Cell Physiology Review Questions/WEEK #1 (NURS 534)Latest Solutions

1. What are the three major constitutes of plasma membranes and how are membranes of eukaryotic cells organized? - answer--cholesterol, integral membrane protein, phospholipids. Cells are enclosed by a semipermeable membrane. The membrane serves as a barrier and regulates cell size and function. Membranes also surround intracellular structures (ex. mito, lysosomes). Within the cell (cytosol): ions, proteins, water, and many organelles. 2. There are several types of proteins in the plasma membrane. Describe these proteins along with their function. - answer--Intermediate filaments, microtubules, actin filaments. These serve as organizational and sense change. Peripheral(extrinsic)- on cell surface and integral-span the width of the membrane. Functions: Structural Carriers/Pumps (actively transport substances across memebranes, ex transport proteins) Pores/Channels Receptors Enzymes (ex. NAa/K atpase, aminopeptidase) Cell adhesion molecules (CAMS) (integrins-located on the outside of a cell membrane) or cadherins-span the membrane enter into the cell 3. Membrane junctions were discussed; describe the membrane junction and describe their role in the membrane. - answer--Desmosome-Fibrous protein connection between 2 cells. Usually in those that stretch ex. the skin or smooth muscle cells. Tight Junctions-Physical joining of 2 cells that impede passage of ions and molecules. Example: Endothelial cells of BBB and Epithelial cells of the renal ascending limb.