroids slightly soluble in water?
They have a hydroxyl group
What are the three components of a phospholipid?
Phosphate group, glycerol, two fatty acids
What makes up the polar (hydrophilic) head of a phospholipid?
Phosphate group
What makes up the nonpolar (hydrophobic) tail of a phospholipid?
Fatty acid
What are the two main components of the cell membrane?
Steroids and phospholipids
What are the three mechanisms of membrane transport?
- Diffusion
- Facilitated diffusion
- Active transport
Rank the four types of molecules in order of decreasing membrane permeability:
- Small, nonpolar molecules (O2, CO2)
- Small, uncharged, polar molecules (H2O, glycerol)
- Large, uncharged, polar molecules (glucose)
- Ions (Cl-)
What are four factors that affect membrane permeability?
- Number of double bonds on the fatty acids
- Length of the tail
- Number of cholesterol molecules (more cholesterol = less permeable
- Temperature