PART I BIOCHEM PRACTICE SET Questions With Correct Answers 2023 Graded A+

PART I BIOCHEM PRACTICE SET Questions With Correct Answers 2023 Graded A+ What vitamin does not travel through the bloodstream in the form of a lipid micelle? *ANS* Vitamin C Which lipid has a 4-ring structure? *ANS* Sterol Which of the following situations is MOST likely to increase the rate of beta oxidation? *ANS* fasting A patient who is on a no-fat diet is at particular risk of deficiency in: *ANS* Vitamin A During starvation, triglycerides can help supply some of the body's glucose needs. Which breakdown product of triglycerides can be used to make glucose? *ANS* glycerol CH3(CH2)6CH=CH(CH2)2COOH *ANS* liquid at the lowest temperature Describe the steps involved in fatty acid synthesis *ANS* Acetyl-CoA is transported to the cytoplasm - Biotin transfers a carboxylate group to acetyl-CoA - the malonyl group is transferred to a carrier protein - malonyl ACP combines with acetyl-CoA, - malonyl-CoA is added repeatedly to the growing fatty acid What fatty acid will produce 8 Acetyl CoA molecules after it is completely metabolized via beta oxidation? *ANS* CH3(CH2)4CH=CH(CH2)4CH=CH(CH2)8COOH Which set of molecules are produced by the beta oxidation of fatty acids? *ANS* Acetyl CoA, NADH, FADH2 Gastric bypass surgery results in an increase in the production of GLP-1, a peptide that promotes insulin secretion. This is thought to be associated with the tendency for these patients' type II diabetes to resolve after the surgery. If a gastric bypass patient has a mutation in GLP-1 that impairs its function, what is to be expected? *ANS* The patient would have reduced insulin secretion compared to patients with normal GLP-1, and this reduction results in increased fatty acid oxidation Through mandatory state testing, a 2-day-old newborn is found to have a medium chain acyl-COA dehydrogenase deficiency (MCADD). This enzyme deficiency interferes with the baby's ability to break down medium chain fatty acids via beta oxidation. Her parents need to be given specific instructions on what the baby can ingest. What is correct? *ANS* She will not be able to utilize adipose tissue for ATP production as effectively as a baby without the disorder Which of the following contributes to the development of ketoacidosis in a diabetic patient *ANS* A reduction in citric acid cycle intermediates, which decreases the amount of oxaloacetate that acetyle-CoA can combine with to enter the citric acid cycle What describes a fatty acid? *ANS* C16H3202 Unsaturated fatty acids can have different arrangements of hydrogen atoms at the double bond depending on whether the bonds are cis- or trans- configuration. A consequence of this : *ANS* fatty acids with cis-configuration double bonds do not pack together well which lowers their melting point What best describes fatty acid hydrogenation? *ANS* Hydrogenation converts some unsaturated fatty acids into saturated fatty acids Phospholipids have parts that are hydrophobic (non-polar, not soluable in water) and a part that is hydrophilic (polar; water-soluable). What term do we use to describe a molecule that is both polar and non-polar? *ANS* amphipathic Which compounds make up the greatest reserves of energy in our bodies? *ANS* triglydercides Acetyl-CoA is a central to metabolism. Carbohydrates, proteins, and fats can all produce Acetyl-CoA, though they use different pathways to make it. *ANS* True Beta oxidation of a C14 fatty acid will make 6 acetyl-CoA units after 7 rounds of beta-oxidation *ANS* True Mammals and plants have the ability to synthesize their fatty acids. Which one of the following molecules is the precursor to building fatty acids? *ANS* Acetyl-CoA Acetyl-CoA, a central molecule in metabolism, is produced in the mitochondrial matrix. However, it is used for the synthesis of fatty acids in the cytosol. The transport of the acetyl-CoA from the matrix to the cytosol occurs by the conversion of acetyl-CoA to *ANS* citrate The inability to tolerate long-chain fatty acids in the diet could stem from a defect in *ANS* beta-oxidation of long-chain fatty acids Ketoacidosis is a dangerous outcome of uncontrolled diabetes. It is a result of the buildup of ketone bodies. What is the primary metabolic fuel that results in the build-up of the ketone bodies? *ANS* fatty acids Fatty acid synthesis occurs in the cytosol, so its building block molecule acetyl-CoA must be transported out of the mitochondria and into the cytosol using the citrate transport system. The acetyl-CoA is then combined with carbon dioxide with the help of the coenzyme molecule biotin in order to form malonyl-CoA in the first committed step of fatty acid synthesis. *ANS* True Which molecule is considered a lipid? *ANS* 1. sterol 2. fat 3. wax The acid portion of a fatty acid corresponds to which one of the following groups/molecules? *ANS* COOH is a carboxylic acid group. A fatty acid consists of a hydrocarbon chain bound to the carbon atom of the COOH. Answer: COOH Saturated fatty acids have more hydrogen atoms than unsaturated fatty acids of the same length *ANS* True How many hydrogens can be accommodated by the carbon -C-C(*)=C-C- *ANS* * 1 Phospholipids that make up the cell membrane contain 2 fatty acids attached to a glycerol backbone. An additional phosphate polar group bonds to the molecule and creates a polar end of the molecule. The 2 long chain fatty acids that are a part of the phospholipid can be of either variety - saturated or unsaturated fatty acids *ANS* True Which one is a fat storage molecule? *ANS* Triglyeride Due to their amphipathic nature, phospholipids can form micelles and transport other lipids. The fatty acid chains that make up the phospholipids are the basis for their non-polar character, and the phosphate group is the basis of its polar nature *ANS* True If Zoey continues on her path of a no-fat diet, she could have very poor wound healing response. Which one of the following lipid molecules can have an affect on this response? *ANS* phospholipid The nutritionist explains the importance of including diets rich in essential fatty acids. The essential fatty acids are polyunsaturated fatty acids. *ANS* True Fats are necessary to deliver the fat-soluable vitamins such as A, D, E, and K. Absence of fat in the diet impact the absorption and delivery of the fat soluable vitamins that result in vitamin related deficiencies. *ANS* True