BPSC 70th CCE Re-exam Prelims General Studies · Question 132 of 142

Correct — B, A, B, C and D vitamins. Start with what is physiologically true, because this question's options do not reproduce it. The liver is the body's principal storage depot, and what it holds in reserve is the four fat-soluble vitamins A, D, E and K together with the water-soluble vitamin B12 — roughly one to two years' supply of vitamin A, one to four months' of vitamin D and three to five years' of vitamin B12, alongside iron, copper, zinc, cobalt and molybdenum and the body's main glycogen store. Not one of the four options prints that list, and the card says so plainly rather than pretending otherwise. What the option set actually offers is three nested guesses — 'Only A and B vitamins', then 'A, B and C vitamins', then 'A, B, C and D vitamins' — plus an escape. Read as a nested set, the question resolves by containment rather than by recall. Vitamin D is beyond argument one of the vitamins the liver stores, and the liver is in fact where vitamin D from diet and skin is first hydroxylated, to 25-hydroxyvitamin D, which is both the circulating reserve form and the form a blood test measures. Only option (b) contains D. Options (a) and (c) are strict subsets of (b) with D deleted, so neither can stand while (b) is on the page — if 'A, B and C vitamins' were true, then 'A, B, C and D vitamins' is truer, because it adds a vitamin the liver certainly stores and takes nothing away. Option (b) is also right about B in the only sense that matters: vitamin B12 is the most durably stored vitamin in the human body and the liver is where it sits. Its single weak member is C. Ascorbate is water-soluble, hepatic tissue does carry a high concentration of it, but there is no reserve of the kind vitamin A or B12 has, which is why scurvy can appear within a few months of deprivation while a B12 reserve lasts years. So (b) is the most complete true statement available and that is why our two independent derivations both settled on it — by containment, not by matching a textbook list.

• (a)A, B and C vitamins — The three vitamins a candidate names first, and the trap is exactly that familiarity. It omits vitamin D, which the liver unquestionably stores and, more than stores, chemically prepares — the 25-hydroxylation step happens in hepatocytes. Everything this option claims, option (b) also claims; it simply claims one true thing less.
• (c)Only A and B vitamins — The narrowest reading, and the word 'Only' makes it exclusive rather than partial — it asserts that the liver stores no vitamin outside A and B. That is false twice over: vitamin D is stored and hydroxylated there, and vitamins E and K are stored there too. An option that closes the list is the easiest kind to disprove, since a single counter-example kills it.
• (d)None of these — The honest runner-up, and a strict physiologist could defend it: the exact list is A, D, E, K and B12, so every option here omits E and K and option (b) adds C, which is not stored in any comparable sense. We do not key it because the stem 'Liver stores' asks for what the liver stores, not for an exhaustive inventory, and on that reading option (b) states a set of things the liver does store. A None-of-the-above option is correct only when each of the other three can be shown to fail, and (b) does not fail on this reading — but this is the weakest item in its block and the reason our confidence here is medium rather than high.

Vitamins split into two groups by solubility, and the split decides almost everything else about them. The fat-soluble vitamins — A, D, E and K — are absorbed with dietary fat, need bile for that absorption, and are stored in the liver and in adipose tissue, so intake can be intermittent and excess accumulates rather than being flushed away, which is why hypervitaminosis A and D are real clinical conditions. The water-soluble vitamins — the B group and C — are carried in the blood plasma, surplus is largely excreted in urine, and they must be taken in regularly. Vitamin B12 is the one large exception: it is water-soluble but is bound, transported by intrinsic factor and salvaged so efficiently that the liver holds a three-to-five-year reserve. The liver itself is the body's largest internal organ and its chemical plant — it produces bile, runs the urea cycle that converts toxic ammonia to urea, stores glycogen and iron, synthesises plasma proteins, and detoxifies drugs and alcohol. Storage is only one of its jobs, but it is the one this question tests.

Two moves answer this without a memorised list. First, notice that the positive options are nested: 'Only A and B' sits inside 'A, B and C', which sits inside 'A, B, C and D'. Whenever options are nested like this, the correct one is the largest that is still true, because a smaller list cannot be right while a larger true list is on offer — and a None-of-the-above option only wins if even the largest list contains a definite falsehood. Second, find the one item that discriminates. Here it is vitamin D, and the fact that settles it is not merely that the liver stores D but that the liver is a station in vitamin D's own metabolism: cholecalciferol from skin or diet is converted in the liver to 25-hydroxyvitamin D, and only then does the kidney add the second hydroxyl to make the active 1,25-dihydroxy form. A vitamin the liver processes and holds cannot be excluded from a list of what the liver stores. That single fact eliminates both (a) and (c) at once and leaves the choice between (b) and the escape option — where the question's genuine defect lies, since the textbook list is A, D, E, K and B12 and no option prints it.

• The liver stores vitamin A (1–2 years' supply), vitamin D (1–4 months' supply) and vitamin B12 (3–5 years' supply), along with vitamin K, vitamin E, iron, copper, zinc, cobalt and molybdenum
• Fat-soluble vitamins A, D, E and K need bile for absorption and are stored in liver and fat tissue; the water-soluble B group and vitamin C are largely excreted in urine when in surplus, B12 being the standing exception
• Vitamin D is hydroxylated twice: to 25-hydroxyvitamin D in the liver, then to the active 1,25-dihydroxyvitamin D in the kidney
• Because fat-soluble vitamins accumulate instead of being excreted, chronic excess is toxic — hypervitaminosis A and hypervitaminosis D — while surplus water-soluble vitamins are mostly passed out
• The liver is also the body's main glycogen store and its main iron store, holding iron as ferritin, and in the first-trimester foetus it is the chief site of red blood cell formation
• Vitamin C's body pool is small and scurvy can follow within a few months of deprivation, which is the contrast that makes calling C a 'stored' vitamin loose

• Assuming only fat-soluble vitamins are stored — B12 is water-soluble and yet has the longest reserve of any vitamin, and it sits in the liver
• Reaching for 'None of these' the moment an option list looks imperfect; the test is whether every option contains a definite falsehood, not whether one is incomplete
• Placing vitamin D's activation in the liver — the liver makes 25-hydroxyvitamin D, the kidney makes the active 1,25-dihydroxy form

BPSC asks this as a one-line recall wrapped in nested option lists, so the mark comes from spotting containment — the largest true list wins — rather than from reciting physiology. UPSC almost never asks a bare storage list; it asks the consequence instead, pairing a vitamin with its deficiency disease or asking which substance the liver produces, so the same material has to be held as function and effect rather than as an inventory.

• practice — not a real PYQ

  Which vitamin is held in the human liver in a reserve large enough to last three to five years ?

  • (a)Vitamin C
  • (b)Vitamin B12
  • (c)Vitamin B1
  • (d)Vitamin K

  Answer(b) Vitamin B12 — water-soluble, yet stored in the liver for three to five years, which is why dietary deficiency takes years to show as pernicious anaemia.

• practice — not a real PYQ

  The liver converts vitamin D into 25-hydroxyvitamin D. Its conversion to the biologically active form takes place mainly in the

  • (a)Skin
  • (b)Kidney
  • (c)Small intestine
  • (d)Pancreas

  Answer(b) Kidney — the second hydroxylation, to 1,25-dihydroxyvitamin D, occurs in the kidney; the skin only makes the precursor cholecalciferol from sunlight.