In Passive Processes, Substances Move Across the Plasma Membrane 1

question 12

Multiple Choice

In passive processes, substances move across the plasma membrane 1. with the use of ATP
2) up (or against) a concentration gradient
3) down (or along) a pressure gradient
4) equally in all directions

• A) 3 only
• B) 2 only
• C) 1, 2, 3
• D) 2, 3, 4

---

Definitions:

Connexin Molecules

Protein molecules that assemble into gap junctions, facilitating communication between adjacent cells by allowing the passage of ions and small molecules.

Sodium-Potassium Pump

A vital cell membrane protein that transports sodium ions out of and potassium ions into cells, maintaining cellular electrochemical gradients.

Carrier Protein

A type of membrane protein involved in facilitated diffusion, helping to transport substances across a cell membrane without expenditure of energy.

Sodium Ion

An atom of sodium that has lost one electron to form a positively charged ion (Na+), crucial for nerve transmission and fluid balance in the body.