front 1 What are the specific functions of a cell membrane? | back 1
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front 2 What is a cell membrane made up of? What are they held together by? | back 2 Lipids and proteins held together by non-covalent interactions |
front 3 What are the three main types (+) of membrane lipid molecules? | back 3 Glycerophospholipids, sphingolipids and sterols (+ glycolipids) |
front 4 What are the parts of a glycerophospholipid molecule like phosphatidylcholine | back 4 A glycerol with 3 linking sites. 2 of them are to fatty acid residues and the 1 is to a phosphate linked to another organic substance like choline |
front 5 What are the 4 phospholipids in mammalian plasma membranes? | back 5 Phosphatidyethanolamine, phosphatidyserine (-), phosphatidylcholine, and sphingomyelin with sphingosine and the basic building block |
front 6 What is the structure of a sterol? Give an example of a sterol. | back 6 Smaller than the others, with ring like structures, a single polar hydroxyl group and variable side chains. Cholesterol! |
front 7 Phospholipids _____ self-assemble | back 7 spontaneously. It's favorable because it minimizes water interactions with the hydrophobic tails of the lipids |
front 8 What are the consequences of sealed compartments being energetically favored? | back 8 If damaged, they will quickly try their best to reseal and polar molecules cannot pass through the lipid bilayer freely |
front 9 What is a phase transition? | back 9 The temperature at which a bi-layer changes from liquid state to a rigid crystalline state (basically a range). Temp phase transition down = membrane fluidity up |
front 10 Why does a membrane have to be fluid? | back 10 To ensure they can efficiently regulate and maintain enzyme activities and transport proteins |
front 11 How do hydrocarbon tail lengths and cis double bonds affect fluidity? | back 11 The shorter the tail, the more fluid. This is due to the reduced interactions and more kinks prevent the membrane from packing tightly together |
front 12 Cholesterol decreases the _______ of the membrane | back 12 fluidity |
front 13 Wat are glycolipids? | back 13 A carbohydrate linked to a polar head group providing great diversity. Attached to the external side of the plasma membrane. Plays a role in cell recognition and adhesion to one another |
front 14 The lipid bilayer is an _______ structure A) Symmetric B) Asymmetric | back 14 B) Asymmetric
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front 15 Cholesterol is distributed _______ in both leaflets A) Equally B) Unequally | back 15 A) Equally |
front 16 Explain the 2 types of examples using PI (phosphotidylinositol) as a signaling molecule | back 16 Type 1: The extracellular signal causes the cell to activate a relay signal within the cell Type 2: The extracellular signal causes the cell to send a signaling lipid fragment into the cell |
front 17 Explain how cell recognition plays an important role in cell death. | back 17 Once a cell dies, phosphotidylserine (- charge) that was once inside the cell relocates to the external leaflet . The phosphotidylserine stimulates/attracts the macrophages to engulf and digest the dead cell it is attached to. |
front 18 What part of the cell is the site of lipid synthesis? | back 18 The cytosolic leaflet of the endoplasmic reticulum sends new lipids to the plasma membrane through vesicles |
front 19 Proteins make up _______% of the membrane mass | back 19 25-75% |
front 20 Draw a fluid mosaic model | back 20 A lipid bilayer with hydrophobic tails, hydrophilic heads and scattered proteins embedded or on top of the bilayer |
front 21 What is the freeze fracture EM? | back 21 Where they freeze cells in liquid nitrogen then fracture it with a knife then study it under a microscope |
front 22 Membrane proteins are typically ______ a) Hydrophobic b) Hydrophilic c) Amphiphilic | back 22 c) amphiphillic |
front 23 How are membrane proteins associated with the lipid bilayer? | back 23
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front 24 What are the 3 types of lipid anchors? | back 24
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front 25 Multi-pass membrane proteins are shaped in _____ and can be predicted using _____ | back 25 Alpha helix shaped and can be predicted using its amino acid sequence |
front 26 What are beta barrels in the membrane? | back 26 B sheet strands that form the shape of an empty barrel and are hydrophilic allowing passage of small molecule and hydrophobic in the areas that bind to the interior of the lipid bilayer |
front 27 Proteins are coated with a ______ layer | back 27 carbohydrate |
front 28 Rates of membrane movement can be measured by FRAP method. What is the FRAP method? | back 28 Fluorescent dyes are attached to membrane lipids/proteins and then a portion is bleached. Then the recovery rate is monitored |
front 29 Go over regulation of protein movement within membranes | back 29 slide 40 |
front 30 Protein are restricted to a certain domain by ______ | back 30 The antibodies on the surface of the cells |
front 31 T/F membrane proteins can deform/bend lipid bilayers | back 31 True |
front 32 What are lipid rafts | back 32 Regions in the membrane that are enriched in sphingolipids, cholesterol, and proteins. Purpose to help proteins with their designated function or transport |