1 A Uhcl Biochem Ii Exam3.1 - L6 Cholesterol Metabolism

Front 1

--- Cholesterol ---
Is an organic chemical substance classified as a waxy steroid of ***.

Back 1

fat

Front 2

Cholesterol...
derived from greek....

Back 2

chole- (bile)
stereos (solid)
chemical suffix -ol for an alcohol

Front 3

--- Cholesterol ---
1) Dampens influence of *** variations on cell membrane permeability / fluidity.
2) In high t, cholesterol acts to *** fluidity.
3) In low t, cholesterol acts to *** fluidity.

Back 3

1) temperature
2) decrease
3) increase

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--- Cholesterol ---
Important component for the manufacture of *** acids, *** hormones, and vitamin ***.

Back 4

bile --- steroid --- D

Front 5

--- Cholesterol ---
Cholesterol is the principal *** synthesized predominantly in the *** by animals .

Back 5

sterol --- liver

Front 6

--- Cholesterol ---
1) Belongs to a family of molecules called ***
2) which are all synthesized from the compound ***.
3) Family includes steroids, bile acids, g***, c*** and u***.

Back 6

1) terpenes
2) isoprene
3) gibberellins --- carotenoids --- ubiquinone

ubiquinone AKA CoQ10

Front 7

--- Cholesterol Biosynthesis ---
1) Pathway consists of ### stages and is
2) located in the *** of liver cells where
3) it begins with the starting compound ***.

Back 7

1) 4
2) cytosol
3) acetyl-CoA

Front 8

--- Stages of Cholesterol Biosynthesis ---
1) Condensation of ### acetate units forming ***... which is
2) converted into molecule *** (#-C)... which undergoes self
3) polymerization into molecule *** (#-C)... which undergoes
4) cyclization forming the steroid nucleus.

Back 8

1) 4 --- mevalonate
2) isoprene --- 5C
3) squalene --- 30C
4)

Front 9

--- Action Words of Cholesterol Biosynthesis ---
1) ***
2) ***
3) ***
4) ***

Back 9

1) Condensation
2) Conversion
3) Polymerization
4) Cyclization

Front 10

--- HMG-CoA Reductase ---
1) Is used in Step ### of *** synthesis and
2) exists as an *** membrane protein of the ***(organelle)
3) where it serves as a *** *** *** and synthesizes mevalonate.

Back 10

1) 1 --- Cholesterol
2) integral --- ER
3) key regulatory enzyme

Front 11

--- Cholesterol Biosynthesis ---
*** is the key regulatory enzyme.

Back 11

HMG-CoA Reductase

Front 12

--- Cholesterol/Lipid Transport ---
1) C/L from food is packaged as....
2) C/L from the liver is packaged as...
3) Reverse C/L transport is packaged as...

Back 12

1) Chylomicrons
2) VLDL
3) HDL

Front 13

--- Cholesterol Biosynthesis ---
1) Acetate is shuttled out of the *** (organelle) into the ***
2) as *** in a shuttle system also used during *** *** synthesis.

Back 13

1) mitochondria --- cytosol
2) Citrate --- Fatty Acid Synthesis

Front 14

--- Cholesterol/Lipids ---
1) ***(modification) of Cholesterol increases lipophilicity.
2) Both C&L are transported in the blood as ***.

Back 14

1) Esterification
2) Lipoproteins

Front 15

--- Lipoprotein Compositions ---
1) *** are the least dense.
2) *** are highest in Protein.

Back 15

1) Chylomicrons
2) HDL

Front 16

--- Lipoprotein Compositions ---
1) *** are highest in Cholesteryl Esters.
2) *** are highest in Free Cholesterol.

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1) LDL
2) VLDL & LDL

Front 17

--- Lipoprotein Compositions ---
1) The *** converts cholesterol into bile salts....
2) it does NOT uptake cholesterol packaged as...

Back 17

1) liver
2) HDL

Front 18

--- Cholesterol Delivery ---
1) Xport from liver to extrahepatic tissue as...
2) Excess extrahepatic cholesterol is transported back as...
3)
4)

Back 18

1) LDL
2) HDL
3)
4)

Front 19

--- Cholesterol Delivery ---
The liver takes up the *** of LDL, VLDL, and chylomicron by ***.

