Passive vs. Active Transport - Video Tutorials & Practice Problems
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concept
Passive vs. Active Transport
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4m
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Video transcript
In this video we're going to briefly distinguish between passive transport and active transport. And so really there are 2 general types of molecular transport of small molecules across biological membranes and those 2 general types of molecular transport are passive transport and active transport. Now notice that passive transport is numbered with number 1 and active transport is numbered with number 2. And so the number 1 that you see down below in our image, corresponds with passive transport and the number 2 that you see down below in our image corresponds with active transport. So that's important to keep in mind. Now passive transport as its name implies requires absolutely no energy and we can tell because this process is passive. Now, passive transport, the reason that it requires no energy is because molecules are transported down or with their concentration gradients from an area of high concentration down to an area of low concentration, which is the way that molecules will naturally diffuse and that is why it requires no energy. Now on the other hand, active transport as its name implies requires an energy input and so it is an active process. And so the reason that active transport requires energy is because molecules are going to be transported against or up their concentration gradients from an area of low concentration to an area of high concentration, which is not the natural tendency for molecules to diffuse and so it requires an energy input in order for these molecules to be actively transported. And so when we move forward in our course we're going to talk mostly about passive transport but then later in our course we'll talk more on active transport. But let's take a look at our image down below to get a better understanding of passive versus active membrane transport. So notice on the left hand side over here we're showing you a little snippet of our map of the lesson, on molecular transport of small molecules. And again it can be broken down into passive transport, which again requires no energy, and active transport, which does require an energy input. So this image over here on the left hand side right here, is an image showing you passive transport. And so what you'll notice is that we have our biological membrane here in the middle and notice that we have a relatively high concentration of these molecules on this side of the membrane, so we can label it as a high concentration. And then on this side of the membrane we have a relatively low concentration of those same molecules. But notice that these molecules are being transported across the membrane in this direction, from the area of high concentration towards the area of low concentration And when they're transported from high to low concentration, that is going to be passive transport. And so passive transport requires absolutely no energy. Now over here on the right hand side what we're showing you is active transport and so here what you'll notice is that the biological membrane is right here and active transport is going to utilize a membrane protein and that's what this green structure is right here that we're circling. And what you'll notice is that on this side of the membrane there's quite a high concentration of these purple molecules, but on this side of the membrane there's quite a low concentration of these molecules. So we can write low right here. And what you'll concentration of these molecules so we can write low right here. And what you'll notice is that these molecules are being transported against or up their concentration gradient in this direction from an area of low concentration towards an area of high concentration. And so this is active transport and active transport requires energy and in many cases that energy will be in the form of ATP and so here we're showing you an ATP molecule. And so you can think that the a in active is for the a in ATP, but really active transport just means that an energy input is required. And so later in our course we'll be able to distinguish between primary active transport and secondary active transport. But we'll talk more about active transport after we talk about the different types of passive transport. And so this here concludes our brief lesson on passive versus active transport and again we'll be able to learn a lot more and apply these concepts as we move forward. So I'll see you all in our next video.
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Problem
Problem
Passive membrane transport processes include___________.
A
Consumption of ATP for energy.
B
The use of transport proteins to move a substance from low to high concentration.
C
Movement of a substance down its concentration gradient.
D
Movement of a substance up its concentration gradient.
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Problem
Problem
What is the difference between active and passive transport across a membrane?
A
Both active and passive transport move substances down their concentration gradients.
B
Active transport is ATP dependent. Passive transport does not require energy.
C
Active transport requires cell to cell communication. Passive transport does not require cell communication.
D
Active transport can be performed without transport proteins while passive transport cannot.
4
concept
Classes of Membrane Transport Proteins
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3m
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Video transcript
In this video we're going to briefly discuss the classes of membrane transport proteins. And so really there are 3 types of membrane transport proteins that can be either used for passive transport or active transport and these three types of transport proteins are classified according to how they operate and so notice that we have the 3 types of membrane transport proteins numbered down below and those numbers correspond to the image down below as well. And so the first type of membrane transport protein that you should be aware of are the uniporters and the root uni is a root that means one or singular and so uniporters are going to be membrane transport proteins that transport just one molecule at a time in just one direction across the membrane. And so if we take a look at our image down below on the left hand side over here notice we're showing you our uniporter, which is this, membrane transport protein that you see embedded in the membrane here. And notice that this uniporter again has the root uni which means 1, so it's transporting just 1 molecule across the membrane at a time in just one direction. And so you can think Uni Porter is just 1 molecule being transported. Now the second type of membrane transport protein is going to be the symporters. And the symporters are going to co greater than or equal to 2 molecules at a time, so multiple molecules at a time, but these molecules that are being transported at the same time are going to be transported across the membrane in the same direction. And so really this is the most important part and you can think that the S in symporter is for the s in same direction. And so if we take a look at our image down below in the middle here, notice we're showing you our symporter which is really this membrane transport protein that you see embedded in the membrane here and notice that it is transporting 2 molecules at the same time. It's transporting this red molecule and it's transporting this green molecule. And notice that both the red and green molecule are being transported across the membrane in the same direction and again that's the most important part and you can think that the s in symporter is for the s in same direction. And so here you can see the symporter is transporting these 2 molecules in the same direction. Now the third and final type of membrane transport protein that we're going to discuss is, the anti porter. And so anti porters, as their root implies with this root anti which means opposite, are going to cotransport greater than or equal to 2 molecules at the same time. However, these 2 molecules are going to be transported in opposite directions across the membrane. And so that is what distinguishes the Antiporter from the Symporter. And so if we take a look at our image down below on the right hand side over here, we're showing you our antiporter. And again, it's transporting, 2 molecules, the red molecule and the green molecule across the membrane. However, notice that the red molecule is being transported in the opposite direction as the green molecule is being transported. And so because these 2 molecules are being transported in opposite directions, that is what makes this an anti porter. And so this here concludes our brief lesson on these three classes of membrane transport proteins and we'll be able to apply these concepts as we move forward in our course. So I'll see you all in our next video.
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Problem
Problem
A transport protein that simultaneously transports two different molecules in different directions is called:
A
A uniporter
B
A symporter
C
An equilibrium protein
D
An antiporter
E
A simple diffuser
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Problem
Problem
Which option below best describes a transporter that requires ATP to move molecules A and B out of the cell?