Q.Why are vitamin A and vitamin C essential to us? Give their important sources.
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🔒 Start your 14-day free trial to unlock the full solution →Concept understanding — Vitamin Classification
Water Soluble Vitamins: The First Meeting
Imagine you drop a spoonful of sugar into a glass of water. It dissolves completely, disappears into the liquid, and you can't see it anymore — but it's still there, molecule by molecule, spread evenly throughout the water. That's exactly what "water soluble" means: the substance mixes with water at the molecular level.
Now, a vitamin is a tiny organic compound your body needs in small amounts to function properly — it helps enzymes do their jobs, keeps your skin healthy, helps you see, and so on. Your body cannot make most vitamins on its own, so you must get them from food.
Put the two together: a water soluble vitamin is a vitamin that dissolves in water. This single property — solubility — determines almost everything about how these vitamins behave in your body.
The Precise Statement
Water soluble vitamins are vitamins that dissolve in water, are not stored in significant amounts in the body, and are excreted in urine when consumed in excess. They must be consumed regularly (daily or almost daily) to prevent deficiency.
The group includes the B-complex vitamins (B1, B2, B3, B5, B6, B7, B9, B12) and Vitamin C. That's 9 vitamins total.
Why Solubility Matters So Much
Think about fat. Fat and water don't mix — oil floats on top of water. Fat soluble vitamins (A, D, E, K) behave like oil: they dissolve in fat, get stored in your liver and fatty tissues, and can stay in your body for weeks or months. You don't need them every single day.
Water soluble vitamins are the opposite. Because they dissolve in water, they travel freely in your blood (which is mostly water). But your kidneys are constantly filtering your blood and removing excess water-soluble substances into urine. So if you take more Vitamin C than your body needs right now, the extra gets flushed out within hours.
This does not mean you can take unlimited amounts safely. Very high doses of some water soluble vitamins (especially B6 and niacin/B3) can cause toxicity — just not as easily as fat soluble vitamins.
The Practical Consequences
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You need them frequently — ideally every day. Missing a day won't cause immediate harm, but weeks of low intake will lead to deficiency diseases (scurvy for Vitamin C, beriberi for B1, pellagra for B3, etc.).
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Cooking destroys them — because they dissolve in water, boiling vegetables leaches vitamins into the cooking water. If you throw that water away, you lose the vitamins. Steaming or microwaving with minimal water preserves them better.
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They are fragile — heat, light, and air can break them down. That's why fresh fruits and vegetables lose vitamin content over time.
The Two Families
| Family | Members | Key Role |
|--------|---------|----------| …
Why this formula?
Vitamin Classification: Understanding the Why Behind the System
Vitamins are organic compounds that our body needs in small amounts for normal metabolism, growth, and health — but cannot synthesize in sufficient quantities. The classification system exists because it helps us understand how vitamins work and why deficiencies cause specific diseases.
Why Are Vitamins Classified This Way?
The primary classification is based on solubility — not chemical structure or function. This is because solubility determines:
- How vitamins are absorbed (with fat or water)
- How they are transported in the blood
- How they are stored in the body
- How they are excreted (risk of toxicity)
The Two Major Groups
| Group | Key Property | Why This Matters |
|---|---|---|
| Fat-soluble vitamins (A, D, E, K) | Dissolve in fats & oils | Require dietary fat for absorption; stored in liver & adipose tissue; can accumulate to toxic levels |
| Water-soluble vitamins (B-complex, C) | Dissolve in water | Absorbed directly into blood; not stored in significant amounts; excess excreted in urine (low toxicity risk) |
The Reasoning Behind Each Group
1. Fat-Soluble Vitamins (A, D, E, K)
Why they are grouped together:
- They are nonpolar molecules — they dissolve in lipids, not water.
- Absorption requires bile salts and dietary fat (emulsification).
- They travel in blood bound to carrier proteins (since blood is water-based).
- They are stored in liver and fat tissue — the body can draw on these reserves for weeks or months.
The key formula for remembering them:
All Dogs Eat Kittens
Why this matters for exams:
- Deficiency of A → night blindness (retinol needed for rhodopsin)
- Deficiency of D → rickets (calcium absorption fails)
- Deficiency of E → hemolytic anemia (antioxidant protection lost)
- Deficiency of K → bleeding (clotting factors need K)
Toxicity risk: Because they are stored, hypervitaminosis is possible (especially A and D).
2. Water-Soluble Vitamins (B-complex + C)
Why they are grouped together:
- They are polar molecules — dissolve readily in water.
- Absorption is direct into the bloodstream (no fat needed).
- They act as coenzymes — essential helpers for enzyme reactions.
