Cell Membrane and Active/Passive Transport

The cell membrane is also referred to as the?

plasma membrane

Cell membrane consists of?

Phospholipids, studded with proteins

Serves as a sort of gate, separating the inside of the cell from the outside of it.

Cell Membrane

T or F: The top of the phosphate (head) are polar (having +/- charge) and are located on the outside of cell membrane.

True

T or F: Lipid tails are non-polar (no charge) and are on the inside of the membrane.

True

T or F: Phosphates are Hydrophilic.

True

Proteins in the bilayer serve what purpose?

They act as “doors” or gateways to let certain molecules inside and out of the cell membrane.

T or F: Each protein is very specific to its job.

True

Passive Transport

Moves molecules from areas of high to low concentration, does NOT require ATP (energy).

Active Transport

Moves molecules from areas of low to high concentration, requires ATP (energy).

Diffusion and Facilitated Diffusion are both types of ________transport.

Passive

Without a protein, movement across the membrane is referred to as?

Diffusion

Movement across the membrane with help from transport/channel proteins is referred to as?

Facilitated Diffusion

Facilitated Diffusion occurs when?

Molecules are simply too big to pass through on their own and therefore require additional assistance from transport or channel proteins.

Osmosis

Diffusion of water

T or F: Water always moves from an area of high to low concentration, without ATP (energy). → Also considered Passive Transport because of this.

True

Isotonic

Solution that has the same solute concentration as the cell; water will not move across the membrane.

Hypotonic

Solution that has a lower solute concentration than the cell; water will move into the cell.

Hypertonic

Solution that has a higher solute concentration than the cell; water will move out of the cell.

Active Transport

Movement across the membrane using ATP from the cell. Molecules are ‘pumped’ from low to high concentration.

• Process requires carrier proteins and ATP

• 40% of the cell’s energy goes into this transport

• Mitochondria near the plasma membrane supply ATP for this process

Endocytosis

Things coming into the cell.

1. Cell membrane surrounds material.

2. Membrane encloses to form vesicle.

Exocytosis

Things leaving the cell.

1. Vesicles containing the cell waste join with the cell membrane.

   1. Waste is released, and vesicle becomes part of the cell membrane.

Vesicle

A small, bubble-like structure enclosed by a lipid bilayer membrane that stores and transports materials within a cell