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34 Cards in this Set
- Front
- Back
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Define a cell-
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the smallest structural unit of an organism capable of functioning
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What are the functions of a membrane?
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permeability, compartmentalization, metabolism, communication, structural stability
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What is the most common phospholipid in cell membranes?
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phosphatidylcholine
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What are the type of membrane lipids?
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phospholipids, cholesterol, glycolipids, phosphatidylserine
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What is a fatty chain?
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hydrocarbon chains with a carboxyl group (COOH)
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How can lipids flip from one leaflet to another?
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through the enzyme flippases
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Name 3 things that increase the fluidity of a cell membrane.
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lower Cholesterol, high temperature, and lots of double bonds
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What did FRAP prove?
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Fluorescence Recovery After Photobleaching (FRAP) proved that the phospholipids can move on the periphery
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What does Freeze Fracture Prove?
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proves that the outer and inner leaflet are disproportional with proteins and helps to make a replica of the membrane
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What does the exterior membrane leaflet contain?
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1. Glycoproteins and glycolipids
2. mostly positive charged lipids |
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What does the inner leaflet mostly contain?
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mostly neutral and positive charged lipids
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What are the 4 functional classes of membrane proteins?
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Transporters, anchors, receptors, and enzymes
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What in an example of a membrane enzyme? membrane anchor?
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enzyme- adenyl cyclase
anchor - integrin |
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How does the CFTR protein function normally?
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a choride channel that secretes Cl- to the extracellular fluid
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What type of structure of a protein is found within the lipid bilayer?
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alpha helical transmembrane domains
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What is the nucleus the site of?
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transcription and mRNA processing (splicing)
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Where does the outer and inner nuclear membrane fuse?
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at the nuclear pore
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What is the chromosome scaffold?
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made of nonhistone protein and the chromatin attaches to it at the SAR
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In the chromosome scaffold were are actively transcribing genes? and non active?
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active is in the loops(euchromatin) and non active (heterochromatin) or few genes is in the SAR
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What is the ER?
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a network of interconnected, closed, membrane bound vesciles, continuous with the outer nuclear membrane
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What is made at the sER?
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fatty acids, phospholipids, glycogen, steroid hormones,
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What are 2 characteristics of the sER?
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no ribosomes and smaller than the rER
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What are some characteristics of rER?
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ribosomes,
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What is formed at the rER and what does it do?
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disulfide bonds, glycosylation of proteins, and protein quality control
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Where do the molecules go after the ER?
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to the golgi
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In what direction does vesicles travel through the golgi?
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Transfer vesicles goes into the Cis region and then leaves the trans region as secretory vesicles
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What are the functions of the golgi?
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Modification -- (complex glycosylation of proteins)
Sorting of proteins based on their final destination |
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What does the lysosomes originate from the golgi as?
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primary lysosomes and they do not yet digest material
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What happens to the residual bodies once they get in the lysosome/
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they are excreted by exocytosis
or in long-lived cells (neurons and cardiac) they can become permanent deposits of lipofuscin granules |
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What is lysosomal storage disease?
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caused by a failure to digest certain marcomolecules in lysosomes due to mutations in specific enzymes
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Why is the surrounding tissue not degraded when a lysosome bursts?
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because their enzymes only work at a pH around 5
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What makes cholesterol?
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Lysosomal lipoprotein degradation -- made out of LDL which is broken down to produce free cholesterol
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What do peroxisomes do?
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1. breakdown fatty acids
2. cholesterol synthesis 3. degradation of peroxides 4. steroid production |
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What do all peroxisonal enzymes contain?
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Ser- Lys-Lec uptake targeting motif and are imported from the cytoplasm
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