- Not stored in significant amounts — excess is excreted in urine.
The key formula for remembering them:
B-complex (B₁, B₂, B₃, B₅, B₆, B₇, B₉, B₁₂) + C
Why this matters for exams:
- B₁ (thiamine) → beriberi (energy metabolism fails)
- B₃ (niacin) → pellagra (dermatitis, dementia, diarrhea)
- B₉ (folate) → neural tube defects in pregnancy
- B₁₂ (cobalamin) → pernicious anemia (needs intrinsic factor)
- C (ascorbic acid) → scurvy (collagen synthesis fails) …
Concept: Vitamin Classification — Vitamins are organic compounds essential in small amounts for normal physiological function. They are classified as fat-soluble (A, D, E, K) or water-soluble (B-complex, C), which determines their storage, absorption, and role.
Reasoning:
- Vitamin A (fat-soluble) is essential for vision (retinal in rhodopsin), immune function, and epithelial cell integrity. Deficiency causes night blindness and xerophthalmia.
- Vitamin C (water-soluble) is essential for collagen synthesis (wound healing), as an antioxidant, and for iron absorption. Deficiency causes scurvy.
- Both must be obtained from diet because the human body cannot synthesise them in adequate amounts.
Sources: …
Vitamins A and C are essential because our bodies cannot synthesise them in sufficient amounts — they must come from food. Vitamin A is crucial for vision, immune function, and skin health; its rich sources include liver, carrots, and leafy greens. Vitamin C is vital for collagen synthesis, antioxidant protection, and iron absorption; its best sources are citrus fruits, amla, and bell peppers.
Why Are Vitamins A and C Essential?
The word "essential" in nutrition means the body cannot make enough of a compound on its own — it must be obtained from the diet. Both vitamin A and vitamin C are essential for this reason, but their specific roles in the body are very different.
Vitamin A (Retinol and its derivatives)
Vitamin A is a fat-soluble vitamin stored in the liver. It is essential for:
- Vision: It forms rhodopsin, the light-sensitive pigment in the retina's rod cells. Without it, night blindness develops.
- Immune function: It maintains the integrity of mucous membranes (skin, gut, lungs) — the body's first barrier against pathogens.
- Cell growth and differentiation: It regulates gene expression for healthy skin, bone growth, and reproduction.
- Antioxidant activity: Beta-carotene (a provitamin A carotenoid) neutralises free radicals.
A common mistake is thinking vitamin A is only about eyesight. Its role in immune defence and skin health is equally critical — deficiency leads to increased infection risk and dry, rough skin.
Vitamin C (Ascorbic Acid)
Vitamin C is a water-soluble vitamin that cannot be stored in large amounts — excess is excreted in urine. It is essential for:
- Collagen synthesis: Collagen is the structural protein in skin, blood vessels, tendons, and bones. Without vitamin C, wounds heal poorly and blood vessels become fragile.
- Antioxidant protection: It protects cells from oxidative damage and regenerates other antioxidants like vitamin E.
- Iron absorption: It enhances the absorption of non-heme iron (from plant foods) by converting it to a more absorbable form.
- Immune function: It supports white blood cell activity and reduces the duration of common colds.
Unlike most mammals, humans cannot synthesise vitamin C because we lack the enzyme L-gulonolactone oxidase. That's why it's essential — we lost the ability during evolution.
Important Sources
Vitamin A Sources
| Source Type | Examples | Key Notes |
|---|---|---|
| Animal sources (preformed vitamin A) | Liver (beef, chicken), fish liver oils, egg yolks, butter, whole milk | Highly bioavailable — body uses it directly |
| Plant sources (provitamin A carotenoids) | Carrots, sweet potatoes, spinach, kale, mango, papaya, pumpkin | Body converts beta-carotene to vitamin A; efficiency varies |
Conversion factor: 1 µg of retinol activity equivalent (RAE) = 1 µg retinol = 12 µg beta-carotene from food.
Vitamin C Sources …
Method: Functional Classification of Vitamins
This method groups vitamins by their biological role and solubility, which explains why they are essential and where they come from.
Steps
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Identify the vitamin’s solubility
- Vitamin A → Fat-soluble (stored in liver, requires fat for absorption).
- Vitamin C → Water-soluble (not stored, excreted in urine).
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State the essential function (why the body cannot survive without it)
- Vitamin A → Essential for vision (forms rhodopsin in retina), immune function, and cell growth.
- Vitamin C → Essential for collagen synthesis (wound healing), antioxidant protection, and iron absorption.
