Lipids Quiz
Questions: 16 · 10 minutes
1. Which description best fits a saturated fatty acid?
A fatty acid containing one or more carbon-carbon double bonds
A fatty acid whose carbon chain contains no carbon-carbon double bonds
A lipid composed of four fused carbon rings
A glycerol molecule joined to three phosphate groups
2. Why are triglycerides and cholesterol packaged into lipoproteins for transport through blood?
Their structure allows largely water-insoluble lipids to travel in an aqueous fluid
Lipoproteins digest lipids before they reach the small intestine
Lipoproteins prevent lipids from ever entering body cells
Lipoproteins convert every lipid into a water-soluble carbohydrate
3. A phospholipid is placed in water. Which arrangement is most likely?
Its hydrophobic tails point toward the water while its heads cluster inside
It dissolves into separate glycerol and fatty-acid molecules immediately
Its hydrophilic heads face the water while its hydrophobic tails turn away
It forms a rigid carbohydrate layer around the water
4. A blockage prevents bile from reaching the small intestine. Which normal function involved in fat digestion is most directly reduced?
Breaking peptide bonds in dietary proteins
Emulsifying large fat droplets into smaller droplets
Absorbing glucose through intestinal transporters
Converting amino acids into stomach acid
5. Two fatty acids have equal chain lengths, but one contains several cis double bonds. Why is that fatty acid generally less able to pack tightly?
The cis configuration removes every hydrogen atom from the chain
The double bonds turn its hydrocarbon chain into a charged region
The double bonds attach extra glycerol molecules to the chain
The cis double bonds introduce bends into its carbon chain
6. During prolonged exercise, stored triglycerides in adipose tissue are mobilized. What directly results from triglyceride breakdown there?
The triglycerides are converted intact into glycogen
The adipose cells release only amino acids
Fatty acids and glycerol are produced for further transport or metabolism
The fatty acids remain permanently trapped inside the triglycerides
7. During digestion in the small intestine, pancreatic lipase acts mainly on triglycerides to produce which substances?
Glucose and phosphate
Amino acids and glycerol
Cholesterol and nucleotides
Free fatty acids and monoacylglycerols
8. A cell is breaking fatty acids into acetyl-CoA for energy. In human cells, where does most routine fatty-acid beta-oxidation occur?
Inside the Golgi apparatus
In the nucleus
In the mitochondria
Within the extracellular fluid
9. What are the three main components of a typical triglyceride molecule?
Three glycerol molecules and one fatty acid
One glycerol molecule and three fatty acids
One phosphate group, glycerol, and one amino acid
Four fused carbon rings and a hydroxyl group
10. A condition greatly reduces a person's ability to absorb dietary fat. Which vitamin group would be most directly affected?
Vitamins A, D, E, and K
Vitamins B1, B2, B6, and B12
Vitamin C and the B vitamins
Vitamins B9 and C only
11. How can a layer of subcutaneous fat contribute to temperature regulation in a cold environment?
It converts all stored energy directly into heat without metabolism
It increases heat transfer from internal tissues to the skin
It prevents blood from circulating near the skin
It slows heat transfer between the body and the surroundings
12. Compared with hydrated glycogen, why are triglycerides especially efficient for long-term energy storage?
They are highly reduced and stored with little associated water
They bind large amounts of water, increasing stored energy per gram
They contain nitrogen that can be released as usable energy
They produce energy without undergoing chemical reactions
13. Why are phospholipids described as amphipathic?
They alternate between solid and gaseous states in water
They contain both a water-attracting region and a water-repelling region
They are built entirely from charged amino acids
They can store genetic information as well as chemical energy
14. What does it mean when a fatty acid is described as essential in human nutrition?
It can be obtained only from animal-derived foods
It is the only type of fatty acid the body can store
The body cannot make enough of it, so it must be obtained from the diet
It must be consumed at every meal because it cannot be stored
15. A cell must keep its membrane functional as environmental temperature falls. Which change would generally help preserve membrane fluidity?
Increasing the proportion of unsaturated fatty-acid tails
Replacing phospholipids with long carbohydrate chains
Removing all membrane proteins and cholesterol
Increasing only long, fully saturated fatty-acid tails
16. A cell uses cholesterol to synthesize another class of signaling molecules. Which products can be made from cholesterol?
Glycogen molecules
Nucleic acids
Most protein hormones
Steroid hormones