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0:06 good day students you are welcome to another lecture episode on passive and active transport so today we are going to be discussing about passive and active transport and um before we start uh discussing we need to understand that we are going to talk about transportation across the cell membrane and if we remember cell membrane is the what the outer covering of the cell that provides uh protection and also it serves as a uh as a channel for transporting materials
0:53 across the cell membrane across the uh the the cell membrane Ser as a channel for transport of materials so and the transportation of materials across the cell membrane uh is one of the function of the cell membrane or the plasma membrane and the cell membrane act as a semi- permeable membrane which allows only some substance to pass through and act as a barrier for other substances for example small hydrophobic molecules such as carbon dioxide oxygen and small
1:41 lipids dissolve in the membrane and it can also pass through it rly because uh these are small molecules and also lipids small lipid molecules they can dissolve and pass through the membrane without the help of transp so we are going to talk about this transportation and the mechanism of this transportation and different types of the transportations so if you look at some tiny molecules such as water and and also alcohol they can sleep between the phospholipids B layer and it it can and they can also be transported across the membrane so ions and most nutrient
2:26 molecules they do not move freely through the cell membrane but they are often uh they have transporter molecules or transporter proteins that uh are transport them either without energy or with with theuse of energy that is when there is energy it means it is becoming uh active transport so active transport is when the transportation take place but with the utilization of energy while passive transport uh it occurs without the utilization of energy so uh if you look at what we call uh gradients and these
3:12 gradients are important in moving materials through the membrane and this will involve either passively without the use of the energy from the cell or actively which requires the energy to provide by the by the cell so so the transport mechanism can be either passive as we explained or uh or simple uh diffusion or it can be uh facilitated so for passive transport we can say passive transport can be divided into two either simple diffusion or facilitated diffusion in simple diffusion the molecules uh uh the simple
3:58 the molecules or the uh substance that can be that will be transported across the membrane can be transported without the Ed of any molecules so materials that can move through the membrane by the process of simple diffusion water carbon dioxide oxygen and some lipid molecules and also alcohol so while for facilitated diffusion molecule that cannot freely move through the membrane has to pass through the membrane by the help of Transporter molecules which are proteins in nature so transport proteins in the membrane helps in uh carrying out
4:45 passive transport in form of facilitated diffusion so this Transportation uh of course when this protein molecules temporarily bind the substance and they move them through the membrane and this process is called facilitated or passive transport so no energy is involved in the process and both the carer protein and all channel proteins are involved in the facilitated diffusion so materials that can pass through the membrane by facilitated diffusion include glucose Amo acid and many other small ions the movement of water through the membrane
5:30 is also involved facilitated diffusion so because the movement of water molecules through the membrane requires a specific protein that is called aquaporin and these aquaporin are of different different types and these aquaporin molecules they are proteins that are in the cell membrane that helps in the what transportation of water so aquaporin are membrane proteins that that transport water by what what we call facilitated diffusion so for facilitated diffusion may be coupled to the movements of other molecules so if we look at this diagram is trying to
6:17 summarize what passive and active transport is all about so for passive transport process it proceed as a diffusion from areas of high concentration to areas of low concentration so look at transportation of oxygen course by diffusing through the membrane transportation of sodium diffuses through the aquous channel and also if you look at this active transport involving the transportation of sodium and potassium and it requires what energy because it's against the concentration gradient so it requires sodium potassium pump okay to to
7:02 actually carry out the the process so uh we say facilitated process may be coupled to the movement of other molecules in the same direction or opposite direction so this bring us to discuss about what what we call uh Co Transportation so in core Transportation or in core transport the transport of one molecule depend on the quential transfer of another molecule for transport may be a sort or antiport a syot system moves two molecule in the same direction so syot is a type of cor
7:50 Transportation which it requires two molecules to be transported in the same direction for instance if you look at this chart we have simp po here and this simp protein transported transport A and B molecule in the same direction okay while for antip we look at for for molecules in the body or in the system that pass through the membrane VI sort we have sodium glucose transporter okay while for antiport system it moves two molecules in opposite direction which is known as also counter transport example sodium potassium transporter so
