Mastering biology ch 6- lipids

fats steroids phospholipids

3 most important types of lipids found in cells:

Cholesterol and phospholipids contain both hydrophilic and hydrophobic regions; fats are primarily hydrophobic.

why cholesterol and phospholipids are amphipathic but fats are not?

as a component of animal cell membranes

A function of cholesterol that does not harm health is its role _____. -All of cholesterol's effects cause the body harm. -the most abundant male sex hormone -as a component of animal cell membranes -in calcium and phosphate metabolism -as the primary female sex hormone

Lipids are mostly nonpolar

How can a lipid be distinguished from a sugar?

Hypotonic (The salt concentration in the solution is lower than it is in the cell, so water enters the cell, causing it to burst.)

If a red blood cell is placed in a salt solution and bursts, what is the tonicity of the solution relative to the interior of the cell?

polar heads and nonpolar tails; the polar heads interact with water

Lipids that form membranes have what kind of structure?

the most double bonds.

The most unsaturated fats have ... the fewest double bonds. the most double bonds. the highest ratio of H to C. the longest hydrocarbon tails. the shortest hydrocarbon tails.

(a) rich in energy. (b) insoluble in water.

The presence of many C-C and C-H bonds causes fats to be ... (a) rich in energy. (b) insoluble in water. (c) low in energy. Both (a) and (b). Both (b) and (c).

True (The hydrophilic, or water-loving, portion of a phospholipid is the polar head, whereas the hydrophobic portion is the nonpolar tail.)

True or false? The water-soluble portion of a phospholipid is the polar head, which generally consists of a glycerol molecule linked to a phosphate group.

They contain carbonyl groups.

What do DNA, proteins, and fats have in common?

Amphipathic nature (Detergents form micelles around the grease, which are then washed away because the polar head groups facing outward on the micelle are water-soluble.)

What property of dishwashing liquid (detergent) makes it useful to wash grease from pans?

The polarity of membrane phospholipids

Which of the following factors does not affect membrane permeability? -The polarity of membrane phospholipids -The saturation of hydrocarbon tails in membrane phospholipids -The amount of cholesterol in the membrane -Temperature

Because cholesterol is amphipathic, it fits in between the phospholipids and blocks diffusion through the membrane

Which of the following is the best explanation for why cholesterol decreases the permeability of biological membranes?

Oxygen (O2) (Small nonpolar molecules such as oxygen can diffuse across cell membranes.)

Which of the following particles could diffuse easily through a cell membrane? Sodium ion (Na+) Glucose Hydrogen ion (H+) Oxygen (O2)

RNA (RNA is a nucleic acid)

Which of these is NOT a lipid? cholesterol wax phospholipid steroids RNA

Olive oil (It is a plant oil, and most plant oils are rich in unsaturated fats.)

Which of these is rich in unsaturated fats? olive oil lard butter beef fat a fat that is solid at room temperature