PCOL 832 FINAL Questions with Complete Solutions (Latest 2025) Humans can fix elemental nitrogen T/F (11/19) - Correct Answers ✅F Humans have largely left this task behind and can only fix reduced N - NH4+or NH3.How much protein should be consumed each day? (11/19) - Correct Answers ✅Humans are dependent on essential amino acids & adequate total protein. Both quantity and quality of the dietary protein is very important. Requirements are 0.8g protein/Kg body weight; 56g for average male and 44 g for average female; average US consumption is about 120 g per day.What is the function of proteases? (11/19) - Correct Answers ✅Proteases breakdown proteins into peptides and amino acids in the stomach and intestine.What causes Kwashiorkor? What are the signs? (11/19) - Correct Answers ✅Protein deficiency despite of adequate calories
- Edema and distended abdomen
- Muscle wasting due to the lack of essential amino acids
- Compounded by inability to make digestive enzymes and
new intestinal epithelial cells 1 / 4
PCOL 832 FINAL Questions with Complete Solutions (Latest 2025) What initiates protein breakdown in the stomach? (11/19) - Correct Answers ✅Pepsin initiates the protein breakdown in the stomach How is pepsinogen activated? (11/19) - Correct Answers ✅Gastric parietal cells produce HCl which causes a conformational change to activate pepsinogen to pepsin, an autocatalytic process. Acid is also important in denaturing dietary proteins and unfolding them.Where does pepsinogen come from? (11/19) - Correct Answers ✅Pepsinogen is secreted by the chief cells of the stomach.Bicarbonate is responsible for _____. (11/19) - Correct Answers ✅neutralizing the stomach acid that has reached the small intestine Bicarbonate is first released from the pancreas then the pancreatic enzymes, besides digesting the proteins what else are they capable of digesting? (11/19) - Correct Answers ✅The digestive enzymes digest themselves too.
- They also digest the intestinal cells, which are constantly
replaced by the precursor cells 2 / 4
PCOL 832 FINAL Questions with Complete Solutions (Latest 2025) What is inspissation? What does it lead to in the pancreas?(11/19) - Correct Answers ✅Inspissation (drying and thickening) of pancreatic exocrine secretions
- Leads to obstruction of ducts
- Inability of pancreatic enzymes to enter intestinal lumen
- enzymes can't reach the small intestine because of the
mucus buildup, causing pancreatitis Which zymogen is especially important to activate the rest of the zymogens? (11/19) - Correct Answers ✅trypsinogen (zymogen) --(enteropeptidase)--> trypsin (active enzyme) How is carbamoyl phosphate synthesized? (11/26) - Correct Answers ✅Carbamoyl phosphate is a high energy compound, requiring 2 ATPs for formation from carbon dioxide and ammonium ion.-first step of the urea cycle Which enzyme catalyzes the first step of the urea cycle?(11/26) - Correct Answers ✅Carbamoyl phosphate synthetase I (CPSI), the enzyme that catalyzes this first step of the urea cycle, is found mainly in mitochondria of the liver and intestine. CPSII, located in the cytosol, is for pyrimidine biosynthesis.Which products of the urea cycle can cross the mitochondrial membrane? (11/26) - Correct Answers ✅Ornithine and 3 / 4
PCOL 832 FINAL Questions with Complete Solutions (Latest 2025) citrulline are exchanged for one another across the mt membrane Ornithine is an amino acid, why does it not appear in proteins? (11/26) - Correct Answers ✅ornithine is very abundant, but no codon matches for ornithine, so it does not happen in nature not an essential amino acid How is ornithine synthesized? (11/26) - Correct Answers ✅Ornithine is normally regenerated by the urea cycle.Ornithine also can be synthesized de novo by a transamination reaction catalyzed by ornithine aminotransferase under specific conditions in the intestine.
Note: PLP is needed.
When comparing the urea cycle to the TCA cycle, what would be analogous to oxaloacetate? Why? (11/26) - Correct Answers ✅Ornithine functions analogously to oxaloacetate in TCA cycle as it initiates the cycle and is also reformed in the cycle Where are the first and second nitrogens donated in the urea cycle? (11/26) - Correct Answers ✅Carbamoyl phosphate (from ammonium ion) donates the first nitrogen to form urea.Aspartate donate the second nitrogen to form urea
- / 4