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List important dietary sources
- Vitamin A sources:
- Animal: liver, egg yolk, milk, butter (preformed retinol). …
- Vitamin A sources:
Here are the most common mistakes students make when answering questions about Vitamin A and Vitamin C, along with clear strategies to avoid them.
1. Confusing "Fat-Soluble" vs. "Water-Soluble" Properties
- The Mistake: Students often mix up which vitamins are stored in the body and which are excreted. They might say Vitamin C is stored (it isn't) or that Vitamin A is easily washed out (it isn't).
- Why it happens: The terms "fat-soluble" (A, D, E, K) and "water-soluble" (B-complex, C) sound similar, and students memorize them without understanding the consequence.
- How to avoid: Link the property to the function.
- Vitamin A (Fat-soluble): Stored in the liver. This means excess can be toxic (hypervitaminosis). You don't need it every single day.
- Vitamin C (Water-soluble): Excreted in urine. This means deficiency is common if not taken daily, and excess is rarely toxic (just expensive urine).
2. Vague or Incorrect "Essentiality" (Why we need them)
- The Mistake: Writing "Vitamin A is good for eyes" or "Vitamin C prevents colds." This is too vague and often scientifically inaccurate (Vitamin C does not prevent colds, it may reduce duration).
- Why it happens: Students rely on common sayings rather than the precise biological role.
- How to avoid: Use the specific biochemical function.
- Vitamin A: Essential for rhodopsin formation (a pigment in the retina needed for dim light vision). Also maintains epithelial cells (skin, mucous membranes).
- Vitamin C: Essential for collagen synthesis (a protein that holds tissues together, heals wounds, and strengthens blood vessels). It is also a powerful antioxidant.
3. Mixing Up Sources (Especially Animal vs. Plant)
- The Mistake: Listing "carrots" as a source of Vitamin A (technically correct, but incomplete) or forgetting that Vitamin C is destroyed by heat.
- Why it happens: Students don't distinguish between preformed Vitamin A (retinol) and Provitamin A (beta-carotene).
- How to avoid: Be precise in your source lists.
| Vitamin | Best Sources (Exam-Focused) | Key Exam Point |
|---|---|---|
| Vitamin A | Animal: Liver, fish liver oil, egg yolk, milk. Plant: Carrots, spinach, papaya, mango (contain beta-carotene). | Beta-carotene is a precursor; the body converts it to Vitamin A. |
| Vitamin C | Fresh citrus fruits (orange, lemon, amla/Indian gooseberry), tomatoes, green leafy vegetables, strawberries. | Heat-sensitive and water-soluble. Cooking destroys it. Amla is one of the richest natural sources. |
4. Forgetting the Deficiency Disease Link
- The Mistake: Stating the function but not linking it to the deficiency disease (or getting the disease wrong, e.g., saying Vitamin C causes night blindness).
- Why it happens: Students memorize functions and diseases as separate lists.
- How to avoid: Create a direct cause-effect chain.
- Vitamin A deficiency → Lack of rhodopsin → Night blindness (Nyctalopia). Severe deficiency leads to Xerophthalmia (dryness of cornea) and blindness. …
Showing the 12 most recent of 16 on this concept.
- AP EAPCET 2025Set eng-2025-05-23-AN1 markMCQQ.The deficiency of vitamin (X) causes convulsions. Source of X is Y. What are X and Y? (A) Riboflavin, milk (B) Riboflavin, fish (C) Pyridoxine, curd (D) Pyridoxine, cereals
›Reveal solutionSolution
This tests recall of a vitamin-deficiency-disease-source table (Biomolecules chapter). The answer is (D).
Concept and Intuition
Each water-soluble/fat-soluble vitamin has a characteristic deficiency disease and characteristic dietary sources, which are standard memorised facts in the biomolecules/vitamins topic.
Step-by-Step Solution
- Convulsions as a deficiency symptom is specifically associated with Vitamin B6 (Pyridoxine) deficiency (as opposed to Riboflavin, whose deficiency causes cheilosis/digestive disorders/eye issues).
- This rules out options (A) and (B), which name Riboflavin. …
- AP EAPCET 2024Set eng-2024-05-21-AN1 markMCQQ.Identify the correctly matched set from the following (A) Vitamin A – Water soluble – Xerophthalmia (B) Vitamin B6 – Water soluble – Scurvy (C) Vitamin D – fat soluble - Rickets (D) Vitamin C – fat soluble - convulsions
›Reveal solutionSolution
Checking solubility and deficiency disease for each vitamin, only Vitamin D – fat soluble – Rickets is a fully correct match.
