Active & Passive Transport - Transport in Plants, Biology, Class 11 Video Lecture

hello friends this video on transport in
plants part 5 is brought to you by exam
few calm no more fear from exam so now
that we have discussed about the types
of diffusion let us quickly talk about
active and passive transport there when
we talk about transport in terms of this
diffusion basically there are two modes
of transport active transport and
passive transport
so first let us try to define transport
in simple words it is nothing by
movement of molecules across plasma
membrane because when I am talking about
the transport inside a plant as I said
the transport has to happen from on a
cell level from one cell to another the
transport has to happen so that movement
of molecules across the plasma membrane
is often known as transport there are
two modes of transport passive transport
and active transport now we have
discussed about these before also but
now since we are discussing about
diffusion in detail detail it will be
biased to talk about them as well so now
whatever we have spoken so far simple
diffusion or facilitated diffusion they
were all examples of passive transport
so let us see what is a passive
transport so it is the movement of
molecules across a membrane requires no
energy from cell so it is that kind of
movement of particles so that there is
no energy expenditure or there is no
energy input from the cells and that is
because here the particles are moving
from a region of high concentration
towards a region of lower concentration
so in passive transport there is no
energy input from the cell so that is
the main catch when we talk about
passive transport and that is why I told
whatever types of diffusion we spoke
about so far whether it is simple
diffusion or facilitated diffusion there
was no energy input from the cell so
they are all examples of passive
transport movement occurs along the
concentration gradient either by
diffusion or osmosis
what does osmosis that is again a
special form of diffusion we will talk
about that a little later but there also
there is no energy input from the same
two types of diffusion take place as we
have discussed simple diffusion and
facilitated diffusion in simple
diffusion particles directly move across
membrane facilitated diffusion you need
transport proteins to help particles
move across the membrane so this was a
gist of the passive transport which we
have already discussed so now the
question is what are what is active
transport so let us see that now it is
very evident that here some energy input
has to be there from the same
so here movement of molecules across the
membrane requires some energy from the
cell so now again the same question
would strike your mind that why is it
true only for certain one fuels why
certain molecules would need energy from
the cell that is because here the
movement has to happen against the
concentration gradient so that is the
most important catch here here we are
asking the substances or the particles
to move from a region of low
concentration to a region of high
concentration so that will not happen
automatically it is suppose if you keep
a cup of hot coffee in the thick on the
table and you expect that the coffee
becomes hotter when you see it after one
hour that is little difficult because
heat will flow from high temperature to
low temperature right so similar is the
case here so now if you want the
particles to forcefully move from region
of low concentration to high
concentration then you will have to
supply some energy from outside so who
will supply that energy that energy has
to be supplied by the cell so there are
some proteins which help in passive
transport whereas there are some other
proteins which help in active transport
so let us suppose this is our cell
membrane so now here this region has low
concentration and this region has high
concentration but we still want this
particles to move towards this side
against the concentration gradient so in
this case what will happen the carrier
proteins of cell membrane will act as a
pump as I said some proteins just acted
as transport proteins in case of
facilitated diffusion so they were just
carrying the particles from one side to
the other side but here these proteins
which participate in active transport
they act like a pump white pump so that
they can pump in some energy which will
help the particles to move against the
concentration gradient so what is this
energy these energy is in the form of
ATP molecules so the from where do we
get this ATP molecules inside the cell
so from where the same its energy cell
produce energy by the process of
cellular respiration cellular
respiration will take place inside each
and every cell during the process of
cellular respiration energy will be
produced in the form of ATP molecules
and these ATP molecules will provide the
energy required for active transport so
due to this cells which are capable of
active transport usually have more
mitochondria in their cells that is
because mitochondria are the powerhouses
of the cell so mitochondria participate
in cellular respiration they produce ATP
molecules so those cells which
participate in active transport they
need a lot of energy they need a lot of
ATP molecules then ATP molecules are
produced by mitochondria so they
generally have more mitochondria so here
ATP provides the energy input from the
cell so this is active transport so now
we talked about three different ways of
