NTA Nutritional Science Fundamentals 2 — Questions and Answers
Question 1: Which enzyme is primarily responsible for breaking down dietary triglycerides in the small intestine?
- Pepsin
- Pancreatic lipase (Correct answer)
- Amylase
- Trypsin
Correct answer: Pancreatic lipase
Pancreatic lipase, secreted by the pancreas into the small intestine, is the primary enzyme responsible for hydrolyzing dietary triglycerides into monoglycerides and fatty acids.
Question 2: What is the primary role of bile salts in fat digestion?
- Hydrolyzing triglycerides into fatty acids
- Emulsifying fat globules to increase surface area for lipase activity (Correct answer)
- Transporting fatty acids into intestinal cells
- Stimulating pancreatic enzyme release
Correct answer: Emulsifying fat globules to increase surface area for lipase activity
Bile salts emulsify large fat globules into smaller droplets, dramatically increasing the surface area available for pancreatic lipase to act upon.
Question 3: Which form do long-chain fatty acids primarily take when absorbed from the intestinal lumen into enterocytes?
- Free fatty acids only
- Chylomicrons
- Mixed micelles (Correct answer)
- VLDL particles
Correct answer: Mixed micelles
Long-chain fatty acids are incorporated into mixed micelles (with bile salts and monoglycerides) to be transported across the unstirred water layer before absorption into enterocytes.
Question 4: What is the term for the process by which glucose enters cells via carrier proteins without requiring energy?
- Active transport
- Facilitated diffusion (Correct answer)
- Endocytosis
- Pinocytosis
Correct answer: Facilitated diffusion
Facilitated diffusion uses specific carrier proteins (GLUTs) to move glucose down its concentration gradient without energy expenditure.
Question 5: Which mineral is a critical cofactor for the enzyme superoxide dismutase (SOD), a key antioxidant enzyme?
- Iron
- Calcium
- Copper and zinc (Correct answer)
- Selenium
Correct answer: Copper and zinc
Superoxide dismutase (SOD) requires copper and zinc as cofactors, and manganese for the mitochondrial form, making these minerals essential for antioxidant defense.
Question 6: In the context of protein quality, what does the PDCAAS score measure?
- The total protein content per gram of food
- Protein digestibility corrected for amino acid score relative to human requirements (Correct answer)
- The branched-chain amino acid ratio in a protein
- The nitrogen balance of a protein source
Correct answer: Protein digestibility corrected for amino acid score relative to human requirements
The Protein Digestibility Corrected Amino Acid Score (PDCAAS) evaluates protein quality by comparing its essential amino acid profile to human requirements and adjusting for digestibility.
Question 7: What distinguishes a 'complete' protein from an 'incomplete' protein?
- Complete proteins contain more total grams of protein per serving
- Complete proteins provide all nine essential amino acids in adequate amounts (Correct answer)
- Complete proteins are only found in animal foods
- Complete proteins have a PDCAAS score above 0.5
Correct answer: Complete proteins provide all nine essential amino acids in adequate amounts
A complete protein contains all nine essential amino acids in sufficient quantities to support protein synthesis, whereas incomplete proteins are deficient in one or more essential amino acids.
NTA Nutritional Science Fundamentals 2
Which enzyme is primarily responsible for breaking down dietary triglycerides in the small intestine?