Concept and Intuition
Vitamins split cleanly into two solubility classes: fat-soluble (A, D, E, K — stored in body fat, absorbed with dietary lipids) and water-soluble (B-complex and C — not stored, need regular dietary intake). Each vitamin also has a specific, well-defined deficiency disease. A "correctly matched set" question requires BOTH the solubility class and the deficiency disease to be right simultaneously.
Step-by-Step Solution
- (A) Vitamin A – Water soluble – Xerophthalmia: Vitamin A is fat-soluble, not water-soluble (it belongs to the A-D-E-K group). The disease Xerophthalmia (dryness of the cornea/conjunctiva, can progress to night blindness) is correctly linked to Vitamin A deficiency, but the solubility is wrong. → mismatch.
- (B) Vitamin B₆ – Water soluble – Scurvy: Vitamin B₆ (pyridoxine) is correctly water-soluble, but scurvy is the deficiency disease of Vitamin C, not B₆ (B₆ deficiency instead causes conditions like convulsions in infants, anaemia, and dermatitis). → mismatch on disease.
- (C) Vitamin D – fat soluble – Rickets: Vitamin D is correctly fat-soluble, and its deficiency causes Rickets in growing children (bone deformity due to poor calcium/phosphate deposition) — this is the standard, textbook-correct pairing. → fully correct. …
- AP EAPCET 2024Set eng-2024-05-21-FN1 markMCQQ.Carrot and curd are sources for the vitamins respectively (A) A, B12 (B) A, B1 (C) E, Pyridoxine (D) E, Riboflavin
›Reveal solutionSolution
Carrot supplies Vitamin A (via β-carotene) and curd supplies Vitamin B₁₂ (via bacterial fermentation), matching option (A).
Concept and Intuition
Vitamin sources are commonly tested by pairing a familiar food with its characteristic vitamin. Carrot's orange colour comes from β-carotene, the plant-derived precursor the body converts to Vitamin A (important for vision — its deficiency causes night blindness). Curd, being a fermented milk product, is enriched in Vitamin B₁₂ relative to plain milk because the fermenting bacteria synthesise it.
Step-by-Step Solution
- Identify carrot's vitamin: β-carotene → Vitamin A.
- Identify curd's vitamin: bacterial fermentation of milk enriches Vitamin B₁₂ content.
- Match to the option listing A and B₁₂ together.
Common Mistakes …
- AP EAPCET 2024Set eng-2024-05-23-FN1 markMCQQ.The deficiency of vitamin(x) causes beri beri and deficiency of vitamin (y) causes convulsions. What are x and y respectively? (A) B2, B12 (B) B1, B12 (C) B2, B6 (D) B1, B6
›Reveal solutionSolution
This tests memorised vitamin-deficiency disease pairs; beriberi is caused by B1 (thiamine) deficiency and convulsions by B6 (pyridoxine) deficiency.
Concept and Intuition
Water-soluble B-vitamins each have a specific coenzyme role, and their deficiency diseases follow directly from which metabolic pathway breaks down without them:
- B1 (Thiamine): coenzyme in carbohydrate metabolism (as thiamine pyrophosphate, needed for pyruvate dehydrogenase and related steps). Deficiency → beriberi (nerve and cardiovascular symptoms — because neurons and heart muscle depend heavily on efficient glucose metabolism).
- B6 (Pyridoxine): coenzyme (as pyridoxal phosphate) in amino acid metabolism, including synthesis of neurotransmitters like GABA. Deficiency disrupts normal neuronal signalling → convulsions.
- (For contrast: B2/riboflavin deficiency → cheilosis/skin disorders; B12 deficiency → pernicious anaemia.)
Step-by-Step Solution
- Identify vitamin (x), whose deficiency causes beriberi: this is the textbook-classic association with thiamine, B1.
- Identify vitamin (y), whose deficiency causes convulsions: pyridoxine, B6, is the NCERT-cited vitamin whose deficiency leads to convulsions (via impaired neurotransmitter synthesis).
- So x = B1 and y = B6, matching option (D). …
- AP EAPCET 2023Set eng-2023-05-16-AN1 markMCQQ.Deficiency of which vitamin causes convulsions? (A) Riboflavin (B) Thiamine (C) Ascorbic acid (D) Pyridoxine
›Reveal solutionSolution
Pyridoxine (Vitamin B6) deficiency is specifically linked to convulsions.
Concept and Intuition
Each B-vitamin deficiency has characteristic clinical symptoms tested commonly in biomolecule chapters: Riboflavin (B2) deficiency causes cheilosis (cracked lips) and eye/skin lesions; Thiamine (B1) deficiency causes beriberi; Ascorbic acid (Vitamin C) deficiency causes scurvy; Pyridoxine (B6) deficiency is specifically associated with convulsions (it's essential for neurotransmitter synthesis).
