Lipids 1-3 Flashcards

Question

What is steatorrhea?

Answer 1

* Excess lipid in feces (very tinky, floats) * Can occur because: 1. There is o_bstruction of bile duct_ 2. _Pancreatic juice duct obstruction_ (or lack of pancreatic juice?) 3. _Defective intestinal mucosal cells_

Answer 2

**1) Abetalipoproteinamia**: apo B-100 defect (no VLDL /chylomicrons/LDL, so no long chain FA absorption; GI symptoms, cognitive problems) **2) LPL deficiency**: high blood levels of chylomicrons **3) Apo C-II deficiency**: on surface of chylomicrons & VLDL, & is normally required for LPL activation. Mutation prevents clearance of chylomicrons from blood **4) Low LPL activity**: extreme plasma chylomicron & TAG levels; liver & pancreas problems. Fat-restricted diet.

Answer 3

\* _Adaptive thermogenesis_: variable, regulated by brain. Responds to temperature and diet. Brown adipose tissue. \*_Physical activity_: variable _\*Obligatory energy expenditure_: resting metaboic rate ~1300 kcal/day

Answer 4

* **Olestra**: "fake fats," cannot be digested. 6-8 FA on sucrose * **Orlistat:** lipase inhibitor. Do not figest TAGs from diet. Can cause GI problems.

Answer 5

* Lipoprotein Lipase Triglycerides -------\> glycerol + 3 FAs

Answer 6

* TAGs are the preferred storage form * FA degradation is a cylcic process (β-oxidation) * β-oxidation: in _inner mitochondrial matrix_ * The brain cannot break down FAs * More reduced -\>more energy content

Answer 7

In adipose tissue: **1) triacyl glycerol** ---_lipases----\> **FA + glycerol** **2) glycerol**-- _{deihydroxyacetone phosphate}---\> **glucose + acetyl-CoA**

Answer 8

1) **FA** + ATP --\> Acyl adenylate 2) **Acyl adenylate** + HS-CoA --\> AcylCoA 3) **AcylCoA** + FAD ---\> trans-Δ²-EnoylCoA + FADH₂ 4) **trans-Δ²-Enoyl CoA** + H₂O ---\> L-3-Hydroxyacyl CoA 5) **L-3-Hydroxyacyl CoA** + NAD⁺---\> 3-Ketoacyl CoA + NADH 6) **3-Ketoacyl CoA** + HS-CoA ---_thiolysis--\> **Acyl CoA + Acetyl CoA**

Answer 9

* Biotin * Vitamin B12 * Mn & Co

Answer 10

-Carnitine Pamitoyl Shuttle 1. FA --\> FattyAcyl-CoA 2. Into mito-intermembrane space 3. C.P. Transferase I converts FattyAcyl-CoA into Acyl-Carnitine 4. Acyl-Carntine goes through inner membrane 5. CP. Transferase II converts it back to FattyAcyl-CoA

Answer 11

12:0 5 FADH2 (x2) --\> 10 5 NADH (x3) --\> 15 6 AcetylCoA (x12) --\> 72 1 AcylCoA synthesis --\> -2 \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ 95 ATPs (2.5 more than glucose per unit weight)

Answer 12

* No functional peroxisomes * Defect in degradation of FAs 26+ & α-oxidation * Affects CNS and other organs * No treatment, do nt survive beyond 1 year

Answer 13

* Defect in degradation of 3-methyl-branched FA (phytanic acid) * Neurological disease caused by accumulation of phytanic acid * Treatment: phytanic acid restricted diet (fat-containing products from ruminant animals & high-fat fish)

Answer 14

* Late pregnancy * Neonatal period * High fat diet * Starvation * Extreme exercise

Answer 15

- Refers to diabetic & alcoholic ketoacidosis - Cells cannot absorb glucose, liver does gluconeogenesis - Oxaloacetate decreases (no TCA), and B-oxidation increases - Ketone bodies increase causing acidosis & loss of fliud & minerals. Can lead to comma id pH is too low

Answer 16

* Symptom of starvation due to inefficient use of FAs as 1ry E-source * Muscle weakness, sleepiness, mood changes * Treatment: dietary modification, frequent intake of low-fat, high-carb food, (to keep adequate glucose levels to prevent body from moving fat to the liver for energy)

Answer 17

* Glucose from gluconeogenesis * 3-Hydroxy-butyrate/ketone bodies (from acetyl-CoA from FAs) * Acetoacetate (ketone body) * Amino acids

Answer 18

* glucose preferred fuel * no ß-oxidation * starvation ketone bodies

Answer 19

* Glucose, FA, ketone bodies * Large glycogen storage (1200 kcal) * ß-oxidation in resting muscle * little citric acid cycle when glucose is used (--\> Cori cycle)

Answer 20

* FA, ketone bodies * has no glycogen * almost exclusively aerobic

Answer 21

* glucose, FA * needs glucose to make glycerol * TG storage (135.000 kcal)

Answer 22

* glucose, FA, ketone bodies * uses about 10% of total oxygen * very important for gluconeogenesis

Answer 23

* glycogen storage (400 kcal) * glycolysis to get building blocks for biosynthesis * does not use glucose, FA or ketone bodies * makes glucose from ala, lactate, pyruvate * energy from alpha-keto acids (aa degradation) * under starvation cond. ß-oxidation