Back 19

remnants
endocytosis

Front 20

--- Lipoprotein Compositions ---
1) Good cholesterol is AKA...
2) Bad cholesterol is AKA...

Back 20

1) HDL
2) LDL

Front 21

--- Apolipoprotein Location ---
1) ApoA-I???
2) ApoB-100??
3) ApoC-II???
4) ApoE???

Back 21

1) HDL
2) LDL
3) Chylomicrons, VLDL and HDL
4) Chylomicrons, VLDL and HDL

Front 22

--- Apolipoprotein Location ---
Apo*** is found in HDL

Back 22

ApoA-I

Front 23

--- Apolipoprotein Location ---
Apo*** is found in LDL

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ApoB-100

Front 24

--- Apolipoprotein Location ---
Apo*** is found in Chylomicrons, VLDL and HDL

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ApoC-II
ApoE

Front 25

--- Cholesterol ---
1) Greatest Consumer of Cholesterol...
2) # distinct mechanisms control Cellular Supply of Cholesterol.

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1) synthesis of bile acid
2) 3

Front 26

--- Cholesterol in Normal Adults ---
1) Synthesize # ***/day
2) Consume # ***/day
3) De *** synthesis maintains constant cholesterol level
4) in the body of # - # weight/volume.

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1) 1 g/day
2) 0.3 g/day
3) novo
4) 150 - 200 mg/dL

Front 27

--- Regulation: Cholesterol Metabolism ---
1) Regulation of *** activity / level.
2) Regulation of excess intracellular free cholesterol by ***.
3) Regulation of *** cholesterol levels via...
LDL receptor-mediated *** and HDL-mediated *** ***.

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1) HMGR (HMG CoA Reductase)
2) ACAT (acyl-CoA:cholesterol acyltransferase)
3) plasma
uptake --- reverse transport

Front 28

--- Regulation: HMG CoA Reductase ---
1) Main function is to...
2) Most active form is...
3) P'tion occurs through the enzyme *** when
4) the levels of *** decrease/increase.

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1) synthesize cholesterol
2) deP'ed
3) AMPK (AMP-activated protein kinase)
4) AMP --- increase

Front 29

--- Regulation: AMPK Activity ---
1) Main function of enzyme is to...
2) It activates *** functions...
3) and deactivates *** functions...

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1) P(inhibit) HMGR (HMG CoA Reductase)
2) catabolism - (glucose Xport, glycolysis, fatty acid oxidation)
3) anabolism (fatty acid, cholesterol, protein biosynthesis)

Front 30

--- HMG-CoA Reductase ---
1_ Rate controlling enzyme of the *** pathway
2) which controls synthesis of ***.

Back 30

1) Mevalonate Pathway
2) cholesterol

Front 31

--- Mevalonate Pathway ---
1) Rate-controlling enzyme is...
2) Pathway produces cholesterol and other ***.

Back 31

1) HMGCR (HMG-CoA Reductase)
2) isoprenoids

Front 32

--- ATP VS AMP ---
1) *** is a better indicator of a cell’s energetic state.
2) *** is normally found at higher concentrations.

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1) AMP
2) ATP

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--- ATP VS AMP ---
1) Typical ATP concentrations are...
2) Typical AMP concentrations are...

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1) 5-10 mM
2) 0.1 mM or less

Front 34

--- ATP VS AMP ---
If ATP drops by 10% then AMP drops by ***%.

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600%

Front 35

muscular contraction
1) ATP + H2O > ???
adenylate kinase
2) ADP + ADP > ???

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1) ADP + Pi
2) AMP + ATP

Front 36

adenylate kinase
??? > ???

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ADP + ADP
>>>
AMP + ATP

Front 37

--- Regulation: Other Hormones & Cholesterol Metabolism ---
1) Glucagon and Epinephrine reduce HMGR activity via ***...
2) Insulin increases HMGR activity via ***....

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1) PKA and PPI-1 (deP'ed HMGR = less C)
2) PKB (P'ed HMGR = more C)

Front 38

--- Regulation: Other Hormones & Cholesterol Metabolism ---
1) Hormones *** reduces C synthesis.
2) Hormones *** increases C synthesis.

