Q: Which of the following statements about the structure of starch and cellulose is correct?

Both are composed of glucose monomers, but starch has $oldsymbol{\alpha}$-glycosidic linkages while cellulose has $oldsymbol{\beta}$-glycosidic linkages.

Question 1

Which type of chemical bond is primarily responsible for the unique properties of water, such as its high surface tension and ability to dissolve many substances?

Accepted Answer

Hydrogen bonds

Question 2

A scientist is studying a protein and finds that a mutation has replaced a hydrophobic amino acid in the core of the protein with a hydrophilic one. What is the most likely effect on the protein's tertiary structure?

Accepted Answer

The protein will likely misfold or lose its functional shape.

Question 3

Which of the following best describes the difference between DNA and RNA?

Accepted Answer

DNA is usually double-stranded, while RNA is usually single-stranded.

Question 4

Given the DNA sequence $5'	ext{–}ATCGGTA–3'$ , what is the sequence of the complementary strand?

Accepted Answer

$3'	ext{–}TAGCCAT–5'$

Question 5

Which of the following is a correct statement about the formation of a peptide bond?

Accepted Answer

It is a covalent bond formed by dehydration synthesis between the amino group of one amino acid and the carboxyl group of another.

Question 6

A patient is diagnosed with a genetic disorder that affects the Na$^+$/K$^+$ ATPase pump in their cell membranes. Which of the following symptoms would most likely result from this defect?

Accepted Answer

Disrupted nerve impulse transmission due to inability to maintain proper ion gradients.

Question 7

Which of the following best explains why phospholipids form bilayers in aqueous environments?

Accepted Answer

Phospholipids have both hydrophilic heads and hydrophobic tails, causing them to arrange with heads facing water and tails facing inward.

Question 8

Which of the following molecules is most likely to cross a cell membrane by simple diffusion?

Accepted Answer

O$_2$

Question 9

A researcher adds a noncompetitive inhibitor to an enzyme-catalyzed reaction. What is the most likely effect on the reaction rate?

Accepted Answer

The maximum reaction rate ($V_{max}$) will decrease, but the substrate affinity ($K_m$) will remain unchanged.

Question 10

Which of the following best describes the role of chaperone proteins in cells?

Accepted Answer

They assist in the proper folding of other proteins and prevent aggregation.

Question 11

Which of the following is a correct statement about glycosidic linkages?

Accepted Answer

They are covalent bonds formed by dehydration synthesis between two monosaccharides.

Question 12

A cell is placed in a solution containing a high concentration of Na$^+$ ions. Which membrane protein would be most directly involved in maintaining the cell's internal environment?

Accepted Answer

Na$^+$/K$^+$ ATPase pump

Question 13

Which of the following statements about the structure of starch and cellulose is correct?

Accepted Answer

Both are composed of glucose monomers, but starch has $oldsymbol{\alpha}$-glycosidic linkages while cellulose has $oldsymbol{\beta}$-glycosidic linkages.

Question 14

Which of the following is NOT a function of membrane proteins?

Accepted Answer

Synthesizing DNA

Question 15

A mutation causes a protein to lose its quaternary structure but retain its tertiary structure. Which of the following is most likely true?

Accepted Answer

The protein is composed of a single polypeptide chain.

Question 16

Which of the following best explains why saturated fatty acids tend to make membranes less fluid than unsaturated fatty acids?

Accepted Answer

Saturated fatty acids lack double bonds, allowing them to pack closely together.

Question 17

Which of the following is a correct statement about passive and active transport across membranes?

Accepted Answer

Active transport moves molecules against their concentration gradient using energy.

Question 18

A scientist is analyzing a gel electrophoresis result for DNA, RNA, and protein samples. Which factor primarily determines how far each molecule migrates through the gel?

Accepted Answer

The molecule's size and charge

Question 19

Which of the following best describes the role of aquaporins in the cell membrane?

Accepted Answer

They facilitate the passive movement of water molecules across the membrane.

Question 20

A cell is exposed to a toxin that blocks GLUT transporters. Which process will be most directly affected?

Accepted Answer

Facilitated diffusion of glucose

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