2.6.3 Phospholipids, Waxes, and Steroids Flashcards
1
Q
phospholipids
A
- components of cell membranes that have both polar and nonpolar ends
- similar to triglycerides, but they have two fatty acids
attached to the glycerol molecule instead of three, and they have a phosphate group. - The phosphate end of a phospholipid can have charged molecules attached to it. This end is polar, and thus hydrophilic. The fatty acid end is nonpolar, and therefore hydrophobic. Because phospholipids have both polar and nonpolar ends, they can readily form a lipid bilayer.
2
Q
waxes
A
- lipids that make up the cuticle of a leaf and serve as protective filters for organs, such as the ear
3
Q
steroids
A
- lipids that are composed of four fused rings
- water insoluble molecules that consist of four fused carbon rings. One important steroid is cholesterol.
• Cholesterol is a component of bile, a substance that the body makes for the digestion of fats.
• When exposed to UV light, cholesterol forms Vitamin D.
• Many sex hormones are formed from a cholesterol precursor.
4
Q
Which are the most abundant lipids in the body?
A
- phospholipids
5
Q
Which lipid has a structure that consists of a backbone formed by four fused carbon rings?
A
- cholesterol
6
Q
True or false?
Some sex hormones are produced from cholesterol.
A
- true
7
Q
Phosphorus is an important component of lipids that are involved in
A
- cell membranes
8
Q
Which statement about membrane phospholipids is not true?
a. Membrane phospholipids have three fatty acid components.
b. Membrane phospholipids have hydrophilic heads.
c. Membrane phospholipids have hydrophobic tails.
d. Membrane phospholipids can contain unsaturated fatty acids.
A
- a. Membrane phospholipids have three fatty acid components
9
Q
Fats, phospholipids, and steroids have which of the following characteristics in common?
A
- they are not soluble in water
10
Q
Which of the following is the most abundant membrane lipid?
A
- phospholipids
