Lipid Metabolism Lipid oxidation for energy source - Glucose not - - PowerPoint PPT Presentation

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Lipid Metabolism Lipid oxidation for energy source - Glucose not - - PowerPoint PPT Presentation

Jun 12, 2023 469 likes •850 views

Lipid Metabolism Lipid oxidation for energy source - Glucose not the only source of energy for an organism - _________________________________ used as an energy source Glucose Fatty acids - ____________________ of energy - readily available

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SLIDE 1

Lipid Metabolism

  • Glucose not the only source of energy for an organism
  • _________________________________ used as an energy source

Glucose Fatty acids

  • readily available energy source
  • used when energy demands normal
  • ____________________ of energy
  • used when energy ________________
  • release more energy than glucose

Lipid oxidation for energy source

b-oxidation: process of

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SLIDE 2

Lipid Metabolism

Lipid synthesis Acetyl-CoA from TCA cycle used to _____________________________ _____________________ converted to acetyl-CoA

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SLIDE 3

Lipid Metabolism

Cellular localization of lipid metabolism

b-oxidation - ____________ Acetyl-CoA formation - ______ Fatty acid chain elongation - ___

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SLIDE 4

Fatty Acids

amphipathic lipid -carboxyl group polar end (hydrophilic)

  • hydrocarbon chain nonpolar tail (hydrophobic)
  • even # of carbon atoms
  • hydrocarbon chain

unbranched

  • saturated: no C - C

double bonds

  • unsaturated: C - C

double bonds

  • double bonds almost

always cis

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SLIDE 5

Triacylglycerols

(triglycerides)

Triacylglycerols - ester linkage of a fatty acid to each OH of glycerol polar nonpolar Generally, same F.A. esterified to all three positions on glycerol Not found in membranes but act to store F.A.’s for metabolic energy source

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SLIDE 6

Phosphoacylglycerols

(phospholipids)

Phosphatidyl esters

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SLIDE 7

Lipid Metabolism

Release of fatty acids from triacylglycerols and phospholipids triacylglycerols

  • ______________
  • breaks bonds between ____

_______________________

  • most often _______________

phospholipids

  • _____________________
  • breaks bonds between F.A.

and OH of glycerol

  • not so often _______________

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SLIDE 8

Lipid Metabolism

Release of fatty acids from triacylglycerols

  • Epinephrine hormone activates

_________________________.

  • Each F.A. released from glycerol
  • F.A. has _____________________
  • caffeine ______________________

Why do distance athletes drink coffee before event?

  • induces F.A. __________________
  • saves carbohydrates for later in the

event

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SLIDE 9

Lipid Metabolism

Activation of F.A. - bonding of F.A. carboxyl group ____________________

  • general term of ______________________
  • exact name depends ______________________
  • ___________________________________
  • energy, by hydrolysis of two phosphate bonds
  • takes place in cytoplasm

Oxidation of F.A.

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SLIDE 10

Lipid Metabolism

b-oxidation

  • acyl-CoA moved from cytoplasm to ____________________________
  • ___________ units removed from F.A. in

4 rxn cycle

  • carbons removed from _________

___________________

  • b carbon becomes carboxyl

carbon

  • cycle repeats until F.A.

_____________ in successive 2 carbon acetyl-CoA removals

  • produced acetyl-CoA put

into ________________

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SLIDE 11

Lipid Metabolism

b-oxidation Step 1: oxidation of Ca - Cb bond to ____________________

  • acyl-CoA __________________
  • FAD reduced to FADH2
  • double bond in __________

configuration

  • product: trans-D2-Enoyl-CoA

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SLIDE 12

Lipid Metabolism

b-oxidation Step 2: Ca - Cb double bond hydrated _______________________

  • enoyl-CoA __________________
  • uses H2O
  • product: b-hydroxyacyl-CoA

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SLIDE 13

Lipid Metabolism

b-oxidation Step 3: Cb _______________________

  • hydroxyacyl-CoA ______________
  • reduces NAD+ to NADH
  • product: b-ketoacyl-CoA
  • set up for Cb to become

__________________

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SLIDE 14

Lipid Metabolism

b-oxidation Step 4: Ca - Cb___________________

  • ___________________
  • requires CoA, added to remaining

F.A.

  • _____________________

undergoes a new round of b-oxidation

  • product: acetyl-CoA
  • Cb becomes
  • Ca goes with acetyl-CoA
  • acetyl-CoA enters ________

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SLIDE 15

Lipid Metabolism

b-oxidation

  • b-oxidation of even # F.A. gives __________________________
  • C-18 stearic acid = ____________________________
  • requires ____________________ of b-oxidation

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SLIDE 16

Lipid Metabolism

b-oxidation energy production

__________ __________ __________ __________ __________ __________ __________ __________

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SLIDE 17

Lipid Metabolism

b-oxidation energy production 3 Glucose = 18 carbons = __________ 1 stearic acid = 18 carbons = ________ Why the difference in ATP production? A more ______________ can donate more e- for ATP production

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SLIDE 18

Lipid Metabolism

b-oxidation H2O production Metabolic H2O - _____________________________ aerobic metabolism Large amount of water from b-oxidation can be used ___________________ _____________________________________ Camels - hump contains stored lipids Kangaroo rats

  • diet of seeds high in lipids
  • live indefinitely with out

external H2O

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SLIDE 19

Lipid Metabolism

Fatty Acid Biosynthesis Acetyl-CoA is transported to the ___________________ Once in cytoplasm, converted _____________

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SLIDE 20

Lipid Metabolism

Fatty Acid Biosynthesis 2 Priming events:

