front 1 The _______ ___________ is a boundary between what's inside and outside of the cell. | back 1 plasma membrane |
front 2 until about 1970 the ____________ model was widely accepted. It had a layer of ______________ in the middle between two layers of ___________. | back 2 sandwich, phospholipids, proteins |
front 3 Today we use the ________ __________ model which has ________ embedded into the phospholipid bilayer | back 3 fluid mosaic, proteins |
front 4 What does semi-permeable mean? | back 4 Passage from one side of the membrane to the other is restricted due to multiple factors. |
front 5 What is the most common molecule in the membrane according to the fluid mosaic model? | back 5 Phospholipids |
front 6 Why do phospholipids form a bilayer? | back 6 Because they orientate their hydrophobic tails together and shield them from surrounding water with their hydrophilic heads. |
front 7 Phospholipids are __________ molecules, containing hydrophobic and hydrophilic regions | back 7 amphipathic |
front 8 What are the hydrophobic and hydrophilic regions of phospholipids made of? | back 8 Fatty acid tails and phosphate group heads |
front 9 If you transposed part of a dog cell's membrane into a cat cell's membrane would they stay separate or would they mix? Why? | back 9 They would mix because the molecules of the membrane will move around |
front 10 A membrane rich in unsaturated fatty acids will be more
(fluid/viscous) than | back 10 Fluid The bends in unsaturated fatty acids prevent close packing of the membrane |
front 11 How does cholesterol affect the membrane? | back 11 At warm temperatures, it restrains movement of phospholipids and at
cool temperatures, it |
front 12 __________ proteins are bound to the surface of the membrane | back 12 Peripheral |
front 13 ____________ proteins penetrate the hydrophobic core, and are embedded in the membrane | back 13 Integral |
front 14 What are transmembrane proteins and are they integral or peripheral, why? | back 14 Integral, despite not reaching both sides of the bilayer they still penetrate the hydrophobic core of the membrane. |
front 15 What does the hydrophobic regions of an integral protein consist of? | back 15 One or more stretches of nonpolar amino acids, often coiled into alpha helices |
front 16 In the membrane, proteins have six major functions. What are they? | back 16 Transport |
front 17 Which protein function does HIV take advantage of in order to enter the cell? | back 17 no data |
front 18 Extracellular surface molecules, often containing carbohydrates, do what? | back 18 Allow Cell-Cell Recognition when they bind to each other. |
front 19 Membrane carbohydrates may be covalently bonded to ______ or more commonly to __________. The resulting molecules are called...? | back 19 lipids, proteins glycolipids, glycoproteins |
front 20 The Carbohydrates of plasma membranes vary among species, individuals, and cell types in an individual, true or false? | back 20 True |
front 21 Does the plasma membrane have sidedness? | back 21 Yes |
front 22 (nonpolar/polar) molecules can dissolve in lipid bilayer and pass through membrane rapidly. | back 22 nonpolar |
front 23 ___________ proteins allow hydrophilic substances to pass across membrane | back 23 Transport |
front 24 _________ proteins have hydrophilic tunnel that certain molecules or ions can use as a tunnel | back 24 channel |
front 25 Which channel protein is used to specifically transport water? | back 25 aquaporins |
front 26 ______ proteins bind molecules and change shape to shuttle them across membrane | back 26 carrier |
front 27 A transport protein is specific for the substance it moves, true or false? | back 27 True |
front 28 _________ is the tendency for molecules to spread out evenly into available space | back 28 Diffusion |
front 29 In diffusion each molecule moves randomly, true or false? | back 29 True, however diffusion of a population |
front 30 Explain dynamic equilibrium. | back 30 When the total movement of molecules both directions across the membrane is net 0. |
front 31 Substances diffuse (up/down) their concentration gradient | back 31 down |
front 32 Diffusion of a substance across a biological membrane is ________ transport | back 32 passive |
front 33 ________ is the diffusion of water across a selectively
| back 33 Osmosis |
front 34 Water diffuses across a membrane from the region of _____ solute concentration to the region of _____solute concentration | back 34 lower, higher |
front 35 When does water stop diffusing across a membrane? | back 35 When the solute concentration is equal on both |
front 36 _______ is the ability of a surrounding solution to cause cells to gain or lose water | back 36 Tonicity |
front 37 What happens to a cell in an isotonic, hypotonic and hypertonic solution? | back 37 no net water movement across the plasma |
front 38 Define Osmotic concentration | back 38 total solute concentration of a |
front 39 Which three terms are used to describe an animal cell in the three types of tonicity? What kind of solution do they prefer? | back 39 Shrivelled, normal and lysed Prefer isotonic |
front 40 Which three terms are used to describe a plant cell in the three types of tonicity? Which do they prefer? | back 40 Plasmolyzed, turgid, flaccid Prefer hypotonic |
front 41 Define Osmoregulation | back 41 the control of solute concentrations and |
front 42 In __________ ___________, transport proteins aid the passive movement of molecules across the plasma membrane | back 42 facilitated diffusion |
front 43 ___ channels are a type of channel protein which facilitate the diffusion of ions | back 43 ion |
front 44 Some ion channels are _________ _________, which open or close in response to a stimulus | back 44 gated channels |
front 45 _______ proteins undergo a subtle change in shape | back 45 Carrier, conformation |
front 46 Active transport requires _______, usually in the form of ________ | back 46 energy, ATP |
front 47 ________ ___________ is the voltage difference across a membrane | back 47 Membrane potential |
front 48 What is membrane potential caused by? | back 48 Voltage is created by differences in the distribution of positively and negatively charged ions across a membrane |
front 49 Two combined forces, collectively called electrochemical gradient, drive diffusion of ions across a membrane. What are they? | back 49 A chemical force, An electrical force |
front 50 An ___________ ______ is a transport protein that generates voltage
across a membrane. The sodium-potassium pump is the major __________
______ of | back 50 electrogenic pump, electrogenic pump |
front 51 The main electrogenic pump of plants, fungi, and bacteria is a _________ pump | back 51 proton |
front 52 Electrogenic pumps help store energy that can be used for ___________ ______ | back 52 cellular work |
front 53 ________ occurs when active transport of a solute indirectly drives transport of other solutes | back 53 Cotransport |
front 54 Large molecules, such as polysaccharides and proteins, cross membrane via __________ | back 54 vesicles |
front 55 Does bulk transport require energy? | back 55 Yes |
front 56 Describe exocytosis | back 56 transport vesicles migrate to the membrane, fuse |
front 57 Describe endocytosis | back 57 cell takes in macromolecules by forming |
front 58 What are the three types of endocytosis? | back 58 Phagocytosis, Pinocytosis, Receptor-mediated endocytosis |
front 59 In Phagocytosis what fuses to the newly made vesicle to digest its contents? | back 59 lysosome |
front 60 In receptor-mediated endocytosis, binding of ________ to receptors triggers vesicle formation | back 60 ligands |
front 61 Human cells use receptor-mediated endocytosis to take in __________ for synthesis of membranes and other steroids | back 61 cholesterol |