1.3: Cell membranes and transport

What the cell membrane is made of.

Sheets of phospholipids facing each other.

Proteins that can be embedded in either surface of the phospholipid bilayer, and provide structural support, form recognition sites, identify cells and form receptor sites for hormone attachment.

Proteins that extend across both layers of the phospholipid bilayer, includes transport proteins.

Proteins that allow molecules or ions to pass through during active transport or facilitated diffusion.

Structural model of the plasma membrane where molecules are free to move within the bilayer.

A protein with one or more covalently attached carbohydrates. Used for cell-to-cell recognition.

Membrane carbohydrates that are covalently bonded to lipids. Used for cell-to-cell communication and maintaining stability of the membrane.

A carbohydrate coat that covers the cell surface, used in hormone receptors and cell-to-cell recognition and adhesion.

Passive transport that occurs when ions and molecules move from a high to low concentration area.

Allows water-soluble molecules through the membrane via transport proteins.

A transport protein that works with molecules binding to the protein, which reshapes to allow them through. Less efficient.

Transport protein that works by opening to allow molecules through and closing to stop them. More efficient.

Diffusion that occurs against a concentration gradient - requires ATP.

Water diffusion, where an area of high water potential will move down a gradient to an area of low water potential.

The measure of free water molecules and the tendency of water to move.

The meaure of how easily water molecules can leave a solution.

How water, solute and pressure potential are measured.

The pull of a solution with a low water potential on neighbouring water molecules.

The pressure exerted by the cell wall on the cell contents.

When a plant cell can take in no more water, supporting the cell structure.

A solution with a higher water potential than the cell it surrounds.

A solution with a lower water potential than the cell it surrounds.

The start of plasmolysis - when the cytoplasm begins to move away from the cell wall.

A process where the vacuole shrinks, causing the cytoplasm to move away from the cell wall.

A solution with the same water potential as the cell it surrounds.

When an animal cell bursts due to being surrounded by a hypotonic solution.

When an animal cell shrinks due to being surrounded by a hypertonic solution.

When materials are absorbed by extensions of the cell membrane or cytoplasm and converted into vesicles, requiring ATP.

A form of endocytosis, occurs when solid material is too big to be taken up by other methods.

A form of endocytosis, occurs when liquids are unable to be taken up by other methods.

How substances leave the cell - turning into vesicles and fusing with the cell membrane.

Inhibit the production of ATP, therefore limiting active transport.

Occurs when molecules that use facilitated diffusion bond to other molecules to move them against a concentration gradient.

Special carrier proteins used in co-transport.

Sterol in animal cell membranes. Inbetween the phospholipid molecules, maintaining stability at higher temperatures and fluidity at lower temperatures.

When a plant has completed plasmolysis, so the cell has no structural support.