Question 1

Which of the following best describes the difference between an aldosugar and a ketosugar, as shown in the provided images?

Accepted Answer

Aldosugars have a terminal carbonyl group, while ketosugars have an internal carbonyl group.

Question 2

Which type of glycosidic bond is found in cellulose, and what is its significance for the structure of plant cell walls?

Accepted Answer

Cellulose contains $\beta(1 \rightarrow 4)$ glycosidic bonds, which allow the formation of rigid, linear microfibrils.

Question 3

A seed’s storage material is dissolved only by amylase, not by peptidase or glycoside hydrolases. What does this indicate about the storage material?

Accepted Answer

The seed contains starch as its storage material.

Question 4

Which of the following statements about fatty acids is correct?

Accepted Answer

Fatty acids are long, unbranched hydrocarbon chains with a carboxyl group at one end, serving as building blocks for other lipids.

Question 5

Which of the following best explains why triacylglycerols with mostly saturated fatty acids are solid at room temperature?

Accepted Answer

Saturated fatty acids pack closely together due to the absence of double bonds, increasing van der Waals interactions.

Question 6

Which of the following is a correct description of the amphipathic nature of phospholipids?

Accepted Answer

Phospholipids have both a polar (hydrophilic) head and a nonpolar (hydrophobic) tail.

Question 7

Which of the following is a major structural difference between starch and cellulose?

Accepted Answer

Starch is composed of $\alpha$-D-glucose units, while cellulose is composed of $\beta$-D-glucose units.

Question 8

Which of the following fatty acids is polyunsaturated, based on the provided table?

Accepted Answer

Linolenate (18 carbons, 3 double bonds)

Question 9

Which of the following best describes the process of triacylglycerol synthesis?

Accepted Answer

Three fatty acids are esterified to a glycerol backbone, releasing three molecules of water.

Question 10

Which of the following statements about steroids is correct?

Accepted Answer

Steroids are characterized by a four-ringed hydrocarbon skeleton and include hormones such as testosterone and estradiol.

Question 11

Which of the following best explains why cis double bonds in unsaturated fatty acids increase membrane fluidity?

Accepted Answer

Cis double bonds introduce kinks in the fatty acid chains, preventing tight packing.

Question 12

Which of the following is a function of glycolipids in the plasma membrane?

Accepted Answer

They are involved in cell recognition and are found mainly on the outer monolayer of the plasma membrane.

Question 13

Which of the following best describes the general trend in the structure of biological polymers?

Accepted Answer

The order and bonding of monomers form the basis for the three-dimensional structure and therefore function of the polymer.

Question 14

A patient is found to have a genetic defect that prevents the synthesis of $\beta(1 \rightarrow 4)$ glycosidic bonds. Which of the following would most likely be affected?

Accepted Answer

The structure of cellulose in plant cell walls.

Question 15

Which of the following is true regarding the difference between amylose and amylopectin?

Accepted Answer

Amylose is unbranched, while amylopectin is branched due to $\alpha(1 \rightarrow 6)$ linkages.

Question 16

Which of the following best explains why trans fats are considered unhealthy compared to cis fats?

Accepted Answer

Trans fats have straighter chains, allowing tighter packing and increasing the risk of cardiovascular disease.

Question 17

Which of the following is a correct pairing of a polysaccharide and its primary biological function?

Accepted Answer

Glycogen – energy storage in animals

Question 18

Which of the following is a correct statement about the role of cholesterol in animal cell membranes?

Accepted Answer

Cholesterol modulates membrane fluidity by preventing tight packing of phospholipids at low temperatures.

Polysaccharides and Lipids: Structure, Function, and Biological Significance

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