Answer 24

* Liver and adipose tissue (humans: almost exclusively in liver) * Synthesis from acetyl-CoA & malonyl-CoA * In cytosol * Acyl units are carried by Acyl Carrier Protein (ACP) * Glucose or AA --\> acetylCoA 8 acetyl CoA + 14 NADPH + 14 H+ + 7 ATP --------\> palmitic acid (16:0)

Answer 25

* Alcohol increases liver NADH levels. This will inhibit isocitrate dehydrogenase in mito * Accumulation of citrate, & so it goes to cytosol through a shuttle * In the cytosol, citrate releases acetylCoA when coverted to oxaloacetate

Answer 26

* **Short-term**: RAPID: allosteric covalent modification * **Long term**: SLOW: rate of synthesis (ex. after a few days of diet)

Answer 27

Lipogenic enzymes: * Acetyl CoA Corboxylase * FA Synthase * Citrate Lyase * Malic enzyme * DH of Pentose Phosphate Pathway --\> are upregulated by: high CH diet, high insulin levels --\>downregulated by: high fat/low carb diet & fasting

Answer 28

**Isocitrate DH:** allosteric inhibition by ATP **CPT1** (Cartnitine-Palmitoyl-Translocase): allosteric inhibition by malonyl CoA (prevents ß-oxidation) **Acetyl CoA carboxylase**: inhibited by phosphorylation (AMPK), activated by citrate, inhibited by palmitoyl CoA _Insulin_: activates _Glucagon and epinephrine_: inactivate

Answer 29

* Energy storage * Protection of organs * Insulation * Storage fat soluble vitamins * Synthesis of adipokines

Answer 30

* Modest weight gain: in a non-obese person, adipocytes get bigger * Big weigth gain: if adipocytes reach their maximum size, there is recruitment and proliferation of new pre-adipocytes * Weight loss: decrease in fat cel size

Answer 31

**LEPTIN** * produced by adipocytes * decreases appetite * increases caloric expenditure (inc. metabolic rate) * long term effects **GHRELIN** * produced by stomach * increases appetite * short and long term effects * injection into the bloodstream dramatically increases appetite

Answer 32

* Cholic acid (a bile acid) increases energy expenditure * In mice, high fat diet + cholic acid had weight similar to a mice in regular diet * By increasing activity of brown adipose tissue, which prevents diet-induced obesity & insulin-dependent diabetes

Answer 33

--\>Store fat in muscle. They use a lot of energy in producing heat (instead of aTP) in the mitochondria.

Answer 34

- Between FAs and glycerol - Between phosphate and alcohol - Between glycerol and phosphat_e (Phospholipase C)_

Answer 35

* Enzyme deficiency in lysosomes that is in charge of cleaving a sugar in gangliosides * Fatal neurodegeneration, blindness, macula, muscle weakness, seizures * Recessive

Answer 36

* Accumulation of cerebrosides * Hepatosplenomegaly, osteoporosis, may have CNS involvement * Recessive

Answer 37

1. Receptors in cell membrane bind ligands (glu, AAs, G-6-P) and cluster 2. Early endosome forms 3. Late endosome undergoes pH drop bc of proton pump 4. Receptors & ligands dissociate. Some receptors (like LDL) are recycled

Answer 38

1. Diferric transferin (Apo-transferrin + Fe) bind the transferrin receptor 2. This trigger endocytosis 3. Endosome fusion and pH drop (ions are free and exit endosome) 4. pH increases, and receptors are recycled

Answer 39

- A series of defects in steroid hormone synthesis - Ex. hydroxylase deficiency -\> no cortisol, no sex hormones

Answer 40

* 0.5g/day from diet taken from LDL * 0.5g/day from cytoplasmic synthesis (from acetyl CoA) * no degradation pathway, excreted as bile salts

Answer 41

-High LDL-cholesterol plasma levels: -**Heterozygous**: 1/500. Blood cholesterol: \>_300 mg/dl_. LDL: \>220. Untreated: 85% myocardial infarction bx 60 Treatment: _statins_ (Lipitor, Crestor) -**Homocygous**: frequency 10-6 Blood cholesterol: _500-1200 mg/dl_ Untreated: myocardial infarction before age of 30 Treatment: _LDL apheresis_ (physical removal of LDL)

Answer 42

(1) _no LDLR_ made (gene deletion) (2) LDL_R not localized_ properly (mutant) (3) LDLR has _low affinity for apo B-10_0 (4) _LDLR does not accumulate in coated pits_ (5) _LDLR does not release LD_L in late endosomes, so LDL receptor is degraded in lysosome

Answer 43

LDL chol: 160 or less, HDL chol: less than 45, TG: less than 150. Mg/dL

Answer 44

- Oxidized LDL+B100 get taken up by macrophages - Macrophages can take up more oxidized LDL from blood, and they can get very big and make foam cells - Foam cells can attach to epithelial layer of vessels, which can cause inflammation and plaques that block flow - Only oxidizes if LDLRs are in the bloodstream too long (stimulated by NO, O2-, H2O2. Inhibited by vitE)

Lipids 1-3 Flashcards

(68 cards)