2.7-CHOLESTEROL=CATALINA WINE MIXER Flashcards
How many carbons are in a cholesterol molecule?
27 (is it odd that this lecture is #2.7?)
Perspective: What are the 4 steps of CHOLESTEROL synthesis?
- MEL-VAL-ON-ATE (6C) Formation 2. Formation of an ISO-PREN-OID (5C) 3. Condensation of ISO-PRE-NE to SQUAL-ENE 4. Cyclization of SQUAL-ENE to MF’n Cholesterol!
Where does Cholesterol synthesis occur?
The MF’n cytoplasm
How many molecules of Acetyl CoA are used to make Mel-Val-On-Ate in the first step of Cholesterol Syn?
3 AcetylCoA= 6C in MelValOnAte
What is the rate limiting step in Melvalonate Formation? HUGE Freaking Question! Billions of dollars spent on regulating this rxn to lower cholesterol!!!
HMG-CoA—–>MelValOnAte using HMG-CoA Reductase. Block the reductase, block cholesterol syn! Saving lives, people helping people. Its powerful stuff.
What is Mitochondrial HMG-CoA used to make?
Ketone Bodies
What is the beginning reactant of Step 2 of Cholesterol Syn and what is the end product? How many Cs in each?
Begin with MelValOnAte (6C) and end with an IsoPrenOid (5C)…We lose a C by decarboxylatoin (CO2)
How much ATP does Step 2 of Cholesterol Synthesis need?
3 ATP needed
How many Cs do we start Step 3 of Cholesterol Synthesis with? How many do we end Step 3 with? What are the names of these structures?
Start with 5Cs (IsoPenTenYL Pyrophosphate) and end with 30!!!! (Squalene)
What two main things have to happen to turn Squalene to Cholesterol in Step 4 of Cholesterol Synthesis? What is the name of the intermediate?
- It has to become cyclic to become LAN-O-Sterol (30Cs) 2. 19 MORE STEPS to get from Lan-O-Sterol to Cholesterol(27Cs)!!!!
What is Cytosolic HMG-CoA used to make?
Cholesterol
WTF is SCAP?
SREBP Cleavage-Activaing Protein
WTF is SREBP?
Sterol Regulatory Element Binding Protein
What is the regulation of Cholesterol Synthesis when there is a HIGH [cholesterol]?
SCAP sequesters SREBP in the ER (the cop has arrested the criminal)
What is the regulation of cholesterol synthesis in LOW [cholesterol]? Tell me a story :)
SCAP-SREBP complex leaves ER and enters the golgi. SREBP breaks off on own and enters the NUCLEUS to become a transcription factor..
Would blocking the ReUp of bile back to the liver lower or raise cholesterol?
Blocking Bile ReUptake would lower cholesterol
What are the two products of bile from cholesterol? review…
GlycoCholate & TauroCholate
What makes Vitamin D a steroid WANNABE? What starts its synthesis?
It would look like a steroid, but one of the rings is broken…Synthesized by sunlight hitting cholesterol
Which hormone promotes the breakdown of cholesterol to sex hormones?
ACTH
What is the enzyme that cleaves Cholesterol in the first step of sex hormone synthesis?
Des-Mol-Ase
What is the CROSSROADS molecule in sex hormone formation?? How many Cs?
PRE-GNEN-OL-ONE (21Cs)
What is PRE-GNEN-OL-ONE converted to before it can be made into a sex hormone?
PRE-GNEN-OL-ONE—–>PRO-GES-TA-GEN (then you can make your precious hormones…)
Review (or should be haha :) :What is the CROSSROADS molecule for deciding to make a TAG or a PL?
Phosphidate
What is the nucleotide involved with PL synthesis?
CDP-DiGlyceride (like in Glycogen syn but that was UDP)
