Lipids Flashcards
(170 cards)
1
Q
Functions of lipids
A
a mjor source of energy for the body, structural elements, hydrophobic barriers, protection against trauma, thermal and electrical insulators, metabolic regulators, important for homeostais
2
Q
why are lipids important for homeostasis
A
main component of prostaglandins and steroid hormones
2
Q
hydrophobic/lipophalic
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water fearing, nonpolar
2
Q
Amphipathic
A
both hydrophobic and hydrophilic
2
Q
hydrophalic/lipophobic
A
water loving, polar molecule
3
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common simple lipis
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saturated and unstaturated fatty acids, MAG DAG TAG - glycerides, natural fats, cholesterol
3
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common complex lipids
A
phospholipids, glycolipids, lipoproteins
4
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common derived lipids
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steroids, eicosanoids, ketone bodies, fat soluble vitamines (ADEK)
5
Q
Fatty acids
A
exist free in the body, fatty acyl esters,
6
Q
Function of fatty acids
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building blocks of lipids, provide energy during fasting, hormone precursors, energy reserve/storage
7
Q
example of structural components of fatty acids
A
phospholipids and glycolipis in plasms membrane
7
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example of hormone precursors of fatty acids
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prostaglandins (hormone-like molecules)
7
Q
unsaturated fatty acids have
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one or more double bonds
7
Q
Example of energy reserve/storage of fatty acids
A
TAG in whote adipose tissue
7
Q
fatty acid structure
A
consists of hydrocarbon chain with termial carboxyl group, long chain length (high water insoluble)
8
Q
Fatty acids must associate with what for blood plasma circulation
A
a protein, mainly albumin and lipoproteins
8
Q
Saturated fatty acids have
A
no double bonds
9
Q
what do Cis double bonds cause
A
Bend or kink in that position
9
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what is the interval on USFA of double bonds
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3-carbon intervals
10
Q
what do the addition of double bonds do
A
decrease melting temperature
11
Q
where are carbon numbering started
A
the carbonyl carbon
12
Q
what do the colon indicate
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before - number of carbons
after- positions of double bonds
13
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carbon 2 is
A
alfa
14
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carbon 3 is
A
beta
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carbon 4 id
gamma (y)
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Carbon of the methyl group
omega
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arachidonic acid
w-6 fatty acid (first double is at 6)
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Palmitic acid
16:0
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Linoleic acid
18:2 (9,12)
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alfa-linoleic acid
18:3 (9,12,15)
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Arachidonic acid
20:4 (5,8,11,14)
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example of structural FA
Palmitic acid
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example of essential FA
Linoleic and alfa linoleic acids
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essential fatty acids
are essential for metaboloism and cannot be synthesized in the body
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Eicosanoids
lipid derivatives, signaling molecules, extremely potent
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physiological va pathologic
inflammaroty response / hypersensitivity
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what are produced in very little amounts while acting locally with out being stored and have short half-lives
eicosanoids
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Archidonic acids is
immediate precursor and is part of membrane phospholipids
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what are derived from w-3 and w-6 polyunstaurated FA with 20 carbons
eicosnoids (prostaglandins, thromboxane, leukotrienes)
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Function of Prostaglandin (PGs)
pain and fever response, action on reproductive and gastrointestinal tract, on bronchopulmonary tone and vascular smooth muscle tone, regulate hormones, calcium movement, inflammation
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function of thromboxane (TXs)
synthesized primarily in platelets, promote platelet homeostasis
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Function of Leukotrine (LTs)
synthesized primarily in leukocytes, mediators of allergic responce and inflammation, synthesis is not inhibited by NSAIDS
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Thrombo
blood clot
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Leuko
white
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Phosphlipid structure
polar phosphate head group with 2 non polar fatty acid trails joined by a glycerol backbone
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general structure
2 fatty acids + glycerol + phosphate + alchol
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what are the main lipids in cell membranes
phospholipids
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What are nonmembrane phosphate lipids important components of
lung surfactants and detergent-like molecules (bile)
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what can phospholipids store
intracellular messenger molecules
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surfactants
detergent, ine area likes water another likes fat
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sphingophospholipids
contain sphingosine as their backbone
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sphingomyelin
important component of my myelin sheath
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example(s) of glycerophospholipids
phosphatidylerine, phosphatiidylcholine, phosphatidylethonalamine, phospatidylinositiol, phosphatidylglycerol
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2 classes of phospholipids
glycerophospholipids, sphingophospholipids
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glycerophospholipids
contain glycerol as their backbone
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example(s) of sphingophospholipids
Sphingomyelin
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Glycerophospholipids make up
phosphatitic acid + alchohol group
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phosphatidic acid
precursor of plyceropholipids
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phosphatidylerine
serine + PA
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phosphatitdylethanolamine
Ethanolamine + PA (cephalin)
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phosphatidylchorline
choline + PA (lecithin, in lung surfactant
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phosphatidylinositonl
inositol + PA (IMPORTANT TO REGULATE IC signaling)
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phoosphatidylglycerol
glycerol + PA ( also in lung surfactant)
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Cardiolipin
