Term
| Name main functions of biological membranes |
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Definition
1)delineate cells (in vs. out )
2)formation of cell compartments
3)transport and sequestering of metabolites
4)membrane-bound biosynthesis pathways
5)charge separation (electrochemical gradients as energy storage, photosynthesis, respiration )
6)signal-reception and transduction ,
7)cell-cell contacts |
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Term
| Is the presence of biological membranes self-evident for life? |
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Definition
We CAN NOT say that the presence of biological membrane is an self-evidence for life. |
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Term
| Outline the most recent theory of life origine |
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Definition
Life originated in the bottom of the ocean in the black smokers under influence of abiotic geochemical events. The black smoker's stones structure is porous, so these pores could serve as agents of compartmentalization. Also the system comes with a built-in source of energy, sulfides of iron and other minerals. The energy released from redox reactions of these metal sulfides is available for the synthesis of organic molecules, but also for the formation of oligomers and polymers (there was no oxygen!) . Lipids are self-assembling, so they are able to cover the surface of the stone pore. Thus, then the pore occasionally got disrupted the LUCA was released into the ocean and could survive. |
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Term
| What is the most acceptable model for biomembrane now? |
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Definition
Bilayer of lipids with embedded proteins and carbonhydrates. NO DNA. |
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Term
| Name types of membrane proteins |
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Definition
| Integral, periferal, anchorine |
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Term
| Name structural classes of integral membrane proteins |
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Definition
| Alpha helical and betta barrels |
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Term
| Name three types of alpha helices participating in the formation of integral membrane proteins |
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Definition
Hydrophobic
Hydrophilic
Amphiphilic
The properties of the helices are determined by the distribution of charged/polar/unpolar side chains |
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Term
| Name the types of alpha helical integral membrane proteins topologies |
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Definition
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Term
| What do betta barrels based on? Which type of betta sheet can we find in them? |
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Definition
β–barrel proteins are based on beta-sheets formed from beta-strands. Beta-sheets exist in two different forms: antiparallel and parallel. β-barrel proteins contain multiple ANTIPARALLEL beta-sheets formed into a barrel-like structure. |
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Term
| What feature do side chains of betta sheets posses? |
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Definition
Every second side chain should be hydrophobic |
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Term
| What are the functions of integral membrane proteins? |
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Definition
Ionnpumps
Channels
Transporters
Receptors |
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Term
| What are the functions of peripheral membrane proteins? |
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Definition
Cytoskeleton linker
Signal transducers
Components of the extracellular matrix |
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Term
| What types of anchor do non-integral membrane proteins have? |
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Definition
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Term
| Outline the main feature of membrane lipids |
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Definition
| They are amphiphilic. They have polar (hydrophilic) and nonpolar(hydrophobic) parts |
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Term
| What is the typical size of membrane lipid? |
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Definition
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Term
| What is main classes of membrane's lipids backbones? |
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Definition
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Term
| Classification of lipids, based on phosphatidate, by headgroup |
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Definition
Phosphoglycerides ( Phosphatidylserine (PS), Phosphatidylethanolamine (PE), Phosphatidylcholine (PC), Phosphatidylinositol (PI), Phosphatidylglycerol (PG))
Galactoglycerides MGDG, DGDG, SQDG |
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Term
| Classification of lipids, based on ceeramide, by headgroup |
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Definition
Sphingolipids (head groups similar to phosphoglycerides)
Glycosphingolipids ( head group is a mono- or poly-saccharide) |
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Term
| Where can we find a sterols? |
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Definition
Sterols are eukaryotic lipids and not commonly found in membranes of bacteria (exceptions are certain species of mycoplasma and methanotrophic bacteria). |
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Term
| What are the types of linkage in the lipids of Bacterial/Eucariotes and Archea? |
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Definition
Bakteria/Eukaryotes: Ester-linkage (CH2 - O-C=O_R) of fatty acids with glycerol.
Archaea: Ether-linkage(CH2 - O-C-R) of isoprenoids with glycerol occur often as monolayer-lipids |
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