Respiratory distress syndrome in premature infants is caused by a deficiency of

Question

Respiratory distress syndrome in premature infants is caused by a deficiency of a lipid surfactant in the lungs. The line-angle structure of this surfactant is shown to the right. Which of the following is not correct concerning this lipid? a. This is phosphatidyl choline which is also referred to as "lecithin." b. This substance is amphipathic. c. This compound is classified as a phosphoacylglycerol or a "phosphoglyceride." d. This compound is an example of a glycolipid because it contains a glycerol residue. e. The fatty acid residues in this lipid are attached by ester bonds. Which of the following is correct concerning membrane transport? a. Facilitated diffusion of glucose across the membrane of the erythrocyte (red blood cell) involves a specific transporter protein which moves it across the membrane down its concentration gradient. b. Since the structures are so similar, the same transporter protein is used for both glucose and glucose-6-phosphate. c. Small ions such as Cl^- (chloride) and Ca^2+ can freely cross membranes by simple passive diffusion. d. Active transport consumes energy to transport a substance from higher concentration to a lower concentration and produces energy when the substance moves from lower to higher concentrations. e. Facilitated transport and simple passive diffusion are essentially the same process.

Explanation / Answer

4)

It has choline residue as head group. So it is a phosphatidyl choline.

It has both hydrophilic and lipophilic group. So it is amphipatic.

Glycerophospholipids, also called phosphoglycerides, are membrane lipids in which two fatty acids are attached in ester linkage to the first and second carbons of glycerol, and a highly polar or charged group is attached through a phosphodiester linkage to the third carbon. So it is a phosphoglyceride.

Glycolipids are lipids with a carbohydrate attached by a glycosidic bond. Since there is no carbohydrate, this is not an example of glycolipid.

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