Question

Which one of the following species CANNOT synthesize Vitamin C?

• A. Cat
• B. Chicken
• C. Dog
• D. Monkey

Hint:

Species Unable to Synthesize Vitamin C (Lack GULO Enzyme): Primates (Monkeys, Humans), Guinea Pigs, Fruit Bats, Red-vented Bulbul, Rainbow Trout.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Evolutionary loss of ascorbic acid biosynthesis: anthropoid primates, guinea pigs, fruit bats, and teleost fish possess non-functional pseudogenes for L-gulonolactone oxidase (GULO).
Key Formula or Approach:
\[ \text{D-Glucose} \rightarrow \text{UDP-Glucuronate} \rightarrow \text{L-Gulonate} \rightarrow \text{L-Gulonolactone} \xrightarrow{\mathbf{L\text{-Gulonolactone Oxidase (GULO) Mutated in Monkeys}}} \text{L-Ascorbate (Vitamin C)} \]

Step 2: Detailed Explanation:
Biosynthesis of Ascorbic Acid (Vitamin C) in animal physiology:
1. Most Domestic Animals (Dogs, Cats, Cattle, Sheep, Pigs, Chickens): Possess an active hepatic or renal enzyme L-Gulonolactone Oxidase (GULO), allowing them to synthesize abundant Vitamin C from D-glucose de novo.
2. Species Lacking GULO (Obligate Dietary Requirement): Haplorhine Primates (Monkeys, Apes, Humans), Guinea pigs, Indian fruit bats, and passerine birds carry evolutionary loss-of-function inactivating mutations in the GULO gene and CANNOT synthesize Vitamin C, developing scurvy without dietary ascorbic acid.

Step 3: Final Answer:
Therefore, Monkey CANNOT synthesize Vitamin C, matching option (D).