component of inner mitochondrial membrane, important for blood clotting
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Platelet-activating factor (PAF)
activates inflammatory cells, platelets aggregation, in hypersensitivity, anaphylactic reactions
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what cells cannot synthesize phosphlipids
erythrocytes (RBC)
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what are glycerophospholipids synthesized from
fatty acid CoA, glycerol-3-phosphate
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where does synthesis occure
sER membrane
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how important id polar head groups
different attchments create different formations which is different molecules
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what are present in many toxins and venoms
phdpholipase
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what is phosphatolipase inhibited by
glucocorticoids
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where is phospholipase C found
liver lysosomes and alpha-toxin of clostridia ad other bacilli
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glycolipids contain
both carbohydrate and lipid components
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what is the backbone of glycosphingolipids
ceramide
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glycosphingolipids
essential compund in membranes, high conentration in nerve tissuse, outer parts of plasma membrane, interact with extracellular environment
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important fact about glycophingolipids
do not contain phosphate
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difference between blood types
A - have N-Acetylgalactoseamine (GalNAc)
B - have galactose (Gal)
O - have neither Gal or GalNA
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things about cholesterol
very hydrophobic compound, four fused hydrocarbon rings, can be taken in or synthesized, structural component
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things about cholesteryl esters
most plamsa cholesterol is an esterified form, makes them even more hydrophobic, transport must be associated, not found in membranes, present only im low levels with lipoproteins
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funcions of cholesterol
structural component of cell membranes and lipoproteins, precursor of bile acid, steroid hormone and vitamin D
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where does cholesterol enter the liver from
diet, cholesterol de novo synthesis
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what is cholesterol a precursor for
glucocorticoids, mineralocorticoids, sex hormones
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VLDL
very low density lipoproteins
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HDL
high density lipoproteins
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LDL
low density lipoproteins
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functon of plasma lipoproteins
keep component lipids soluble for transport in plasma and provide transport mechanism of lipids to and from tissues
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HDL composition and function
lowest TAG, high cholesterol ; deliver cholesterol from peripheral tissuse to the liver
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VLDL composition and function
high TAG, low cholesterol ; deliver endogenous TAG to peripheral
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LDL composition and function
Low TAG, highest cholesterol ; deliver cholesterol to peripheral tissues and back to liver
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Chylomicrons compostion and function
highest TAG, lowest cholesterol ; deliver diestary TAG to peripheral tissuses
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what can accumulate and clog blood vessels
LDL
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which cholsterol is good and bad
good - HDL
bad - LDL
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where is enzymatic lipid digestion
the stomach
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lipid digestion enzymes
lingual lipase, gastric lipase
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are lipids phobic or phillic
hydrophobic
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what are acid lipase important for
lipid digestion in infants
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4 phases of lipid assimilation
1. emulsification
2. hydrolysis
3. micelle formation
4. absorption
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what is the main organ for synthesis and secreation of lipases
pancreas
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what two mechanisms make up the emulsification
mechanical mixing due to peristalsis
use of detergent protperties of conjugated bile salts
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things of bile salts
synthesized in liver, stored in gall bladder, amphipathic cholesterol derivatives, has sterol ring with side animo acid chain, emulsify fat droplets
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Bile
mixture of ble salts, PL and free cholesterol
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Pancreatic enzymes
Triaclglycerol, cholesteryl ester, phospholipids
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lipid mixed micelles
end products of lipid digestion combine with bile saltsw
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what do mixed micelles form
a colloidal suspension
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end products of lipid digestion
FFA, free cholesterol, lysophospholipids, and monolycerides
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where are short and medium chain FA taken
by enterocyte membranes without the aid of mixed micelles
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what are bile and lipid soluble vitamins
A,D,E,K
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4 re-esterification in enterocytes
1. enterocytes -> move to smooth endoplasmic reticulum
2. monoglycerides (MAG) + fatty acids -> triglycerides
3. Lysophopholipids + fatty acids -> phospholipids
4. cholesterol + fatty acids -> cholesteryl ester
all goes to Golgi for maturation of chylomicron
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chylomicron
highly hydrophobic TAG + Cholesteryl ester with a layer of PL, fress Cholesterol and protein
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are short and medium chain reesteridied
no, they are absorbed into hepatic portal circulation
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what are packed in golgi apparatus into structures called chylomicron
re-esterefied lipids, cholesterol and proteins
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where are chylomicrons released from
enterocytes via exocytosis
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What absorbes chylomicrons
lymphatic system
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TAG from chylomicrons
degraded to free fatty acids and glycerol
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where do the FAA from chylomicrons go
muscle or organ cells to produce energy or adipocytes (to store) or remain in blood (bound to plasma proteins)
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Glycerol from chylomicrons
enter liver to synthesize glycerol 3-phosphate by glycolysis or gluconeogensis
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chylomicron remnants
