Active Transport

Active Transport All of the previous types of transport were passive Diffusion Osmosis Facilitated Diffusion Passive transport happens from an area of high concentration to low concentration

Active Transport Active transport is the movement of molecules from an area of low concentration to high concentration This takes molecules from outside the cell and moves them inside These processes take energy

Active Transport There are two main types of active transport Pumps Vesicles These two processes require energy and move molecules “up” a concentration gradient

Cell Membrane Pumps Membrane proteins can help both active and passive transport Membrane proteins that assist active transport are referred to as Cell Membrane Pumps These pumps assist charged particles into the cell

Cell Membrane Pumps These pumps are a little different than the passive transport carrier proteins These have a certain amount of binding sites These binding sites will fill with ions or other small molicules Once those are full, the cell uses energy to move the molecules into or out of the cell

Cell Membrane Pumps The energy that is used by these pumps is ATP ATP is a molecule that supplies energy when it is broken apart After it is broken the cell can use the energy that is released

Sodium Potassium Pump One example of active transport in animal cells is the sodium potassium pump This pump carries sodium and potassium up their concentration gradients

Sodium Potassium Pump Sodium is an element that can be toxic to a cell in high enough concentration Potassium is something that a cell needs for many processes however it is not always found in abundance in the environment

Sodium Potassium Pump The pump starts by binding three sodium atoms from inside the cell With some energy, the sodium ions are released from the cell

Sodium Potassium Pump Next two potassium ions are attached to the protein pump With some energy from ATP, the potassium ions are brought into the cell

Movement in Vesicles Many times there are molecules that are too large to fit through the carrier proteins and membrane pumps These macromolecules, nutrients and molecules need to be brought into the cell in other ways

Endocytosis A cell can take in external fluid, large particles and dissolved particles It does this by creating an indent in its cell membrane The cell membrane then creates a small pouch called a vesicle The vesicle is brought in to the golgi apparatus

Endocytosis When large molecules needs to be brought into the cell, the cell goes through endocytosis Endocytosis is the process of making a vesicle out of cell membrane

Endocytosis What is actually in the vesicle determines what kind of endocytosis it is Pinocytosis involves the movement and transport of solutes and fluids Phagocytosis is the movement of large molecules, bacteria or viruses

Endocytosis Receptor–mediated endocytosis is a specific type of active transport that only happens when receptors on the cell surface pick up specific molecules When the receptors engulf the molecules, a coated vesicle is formed and the cell can bring it where it needs to go

Exocytosis Exocytosis is the process by which a substance is released from the cell Exocytosis is a process that requires energy to create the vesicles involved

Exocytosis During exocytosis a cell takes a vesicle and fuses it with its plasma membrane During this process a cell releases what ever was contained within the vesicle It can be a large molecule, several small molecules or things dissolved