Lipids Chapter 21

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What is the main force driving the formation of lipid bilayers?

Hydrophobic interaction (correct)

Van der Waals forces

Ionic interactions

Hydrogen bonding

What is the characteristic of triglycerides rich in unsaturated fatty acids?

They are generally solids at room temperature

They are generally liquids at room temperature (correct)

They are generally semisolids at room temperature

They have a high melting point

What is the arrangement of hydrocarbon tails in the interior of lipid bilayers rich in unsaturated fatty acids?

Fluid (correct)

Compact crystalline

Disordered

Rigid

Why do triglycerides rich in unsaturated fatty acids have lower melting points?

Due to their three-dimensional shape Signup and view all the answers

What is the characteristic of the polar head groups in a lipid bilayer?

They are in contact with the aqueous environment Signup and view all the answers

What is the characteristic of triglycerides rich in saturated fatty acids?

They are generally semisolids or solids at room temperature Signup and view all the answers

What is the main component of the coatings of nerve axons?

Sphingolipids Signup and view all the answers

What is the name of the molecule from which glycerophospholipids are derived?

Phosphatidic acid Signup and view all the answers

What is the characteristic of the fatty acid on carbon 2 of glycerol in phosphatidic acids?

It is always unsaturated Signup and view all the answers

Why do unsaturated fatty acids have a lower melting point than saturated fatty acids?

Because they have a less ordered structure due to cis configuration of double bonds Signup and view all the answers

What is the most abundant steroid in the human body?

Cholesterol Signup and view all the answers

What is the purpose of hydrogenation hardening?

To produce higher melting point triglycerides Signup and view all the answers

What is the characteristic of glycerophospholipids in plant and animal membranes?

They make up 40% - 50% of the membrane Signup and view all the answers

What is the main carrier of cholesterol in the blood?

LDL Signup and view all the answers

What is a characteristic shared by all lipids?

Insolubility in water and solubility in organic solvents Signup and view all the answers

What type of compounds are produced through the partial hydrogenation of polyunsaturated oils?

Triglycerides with a desired consistency Signup and view all the answers

What is the alcohol component of sphingolipids?

Sphingosine Signup and view all the answers

What is the general structure of a triglyceride?

An ester of glycerol with three fatty acids Signup and view all the answers

What are the female sex hormones synthesized in the ovaries?

Estrogens Signup and view all the answers

What is the role of cholesteryl esters in the liver?

Synthesis of steroid hormones Signup and view all the answers

Where do HDL transport cholesterol from?

Peripheral tissues Signup and view all the answers

What is the function of COX-2?

Producing prostaglandins in inflammation Signup and view all the answers

What are the oxidation products of cholesterol?

Bile salts Signup and view all the answers

Where are androgens synthesized?

Testes Signup and view all the answers

Where are bile salts synthesized and stored?

In the liver and stored in the gallbladder Signup and view all the answers

What is the result of thromboxane A2 on platelets and blood vessels?

It induces platelet aggregation and vasoconstriction Signup and view all the answers

What is the effect of leukotrienes on the lungs?

They produce muscle contractions, especially in the lungs Signup and view all the answers

What is the mechanism of action of aspirin and other NSAIDs?

They inhibit the synthesis of thromboxanes Signup and view all the answers

What is the potency of leukotrienes relative to histamine?

They are 100 times more potent than histamine Signup and view all the answers