K101 Exam 2 Questions and Answers Already Passed Latest Update

K101 Exam 2 Questions and Answers Already Passed Latest Update What are cellular membranes? - Answers Fluid mosaics What are fluid mosaics made of? - Answers lipids and proteins that are selectively permeable and separate the living cell from its surroundings What do membrane proteins give to a plasma membrane? - Answers a unique identity What are the sidedness of the plasma membrane? - Answers P-Face and E-Face E-Face - Answers external to cell P-Face - Answers internal to cell Does passive transport require energy? - Answers no, energy is not required What is passive transport? - Answers Diffusion of a substance across a membrane Does active transport require energy? - Answers Yes, energy is required What does active transport do? - Answers moves solutes against their concentration gradients How does bulk transport across the plasma membrane occur? - Answers By exocytosis and endocytosis What is the most abundant lipid in the plasma membrane? - Answers phospholipid What kind of molecules are phospholipids - Answers amphipathic What does amphipathic mean? - Answers contains hydrophobic and hydrophobic regions How does a phospholipid bilayer exist? - Answers As a stable boundary between two aqueous compartments Structure of plasma membrane: - Answers hydrophilic heads and hydrophobic tails What do protein molecules of the plasma membrane do? - Answers act as a channel for other molecules to enter and leave the cell What process is controlled by the plasma membrane? - Answers the exchange of materials with the surrounding of a cell What kind of permeability do plasma membranes have? - Answers selectively permiable What kind of materials can pass through the plasma membrane rapidly? - Answers Hydrophic(nonpolar) molecules like CO2 and O2 What kind of materials can not pass through the plasma membrane easily? - Answers Hydrophilic (polar) molecules like ions and water How do integral proteins associate with lipid bilayer? - Answers Penetrate hydrophobic interior of lipid bilayer How do peripheral proteins associate with lipid bilayer? - Answers They are not in the lipid bilayer, but are loosely bound to the surface of the membrane. Glycoprotein is _________ to bilayer. - Answers attached Glycolipid ______ of bilayer. - Answers comes straight out When is the asymmetrical distribution of proteins, lipids, and associated carbohydrates in the plasma membrane determined? - Answers When the membrane is built by the ER and golgi apparatus. How does an integral membrane glycoprotein get delivered to the E-face? - Answers By the rER, golgi, and transport vesicle How does the rough ER assist in delivering glycoprotein to the E-face? - Answers through protein synthesis and glycosylation (attachment of carbohydrate) How does the golgi assist in delivering glycoproteins to the E-Face? - Answers It finishes packing into transport vesicle How does the transport vesicle assist in delivering glycoproteins to the E-Face? - Answers it fuses with the plasma membrane What is the result of the glycoprotein being delivering to the E-Face? - Answers protein is integral to membrane; carbohydrate ends up outside cell on the E-Face Most cells synthesize and secrete materials that are _______ to the plasma membrane. - Answers external Animal cells lack ______ but are covered by an elaborate ______. - Answers cell wall; extracellular matrix (ECM) Example of glycoproteins: - Answers collagen, proteoglycans, and fibronectin ECM proteins bind to receptor proteins in the plasma membrane called _______. - Answers Integrins Fibronectin - Answers attaches the ECM to the integrins Collagen - Answers structural proteins- strength and elasticity Proteoglycan - Answers 'sugared proteins' attached to a single long polysaccharide molecule What are three types of cell junctions that are common in epithelial tissues? - Answers Tight junctions, desmosomes, and gap junctions What happens at tight junctions? - Answers membranes of neighboring cells are pressed together, preventing leakage of extracellular fluid What happens at desmosomes? - Answers They fasten cells together in strong sheets (anchoring junction) What happens at gap junctions? - Answers They provide cytoplasmic channels between adjacent cells (communicating junction) What is an example of a tight junction? - Answers intestines Example of desmosome? - Answers skin Example of gap junction? - Answers cardiac cells What kind of junction is the plasmodesmata? - Answers a communicating junction