Lipids PDF

Lipids Mireille Santamaria Sept 26, 2023 Example (group discussion) • The molecule picture below plays a major role: • as an energy source • as a membrane component • as a signal mechanism • two of the above Example (group discussion) • In saturated fatty acids, the carbons are linke...

Lipids Mireille Santamaria Sept 26, 2023 Example (group discussion) • The molecule picture below plays a major role: • as an energy source • as a membrane component • as a signal mechanism • two of the above Example (group discussion) • In saturated fatty acids, the carbons are linked exclusively by single bonds. • Monounsaturated fatty acids have one carbon-carbon double bond and polyunsaturated fatty acids have more than one. • both statements are true • both statements are false • the first statement is true, the second is false • the first statement is false, the second is true Exercise 1 • An apprehensive dental patient comes in and states that he already took ibuprofen for the pain he anticipates from the appointment today. As you know, this inhibits the synthesis of prostaglandins. All of the following statements are true about prostaglandins EXCEPT one. Which one is the EXCEPTION? • they generally act locally or near the tissue that produced them • they are synthesized only in the liver and the adrenal cortex • the common precursor of prostaglandins is arachidonic acid (an unsaturated fatty acid) • their synthesis can be inhibited by a number of unrelated compounds, including aspirin and cortisol Exercise 2 • Which of the following statements about plasma lipoproteins are correct? Select all that apply. • chylomicrons are synthesized in the intestinal mucosal cells and transport triacylglycerol to the peripheral tissues • HDL particles are produced from LDL particles in the circulation by the action of lipoprotein lipase • HDL competes with LDL for binding to receptors on the surface of cells in extrahepatic tissues • very low density lipoprotein (VLDL) particles are the precursors of LDL in the circulation Exercise 3 • All of the following are sources of acetyl-CoA for fatty acid synthesis EXCEPT one. Which one is the EXCEPTION? • creatinine • pyruvate • glucose • citrate Exercise 4 • All of the following statements concerning fatty acid synthesis are true EXCEPT one. Which one is the eXCEPTION? • fatty acid synthesis involves two carbon additions primarily from acetyl-CoA • the important step in fatty acid synthesis is the first one in which acetyl-CoA, ATP and bicarbonate form malonyl-CoA • fatty acid synthesis is not a simple reversal of β-oxidation used for the catabolism of fatty acids • fatty acid synthesis takes place in the mitochondria while fatty acid breakdown (catabolism) occurs in the cytosol (cytoplasm) Exercise 5 •A patient of yours has uncontrolled diabetes mellitus. This causes ketosis, or high levels of ketone bodies, in the body tissues and fluid. Which of the following is NOT a symptom of this condition? • fruity breath • lowered pH of the blood • decreased • ketone potassium in the urine bodies in the urine Exercise 6 • The cell (plasma) membrane is a fluid mosaic of: • lipids and carbohydrates • proteins • lipids and carbohydrates and proteins • carbohydrates