endocytosis by live and hydrolyzed into remaining components an recycled
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hormones that control lipid digestion
cholecystokinin (CCK) and secretin
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what is CCK
cholecystokinin, a peptide produced by I cells of duodenum, produced in reation to lipids and proteins, stimulates Bile from gallbladder and digestive enzymes from pancreas (also decreases motility)
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what is Secretin
peptide produced by S cells of duodenum and release for response of low pH of Chyme, stimulates bicarbonate secretion from pancreas to neutralize pH for pancreatic digestive enzymes
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where are fatty acids oxidized and synthesized
oxidized in the mitochondria
synthesized in the cytoplasm
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physiological condirions that __ FA synthesis largely __ oxidation
promote / inhibits
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where does fatty acid synthesis ocuurs mainly in cytosol of
liver, mammary glands, and adipose tissue cells
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what tissues can synthesize small quantites of FA
kidneys, brain, and lungs
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animals synthesize all FAs they need
no, they have to ingest essential FA from diet
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where are short FA produced
lactating mammary glands
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substrates of De novo synthesis
excess carbohydrates and proteins (acetyl coenzyme A)
109
primary products
Palmitate or palmitic acid (16c)
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what causes desaturation of LCFA
enzymes adding cis double bonds in sER
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how are a variety of polyunsaturated FA (PUFA)
desaturation + elongation
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Cytosolic acetyl CoA production
move acetate units from mitochondrial ACoA to cytosol, MACoAa is porduced by oxidation of pyruvate,
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what is citrate produced by
condensation of ACoA with ocaloacetate,
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how does CoA cross the inner mitochondrial membrane since it can't just cross
the acetyl group must be incorporated into the citriate for membrane transport
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Steps of De Novo Synthesis of FA
1. Cytosolic Acetyl Coa Production
2. ACoA carboxylation to Malonyl CoA
3. Snthesis of Palmitate 16:0
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what are required in the carboxylation process
Biotin (vit h or b7) and ATP
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what enzyme causes carboxylation of ACoA to malonyl CoA
Acetyl CoA caroxylase (ACC)
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what is ACC activated and inactivated by
activated by citrate
inactivated by palmityl CoA
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ACC synthesis is also stimulated by
high-calory and high carbohydrates diets and hormonally (nutrient availability and insulin)
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what are other fatty acid synthesis driven by
fatty acid synthase
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3 types of fatty acids in TAG
C-1 (saturated) C-2 (unstaturated), C-3 (ether)
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how is TAG stored
lipid droplets in adipocytes, a small amount it stored in liver and relased into blood as VLDL
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what is the carnitine shuttle
transports fatty acid coa inro mitochondria
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what is carnitine
compund synthesized from amino acids
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what enzymes synthesize carnitine
lysine and methionione
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where is carnitine synthesized
in liver and kidneys
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what do carnitine deficiencies cause
decreased ability of tissues to use LCFA as fuel
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what is the carnitine shuttle inhibited by
malonyl CoA
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what type of process is fatty acid b-oxidation
cyclic process
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what do b-oxidation cycle produce
1 acetyl-coa + 1 NADH + FADH2
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what is the first b-oxidation cycle
four reactions involving b-carbon and shorten FA by 2 carbons at carboxyl end
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4 reactions of b-oxidation
1 - reduction that produces FADH2
2 - a hydration
3 - second reduction producing NADH
4 - CoA-dependent thiolytic that frees 1 acetyl CoA
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Products of 1 palmitoyl CoA oxidation
8 ACoA, 7 NADH, 7 FADH2
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net products of 1 palmitoyl CoA oxidation
net in mitochondria -
1 palmitoyl CoA -> 31 NADH + 15 FADH2 + 8 GTP
- 129 ATP total
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GTP
another form of energy
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where does the brain get ketone bodies durning a fasting state
liver
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what are ketone bodies
alternative fuel for cells
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main types of ketone bodies
acetoactate, b-hydroxybutyrate, acetone
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what are acetoactate, b-hydroxybutyrate
free soluble lipids
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where are the free soluble lipids transported from to
blood plasma to peripheral tissuea
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where are peripheral tissues
muscle, brain, kidney, mamary gland, small intestine, fetal liver
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what happens to acetone
metbolically inert, cause fruity smell on breath and urine of ketotic patients
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important things about ketone bodies
important energy supple for periplheral tissues, are water soluble, transported without albumin or lipoproteins, can cross both blood brain and placentral barriers, used to concenrate blood by extraphepatic tissue
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what can use highly concentrated of ketone bodies
cardiac and skeletal muscle, intestinal mucosa, renal cortex, brain, and fetus
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what stimulates production of ketone bodies
lipolysis of triglycerides in adipocytes
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when do ketone bodies save glucose
fastring and prolonged ecercise
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what does acid oxiation produce
high amounts of NADH
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what is ketolysis
ketone bodies used by the peripheral tissues
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steps of ketolysis in peripheral tissue
* 3-hydroxybutyrate is oxidizes
* acetoacetat + CoA molecule -> acetoacetyl CoA
* acetocetyl CoA -> 2 acetyl-CoA
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can mammalian RBC and live use KB as energy source
no, RBC lack mitochondria, hepatocyte lack thopphorase