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1) Glucagon and Epinephrine
2) Insulin

Front 39

SCAP?

Back 39

SREBP Cleavage Activating Protein

Front 40

SREBP?

Back 40

Sterol Regulation Element-Binding Protein

Front 41

--- Regulation: Gene Expression & Cholesterol Biosynthesis ---
1) Transcriptional Regulation controls gene expression of *** via a
2) family of proteins called *** which activate transcription upon binding DNA.

Back 41

1) HMG-CoA reductase.
2) SREBPs (Sterol Regulation Element-Binding Proteins)

Front 42

--- SREBP Activation ---
1) SREBP are transcriptional activators of *** and are initially found
2) bound with *** in the membrane of the *** causing it to be inactive.
3) When *** levels decrease, the complex migrates to the *** where its
N-terminal domain is cleaved 2x and migrates to the nucleus
where it activates transcription of sterol-regulated genes.

Back 42

1) HMGR (HMG-CoA Reductase)
2) ER membrane --- SCAP
3) sterol --- Golgi

SREBPs (Sterol Regulation Element-Binding Proteins)
SCAP (SREBP cleavage activating protein).

Front 43

--- Mevalonate Synthesis Pathway ---
High flux through this pathways causes high/low rate of HMGR degradation.

Back 43

high

Front 44

--- Mevalonate Synthesis Pathway ---
1) HMGR is localized to the *** and
2) like SREBP contains a *** domain.
3) *** concentrations of sterol increase HMGR degradation
4) which occurs within a multiprotein complex called the ***.

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1) ER
2) SSD (Sterol-Sensing Domain)
3) Increasing
4) proteosome

Front 45

The primary signal directing proteins to the proteosome is a # kDa protein called ***.

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7.6 kDa
ubiquitination

Front 46

--- Regulation: ACAT & Cholesterol ---
High C concentrations activate ACAT which increases *** of cholesterol for .

Back 46

esterfication --- storage

ACAT (Acyl-CoA-Cholesterol AcetylTransferase)

Front 47

--- Regulation: LDL Receptor & Cholesterol ---
High C levels diminish transcription of LDL receptor genes leading to...
1) +/- number of LDL Receptors and
2) decreased transport of cholesterol from the *** to the ***.

Back 47

1) -
2) blood --- cytosol

Front 48

--- Physiological Functions of Bile Acid ---
1) Only significant mechanism for...
2) Prevents precipitation of *** in the ***.
3) *** agent for triacylglycerols\fat digestion via *** from the ***.
4) Facilitates absorption of...

Back 48

1) cholesterol elimination
2) cholesterol --- gallbladder
3) Emulsifying --- lipases --- pancreas
4) fat-soluble vitamins

Front 49

--- Lipases ---
1) Enzyme that catalyzing the formation or cleavage of *** molecules.
2) They are a subclass of *** enzymes.

Back 49

1) fats
2) esterases

Front 50

--- Conjugated Bile Salts ---
Amide bonds with *** or ***

Back 50

glycine or taurine

Front 51

--- Statin Drugs ---
1) Act through *** inhibition of the enzyme *** which
2) reduces intracellular cholesterol levels causing the ***
3) to upregulate expression of *** leading to the increased
4) clearance of *** from the bloodstream.

Back 51

1) competitive --- HMGR (HMG-CoA reductase)
2) liver
3) LDL receptor
4) LDL (low-density lipoprotein)

Front 52

Bile Acids OR Salts???
1) Best emulsifying agent?
2) pKa of 4-5
3) OH groups on same side

Back 52

1) Salt
2) Salt
3) Acids

Front 53

--- Bile Salts & Acids ---
Conjugated Bile Salts
1) "Good/Better" emulsifying agents
2) pKa is "higher/lower"
3) Chemically unique in that...

Back 53

1) Better
2) lower --- 4-5 pKa
3) Amide bonds with glycine or taurine

Front 54

--- Bile Acids & Salts ---
Primary Bile Acids
1) "Good/Better" emulsifying agents
2) pKa is "higher/lower"
3) Chemically unique in that...

Back 54

1) Good
2) higher --- 5-6 pKa
3) all OH groups are on same side