At a Glance

Life on Earth Chapter 6 Cell Membrane Structure and Function
At a Glance

Cell Walls
The Plasma Membrane: The fluid mosaic model describes the structure of the plasma membrane.
The fluid portion of membranes is produced by a double layer of phospholipids: the phospholipid bilayer.
A variety of proteins in the cell membrane form a protein mosaic.

Transport across Membranes
Molecules in fluids move in response to gradients.
Movement across membranes occurs by both passive and energy-requiring transport.

Passive Transport: Movement down Concentration Gradients
Molecules diffuse from areas of high concentration to areas of low concentration.
Molecules diffuse across membranes down their concentration gradients.
Osmosis is the diffusion of water across membranes.
Osmosis across the cell membrane plays an important role in the lives of cells.

Energy-Requiring Transport across Membranes
Active transport uses energy to move molecules across membranes.
Cells engulf particles or fluids by endocytosis.

Transport across Intracellular Membranes
Vacuoles help regulate cell volume.

Cell Connections and Communication
Desmosomes attach cells together.
Tight junctions leakproof the cell.
Gap junctions and plasmodesmata allow communications between cells.; The fluid portion of membranes is produced by a double layer of phospholipids: the phospholipid bilayer.
A variety of proteins in the cell membrane form a protein mosaic.

Transport across Membranes
Molecules in fluids move in response to gradients.
Movement across membranes occurs by both passive and energy-requiring transport.

Passive Transport: Movement down Concentration Gradients
Molecules diffuse from areas of high concentration to areas of low concentration.
Molecules diffuse across membranes down their concentration gradients.
Osmosis is the diffusion of water across membranes.
Osmosis across the cell membrane plays an important role in the lives of cells.

Energy-Requiring Transport across Membranes
Active transport uses energy to move molecules across membranes.
Cells engulf particles or fluids by endocytosis.

Transport across Intracellular Membranes
Vacuoles help regulate cell volume.

Cell Connections and Communication
Desmosomes attach cells together.
Tight junctions leakproof the cell.
Gap junctions and plasmodesmata allow communications between cells.; A variety of proteins in the cell membrane form a protein mosaic.

Transport across Membranes
Molecules in fluids move in response to gradients.
Movement across membranes occurs by both passive and energy-requiring transport.

Passive Transport: Movement down Concentration Gradients
Molecules diffuse from areas of high concentration to areas of low concentration.
Molecules diffuse across membranes down their concentration gradients.
Osmosis is the diffusion of water across membranes.
Osmosis across the cell membrane plays an important role in the lives of cells.

Energy-Requiring Transport across Membranes
Active transport uses energy to move molecules across membranes.
Cells engulf particles or fluids by endocytosis.

Transport across Intracellular Membranes
Vacuoles help regulate cell volume.

Cell Connections and Communication
Desmosomes attach cells together.
Tight junctions leakproof the cell.
Gap junctions and plasmodesmata allow communications between cells.
Transport across Membranes: Molecules in fluids move in response to gradients.
Movement across membranes occurs by both passive and energy-requiring transport.

Passive Transport: Movement down Concentration Gradients
Molecules diffuse from areas of high concentration to areas of low concentration.
Molecules diffuse across membranes down their concentration gradients.
Osmosis is the diffusion of water across membranes.
Osmosis across the cell membrane plays an important role in the lives of cells.

Energy-Requiring Transport across Membranes
Active transport uses energy to move molecules across membranes.
Cells engulf particles or fluids by endocytosis.

Transport across Intracellular Membranes
Vacuoles help regulate cell volume.

Cell Connections and Communication
Desmosomes attach cells together.
Tight junctions leakproof the cell.
Gap junctions and plasmodesmata allow communications between cells.; Movement across membranes occurs by both passive and energy-requiring transport.

