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43 Cards in this Set
- Front
- Back
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Match the following coat protein to what types of vesicles it coats:
1.)Move materials from the TGN to endosomes and plasma membrane. Also used for endocytosis. 2.)Move vesicles from the ERGIC and Golgi "backward" to the ER, or from trans-Golgi cisternae to cis-Golgi cistern. 3.)Move vesicles forward from the ER to the ERGIC and the Golgi complex. A.) Clatherin-coated vesicles B.) COPI-coated vesicles C.) COPII-coated vesicles |
1.) A
2.) B 3.) C |
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Put the the steps of vesicle fusion in their proper order.
A.) A speculative transition state in the fusion of the two membranes. B.) The transmembrane helices are now present in the same bilayer and a fusion pore has now opened between the target vesicle and the target membrane. C.) Synapic vesicle docks to the plasma membrane through the formation of four-stranded protein bundles. |
C, A, B
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Vesicle tethering via Rab protiens is a _____ mediated process.
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GTP
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Match the type of protein coat to its direction of movement:
1.) COPI 2.) COPII A.) antigrade B.) retrograde C.) bi-directional D.) anterograde |
1, B; COPI goes retrograde.
2, D; COPII goes anterograde |
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Tay-Sachs is the most well-known of the lysosomal disorders. Which of the following are true about this disorder?
-Tay-Sachs is caused by a deficiency in producing acid proteases, making the patient unable to degrade proteins. -Tay-Sachs can cause deterioration of nerve cells and mental/physical abilities. -Tay-Sachs can be well-controlled with medication and poses little health risk. -Tay-Sachs is caused by a deficiency in a lysosomal enzyme responsible for degrading sphingolipids, a major component of cell membranes. |
-Tay-Sachs can cause deterioration of nerve cells and mental/physical abilities.
-Tay-Sachs is caused by a deficiency in a lysosomal enzyme responsible for degrading sphingolipids, a major component of cell membranes. |
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In the ER, which of the following are true about how glycosylation occurs?
-For N-linked glycosylation, a core carbohydrate chain is built up first on a lipid carrier molecule called dolichol phosphate. -The enzymes that add the sugars to the proteins are called glycotransferases. -Dolichol phosphate is also used for O-linked glycosylation. - Both N- and O- linked glycosylation occur in the ER. -Only N-linked glycosylation occurs in the ER. -Glycosylation occurs in the rough endoplasmic reticulum. -Glycosylation occurs in the smooth endoplasmic reticulum. |
-For N-linked glycosylation, a core carbohydrate chain is built up first on a lipid carrier molecule called dolichol phosphate.
-The enzymes that add the sugars to the proteins are called glycotransferases. -Only N-linked glycosylation occurs in the ER. -Glycosylation occurs in the rough endoplasmic reticulum. |
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(T/F) There is only one method the cells use for misfolded protein control to see if a protein is suitable for a lumenal compartment: ERAD (ER-associated degradation).
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False
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During the ERAD protein degradation process:
-Three glycine residues area attached to an unfolded protein before it enters the ERAD cycle. -As the protein goes through the folding process, glucosidase enzymes remove glucose residues. - If the protein cannot be successfully folded, it becomes phosphorylated by calnexin. This marks it for removal from the ER. - If the protein remains long enough in the chaperon-binding cycle without reaching its lowest energy conformation, a slow-acting mannosidase will cleave a mannose off the sugar core. - If the protein is not correctly folded, it will continue to cycle on/off chaperone proteins attempting to fold correctly. -When only a single glucose is left on the folding protein, it will bind to calnexin; if the protein reaches its lowest energy folded state, the protein will proceed through the biosynthetic process. - The removal of a mannose residue marks the protein to be sent to the proteasome to be degraded. |
-As the protein goes through the folding process, glucosidase enzymes remove glucose residues.
-If the protein is not correctly folded, it will continue to cycle on/off chaperone proteins attempting to fold correctly. -When only a single glucose is left on the folding protein, it will bind to calnexin; if the protein reaches its lowest energy folded state, the protein will proceed through the biosynthetic process. -The removal of a mannose residue marks the protein to be sent to the proteasome to be degraded. |
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(T/F) Autophagy is the process of organelle turnover by lysozomes. The organelle to be recycled is simply fused with a lyzosome and then destroyed.
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False
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The lysozome has a very low pH, approximately 5. Why does the lysozome have this low pH relative to the rest of the cell?
