Cell Biology
• Chapter 7 o Online questions
• The fluid mosaic model is now generally accepted for the description of all biological membranes
• Transmembrane segments of membrane proteins anchor membrane proteins in the lipid bilayer.
• A ganglioside is not a phospholipid.
• Thin-layer chromatography separates lipids based on hydrophobicity.
• Unsaturated fatty acids have double bonds and increased membrane fluidity.
• Cholesterol increases fluidity at low temperatures and decreases fluidity at high temperatures.
• Ankyrin is a peripheral membrane protein found in erythrocytes. Therefore it lacks discrete hydrophobic sequences.
• Most lipid-anchored proteins are attached to the inner side of a plasma membrane by covalent linkage to a fatty acid or prenyl group.
• A useful technique for studying membrane proteins is SDS-PAGE ( sodium dodecyl sulfate- polyacrylamide gel electrophoresis). In this method, the role of SDS is to coat the proteins with a negative charge.
• Lectins are proteins that bind sugars and have been useful in the study of glycoproteins.
• You discover an integral membrane protein that has amino acid residues N- and O- linked to side groups with a terminal sialic acid. It is therefore most likely a glycoprotein.
• Localized regions of membrane lipids involved in cell signaling are called lipid rafts.
• Hopanoids are sterol-like molecules found exclusively in bacteria.
• Membranes from cells grown in media enriched with stearate are less fluid than normal membranes. This is because the membranes have more saturated fatty acids.
• The functions of the biological membrane are :
• They contain receptors for the detection of external signals
• They provide a means of cell to cell communication
• They regulate movement of a substance into and out of the cell
• They define boundaries of a cell and its organelles
• Within a membrane, phospholipids:
• Have their polar head groups facing outward
• Can switch or “flip-flop” from one monolayer to
• The fluid mosaic model is now generally accepted for the description of all biological membranes
• Transmembrane segments of membrane proteins anchor membrane proteins in the lipid bilayer.
• A ganglioside is not a phospholipid.
• Thin-layer chromatography separates lipids based on hydrophobicity.
• Unsaturated fatty acids have double bonds and increased membrane fluidity.
• Cholesterol increases fluidity at low temperatures and decreases fluidity at high temperatures.
• Ankyrin is a peripheral membrane protein found in erythrocytes. Therefore it lacks discrete hydrophobic sequences.
• Most lipid-anchored proteins are attached to the inner side of a plasma membrane by covalent linkage to a fatty acid or prenyl group.
• A useful technique for studying membrane proteins is SDS-PAGE ( sodium dodecyl sulfate- polyacrylamide gel electrophoresis). In this method, the role of SDS is to coat the proteins with a negative charge.
• Lectins are proteins that bind sugars and have been useful in the study of glycoproteins.
• You discover an integral membrane protein that has amino acid residues N- and O- linked to side groups with a terminal sialic acid. It is therefore most likely a glycoprotein.
• Localized regions of membrane lipids involved in cell signaling are called lipid rafts.
• Hopanoids are sterol-like molecules found exclusively in bacteria.
• Membranes from cells grown in media enriched with stearate are less fluid than normal membranes. This is because the membranes have more saturated fatty acids.
• The functions of the biological membrane are :
• They contain receptors for the detection of external signals
• They provide a means of cell to cell communication
• They regulate movement of a substance into and out of the cell
• They define boundaries of a cell and its organelles
• Within a membrane, phospholipids:
• Have their polar head groups facing outward
• Can switch or “flip-flop” from one monolayer to