Active Transport and Cellular Processes

This page covers essential concepts in cellular transport, focusing on active transport, osmosis, and diffusion. It also explores the structure and function of cell membranes.

Definition: Active transport is the movement of molecules from a low concentration to a high concentration, against the concentration gradient. This process requires energy.

Example: An example of a substance that moves by active transport is starch or other large molecules.

The page includes a question prompting a full description of the active transport process and examples of substances that move by this mechanism.

Highlight: The cell membrane plays a crucial role in controlling the entry and exit of molecules into and out of the cell.

The document introduces key terms related to osmosis:

Vocabulary:

• Osmosis: Passive movement of water molecules from a high water concentration to a low water concentration down a water concentration gradient
• Plasmolysed: A description of a plant cell that has become shrunken due to water loss. Cytoplasm detaches from cell wall.
• Turgid: A description of a plant cell that has become swollen due to water gain. Does not burst due to the cell wall.

The page includes diagrams and questions about osmosis effects on different cell types, such as leaf cells and red blood cells.

Definition: Diffusion is the passive movement of molecules from a high concentration to a low concentration down a concentration gradient.

The document lists examples of substances that move by diffusion substances movement passive gradient, including oxygen, carbon dioxide, glucose, amino acids, and urea.

Highlight: The cell membrane is selectively permeable, allowing only small, soluble molecules to pass through. This explains why glucose can move across the cell membrane, but larger molecules like starch cannot.

The page includes a diagram of a cell membrane, highlighting its two main components: phospholipids and proteins. This osmosis plasmolysed turgid label diagram terms meanings exercise reinforces understanding of membrane structure.

Overall, this page provides a comprehensive overview of cellular transport mechanisms, emphasizing the differences between active transport process description example and passive transport processes like osmosis and diffusion.