-The pH of the lysomal lumen is used to drive a proton gradient that could be coupled to other processes (e.g. ATP synthesis.) - The low pH also unfolds proteins, allowing for better degredation by the acid hydrolyses. - The proteins that function in the lysozome are heavily modified lipoproteins to protect them from the acid hydrolyses. - The low pH in the lysozome lumen allows the acid hydrolases to function. - The proteins that function in the lysozome are heavily glycosylated to protect them from the acid hydrolyses. - It maintains its low pH via a proton pump, H+-ATPase. - The acid hydrolases of the lysozome are enzymes capable of digesting every type of biological molecule. |
The low pH also unfolds proteins, allowing for better degredation by the acid hydrolyses.
- The low pH in the lysozome lumen allows the acid hydrolases to function. - The proteins that function in the lysozome are heavily glycosylated to protect them from the acid hydrolyses. - It maintains its low pH via a proton pump, H+-ATPase. - The acid hydrolases of the lysozome are enzymes capable of digesting every type of biological molecule. |
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An integral membrane protein that localizes/functions in the lysozome is first integrated into the ER membrane. The portion of this lysozomal protein exposed within the ER lumen in the same as the portion of the protein:
1) Exposed within the cytosol. 2) Exposed within the mitochondrial matrix. 3) Exposed within the lysosomal lumen. 4) Exposed within the nucleoplasm. |
Exposed within the lysosomal lumen
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Lysosomal proteins are sorted to be transported to the lysosome via what signal?
1) ubiquitination 2) phosphorylated mannose tags 3) KDEL signal 4) KKXX signal |
Phosphorylated mannose tags
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Match the following with either A) KDEL sequence or B) KKXX sequence:
1)Lysine-lysine-anything-anything 2)Binds to COPI coat proteins 3)Signal for soluble ER resident proteins 4)lysine-aspartic acid-glutamic acid-leucine 5)Found on ER membrane proteins on their cytosolic tails |
1, B
2, B 3, A 4, A 5, B |
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The unfolded protein response (UPR) is triggered by an accumulation of unfolded proteins in the ER. What else is true about the UPR?
-It prevents cell lethality. -In the ATF6 pathway, BiP disassociates from ATF6 proteins in the cell membrane. While in the ER, ATF6's cytosolic domain is cleaved. This cytosolic domain enters the nucleus to alter expression of genes that can alleviate ER stress. - Inhibition of translation gives the cell a chance to clear out accumulated misfolded proteins in the ER. - In the PERK pathway, BiP dissociates from PERK, and PERK dimerizes. This dimer then alters a signaling molecule that inhibits translation. - In the ATF6 pathway, BiP disassociates from ATF6 proteins in the cell membrane. ATF6 then trafficks to the Golgi where its cytosolic domain is cleaved. This cytosolic domain enters the nucleus to alter expression of genes that can alleviate ER stress. -In the PERK pathway, BiP dissociates from PERK, and PERK dimerizes. This dimer then alters a signaling molecule that inhibits translocation into ER. - Inhibition of translation allows for new chaperones proteins to be made to help alleviate ER stress. -There are multiple UPR pathways. -Unfolded proteins in the ER associate with the BiP protein. |
-It prevents cell lethality.
-Inhibition of translation gives the cell a chance to clear out accumulated misfolded proteins in the ER. -In the PERK pathway, BiP dissociates from PERK, and PERK dimerizes. This dimer then alters a signaling molecule that inhibits translation. -In the ATF6 pathway, BiP disassociates from ATF6 proteins in the cell membrane. ATF6 then trafficks to the Golgi where its cytosolic domain is cleaved. This cytosolic domain enters the nucleus to alter expression of genes that can alleviate ER stress. -There are multiple UPR pathways. -Unfolded proteins in the ER associate with the BiP protein. |
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The basement membrane in human skin tissue is...
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Basal lamina, a specialized kind of extracellular matrix
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Which of the following statements are true regarding Cell-Cell and Cell-Matrix interactions?
-Homophilic interactions can only be Cell-Matrix interactions. -Unlike Cell-Cell interactions, Cell-Matrix interactions link the cytoskeleton to these contact sites. -Cell-Matrix interactions are always heterophilic interactions. -Cell-Cell interactions are commonly homophilic. |
-Cell-Matrix interactions are always heterophilic interactions.
-Cell-Cell interactions are commonly homophilic. |
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(T/F) Cell adhesion is always the same strength across all cell types and tissues.
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False
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How is a ribosome chosen to be a "free" ribosome or a ribosome on the rough ER?
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It depends on whether the protein it is synthesizing contains an ER localization signal
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The signal on secretory proteins is located at the _________ of the protein.
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N-terminus
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What are the functions of the extracellular matrix?
- It provides cues to the cell about the environment - It provides a network that cells can move upon - It is used to store nutrients for the surrounding cells - It determines strength of the tissue it is in |
-It provides cues to the cell about the environment
-It provides a network that cells can move upon -It determines strength of the tissue it is in |
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Which molecules are secreted to make up the extracellular matrix by the cell?
