Understanding Cell Membrane Transport: Diffusion, Facilitated Diffusion, and Active Transp, Assignments of Biology

Download Understanding Cell Membrane Transport: Diffusion, Facilitated Diffusion, and Active Transp and more Assignments Biology in PDF only on Docsity! Membrane Structure and Function POGIL How do substances move in and out of cells? Advertisements for sports drinks, such as Gatorade®, PowerAde®, and Vitaminwater™, etc. seem to be everywhere. All of these drinks are supposed to help your body recover and replenish lost electrolytes, fluids, and vitamins after exercise. But how do the essential molecules contained in these drinks get into your cells quickly to help you recover after exercise? 1. How many different types of molecules are shown in Model 1? Two. 2 Count and record the number of triangles and circles found on each side of the membrane. Left side: 14 Triangles & 12 Circles. Right side: 0 Triangles & 13 circles. 3. Which shape is larger? The triangle. 4. Describe the direction of the movement of the molecules in Model 1? Very chaotic and busy, all the shapes look as if they’re bouncing off one another and being sent in all kinds of directions. 5. Which molecules are able to pass through the semi-permeable membrane? Justify your answer. The circles/dots, because they are small enough to fit through the dotted line and the open gaps. And because they’re equally distributed on both sides. 6. If you left this “system” for an extended period of time and then viewed it again, would you expect to find any changes in the concentrations of the molecules on either side of the membrane? Justify your answer. I would expect to find little to no changes in the number/concentration of both types of molecules and which side of the membrane they’re on. I say this because I know that the triangles are too big to exit the left side, meaning they are trapped where they are. And the circles are free to roam both sides because they’re small enough to easily travel through onto both sides. When one circle exits one side, another enters. 7. What two major types of biological molecules compose the majority of the cell membrane in Model 2? Phospholipids and proteins (specifically the membrane-spanning protein). 8. How many different protein molecules are found in Model 2? Two different protein molecules, the membrane spanning, and surface proteins. 9. What is the difference between the position of the surface proteins and the membrane-spanning proteins? The membrane spanning proteins span the membrane, while the surface proteins do not. 10. When a carbohydrate chain is attached to a protein, what is the structure called? Some molecules, such as glucose, use gated channels as shown in Model 3; however, not all channels are gated. Some channels remain permanently open and are used to transport ions and water across the cell membrane. 21. Why is the type of protein channel in Model 3 called a gated channel? Because they literally act as gates. The gated channel only allows certain things to go through it such as when the hormone becomes bound with proteins. 22. To facilitate means to help. Explain why this type of diffusion is called facilitated diffusion. Because glucose needs help from the insulin which allows the gated channel to open/get bigger. 23. Which part of the cell membrane is shown in more detail in Model 4? Look back at Model 2 if needed. The membrane-spanning proteins. 24. What shape represents the substance being transported across the membrane in Model 4? A diamond. 25. In which direction is the transported substance moving—from an area of high concentration to low or from an area of low concentration to high? Support your answer. The substance is moving from a place of low concentration to a high concentration as more particles are seen in the place moving toward the direction the arrow is pointing.- (Down) 26. Is the substance being moved along (down) a concentration gradient? Justify your answer. Yes, the direction is going from low to high concentration and more particles are in the area toward where the arrow is pointing to. 27. ATP is a type of molecule that can provide energy for biological processes. Explain how the energy is being used in Model 4. ATP is providing the energy to be able to change the shape/size of the channel, so it can open. 28. What happens to the ATP after it binds to the protein? The ATP changes to ADP. 29. The type of transport shown in Model 4 is called active transport, while diffusion and facilitated diffusion are called passive transport. Given the direction of the concentration gradient in active and passive transport examples, explain why active transport requires energy input by the cell. Moving molecules require energy, and in order to function in the cell. Active transport moves molecules up the concentration gradient while passive transport molecules move down the concentration gradient. 30. With your group, complete the table below to show the difference between active and passive transport. Active Transport Passive Transport Diffusion Facilitated Diffusion Requires energy input by the cell ✓ ✘ ✘ Molecules move along (down) a concentration gradient ✘ ✓ ✓ Moves molecules against (up) a concentration gradient ✓ ✘ ✘ Always involves channel (membrane-spanning)prot eins ✓ ✘ ✓ Molecules pass between the phospholipids ✘ ✓ ✘ 31. Define active transport. Active transport is the movement of ions/molecules across a cell membrane… that enters an area of high concentration.