  • 1. Acetate transferred to ___________________________________
  • 2. Acetate transferred to b-ketoacyl-S-ACP-synthase (_____________)
  • acetyl-KSase combined

with ____________, forming acetoacetyl-ACP malonyl - carboxylated acetate

  • ___________ malonyl lost

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SLIDE 21

Lipid Metabolism

Fatty Acid Biosynthesis

  • next three steps are exact ___________________
  • reduces ketone from acetate
  • ____________________
  • dehydration to double bond
  • reduction to __________________
  • produces butyrl-ACP
  • process requires ______________
  • uses 2 NADH

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SLIDE 22

Lipid Metabolism

Fatty Acid Biosynthesis

  • butyrl-ACP added _________________ malonyl-ACP
  • same 3 reactions take place to

_______________________ 16:0 palmitate

  • process repeated until

required length achieved

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SLIDE 23

Lipid Metabolism

Fatty Acid Biosynthesis F.A. synthesis takes ___________________ Fatty acid synthase - large protein complex containing all the _______________ _________________ As with glycolysis and gluconeogenesis b-oxidation and F.A. synthesis are ____ _______________________________ But, are opposites in terms of end products

  • double bonds introduced by enzymes

in the _________________________

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SLIDE 24

Lipid Metabolism

Triacylglycerol Biosynthesis Generally, free F.A. _____________________ F.A. added to OH groups of ___________

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SLIDE 25

Lipid Metabolism

Phospholipid Biosynthesis

  • 2 F.A. added to ____________________
  • polar head group ___________________________

FA1 FA2

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SLIDE 26

Lipid Metabolism

Cholesterol Biosynthesis

  • essential part of __________________
  • used to make __________________
  • major contributor ___________________
  • synthesized through ______________________________

Isoprenoid pathway - use of ___________ to produce _______ compounds Isoprene Isoprene units can be condensed to form intermediates with carbons ____________________________

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SLIDE 27

Lipid Metabolism

Cholesterol Biosynthesis Isoprenoid pathway involved in synthesis of:

  • ________________

Chlorophyll a

  • ________________ (coenzyme Q, e- transport)

ubiquinone

  • ________________

Vitamin A

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SLIDE 28

Lipid Metabolism

Cholesterol Biosynthesis Plants make many isoprenoids, > 20,000

  • _______________________

capsidiol

  • __________________

carotenoids

  • ________________

b-carotene in tomatoes

b-carotene used by mammals to make vitamin A, ______________________

Vitamin A

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SLIDE 29

Lipid Metabolism

Cholesterol Biosynthesis Isoprenoid pathway general scheme:

acetate

(acetyl-CoA)

____

S-CoA O

acetyl-CoA mevalonate ____ x 3

HO OH O OH

mevalonate Isopentenyl diphosphate isopentenyl diphosphate (_____) ____

OPP

OPP

geranyl diphosphate (_____) geranyl diphosphate ____

OPP

farnesyl diphosphate (_____) ____ farnesyl diphosphate ____ ….C50 ____ Intermediates can be used for ______________ ____________________________________. ____

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SLIDE 30

Lipid Metabolism

Cholesterol Biosynthesis

C2

S-CoA O

acetyl-CoA C6 x 3

HO OH O OH

mevalonate Isopentenyl diphosphate C5

OPP

C10

OPP

geranyl diphosphate

OPP

C15 farnesyl diphosphate x 2

HO

___________ _____ ___________ _____

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  • r
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SLIDE 31

Lipid Metabolism

Cholesterol Biosynthesis C30 Squalene is cyclized to _____________ 19 reactions by 19 enzymes convert C30 lanosterol to C27 cholesterol 3 carbons lost _____________

  • _______________________
  • f liver cells.

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SLIDE 32

Lipid Metabolism

Cholesterol Metabolism Steroid hormone production

  • cholesterol converted to _____________
  • pregnenolone to __________________
  • sex hormones

_______________ _______________

  • glucocorticoids

cortisone

carbohydrate, protein, F.A. metabolism

  • mineralcorticoids

aldosterone _______________________

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SLIDE 33

Lipid Metabolism

Cholesterol Metabolism Atherosclerosis - condition of blocked artery by __________________ ____________________ Cholesterol is transported in the blood in the form of __________________________

  • cholesterol
  • phospholipids
  • proteins

LDL - ____________________ lipoprotein HDL - ____________________ lipoprotein Density determined by amount of protein

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SLIDE 34

Lipid Metabolism

Cholesterol Metabolism

  • LDL internalized to a cell by binding

__________________________

  • LDL broken down into

___________________________

  • cholesterol used in membranes
  • oversupply of cholesterol turns off

________________________. What type of regulation is this?

  • also stops production _____________
  • LDL can not be internalized, builds

up in arteries, clogged arteries

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SLIDE 35

Lipid Metabolism

Cholesterol Metabolism Familial hypercholesterolemia - genetic defect in genes that produce _____________________________________

  • LDL never internalized to cell
  • extremely high _________________________
  • almost always lethal
  • die before 20 years old
  • reported heat attacks in 2 year olds

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SLIDE 36

Lipid Metabolism

Cholesterol Metabolism

Joe Goldstein (1940 - ) Michael Brown (1941 - ) University of Texas Southwestern Medical Center at Dallas

  • 1985 , Nobel Prize in Physiology or Medicine
  • for their discoveries concerning the regulation of cholesterol metabolism

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SLIDE 37

Lipid Metabolism

Cholesterol Metabolism HDL - “good cholesterol”

  • transports cholesterol from blood ___________________________

Ideal blood levels

[LDL] [HDL]

  • HDL can be increased by _______________________________
  • HDL is reduce by _______________________________

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