AP Biology Flashcards: Mechanisms of Transport
Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026
Review key ideas with interactive flashcards. This set includes 10 cards to help you master important concepts.
What is active transport?
Active transport is the movement of molecules and ions across a cell membrane that requires the input of metabolic energy, such as from ATP.
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What is active transport?
Active transport is the movement of molecules and ions across a cell membrane that requires the input of metabolic energy, such as from ATP.
Why is the term 'active' used to describe this form of transport?
It is called 'active' because it requires the cell to expend its own metabolic energy (ATP) to move substances, often against their concentration gradient.
If a cell's production of ATP was suddenly halted, how would this immediately affect the Na+/K+ pump?
The Na+/K+ pump would cease to function because it relies on the metabolic energy from ATP to actively transport ions across the membrane.
What is the role of membrane proteins in active transport?
Membrane proteins, such as the Na+/K+ pump, act as carriers or channels that use energy to move specific ions and molecules across the membrane.
What is the primary outcome of active transport across a membrane?
Active transport establishes and maintains electrochemical gradients across the membrane.
What is the primary source of energy for active transport?
The primary source of energy for active transport is metabolic energy, with ATP being a key example.
What two things are established and maintained by the energy-requiring movement of ions and molecules across a membrane?
The active transport of ions and molecules across a membrane establishes and maintains electrochemical gradients.
What is an electrochemical gradient?
An electrochemical gradient is a difference in both electrical potential and chemical concentration across a membrane, which is established and maintained by active transport.
Name a specific membrane protein that carries out active transport.
The Na+/K+ pump is an example of a membrane protein that carries out active transport.
How are metabolic energy and electrochemical gradients related?
Metabolic energy (from ATP) is used to power active transport, which in turn creates and maintains electrochemical gradients.