VISUAL SKILLS This computer model shows the four parts of ATP synthase, each part consisting of a number of polypeptide subunits (the structure in gray is still an area of active research). Using Figure 9.14 as a guide, label the rotor, stator, internal rod, and catalytic knob of this molecular motor.

Video transcript

Hello. Next question asks based on the following figure which of the following is correctly matched. And we have a diagram here of two labeled enzymes embedded in the cell membrane. Cytochrome oxidase on the left A. T. P synthesis on the right. We can see this is the end of the process of oxidative phosphor relation protons being pumped through cytochrome oxides as the last part of the electron transport chain, creating against the gradient, creating this potential energy and then the protons flowing down the gradient through a T piece in place in the process of keamy osmosis, generating a teepee with that energy. Now we look at our answer choices and we have four things that are not labeled on our diagram. So that can be a little confusing but when we look back at the diagram unlike cytochrome oxidase, the synthesis drawn with a lot of detail to its structure. So we can reason from that that these answers are the different parts of this structure, each being matched with a function. So we need to look at which one is correctly described. So let's start by looking for these parts in the structure. We're gonna start with this upper part we see kind of cylinder shape moving around rotating and this is called the rotor As its name indicates. It rotates one turn clockwise as protons flow through that part. So let's look down at our answer choices. We see that rotor is choice A and it says anchored in the membrane but we know that is not correctly matched. The rotor is not anchored. So let's move on down to the next part here. We see this sort of stock sticking off the back up against the phosphor lipids of the membrane and this part is called the stater. And we get some help from the first part of this name you might think static standing still. So the state are is anchored in that cell membrane and that prevents the lower part of the enzyme from turning with the motion of the rotor. So let's look down at our choices and we see that state or Choice B, which says activates catalytic sites but that is not the function of the status. Let's eliminate choice B. Now let's move down to this central sort of stock coming down from inside the rotor extending down into the lower part of the enzyme. This is called the rod describing its shape. The rod also rotates with the motion of the rotor and that causes it to activate the catalytic sites in the lower part of the enzyme. So let's look at our choices. We see that rod is choice deep changes the shape of each subunit. Well that is not its function. It activates the catalytic site. So let's eliminate choice D. So finally we're down here at the bottom of the molecule. This lower part here and this part is called the knob and the knob is kind of the business end of the molecule we see helpfully labeled on our diagram. We can see this is where this reaction takes place, and the knob is where you have the catalytic site that's catalyzing the reaction of joining a molecule of inorganic phosphate to a molecule of ADP and generating the molecule of a. T. P. So let's look at our choices. We have Choice C. Is knob produce a T. P from a. D. P. So that is indeed its function. So Choice C. Is correctly matched. And is our answer. See you in the next video.