Question 1

Which of the following statements best explains why sucrose does NOT act as a reducing sugar?

Accepted Answer

Because both anomeric carbons are involved in the glycosidic bond, leaving no free hemiacetal group.

Question 2

A carbohydrate has the molecular formula $$C_6H_{12}O_6$. Which of the following best describes this molecule?

Accepted Answer

It is a hexose monosaccharide.

Question 3

Which of the following best describes the difference between D- and L-glucose?

Accepted Answer

The orientation of the -OH group on the chiral carbon furthest from the carbonyl group.

Question 4

How many possible stereoisomers exist for an aldohexose sugar?

Accepted Answer

$$2^4 = 16$

Question 5

Which of the following statements about mutarotation is TRUE?

Accepted Answer

It occurs when a sugar with a free hemiacetal group equilibrates between its α and β forms in solution.

Question 6

Which of the following best explains why cartilage is 'springy' and acts as a shock absorber in joints?

Accepted Answer

Glycosaminoglycans in cartilage are highly negatively charged, causing electrostatic repulsion and attracting water.

Question 7

Which of the following is TRUE regarding the hydrolysis of a glycosidic bond in a disaccharide?

Accepted Answer

It requires an acid catalyst to proceed efficiently.

Question 8

Which of the following best describes the structure and function of waxes in nature?

Accepted Answer

They are esters formed from long-chain fatty acids and long-chain alcohols, providing waterproofing.

Question 9

Which of the following statements about the hydrogenation of vegetable oils is CORRECT?

Accepted Answer

Hydrogenation converts some cis double bonds to trans, increasing the melting point and producing semi-solid fats.

Question 10

Which of the following best explains why soaps are effective at removing grease from hands?

Accepted Answer

Soaps are amphipathic, forming micelles that trap grease with their hydrophobic tails and allow it to be washed away by water.

Question 11

Which of the following is a key difference between phosphoglycerides and sphingolipids in cell membranes?

Accepted Answer

Phosphoglycerides use ester linkages, while sphingolipids use amide linkages to attach fatty acids.

Question 12

Which of the following best describes the role of cholesterol in animal cell membranes?

Accepted Answer

It modulates membrane fluidity, preventing the membrane from becoming too rigid or too fluid.

Question 13

Which of the following statements about the fluid-mosaic model of cell membranes is CORRECT?

Accepted Answer

Membranes are dynamic structures with proteins and lipids that can move laterally within the bilayer.

Question 14

Which of the following best describes the difference between passive and active transport across cell membranes?

Accepted Answer

Passive transport moves substances down their concentration gradient without energy input; active transport moves substances against their gradient using energy.

Question 15

Which of the following is the precursor for all eicosanoid signaling molecules?

Accepted Answer

Arachidonic acid

Question 16

A patient is prescribed aspirin to reduce inflammation. Which enzyme does aspirin inhibit to achieve this effect?

Accepted Answer

Cyclooxygenase (COX)

Question 17

Which of the following best describes how steroid hormones exert their effects on target cells?

Accepted Answer

They diffuse through the cell membrane and bind to cytosolic or nuclear receptors, directly regulating gene expression.

Question 18

Which of the following best describes the sequence of events in the G-protein-coupled receptor (GPCR) mechanism for peptide hormones?

Accepted Answer

Hormone binds receptor → G-protein exchanges GDP for GTP → G-protein activates adenylate cyclase → cAMP is produced.

Question 19

Which of the following best describes the difference between ligand-gated and voltage-gated ion channels in neurons?

Accepted Answer

Ligand-gated channels open in response to neurotransmitter binding, while voltage-gated channels open in response to changes in membrane potential.

Chem 1120 Study Guide: Carbohydrates, Lipids, and Chemical Messengers

Guida di studio - Domande di pratica

Study guide - Flashcard