Question 1

Which of the following statements best explains why lipids do NOT form polymers like carbohydrates, proteins, and nucleic acids?

Accepted Answer

Lipids do not undergo dehydration synthesis to form covalent bonds between monomers.

Question 2

A student adds Benedict's reagent to an unknown solution and heats it. The solution turns red-orange. What does this indicate about the solution?

Accepted Answer

It contains a large amount of reducing sugars.

Question 3

Which of the following best describes the role of enzymes in biological reactions?

Accepted Answer

Enzymes decrease the activation energy, allowing reactions to occur faster.

Question 4

A dialysis bag filled with a solution containing starch and protein is placed in a beaker of water. After 30 minutes, which molecule is least likely to have diffused out of the bag and why?

Accepted Answer

Protein, because it is a large macromolecule that cannot easily cross the semipermeable membrane.

Question 5

Which of the following is a correct example of dehydration synthesis?

Accepted Answer

Linking two glucose molecules to form maltose and releasing a water molecule: $$C_6H_{12}O_6$ + C_6H_{12}O_6$ \rightarrow C$$_{12}$$H_{22}O$$_{11} + H_2O$

Question 6

Which macromolecule is primarily responsible for information storage in cells?

Accepted Answer

Nucleic acids

Question 7

A solution is tested with Lugol's (iodine) reagent and turns blue-black. What does this indicate?

Accepted Answer

The presence of starch, a complex carbohydrate.

Question 8

Which of the following best explains why cells must remain small in size?

Accepted Answer

As cell volume increases, surface area increases at a slower rate, limiting efficient diffusion.

Question 9

Which of the following is NOT a function of proteins in living organisms?

Accepted Answer

Long-term energy storage

Question 10

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

Accepted Answer

Water will leave the cell, causing it to shrink.

Question 11

Which of the following best describes facilitated diffusion?

Accepted Answer

Passive movement of molecules down their concentration gradient with the help of membrane proteins.

Question 12

Which chemical test would you use to confirm the presence of protein in a solution, and what color change would indicate a positive result?

Accepted Answer

Biuret's reagent; bright purple

Question 13

Which of the following best describes the effect of temperature on enzyme catalase activity?

Accepted Answer

Catalase activity increases with temperature up to an optimal point, then decreases as the enzyme denatures.

Question 14

Which of the following is a correct description of active transport?

Accepted Answer

Movement of molecules from low to high concentration using ATP and membrane proteins.

Question 15

Which of the following is a monomer of carbohydrates?

Accepted Answer

Glucose

Question 16

A solution is tested with Sudan IV reagent and forms an orange layer. What does this indicate?

Accepted Answer

The presence of lipids.

Question 17

Which of the following best explains why enzymes are specific to their substrates?

Accepted Answer

The active site of the enzyme has a unique shape that fits only specific substrates ('lock and key' fit).

Question 18

Which of the following is a correct summary of the reaction catalyzed by catalase?

Accepted Answer

$$2H_2O_2 \rightarrow 2H_2O + O_2$

Question 19

Which of the following conditions would most likely decrease the rate of an enzyme-catalyzed reaction?

Accepted Answer

Adding an enzyme inhibitor that alters the enzyme's shape.

Question 20

Which of the following elements is NOT a major component of all biological macromolecules?

Accepted Answer

Calcium

Organic Molecules, Macromolecules, Membrane Transport, and Enzyme Function: Study Guide

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