transport one is simple diffusion when
it's facilitated diffusion and the third
one is active transport so let us
quickly have a comparison of active
versus passive transport now when we
talk about let us take the example of
the slope so when I talk about passive
transport there is no energy expense
from the cell there are two ways either
the particle can move down the
concentrate
gradient on and so on or the particle
might need a transport protein or a
carrier protein to pass it through the
potential break it whereas an active
transport the situation is something
like this let us suppose if you want a
particle can move from to move up the
hill
so obviously the particle by itself will
not move above up the hill
but the particle in this case is the
particle in itself was able to move down
the hill because it was a slope so it
was able to move on and so on but here
the particle on its own can never move
up the hill so it needs something which
can carry it suppose it take now here
the bottle also cannot help it because
the bottom cannot climb the hill in this
case the bottom was able to come down
the hill and it was able to overcome
this small the small break but here it
cannot move up the hill so you need a
special type of protein which acts as a
pump for example a car so this is
basically a vehicle which has some
energy because of which it can drive up
the hill and that is how it can carry
the particle with itself so here the
cart is not only a single protein like
this jar it also has some energy in it
because of that energy it is able to
move from low concentration to high
concentration so this is the concept of
active transport so I hope that the
concept of facilitated diffusion and
active transport is clear to you okay so
now let us see where do we actually see
or where do we see the application of
active transport when we talk about the
transport in plants so where exactly we
see this concept of active transport now
as I mentioned before also that plant
needs so many things for its survival
growth and maintenance it needs water it
needs minerals it means carbon oxygen so
Eddie's now plants need minerals
minerals like nitrogen phosphorus sulfur
and they are all present in the soil so
in the soil you have all nitrogen
phosphorus sulphur now the concentration
of these minerals in the roads is
already high because the rules already
keeps absorbing these minerals so their
concentration is already high in the
routes but we still want more minerals
to get into the roads so basically we
want this minerals to move from region
of low concentration to region of high
concentration so how can they move from
region of low concentration to high
concentration by active transport so
that more and more minerals can get into
the roads now that is suppose if active
transport does not take place then what
will happen since the concentration of
minerals is high in the roads the winner
is by default will diffuse out by the
process of diffusion that is from high
to low concentration it will start
diffusing around and the minerals were
lost will be lost to the surroundings so
the plants will not be able to get a lot
of minerals so because of active
transport even if the routes already
have a lot of minerals but still the
movement of minerals into the roots will
keep on occurring so that is how active
transport plays an important role in
transport system of plants so let us
have a quick discussion on the different
transport processes which we have
discussed so far we discussed three
types of processes simple diffusion
facilitated diffusion and active
transport so simple and facilitated
diffusion happens from high to low
concentration that is along the
concentration gradient whereas active
transport happens from low to high
concentration for simple diffusion there
is no energy input from the cell because
it is a passive transport
similarly facilitated diffusion also is
a passive transport but the active
transport energy input is required from
cell in the form of ATP molecules in
simple diffusion the particles can move
on their own they do not need any
proteins to carry them but in
facilitated diffusion as well as an
active transport you need transport
proteins to carry them
cannot move on their own in simple
diffusion movement continues till the
equilibrium is reached because there the
particles are moving from high to low
concentration and they will keep moving
until both the concentrations become
equal
whereas in facilitated diffusion the
movement stops as all proteins are used
because here you need proteins to carry
the particles now as soon as all the
proteins have already been used in
carrying particles you don't have
anymore proteins so even if you have
particles to be moved across the
membrane but you don't have proteins to
carry them so the movement will stop so
similar is the case for active transport
because they are all there also the
movement is dependent on carrier
proteins simple diffusion is not
selective it is not that some particles
scatter are allowed and some particles
are not allowed nothing like that
whereas facilitated diffusion and active
transport are very very selective in
nature that means the transport protein
or the carrier proteins will carry only
specific type of particles and not all
particles so this was a quick comparison
between the different transport
processes which we have discussed so far
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