transmembrane protein in the plasma membrane? = Acidic |= Basic NH2 A. 20 CO2 20 NH2 B. = Polar (uncharged) CO2 T 20 NH2 C. CO2 20 NH2 D. = Hydrophobic CO2 ㅏ허 NH2 E. 10

23. Look at the diagram of a cross-section of a cell membrane below. CELL MEMBRANE Low Concentration of Substances Outside Cell Cell Membrane Inside Cell High Concentration of Substances The molecules in the diagram are moving through a protein channel. What type of cellular transport does this represent? a. Passive Transport- Osmosis b. Passive Transport- Facilitated Diffusion c. Active Transport- Facilitated Diffusion d. Active Transport- Endocytosis Direction of Substance Movement

Phospholipids can move from one leaflet (layer) to the other in a cell membrane bilayer by   A. increased diffusion   B. flippases and floppases.   C. lateral diffusion.   D. biosynthesis. Diffusion of membrane proteins was demonstrated by fusing human cells and mouse cells that had membrane proteins labeled with ________ of different colors.   A. stained lipids   B. fluorescent dyes   C. radioactivity   D. EPR detectable spin labels

4. The cell membrane below is divided into three sections to show three different types of transport that can occur across the membrane. For each type of transport: a. draw and label the type of molecule that would use that specific transport (water, glucose, oxygen, etc.) and b. draw an arrow to represent which direction the molecule would be moving across the cell. Diffusion Osmosis Active Transport W a 99+

The shortest α helix segment in a protein that will span a membrane bilayer has about _____ amino acid residues. a. 5 b. 20 c. 50 d. 100 e. 200

16. According to the fluid mosaic model of cell membranes, which of the following is a true statement about membrane phospholipids? A. They can move laterally along the plane of the membrane. 8. They frequently flip-flop from one side of the membrane to the other. C. They occur in an uninterrupted bilayer, with membrane proteins restricted to the surface of the membrane. 17 D. They are free to depart from the membrane and dissolve in the surrounding solution. E. They have hydrophilic tails in the interior of the membrane.

19. If a scientist administers an electrical stimulation to a neuronal cell the most likely results will be to  a. start a membrane water pump b. cause increased saturation of phospholipid tails c. increase membrane fluidity and lipid asymmetry  d. activate the active transport system e. open gated channels

3 ...|III5I I II 6. What factor will most likely increase the rate at which diffusion occurs across a cell's plasma membrane? small concentration gradient across the plasma membrane low temperature high concentration gradient across the plasma membrane large molecule size [ת א dé tv A Aa Pro

Based on the picture, B. What is the primary function of #5 within a cell? A. Form membranes B. Store energy C. Structural support D. Maintain constant pH

What is assumed as the cell membrane function in connection with it as a mechanical structure? Select one: a. Matrix for enzymatic processes b. Control over the membrane potential с. Control over the ionic composition O d. Displacement of organelles