-Proteoglycans -Laminin -Collagen -Phosphotidylcholine -Integrin -RGD -Fibronectin -Cadherin |
-Proteoglycans
-Laminin -Fibronectin -Cadherin |
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Which of the following is an example of a secretory protein within the constitutive secretion pathway?
-Neurotransmitter -Ribosome -Lysosomal hydrolase enzyme -ECM component |
-ECM component
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A protein that has multiple transmembrane domains (TMDs) is being co-translationally translocated across the ER membrane. In order to be integrated into the membrane, the first 'decision' is whether the N-terminus will be inserted into the ER lumen or will remain in the cytosol. The proper orientation of this multi-TMD protein within the ER membrane is determined by...
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The first TMD and its polarity
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Secretory proteins can be moved across the ER membrane ___________.
1) co-translationally 2) post-translationally 3) Both 1 & 2 4) Neither |
3) Both 1 & 2 (co-translationally and post-translationally)
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(T/F) The ER and the Golgi have different ratios of phospholipids in their plasma membranes.
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True
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Proteoglycans such as GAG (glucosaminoglycans) effectively produce a gel outside the cell. What properties contribute to this?
A. They attract water. B. They occupy space. C. Both A and B. D. Neither A or B, the gel is produced by other molecules than proteoglycans. |
C. Both A and B; They attract water and occupy space
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Most abundant mammalian protein
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Collagen
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Quaternary structure is a triple helix
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Collagen
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Quaternary structure has two polypeptides linked by a disulfide bridge at the C-terminus
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Fibronectin
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Forms meshwork, and is major component of basal lamina
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Laminin
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Quaternary structure has α-, β-, and γ-chains with integrin binding sites and self-assembly
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Laminin
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When this ECM protein is pulled, the tension can cause a conformational change and expose new binding sites.
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Fibronectin
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Membrane biosynethesis begins at which organelle?
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The Endoplasmic Reticulum
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(T/F) Cytochrome C is soluble, mitochondrial matrix protein
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False, it is located in the inter membrane space
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Low density lipoproteins are important for cell functioning. Describe one particle.
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-Inside there are approximately 1500 cholesterol ester molecules
-A single molecule of the protein apolipoprotein B -A monolayer of phospholipids and cholesterol |
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What of the following are true about Phosphoinositide phosphate lipids?
-PI and PIP kinases and phosphotases are only located in the Golgi -PIs provide modifiable lipid profiles unique to different organelles -Several PI and PIP kinases and phosphotases are localized to different organelles where they catalyze the production/removal of these lipid species -PI and PIP are used for membrane fluidity, not signaling -PIP head groups interact with specific protein domains found in adaptor proteins |
-PIs provide modifiable lipid profiles unique to different organelles
-Several PI and PIP kinases and phosphotases are localized to different organelles where they catalyze the production/removal of these lipid species -PIP head groups interact with specific protein domains found in adaptor proteins |
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Which of the following molecules involved in Receptor Mediated Endocytosis (RME) causes the formation of coated pits at the plasma membrane?
-actin filaments -clatherin -caveolin -COPI |
Clatherin
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There have been some reports of some species of bacteria hijacking the phagocytic pathway. What are the methods of doing so that were discussed in class?
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- These bacteria affect the way the phagosome fuse with the lysosome
- There are bacteria that can degrade the lysosome - There are pH tolerant bacteria that thrive in the lysosome |
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What metabolites feed into the following processes?
1) Glycolysis 2) Fermentation 3) TCA Cycle 4) Electron Transport Chain |
1) Glucose
2) Pyruvate 3) Acetyl-CoA 4) NADH and FADH2 |
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Consider only the beta subunit of the F1 particle: How many hydrogen molecules must move through the F0 particle in order to generate 1 ATP molecule from this beta subunit?
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Three
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When brewing beer yeast, water and sugar are mixed together. What pathways are used by the yeast to generate alcohol?
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Glycolysis and fermentation
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Match the following MOST correct definitions
1) Uptake of large particulate matter 2) Non-specific uptake of extracellular fluids 3) Uptake of specific extracellular ligands following their binding to their receptors A) Phagocytosis B) Receptor Mediated endocytocis C) Pinocytosis |
1, A
2, C 3, B |
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What is the optimum net number/type of high-energy metabolites produced by the following pathways?
1) Glycolysis 2) TCA cycle (starting with Acetyl-CoA 3) Electron Transport Chain & ATP synthase 4) Pyruvate Dehydrogenase |
1) 2 ATP and 2 NADH
2) 3 NADH, 1 FADH2, 1 GTP 3) many, many ATPs 4) 1 NADH |
