Question 1

Which of the following best describes the structure of the plasma membrane according to the fluid mosaic model?

Accepted Answer

Proteins embedded in two layers of phospholipids

Question 2

A red blood cell is placed in a hypotonic solution. What is the most likely outcome for the cell?

Accepted Answer

It will lyse (burst) due to water entering the cell.

Question 3

Which of the following statements about passive transport is FALSE?

Accepted Answer

Passive transport requires an input of energy from the cell.

Question 4

A cell contains a 1% sucrose solution and is placed in a beaker containing a 4% sucrose solution. The cell membrane is not permeable to sucrose. In which direction will water move?

Accepted Answer

Out of the cell, toward the higher sucrose concentration

Question 5

Which of the following best describes facilitated diffusion?

Accepted Answer

The movement of a polar substance down its concentration gradient through a membrane protein

Question 6

Which type of cellular work is performed when a cell pumps ions against their concentration gradient?

Accepted Answer

Transport work

Question 7

Energy is never created or destroyed. After your lawnmower runs out of gas and stops, what happened to the energy that was stored in the gas tank?

Accepted Answer

It was converted to heat.

Question 8

Which of the following is an example of an exergonic reaction?

Accepted Answer

Cellular respiration, where glucose is broken down to release energy

Question 9

If a chemical reaction is endergonic, how can you make it proceed in a cell?

Accepted Answer

Couple it to an exergonic reaction

Question 10

Which of the following best describes the role of ATP in cellular metabolism?

Accepted Answer

ATP provides energy by transferring a phosphate group to other molecules.

Question 11

The energy needed to initiate a chemical reaction is called:

Accepted Answer

Activation energy

Question 12

Which analogy best describes the relationship between an enzyme's active site and its substrate?

Accepted Answer

A key and a lock

Question 13

Why does sucrase not catalyze the breakdown of maltose?

Accepted Answer

Maltose has a different structure and does not fit into the active site of sucrase.

Question 14

A toxin binds to and removes substance C from a metabolic pathway. What happens to the amount of substance B?

Accepted Answer

It increases because feedback inhibition is removed.

Question 15

Penicillin is effective against bacteria but not human cells because:

Accepted Answer

It targets a structure not found in eukaryotic cells.

Question 16

Which of the following statements about aquaporins is TRUE?

Accepted Answer

Aquaporins form specific protein channels for water diffusion.

Question 17

Which of the following best explains why a plasma membrane is described as a 'fluid mosaic'?

Accepted Answer

It is composed of various molecules that move freely within the layer.

Question 18

Which of the following is a property shared by diffusion, osmosis, and facilitated diffusion?

Accepted Answer

They are all types of passive transport.

Question 19

Which of the following best describes the difference between competitive and noncompetitive enzyme inhibitors?

Accepted Answer

Competitive inhibitors bind to the active site; noncompetitive inhibitors bind elsewhere and change the active site.

Question 20

A protein such as aquaporin can interact with both polar and nonpolar regions of the membrane because:

Accepted Answer

It contains amino acids with both hydrophilic and hydrophobic side chains.

Guided Study: Membrane Structure, Transport, Energy, and Enzymes in Cells

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