Passive Transport: Movement down Concentration Gradients
Molecules diffuse from areas of high concentration to areas of low concentration.
Molecules diffuse across membranes down their concentration gradients.
Osmosis is the diffusion of water across membranes.
Osmosis across the cell membrane plays an important role in the lives of cells.

Energy-Requiring Transport across Membranes
Active transport uses energy to move molecules across membranes.
Cells engulf particles or fluids by endocytosis.

Transport across Intracellular Membranes
Vacuoles help regulate cell volume.

Cell Connections and Communication
Desmosomes attach cells together.
Tight junctions leakproof the cell.
Gap junctions and plasmodesmata allow communications between cells.
Passive Transport: Movement down Concentration Gradients: Molecules diffuse from areas of high concentration to areas of low concentration.
Molecules diffuse across membranes down their concentration gradients.
Osmosis is the diffusion of water across membranes.
Osmosis across the cell membrane plays an important role in the lives of cells.

Energy-Requiring Transport across Membranes
Active transport uses energy to move molecules across membranes.
Cells engulf particles or fluids by endocytosis.

Transport across Intracellular Membranes
Vacuoles help regulate cell volume.

Cell Connections and Communication
Desmosomes attach cells together.
Tight junctions leakproof the cell.
Gap junctions and plasmodesmata allow communications between cells.; Molecules diffuse across membranes down their concentration gradients.
Osmosis is the diffusion of water across membranes.
Osmosis across the cell membrane plays an important role in the lives of cells.

Energy-Requiring Transport across Membranes
Active transport uses energy to move molecules across membranes.
Cells engulf particles or fluids by endocytosis.

Transport across Intracellular Membranes
Vacuoles help regulate cell volume.

Cell Connections and Communication
Desmosomes attach cells together.
Tight junctions leakproof the cell.
Gap junctions and plasmodesmata allow communications between cells.; Osmosis is the diffusion of water across membranes.
Osmosis across the cell membrane plays an important role in the lives of cells.

Energy-Requiring Transport across Membranes
Active transport uses energy to move molecules across membranes.
Cells engulf particles or fluids by endocytosis.

Transport across Intracellular Membranes
Vacuoles help regulate cell volume.

Cell Connections and Communication
Desmosomes attach cells together.
Tight junctions leakproof the cell.
Gap junctions and plasmodesmata allow communications between cells.; Osmosis across the cell membrane plays an important role in the lives of cells.

Energy-Requiring Transport across Membranes
Active transport uses energy to move molecules across membranes.
Cells engulf particles or fluids by endocytosis.

Transport across Intracellular Membranes
Vacuoles help regulate cell volume.

Cell Connections and Communication
Desmosomes attach cells together.
Tight junctions leakproof the cell.
Gap junctions and plasmodesmata allow communications between cells.
Energy-Requiring Transport across Membranes: Active transport uses energy to move molecules across membranes.
Cells engulf particles or fluids by endocytosis.

Transport across Intracellular Membranes
Vacuoles help regulate cell volume.

Cell Connections and Communication
Desmosomes attach cells together.
Tight junctions leakproof the cell.
Gap junctions and plasmodesmata allow communications between cells.; Cells engulf particles or fluids by endocytosis.

Transport across Intracellular Membranes
Vacuoles help regulate cell volume.

Cell Connections and Communication
Desmosomes attach cells together.
Tight junctions leakproof the cell.
Gap junctions and plasmodesmata allow communications between cells.
Transport across Intracellular Membranes: Vacuoles help regulate cell volume.

Cell Connections and Communication
Desmosomes attach cells together.
Tight junctions leakproof the cell.
Gap junctions and plasmodesmata allow communications between cells.
Cell Connections and Communication: Desmosomes attach cells together.
Tight junctions leakproof the cell.
Gap junctions and plasmodesmata allow communications between cells.; Tight junctions leakproof the cell.
Gap junctions and plasmodesmata allow communications between cells.; Gap junctions and plasmodesmata allow communications between cells.

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