CPN CPN Nutrient Metabolism & Physiology 2 — Questions and Answers
Question 1: Which fatty acid is classified as essential for dogs because they lack the delta-6-desaturase activity needed to synthesize it?
- Oleic acid
- Palmitic acid
- Linoleic acid (Correct answer)
- Stearic acid
Correct answer: Linoleic acid
Linoleic acid (18:2 omega-6) is an essential fatty acid for dogs because they cannot introduce double bonds at the omega-6 position of precursor fatty acids.
Question 2: Fat provides how many kilocalories per gram, compared to 4 kcal/g for both protein and carbohydrates?
- 4 kcal/g
- 7 kcal/g
- 9 kcal/g (Correct answer)
- 12 kcal/g
Correct answer: 9 kcal/g
Fat provides 9 kcal per gram, making it the most energy-dense macronutrient and over twice as calorie-dense as protein or carbohydrates.
Question 3: Which metabolic process sequentially cleaves two-carbon units from fatty acids, producing acetyl-CoA for energy generation?
- Lipogenesis
- Beta-oxidation (Correct answer)
- Saponification
- Esterification
Correct answer: Beta-oxidation
Beta-oxidation occurs in the mitochondrial matrix and systematically removes two-carbon acetyl-CoA units from fatty acids, feeding them into the Krebs cycle.
Question 4: Cats have severely limited ability to convert which plant-based omega-3 fatty acid to the longer-chain EPA and DHA?
- GLA
- CLA
- ALA (alpha-linolenic acid) (Correct answer)
- LA (linoleic acid)
Correct answer: ALA (alpha-linolenic acid)
Cats have very low delta-6-desaturase and elongase activity, making them unable to efficiently convert ALA from plant sources (flaxseed, chia) to EPA and DHA.
Question 5: What is the primary short-term carbohydrate storage molecule in the liver and skeletal muscle of dogs and cats?
- Sucrose
- Cellulose
- Starch
- Glycogen (Correct answer)
Correct answer: Glycogen
Glycogen is the branched polysaccharide used for carbohydrate storage in animals, primarily in the liver (for blood glucose regulation) and skeletal muscle (for local energy).
Question 6: Which pancreatic cell type secretes insulin in response to elevated blood glucose concentrations?
- Alpha cells
- Delta cells
- Beta cells (Correct answer)
- Acinar cells
Correct answer: Beta cells
Beta cells of the islets of Langerhans in the pancreas detect rising blood glucose and secrete insulin to promote glucose uptake and glycogen synthesis.
CPN CPN Nutrient Metabolism & Physiology 2
Which fatty acid is classified as essential for dogs because they lack the delta-6-desaturase activity needed to synthesize it?