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NAME SECTION DATE PARTNER GRADE Experiment 50 PRE-LAB QUESTIONS 1. What foods contain appreciable amounts of vitamin C? 2. Vitamin C is ascorbic acid. Yet, in the structure given in the Background, one does not see a -COOH group. Instead, one sees a lactorne in the structure. Cirele the lactone. Explain from what functional groups it is formed, and how it is formed. 3. What is the minimum daily requirement of vitamin C to prevent scurvy in adults? 4. What enzyme is oxidized in the absence of vitamin C and causes the symptoms of scurvy? Which natural product is synthesized by this enzyme?

Answer 1

1- Vitamin C is majorly present in citrus fruits (i.e fruits generally sour in taste). Ex - Lemon, orange, kiwi, grape etc.

Vegetables like broccoli, cauliflower etc

2-

H9 но НО Но 0 НО но он НО OH vinyloge Carbonsäure Lacton

Here the structure of vit -C is like a Lacton. We know that Lactone is an ester which has intramolecular moding. i.e the OR' group is attached with the main chain of R-COOR' compound to form a ring like structure.

Thus in Ascorbic acid, this ester group can break to further produce a carboxylic acid and an alcohol. So it acts as an acid.

3- For an adult, the minimum amount of vit C required to prevent Scurvy is 6.5 to 10 mg per day.

4- In the absence of Vit-C, the enzyme L - gulonolactone oxidase get oxydised and causes Scurvy.