Term
| What tissues make the most cholesterol? |
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Definition
| Liver, intestine, adrenal cortex, and reproductive tissues |
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Term
| Where are the 27 carbons of cholesterol derived from? |
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Definition
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Term
| where does cholest synth take place |
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Definition
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Term
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Definition
| 1st. 2 acetyl CoA molecs to acetoacetyl- CoA |
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Term
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Definition
| 2nd. acetoacetyl- CoA to HMG-CoA |
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Term
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Definition
| 3rd. HMG-CoA to mevalonate; uses 2 NADPH; committed and rate limiting step; integral memb protein of ER |
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Term
| Mevalonate 5- phosphotransferase |
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Definition
| 4th. mevalonate to 5-phosphomevalonate; uses ATP |
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Term
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Definition
| 5th. 5-phosphomevalonate to 5-pyrophosphomevalonate; uses ATP |
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Term
| Pyrophosphomevalonate decarboxylase (First part) |
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Definition
| 6th and 7th. 5-pyrophosphomevalonate to 3-phospo-5 pyrophosphomevalonate then converts this to activated isoprenes, dimethylallyl pyrophosphate and delta 3 pyrophosphate; First part of rxn uses Uses ATP; Second part of rxn pulls off CO2 and Pi |
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Term
| Prenyl transferase (head to tail condensation) (first part) |
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Definition
| 8th. activated isoprenes, dimethylallyl pyrophosphate and delta 3 pyrophosphate (C5) combined to form geranyl pyrophosphate (C10); Takes off PPi |
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Term
| Prenyl transferase (head to tail condensation) (Second part) |
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Definition
| 9th. Geranyl pyrophosphate (C10) combined with delta 3 isopentenyl pyrophosphate to form farnesyl pyrophosphate (C15) ;PPi comes off |
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Term
| Squalene synthase (Head to head condensation) |
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Definition
| 10th. Farnesyl pyrophosphate (C15) combined with another farnesyl pyrophosphate (C15) to form squalene (C30); Uses NADPH; 2 PPi come off |
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Term
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Definition
| 11th. Squalene to squalene 2,3- epoxide; Uses NADPH; Forms an epoxide (O connected to 2 carbons in a triangle) |
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Term
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Definition
| 12th. Squalene 2,3 epoxide is cyclized to lanosterol (C30) which will be converted to cholesterol (C27) thru multiple steps |
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Term
| Effect of glucagon and insulin on cholest synth |
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Definition
| Glucagon p'lates HMG-CoA reductase, inactivating it and causing less cholest synth; insulin dep'lates it leading to activation |
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Term
| Pyrophosphomevalonate decarboxylase (second part) |
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Definition
| 7th. 3-phospo-5 pyrophosphomevalonate to activated isoprenes, dimethylallyl pyrophosphate and delta 3 pyrophosphate; Pulls off CO2 and Pi |
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