Membrane Transport Mechanism

1. passive transport

2. active transport

Two types of Membrane Transport

passive transport

movement of substances across a membrane without any input of energy from the cell

active transport

movement of substrates against their electrochemical gradient, thereby requiring an input of energy

1. diffusion

2. osmosis

2 types of passive transport

diffusion

process by which molecules or particles move from an area of higher concentration to an area of lower concentration

1. concentration gradient

2. temperature

3. size of molecules

4. distance

5. medium

In diffusion, rate is influenced by c______ g_____, t_______, s____ o_ m_______, d_______, m______

simple diffusion

passive movement of molecules or ions across a cell membrane from an area of higher to lower concentration, without the aid of transport proteins or energy input

facilitated diffusion

passive transport of molecules or ions across a cell membrane via specific transmembrane proteins

1. carrier-mediated facilitated diffusion

2. channel-mediated facilitated diffusion

2 types of facilitated diffusion

1. osmosis

2. lower

3. higher

4. higher

5. lower
   
   

(1) - passive movement of water molecules across a selectively permeable membrane from an area of (2) solute concentration ((3) water concentration) to an area of (4) solute concentration ((5) water concentration)

1. endosmosis

2. hypotonic

(1) - movement of water into a cell or compartment when it is placed in a (2) solution (a solution with a lower concentration of solutes than inside the cell).

1. exosmosis

2. hypertonic

(1) - movement of water out of a cell or compartment when it is placed in a (2) solution (a solution with a higher concentration of solutes than inside the cell)

1. hypertonic

2. hypotonic

3. isotonic

3 types of osmotic pressure; (1) higher solute concentration & lower solvent concentration in the outside of the cell (2) lower solute concentration higher solvent concentration in the outside of the cell (3) equal solute & solvent concentration

1. lower

2. higher

3. higher

4. lower

Active transport is the passive movement of water molecules across a selectively permeable membrane from an area of (1) solute concentration ((2) water concentration) to an area of (3) solute concentration (4) water concentration).

Primary active transport

type of active transport that directly uses energy, typically from the hydrolysis of ATP (adenosine triphosphate), to move ions or molecules against their concentration gradient across a cellular membrane

1. Sodium-potassium pump

2. Proton pump

3. Calcium pump

3 types of primary active transport

Secondary Active Transport

form of active transport that does not directly use ATP for moving molecules across a cell membrane

relies on the energy created by primary active transport, which establishes ion gradients

Symport

the driving ion (e.g., sodium) and the cotransported substance move in the same direction across the membrane. e.g. Sodium-glucose co-transporter (SGLT)

antiport

the driving ion (e.g., sodium) and the transported substance moves in the opposite direction. e.g. Sodiumcalcium exchanger (NCX)

Bulk tranport

process that moves large quantities of substances, including entire cells or large particles, into or out of a cell via vesicles

Exocytosis

fusion of secretory vesicles with the plasma membrane and results in the discharge of vesicle content into the extracellular space and the incorporation of new proteins and lipids into the plasma membrane

Constitutive exocytosis

a continuous process where cells release materials like extracellular matrix proteins, lipids, and other molecules regardless of external signals

Regulated exocytosis

triggered by specific signals or stimuli

lysosomal exocytosis

membranebound organelles containing digestive enzymes, fuse with the plasma membrane of a cell to release their contents into the extracellular space.

endocytosis

active process in which a cell forms internal vesicles by invaginating its plasma membrane, allowing the absorption of various molecules and macromolecules from the extracellular fluid

Phagocytosis

Involves the engulfing of large particles or cells, such as pathogens, dead cells, or debris.e.g. macrophage

Pinocytosis

involves the uptake of extracellular fluid and dissolved solutes

Receptor-mediated endocytosis

A selective form of endocytosis where specific molecules bind to receptors on the cell membrane, triggering internalization