Question 1

Which of the following best explains why lipids are not considered true polymers like carbohydrates, proteins, and nucleic acids?

Accepted Answer

Lipids are not made from repeating monomer units joined by covalent bonds.

Question 2

A scientist observes that when she adds a certain enzyme to a reaction, the activation energy decreases and the reaction rate increases. Which property of enzymes does this observation best illustrate?

Accepted Answer

Enzymes act as biological catalysts.

Question 3

Which of the following correctly matches a biological macromolecule with its monomer and the bond formed during polymerization?

Accepted Answer

Protein – amino acid – peptide bond

Question 4

A red blood cell is placed in a hypotonic solution. What will most likely happen to the cell?

Accepted Answer

Water will enter the cell by osmosis, causing it to swell and possibly burst (lyse).

Question 5

Which of the following statements about facilitated diffusion is correct?

Accepted Answer

It requires membrane proteins but does not require cellular energy.

Question 6

Which of the following best describes the difference between saturated and unsaturated fatty acids?

Accepted Answer

Saturated fatty acids have no double bonds between carbon atoms, while unsaturated fatty acids have one or more double bonds.

Question 7

Which of the following molecules can most easily cross a phospholipid bilayer by simple diffusion?

Accepted Answer

Oxygen (O$$_2)$$

Question 8

Which of the following best explains why carbon is uniquely suited to be the backbone of life’s molecules?

Accepted Answer

Carbon can form four covalent bonds, allowing for a diversity of stable structures.

Question 9

A dialysis tubing experiment is set up with a starch solution inside the tubing and water outside. After several hours, iodine is added to the water outside and turns blue-black. What does this result indicate about the permeability of the tubing?

Accepted Answer

Iodine molecules crossed the tubing into the starch solution, but starch did not cross out.

Question 10

Which of the following is a correct statement about dehydration synthesis and hydrolysis reactions?

Accepted Answer

Dehydration synthesis removes a water molecule to build a polymer; hydrolysis adds a water molecule to break a polymer.

Question 11

Which of the following best describes the role of ATP in cellular energy transfer?

Accepted Answer

ATP stores and releases energy by breaking and forming phosphate bonds.

Question 12

Which of the following functional groups is correctly matched with its property?

Accepted Answer

Amino group (–NH$$_2$$): acts as a base and can accept H$$^+$$

Question 13

Which process is responsible for the movement of glucose into a cell when the concentration of glucose is higher outside the cell than inside, and the cell does not expend energy?

Accepted Answer

Facilitated diffusion

Question 14

Which of the following statements about secondary active transport is correct?

Accepted Answer

It uses the energy stored in an electrochemical gradient created by primary active transport.

Question 15

Which of the following best describes what happens to an enzyme when it is denatured?

Accepted Answer

It loses its three-dimensional shape and biological function.

Question 16

Which of the following is a property of phospholipids that allows them to form cell membranes?

Accepted Answer

They have both hydrophilic heads and hydrophobic tails, allowing them to form bilayers.

Question 17

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

Accepted Answer

Passive transport does not require energy and moves substances down their concentration gradient; active transport requires energy and moves substances against their concentration gradient.

Question 18

Which of the following is a true statement about isomers formed by carbon compounds?

Accepted Answer

Isomers have the same molecular formula but different structural arrangements.

Question 19

Which of the following is a correct match between a macromolecule and one of its major functions?

Accepted Answer

Proteins – catalyze biochemical reactions

Question 20

A fermentation tube is used in a lab experiment. After several hours, bubbles are observed in the tube. What do these bubbles most likely indicate?

Accepted Answer

Production of CO$$_2$$ gas from fermentation

Biology Exam 2 Review: Macromolecules, Membranes, Enzymes, and Cellular Processes

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