NUSCTX 103 Exam 1 – Protein Questions and Answers With Verified Solutions
2025
• Need to consume protein daily
- no storage form
- obligate losses of 20-30g/day
- tissue and plasma proteins will be catabolized to make amino acids available to meet body needs
- must be broken down to provide body with amino acids
• to synthesize new proteins
• oxidized for energy /to prevent toxic levels of individual amino acids
- must be broken down to prevent an immune response - ✔✔Protein in the diet
dietary
- Animal products
- Meat, poultry, fish, eggs
- Plant products
- Grains, legumes, nuts/seeds - ✔✔exogenous sources of protein
- Sloughed off cells in the digestive tract
- Digestive enzymes and secreted proteins
- cellular recycling (lysosomal degradation) - ✔✔endogenous sources of protein
small amount
3-5% of ingested nitrogen - ✔✔how much dietary protein is lost in feces
in the stomach - ✔✔where does protein digestion start
, - HCl secretion
- Mediates protein denaturation
- Induces cleavage andactivation of pepsin - ✔✔parietal cells
Secretion of pepsinogen (also gastric lipase) - ✔✔chief cells
• Pepsin is created as an inactive "pro-enzyme" called pepsinogen
• Pepsin is activated under acidic conditions, cleaving the additional amino acids to yield the active
enzyme pepsinogen pepsin catalyticsite
• Pepsin is an endopeptidase
- hydrolyzes interiorpeptide bonds within proteins
- Relatively low specify - ✔✔pepsin features
- Caused by:
• Excessive use of proton pump inhibitors
• hypothyroidism
• H. pylori infection
• VIPomas- endocrine tumors commonly in the pancreatic beta cell that secrete the hormone vasoactive
intestinal peptide (VIP)
• Damage to parietal cells (e.g. autoantibodies, radiation) - Can compromise nutrient digestion
• Protein malnutrition
• Micronutrients- e.g. Vitamin B12 absorption (from foods where it is protein-bound) is reduced 19 -
✔✔reduced or absent (achlorhydria) stomach acid
• Trypsinogen
• Chymotrypsinogen
• Procarboxypeptidase A and B
• Proelastase - ✔✔Several proteases are secreted from the pancreas as"pro-enzymes" such as....
2025
• Need to consume protein daily
- no storage form
- obligate losses of 20-30g/day
- tissue and plasma proteins will be catabolized to make amino acids available to meet body needs
- must be broken down to provide body with amino acids
• to synthesize new proteins
• oxidized for energy /to prevent toxic levels of individual amino acids
- must be broken down to prevent an immune response - ✔✔Protein in the diet
dietary
- Animal products
- Meat, poultry, fish, eggs
- Plant products
- Grains, legumes, nuts/seeds - ✔✔exogenous sources of protein
- Sloughed off cells in the digestive tract
- Digestive enzymes and secreted proteins
- cellular recycling (lysosomal degradation) - ✔✔endogenous sources of protein
small amount
3-5% of ingested nitrogen - ✔✔how much dietary protein is lost in feces
in the stomach - ✔✔where does protein digestion start
, - HCl secretion
- Mediates protein denaturation
- Induces cleavage andactivation of pepsin - ✔✔parietal cells
Secretion of pepsinogen (also gastric lipase) - ✔✔chief cells
• Pepsin is created as an inactive "pro-enzyme" called pepsinogen
• Pepsin is activated under acidic conditions, cleaving the additional amino acids to yield the active
enzyme pepsinogen pepsin catalyticsite
• Pepsin is an endopeptidase
- hydrolyzes interiorpeptide bonds within proteins
- Relatively low specify - ✔✔pepsin features
- Caused by:
• Excessive use of proton pump inhibitors
• hypothyroidism
• H. pylori infection
• VIPomas- endocrine tumors commonly in the pancreatic beta cell that secrete the hormone vasoactive
intestinal peptide (VIP)
• Damage to parietal cells (e.g. autoantibodies, radiation) - Can compromise nutrient digestion
• Protein malnutrition
• Micronutrients- e.g. Vitamin B12 absorption (from foods where it is protein-bound) is reduced 19 -
✔✔reduced or absent (achlorhydria) stomach acid
• Trypsinogen
• Chymotrypsinogen
• Procarboxypeptidase A and B
• Proelastase - ✔✔Several proteases are secreted from the pancreas as"pro-enzymes" such as....
