- Plasma Membrane: The flexible plasma membrane is composed of lipids and proteins, observed through an electron microscope.
- Water Uptake: Unicellular freshwater organisms and most plant cells gain water through osmosis, and plant roots absorb water via osmosis.
- Diffusion’s Importance: Diffusion is vital for gas and water exchange within cells.
- Nutrient Acquisition: Cells obtain nutrition from their surroundings.
- Energy-Dependent Transport: Some molecules move in and out of the cell through active transport mechanisms requiring energy.
- Endocytosis: The cell membrane’s flexibility enables endocytosis, where cells engulf food and materials from their environment. Amoeba uses this process for feeding.