BIOL 1201 Exam 2 Questions with Correct Answers 100% Pass

BIOL 1201 Exam 2 Questions with Correct Answers 100% Pass Plasma membrane - Answers the boundary that separates the living cell from its surroundings the plasma membrane is - Answers selectively permeable what are responsible for controlling passage across cellular membranes - Answers transport proteins fluid mosaic model - Answers The membrane is a mosaic of protein molecules bobbing in a fluid bilayer of phospholipids membranes are held together by - Answers weak hydrophobic interactions what can move sideways within the membrane - Answers most lipids and some proteins peripheral proteins - Answers bound to the surface of the membrane what penetrate the hydrophobic core - Answers integral proteins integral proteins that span the membrane are called - Answers transmembrane proteins cell-surface membrane functions - Answers transport enzymatic activity signal transduction cell-cell recognition intercellular joining attachment to the cytoskeleton and extracellular matrix cells recognize each other by - Answers binding to molecules, often containing carbohydrates, on the extracellular surface of the plasma membrane Membrane carbohydrates may be covalently bonded to what (forming what) or to what (forming what) - Answers lipids (forming glycolipids) or proteins (forming glycoproteins) (more common) A cell must exchange materials with its surroundings, a process controlled by - Answers the plasma membrane what are selectively permeable, regulating the cells molecular traffic - Answers plasma membranes What can dissolve in the lipid bilayer and pass through the membrane rapidly? - Answers hydrophobic (nonpolar) molecules (Ex. hydrocarbons) What allow passage of hydrophilic substances across the membrane - Answers Transport proteins other transport proteins, called carrier proteins do what - Answers bind to molecules and change shape to shuttle them across the membrane A transport protein is specific for what - Answers the substance it moves the tendency for molecules to spread out evenly into the available space - Answers diffusion although each molecule moves randomly, diffusion of a population of molecules may be - Answers directional substances diffuse down their - Answers concentration gradient the diffusion of a substance across a biological membrane is ? because no energy is expended by the cell to make it happen - Answers passive transport passive transport - Answers the movement of substances across a cell membrane without the use of energy by the cell The diffusion of water across a selectively permeable membrane is called - Answers osmosis water diffuses across a membrane from the region of ? solute concentration to a region of ? Solute concentration until the solute concentration is equal on both sides - Answers lower, higher What facilitates the transport of ions - Answers ion channels some ion channels, called what, open or class in response to a stimulus - Answers gated channels facilitated diffusion is passive because - Answers the solute moves down its concentration gradient, and the transport requires no energy some what can move solutes against their concentration gradient - Answers transport proteins active transport requires energy from what to move substances across their concentration gradient - Answers ATP hydrolysis active transport - Answers Energy-requiring process that moves material across a cell membrane against a concentration difference Small molecules and water enter or leave the cell through what or via what - Answers through the lipid bilayer or via transport proteins large molecules such as polysaccharides and proteins cross the membrane how - Answers in bulk via vesicles