$$\text{Water moves from low solute concentration to high solute concentration across a membrane}$$

$$3\ \text{Na}^+ \ \text{out} \ + \ 2\ \text{K}^+ \ \text{in} \ + \ \text{ATP} \rightarrow \text{Pump Activation}$$

Question 1

Which of the following best describes the structure of a phospholipid in the cell membrane?

Accepted Answer

A molecule with two hydrophobic tails and a hydrophilic head

Question 2

What effect does cholesterol have on membrane fluidity at low temperatures?

Accepted Answer

Cholesterol increases membrane fluidity by preventing tight packing of phospholipids

Question 3

A freshwater Paramecium lives in a hypotonic environment. Which cellular structure helps it maintain water balance?

Accepted Answer

Contractile vacuole

Question 4

Which equation best represents the movement of water during osmosis?

Accepted Answer

$$	ext{Water moves from low solute concentration to high solute concentration across a membrane}$$

Question 5

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

Accepted Answer

DNA replication

Question 6

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

Accepted Answer

The cell will lose water and shrivel

Question 7

Which of the following statements about facilitated diffusion is correct?

Accepted Answer

Facilitated diffusion uses transport proteins to move substances down their concentration gradient

Question 8

Which equation describes the sodium-potassium pump’s action in animal cells?

Accepted Answer

$$3\ 	ext{Na}^+ \ 	ext{out} \ + \ 2\ 	ext{K}^+ \ 	ext{in} \ + \ 	ext{ATP} ightarrow 	ext{Pump Activation}$$

Question 9

Which scenario best illustrates cotransport in animal cells?

Accepted Answer

Glucose is transported into intestinal cells along with Na+ as Na+ diffuses down its concentration gradient

Question 10

Which of the following is a real-world consequence of defective LDL receptor proteins in humans?

Accepted Answer

Cholesterol accumulates in the blood, increasing risk of heart disease

Question 11

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

Accepted Answer

Membranes are fluid structures with proteins and lipids able to move laterally

Question 12

Which type of signaling molecule is most likely to bind to an intracellular receptor?

Accepted Answer

A small, hydrophobic steroid hormone

Question 13

Which of the following is NOT a step in cell signaling?

Accepted Answer

Protein synthesis

Question 14

Which equation best represents the electrochemical gradient for ion movement?

Accepted Answer

$$	ext{Electrochemical Gradient} = 	ext{Chemical Gradient} + 	ext{Electrical Gradient}$$

Question 15

Which process is used by cells to secrete large molecules, such as insulin, into the bloodstream?

Accepted Answer

Exocytosis

Question 16

Which of the following is a key feature of receptor-mediated endocytosis?

Accepted Answer

It is triggered by solute binding to specific receptors

Question 17

Which of the following best describes apoptosis?

Accepted Answer

Programmed cell death involving the orderly breakdown of cellular components

Question 18

Which protein acts as a master regulator of apoptosis in Caenorhabditis elegans?

Accepted Answer

Ced-9

Question 19

Which of the following is a real-world example of apoptosis during human development?

Accepted Answer

Formation of fingers and toes by removal of cells between them

Question 20

Which of the following is true about the permeability of the lipid bilayer?

Accepted Answer

Hydrophobic molecules pass through rapidly, while hydrophilic molecules pass through slowly or not at all

Membrane Structure, Function, and Cell Communication: Study Notes

Study Guide - Practice Questions