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Biochemistry
Final Pt 2
| Question | Answer |
|---|---|
| Transport systems confer this important property on membranes | Selective Permeability |
| This is the number of carbons in most common fatty acids | 16 or 18 |
| In addition to phospholipids and glycolipids, this is a major type of membrane lipid. | cholesterol |
| This is a term applied to molecules that have both hydrophilic and hydrophobic moieties. | Amphipathic |
| This substance inhibits prostaglandin H2 synthase-1 by blocking the channel through which the substrate, arachidonate, travels. | Acetylsalicylic acid (aspirin) |
| This is the region between the cell wall and cell membrane of prokaryotes. | Periplasm |
| This procedure is used to determine the probability that a segment of a protein will be found in a membrane. | Hydropathy |
| This is the process by which lipids and proteins move in the membrane bilayer | Lateral Diffusion |
| These membrane components contain carbohydrates. | Glycolipids |
| This is a complex between cholesterol and membrane phospholipids. | Lipid Raft |
| ______ is a membrane lipid composed of sphingosine, fatty acid, and a simple sugar. | Cerebroside |
| The common name of hexadecanoic acid is ______ | Palmitic Acid |
| In phosphoglycerides, the fatty acids are linked to the glycerol backbone by the _____ linkages. | Ester |
| Ionized fatty acids readily form ____ in aqueous solotions. | Micelles |
| _____ are aqueous compartments enclosed by a lipid bilayer. | Lipid vesicles or Liposomes |
| ____ membrane proteins are bound primarily by electrostatic and hydrogen bond interactions with the head groups of lipids. | Peripheral |
| Some proteins are anchored to the membrane by being covalently attached to a _____ group by a thioester linkage to a specific cysteine residue. | Palmitoy1 |
| The rate of diffusion is such that a phospholipid molecule can travel from one end of a bacterium to the other in ____ of time. | One Second |
| The temperature at which a phospholipid membrane transitions from a rigid to a fluid state is referred to as ____ | Tm or melting temperature |
| An increase in the ratio of saturated to unsaturated fatty acid chains in a membrane ____ (increases, decreases) the fluidity of the membrane. | Decreases |
| Membranes are primarily comprised of | Lipids and Proteins |
| Which of the following is true? All of them | Membranes are lipid bilayers. Membrane lipids have both hydrophobic and hydrophilic properties. Many membranes are electrically polarized. |
| How many molecules thick are membranes? | Two |
| Which of the following membranes would be the most fluid? | A Bilayer made of lipids with polyunsaturated 16 carbon-fatty acids |
| Which of the following statements is consistent with the structure of biological membrane? | The membrane lipids self-assemble to form the lipid bilayer. |
| How do the membranes of archaea differ from bacteria and eukaryotes? | The lipids do not contain a carboxylic acid ester, but instead have an ether link to the glycerol. The alkyl chains are branched. The stereochemistry of the central carbon of glycerol is inverted. |
| Carbohydrate residues attached to the membrane lipids are | Always positioned on the extracellular side of the membrane. |
| What force(s)stabilize(s) the lipid bilayers? | van der Waals interactions. Electrostatic and hydrogen bonding between the polar heads and surrounding water. |
| The degree of membrane fluidity depends on | The percentage of unsaturated fatty acids. |
| Which is the proper order of permeability of molecules across a membrane, from the most permeable to the least? | Water, indole, glucose, sodium ion |
| The most common motif found in membrane spanning proteins is | a helices of nonpolar amino acids that pass through the membrane |
| Hydrophobic molecules can be covalently attached to proteins to increase membrane association. Type(s) of group(s) include | Palmitoy1 groups attached via cys residues. Glycolipid structures attached to the carboxy terminus. Farnesy1 groups attached via cys residues. |
| The low incidence of protein or lipid flip-flop in a membrane preserves | Membrane asymmetry |
| Which of the following helps regulate membrane fluidity in animals? | Cholesterol |
| Which is the proper order of permeability of molecules across a membrane, from the most permeable to the least? | Water, indole, glucose, sodium ion |
| The most common motif found in membrane spanning proteins is | a helices of nonpolar amino acids that pass through the membrane |
| Hydrophobic molecules can be covalently attached to protein to increase membrane association. Type(s) of group(s) include | Palmitoy1 groups attached via cys residues. Glycolipid structures attached to the carboxy terminus. Farnesy1 groups attached via cys residues. |
| The low incidence of protein or lipid flip-flop in a membrane perserves | Membrane asymmetry |
| Which of the following helps regulate membrane fluidity in animals? | Cholesterol |
| What does the notation 18:2 for fatty acids imply? | In this fatty acid there are 18 carbons, with 2 double bonds. |
| What are some molecules that form the polar head group of a phospholipids? Provide several examples. | Example of head groups include serine, ethanolamine, choline, glycerol, and inositol. |
| What is cardiolipin? | This is a molecule in which two phospholipids are attached through the phosphate groups to a glycerol molecule, It is also called diphosphatidyl glycerol. |
| Why do most phospholipids preferentially form sheets instead of micelles? | The two tails in phospholipids makes it sterically unstable for them to form micelles |
| What are liposomes? What are some of the current commercial applications? | Liposomes r spherical structures of lipid bilayers, similar to miniature organelles. They r extremely useful as models of cell systems. They can be used to contain or transport molecules such as drugs 4 therapy, & r commonly used n cosmetics/ skin cream |
| How is the nuclear membrane different from other membranes? | The nuclear membrane is not continuous. It is a set of closed membranes that come together at pores. |
| Bacteria must survive in many different conditions. How do they adapt? | Bacteria can regulate the fluidity of the membrane, thus helping them withstand temperature changes. They do this by varying the number of double bond in the fatty acid residues in the phospholipids, and varying the chain length |
| What is receptor-mediated endocytosis? | Receptor-mediated endocytosis is a transport process in which a protein is recognized by a receptor on the cell surface and then that region of the membrane invaginates into the cell. |
Created by:
AshCha
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