Mem and Cyto
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What are the two common choline containing phospholipids?
* use choline as a head group for phospholipid
What are the common non-choline containing phospholipids?
Where is cholesterol for the phospholipid bilayer created?
In the membrane of the ER. Along with the synthesis of the phospholipids.
Where are all of the phospholipids initially synthesized ?
On the cytoplasmic half of the ER membrane bilayer because enzymes and substrates are in the cytoplasm
What is the ratio of lipids : proteins by mass not actualy # of molecules.
What percent does cholesterol account for in lipid molecules of the membrane?
Peripheral proteins are non-covalently bonded to:
Integral proteins or lipids
Where are peripheral proteins made?
- Cytoplasmic side (inner) - made in cytoplasm
- Extra-cellular (outer) are made in ER and secreted.
What is the rare exception for a partially penetrating integral protein to only be in one side of the bilayer?
Caveolin of the Caveolae
What are the three types of integral proteins?
- 1) Covalently tethered integral proteins to a phospholipid or glycolipid
- 2) Transmembrane
- 3) Partially penetrated
What are the 4 ways to restrict lateral mobility of membrane proteins?
- 1_ proteins can self assemble into larger agregates
- 2_ they can attach to macromolecules inside
- 3_ they can attach to macromolecules outside
- 4_they can interact with other proteins of another cell surface
What is a lipid raft?
A lipid raft is a small, specialized are in membranes where some lipids (sphingomyelin and cholesertol) as well as certain proteins are concentrated. Can also form plasma membrane organelles called caveolae. because the lipid rafts created a thick bilayer, certain membrane proteins may accumulate.
What are the 3 Cytoplasmic Inclusions>
- 1) fat droplets
- 2) glycogen granules
- 3) lipofuscin granules
Where are fat droplets found?
Accumulations of lipid molecules in adipose cells in adrenal cortex cells, liver cells, and other. NON membrane.
Where are glycogen granules found?
this carbohydrate polymer is usually found in liver cells.
Where would you find lipofuscin granules?
These would be in stable, non dividing cells - like neurons and consists of a mixture of material derived from residual bodies after lysosomal digestion.
What is another name for the Microtubule Organizing Center?
What are centrioles?
Centrioles are barrel shaped organelles that are at the centrosomes. They have a cloud of pericentrolar matrix around them that is full of proteins where the minus end is embedded.
what protein nucleates the start of a new filament for MT?
gamma - tubulin
Proteosome vs Peroxisome
Proteosome is a proteasome (enzyme) that is used to degrade unneeded or damaged proteins. Occur in the cytoplasm and nucleoplasm - use ubiquitin.
Peroxisomes - (an organelle) - that uses molecular oxygen to oxidize organic molecules, enzymes to produce organic molecules, and enzymes to produce or degrade hydrogen peroxide. DO NOT have DNA, need to import all proteins. Neurons have NO peroxisomes. Major function is to rid the body of toxins, big in the liver.
What organelle is associated with Tay S disease, what happens here?
- The issue is with lysosomes and the enzyme:
- hexosaminidase A
- (it breaks down glycolipids)
- *issue here is because neurons are full of glycopilipds
- A lysosomal storage disease.
Therefor catabolism of its substrate remains incomplete and an increased accumulation of partially degraded insoluble metabolites.
What are porins?
They are ion pores in human cells. The only ion pores in humans are formed by porins.
What is the signalling zip code to direct proteins into the mitochondria?
Every fourth Amino Acid has a positive charge. This creates a positive wall when the protein is folded correctly.
What is cardiolipin?
A specifically made mitochondria phospholipid. It is made in the mitochondria by imported lipids and has a double feature that includes 4 fatty acid chains. It is found in the inner membrane of the mitochondria and helps to support the membrane again the strong proton motor force. It packs tight to resist the stress.
What organelle is associatd with Zellweger's syndrome?
Peroxisomes - have a defect importing proteins and have an empty case from the ER. This implies 2 defect copies of the PTS receptor. They make precursers for myelin by the synthesis of special phosopholipds - plasmalogens.
What happens in the clinical disease ALD?
peroxisomes defect, can't breakdown long fatty chains. so build up.
What is chromosome p450?
enzymes located in the smooth ER to detox. It is an integral membrane protein
What is a KDEL sequence?
It is the sequence for sorting and the ER retention of a protein. As seen in Bif.
What is M6P good for?
Mannose-6-phosphate is the targeting sequence for newly synthesized lysosomal hydrolase to lysosomes.
What is Spectrin?
It is an important actin-binding protein. It forms the supporting network for plasma membrane of red blood cells.
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