Quiz
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1. Why do the B vitamins and vitamin C dissolve in water?
They have many oxygen and nitrogen atoms that form hydrogen bonds with water (Figure 1).
2. Which water-soluble vitamin is stored for years?
B12, in the liver (Figure 6).
3. What is a coenzyme?
A small non-protein helper an enzyme needs to work; B vitamins become coenzymes (Figure 2).
4. Do B vitamins provide energy?
No. They contain no usable calories; they help release energy from food (Figure 2).
5. Which deficiency disease comes from too little thiamin? From too little niacin?
Beriberi; pellagra (Figure 3).
6. Which two vitamins contain sulfur?
Thiamin (B1) and biotin (B7) (Figures 3 and 4).
7. Why is milk sold in opaque containers?
Light destroys riboflavin (Figure 3).
8. How does folic acid differ from the main food folate?
Folic acid lacks the four extra hydrogens and the methyl group; it is synthetic, stable and better absorbed (Figure 5).
9. Why is folic acid recommended for anyone who could become pregnant?
It lowers the risk of neural tube defects such as spina bifida (Figure 5).
10. What metal is at the center of vitamin B12?
Cobalt (Figure 6).
11. Why do vegans need fortified foods or a B12 supplement?
Only bacteria make B12 and plant foods don’t provide reliable amounts (Figure 6).
12. Name three things vitamin C does.
Keeps collagen-making enzymes working, helps absorb plant iron, acts as an antioxidant (Figure 7).