8:39 an antiport we have look at this glucose and sodium are example of what syot molecules that transported we are simp and sodium potassium are example of antiport molecules that are transported VI an anti protein we also also have another example which is called a uniport or a unipo protein now a unip protein uniport is the system antiport is the system sort is the system of transporting molecules in either one direction as in the case of input one molecule transported in One Direction and in simp two molecules
9:24 transported two direction and the same direction two mole transport the same Direction antiport two molecules is transported in what opposite opposite what opposite direction so while for the proteins that are carrying out the function of this Transportation they are called either unip as the case may be or or anti proteins I hope you are getting the the differences so this uh fig summarizes the the two or rather three uh processes so now we have to look at uh
10:11 examples of what we call endocytosis and uh exocytosis so um for endocytosis these are they are what we call vle mediated transport and this vle mediated transport are transport of large substance that require be require changes in the shape of the membrane and also diffusion of the plasma membrane to uh form what we call uh
10:56 vesicle so such changes in membrane occur throughout the lifetime of the cell and movement of materials of movement of materials of the cell involve changes of the membrane and formation of vesicles that are called exocytosis while the movement of materials into the cell are called what we term as uh Endo cytosis so materials movement of the cell involving change of the cell membrane form what vesicles we called exocytosis while movement of material into the cell is called what endocytosis so materials can be
11:42 transported from the cell by fusing vesicles with the plasma membrane in exocytosis for example insulin that is made inside the cell of the pancreas is released to the blood blood stream by exocytosis while if we look at endocytosis we can see that there are various processes endocytosis process in the cell examples we have uh what we call Pino cytosis okay we have also receptor
12:27 mediated uh endocytosis and also fago cytosis so these three are the subcategories or subtypes of uh endocytosis we have pinocytosis we have receptor mediated endocytosis and also we also have the fago cytosis so in pinocytosis we can see that solutes that are going to be transported uh binds to the cell membrane they bind to the cell membrane
13:15 from that is from the extra cellular fluid they are outside the cell the the cell wants to engulf and internalize those substances in the process of endocytosis now we are explaining pinocytosis which is an example of a type of endocytosis so solute binds to the cell membrane and they call they cause what internalization of those molecules so cell membrane forms inward to internalize those molecules that are going to be what taken into the cell and if you look at that what's happened in one and two then in three the cell
14:01 continues to fold until that vesicle or or Pome is formed now Pinos is now a like a vesicle that contains the solute substance that has been internalized by the cell so both ends of the Fall meet and produce what we call the the Pinos okay so for recepto mediated endocytosis we have the extracellular fluid outside the cell and you have the cell membrane contact with the extracellular fluid and you have the internal cellular environment so this
14:49 involves some receptor molecules that are on the surface of the cell membrane are now attaching the molecules that are going to be endocytose inside the cell will now attach themselves to the what receptor molecules now when these receptor molecules now attach to the uh uh uh molecules that are going to be internalized have internalization of the uh molecules and the plasma membrane now is what folded inside to form what we call the coted
15:38 vesicle so this it involves receptors on the surface of the membrane to attach where the molecules now attach themselves so that is why it's called recepto mediated endocytosis well for phagocytosis you have what we call all uh processes that occurs you have the entrapment for instance we are taking example like food particle now you have entrapment now the cell membrane now ENT the the particle and you have formation of food vacle and after the food vacle is been formed you have your fici with
16:25 lomes because in the cell you have lomes you remember lome are digestive uh they are what organ that contain digestive proteins that helps in breaking down or degrading foreign materials or antigen okay so now when this vule is now form it now go and fuse with the lome and now fusion with lomes causes digestion to occur because the liome have they have digestive enzyme so that is how the cell get rid of unwanted materials so that's the uh explanation
17:11 regarding the uh passive and active transportation system so uh let's okay here in summary we can see that active transport it proceeds against the concentration gradient and it requires input of energy right while passive transport proceeds as diffusion from areas of high concentration to area
17:56 of low concentration and it does not require energy more explanation on active transport is that it's some proteins that serve as transporter molecules in active transport which requires uh the the protein to now bind the molecules and transport it it requires energy in that the process to OCC for the process to OCC energy has to be what hydrolyzed so ATP has to be hydrolyzed to produce the the now to push the the the the process to to completion so I think we have discussed and I hope you really enjoy it and
18:44 that's where we are going to stop thank you for watching if you are yet subscribed kindly subscribe to the channel for more content in the future thank you see you next bye-bye
