Term
| In which phase are biomembranes found? |
|
Definition
|
|
Term
| What affects the fluidity of membranes? |
|
Definition
1) Lipid composition and grade of lipid's saturation
2) protein concentration |
|
|
Term
| What membrane fluidity is important for? |
|
Definition
1) function of membrane proteins
2) permeability
3)temperature adaptation
|
|
|
Term
| What is the correlation between protein/lipid ratio and functional complexity? |
|
Definition
| Reduced protein/lipid ratio causes reduced functional complexity |
|
|
Term
| How is the sensing of phase transition works? |
|
Definition
By Hik 33 and DesK (in Synechocystis). Overall principle is following: decrease in temperature → compression of membrane → activation of kinase → P cascade → activation of cascade
phase transition to a more solid state result in the compression of the membrane activation of histidine-kinases activation of fatty acid saturases and desaturases |
|
|
Term
| Name types of lipids' movements in the biomembrane |
|
Definition
1) lateral (withing the same leaflet)
2) flexion
3) rotation
4) flip-flop |
|
|
Term
| What is quicker: lateral diffusion or flip-flop?lateral diffusion or protein diffusion? |
|
Definition
| Lateral diffusion is quicker, than flip-flop 0.1 – 1 μm2/s and 10-100 times faster than protein movement. |
|
|
Term
| How does speed of flip-flop depends from head-group? |
|
Definition
|
DAG (small head group) 0.10 s,
Ceramid (medium) 10 min,
PC(big) – 10 h (this is statistical time)
|
|
|
Term
| Name proteins, which help flip-flop to occur |
|
Definition
Flippases
Floppases
Scrambalases |
|
|
Term
| Outline the role of scrambalases in apoptosis |
|
Definition
|
phosphatidyserine is normally restricted to the inner monolayer of the plasma membrane, under certain conditions PS is brought to the outer monolayer, where it is part of the ‚eat-me‘ signal. Instead of a directed transport of PS to the outer monolayer, an equilibrium of PS in both layers is formed by a scramblase.
|
|
|
Term
| Name the syndrom connected to defect of PS transport |
|
Definition
|
|
Term
| How lateral diffusion could be analysed? |
|
Definition
|
|
Term
|
Definition
|
Lipid molecules undergo short-term confined diffusion within a compartment and long-term ‘hop diffusion’ between compartments.
|
|
|
Term
| What steps are involved in the synthesis of phospho and glycolipids? |
|
Definition
Synthesis of fatty acids
Synthesis of backbones: phosphatidate and ceramide
Activation of head groups
Linking of backbone and head groups |
|
|
Term
| What steps are involved in the synthesis of sterols lipids? |
|
Definition
Synthesis of isoprene (C5)
Synthesis of squalen (C30)
Building of the multiple ring structures further alterations |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| How fatty acids are build? |
|
Definition
|
|
Term
| What enzyme participates in the synthesis of fatty acids? |
|
Definition
|
|
Term
| How Malonyl-CoA is synthesised? |
|
Definition
|
Malonyl-CoA is synthesised in a 2 step reaction by acetyl-CoA Carboxylase (ACCase);the reaction requires energy (ATP) and a co-factor (carboxybiotin).
|
|
|
Term
| How acetyl-CoA Carboxylase (ACCase) from eucariots differs from one from bacteria? |
|
Definition
Ineucariots ACCase is a holoenzyme (one enzyme, one gene). In bacteria and chloroplasts it is composed of multiple units = multiple genes, some units are encoded in chloroplasts.
|
|
|
Term
| How biotin works in the reaction of Malonyl CoA synthesis? |
|
Definition
|
1. ATP-dependent linkage of carbon dioxide onto biotin to form carboxy-biotin
2. Transfer of activated carboxy group onto the final substrate.
|
|
|
Term
| What is the rate - limiting step in fatty acid synthesis? |
|
Definition
|
|
Term
| How is the synthesis of Malonyl CoA regulated? |
|
Definition
Formation of Malonyl-CoA represents the rate-limiting step of fatty acids synthesis and is thus strictly regulated. i.e. in global level by insulin(+), glucagon(-) and adrenaline(-) and on local level by Citrate(+),Palmitoyl–CoA(-), AMP(-).
|
|
|
