Active Transport: Primary, Secondary and Vesicles (Nursing)

00:01 So the other types of transport that allows things to move across the membrane is active transport.

00:07 In an active transport unlike in passive transport, now we're able to move things against the concentration gradient or going uphill or we're able to move large items from one side of the membrane to the other.

00:21 The difference between active and passive transport is that in active transport, an energy expenditure is required.

00:29 So we must use energy in order to move these substances from one place to the other.

00:36 So the first type of active transport is primary active transport.

00:41 In this way, the ATP or the energy from ATP is going to change the shape of a transporter protein and it's going to pump that substance from one side to the other against its concentration gradient.

00:56 This is found in a lot of different processes especially in the nervous system and the muscular system.

01:04 In secondary active transport, we're going to use the energy that is released when something moves down its concentration gradient to drive the movement of another substance against its own concentration gradient.

01:17 So things are kind of moving in opposite directions.

01:21 And then the last type of active transport involves vesicles.

01:25 Vesicles are membrane-bound structures that are going to allow us to move substances throughout the cell.

01:34 And because most of the substances or most of the membranes in our cell are made of the same thing, vesicle transport allow things to be moved and transported and shared between different parts of the cell a lot easier cause everything is made up of the same thing.

01:50 Think about if you're in the tub and you have bubbles, when two bubbles bump into each other, they don't pop, they just kind of fuse and make a bigger bubble.

02:00 And so, there multiple different types of vesicular transport.

02:04 One is endocytosis where we're going to bring substances into the cell in through a vesicle.

02:12 A ligand will bind to a receptor on the membrane and that will trigger the enfolding of that portion of the membrane until it forms a small vesicle and then blebs off toward the inside of the cell.

02:27 Another process that's used is phagocytosis.

02:31 Phagocytosis is also referred to as 'cell eating' because the cell is going to take in large particles by engulfing them from the external environment and bringing them into the cell.

02:45 Usually from here, it will use other processes in order to break that large particle down into usable units.

02:54 As well, we also have a process known as 'cell drinking' or pinocytosis.

03:01 In pinocytosis, we're going to bring in a bunch of smaller substances through the cell by bringing them into small vesicles sometimes referred to as caveoli.