Lipids Part I: Chemical Composition and Properties

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Which fatty acid has four double bonds?

Arachidonic acid (correct)

Myristic acid

Palmitoleic acid

Cervonic acid

What is the effect of increasing carbon length on a fatty acid?

Thickens the membrane and lowers its melting point

Thickens the membrane and raises its melting point (correct)

Makes the membrane less fluid

Decreases the stability of the membrane

Where is cervonic acid abundantly found?

Lung tissue

Skin cells

Kidneys

Retinal photoreceptors (correct)

Which lipid class is essential for the formation and maintenance of cellular membranes?

Phospholipids (B) Signup and view all the answers

What are the breakdown products of triacylglycerols under normal conditions?

Fatty acids and glycerol (D) Signup and view all the answers

Which polar group is NOT possible in phospholipids?

Glutamine (B) Signup and view all the answers

What does increasing double bonds do to a membrane?

Makes it more flexible and lowers its melting point (D) Signup and view all the answers

What is the solubility characteristic of lipids?

Soluble in nonpolar solvents (A) Signup and view all the answers

Where is the amphipathic property of lipids useful?

In cell membrane (A) Signup and view all the answers

How are lipids classified?

Based on chemistry and chemical properties (D) Signup and view all the answers

What do fatty acids consist of?

Long chains of hydrocarbons (A) Signup and view all the answers

How does chain length affect the hydrophobicity and melting point of fatty acids?

Longer chains mean more hydrophobic and higher melting points (A) Signup and view all the answers

What influences the fluidity and melting point of fatty acids?

Degree of unsaturation and chain length (C) Signup and view all the answers

In which type of solvents do lipids associate together?

Polar solvents (C) Signup and view all the answers

What are the two factors influencing the characteristics of fatty acids?

Chain length and degree of saturation (D) Signup and view all the answers

Why does the rod outer segment membrane require a high degree of fluidity?

To facilitate visual transduction function (C) Signup and view all the answers

Which fatty acid is responsible for the high degree of fluidity in the rod outer segment membrane?

Cervonic acid (D) Signup and view all the answers

How does cervonic acid composition vary between red blood cell (RBC) and rod outer segment membranes?

Cervonic acid percent in rod outer segment is almost 6 times greater than that of RBC plasma membranes (B) Signup and view all the answers

What are isoprenoids?

Biological compounds built from 5 carbon units called isoprene (B) Signup and view all the answers

What are the structural components of cholesterol?

Cholesterol, vitamin A, and coenzyme Q (C) Signup and view all the answers

What is the contribution of cholesterol for ocular functions?

Cholesterol makes up 8% of the lipids of disc membranes (B) Signup and view all the answers

What is a chalazion?

A granulomatous inflammation of the eyelid margins (C) Signup and view all the answers