Active Transport in Cells

Overview

This lecture explains the process of active transport in cells, focusing on how plant root hair cells absorb mineral ions from the soil.

Diffusion is the passive movement of substances from high to low concentration and requires no energy.
Active transport moves molecules from low to high concentration, against the gradient, and requires energy from the cell.
Active transport always occurs across a membrane and involves special membrane proteins.

The energy required for active transport comes from cellular respiration.
Cellular respiration mainly occurs in mitochondria and releases energy by breaking down glucose.
The cell stores and transports energy using ATP (adenosine triphosphate) molecules.

Plant roots absorb water and mineral ions from the soil using root hair cells.
Root hair cells have long hair-like extensions, increasing their surface area for absorption.
Mineral ions are often in lower concentration in the soil than inside the cell, so plants use active transport to absorb them.
Root hair cells contain many mitochondria to supply the energy needed for active transport.

Diffusion — passive movement of molecules from high to low concentration, requiring no energy.
Active Transport — movement of molecules across a membrane from low to high concentration, requiring cellular energy.
Cell Membrane — the barrier surrounding cells, regulating molecule entry and exit.
Cellular Respiration — process in mitochondria that releases energy by breaking down glucose.
ATP (Adenosine Triphosphate) — molecule that stores and transports energy within cells.
Root Hair Cell — plant cell specialized to absorb water and minerals, adapted with a large surface area and many mitochondria.