Step-by-Step Solution
- Riboflavin deficiency → cheilosis, digestive problems — not convulsions.
- Thiamine deficiency → beriberi (nerve/muscle/heart problems) — not classically "convulsions." …
- AP EAPCET 2023Set eng-2023-05-17-FN1 markMCQQ.Match the following List - I | List - II A. Beri Beri | I. Riboflavin B. Scurvy | II. Thiamine C. Cheilosis | III. Pyridoxine D. Rickets | IV. Ascorbic acid | V. Vitamin D The correct answer is (A) A – III, B – IV, C – III, D – V (B) A – II, B – IV, C – I, D – V (C) A – III, B – V, C – I, D – II (D) A – III, B – V, C – IV, D – II
›Reveal solutionSolution
This tests matching deficiency diseases to the vitamin whose lack causes them. Answer: A–II, B–IV, C–I, D–V.
Concept and Intuition
Each vitamin deficiency produces a characteristic, well-documented disease. Recognizing these pairings is a matter of biochemical recall: Thiamine (B1) deficiency causes beriberi (nerve/cardiovascular symptoms); Riboflavin (B2) deficiency causes cheilosis (cracking at the corners of the mouth) among other symptoms; Ascorbic acid (Vitamin C) deficiency causes scurvy (bleeding gums, poor wound healing); Vitamin D deficiency causes rickets (bone deformity in children) or osteomalacia in adults.
Step-by-Step Solution
- A. Beri Beri is caused by thiamine deficiency → matches List II item II (Thiamine).
- B. Scurvy is caused by ascorbic acid (Vitamin C) deficiency → matches List II item IV (Ascorbic acid). …
- AP EAPCET 2023Set eng-2023-05-19-FN1 markMCQQ.From the following, number of fat soluble and water soluble vitamins respectively are A D C B1 K B6 (A) 2, 4 (B) 4, 2 (C) 3, 3 (D) 6, 0
›Reveal solutionSolution
This tests classification of vitamins as fat-soluble vs water-soluble; out of A, D, C, B1, K, B6 there are exactly 3 fat-soluble (A, D, K) and 3 water-soluble (C, B1, B6).
Concept and Intuition
Vitamins are classified by their solubility, which determines how the body absorbs, transports, and stores them:
- Fat-soluble vitamins: A, D, E, K — absorbed along with dietary fats and can be stored in the body's fatty tissue/liver (so toxicity from excess is more of a concern for these).
- Water-soluble vitamins: the B-complex vitamins (B1, B2, B3, B5, B6, B7 [biotin], B9, B12) and vitamin C — these are generally not stored in significant amounts and excess is excreted in urine, so regular dietary intake is needed.
Step-by-Step Solution
- List the given vitamins: A, D, C, B1, K, B6.
- Classify each:
- A — fat-soluble
- D — fat-soluble
- C — water-soluble
- B1 — water-soluble (B-complex)
- K — fat-soluble …
- AP EAPCET 2022Set ap-2022-07-11-FN1 markMCQQ.Chose the correct statement (A) Vitamin A & K are insoluble in water and can be stored in Adipose tissue (B) Vitamin A & K are soluble in water and can be stored in Adipose tissue (C) Vitamin A & K are soluble in water but cannot be stored in Adipose tissue (D) Vitamin A & K are insoluble in water but cannot be stored in Adipose tissue
›Reveal solutionSolution
This tests the basic classification of vitamins into water-soluble and fat-soluble groups, and the associated fact that fat-soluble vitamins are stored in adipose tissue.
Concept and Intuition
Vitamins are broadly classified as fat-soluble (A, D, E, K) or water-soluble (B-complex, C). Fat-soluble vitamins dissolve in lipids, are absorbed along with dietary fats, and — because the body has no efficient way to excrete excess lipophilic substances via urine — they accumulate and are stored in adipose (fat) tissue and the liver. Water-soluble vitamins, by contrast, are not stored in significant amounts and excess is excreted in urine.
Step-by-Step Solution
- Classify vitamins A and K: both belong to the fat-soluble group (along with D and E).
- Fat-soluble vitamins are, by definition, insoluble/poorly soluble in water. …
- AP EAPCET 2022Set eng-2022-07-04-AN1 markMCQQ.Pernicious anemia is caused due to deficiency of which vitamin? (A) B12 (B) B1 (C) B6 (D) B2
›Reveal solutionSolution
Direct biochemistry recall: pernicious anaemia is the classic disease of vitamin B12 deficiency. Answer: B12.
Concept and Intuition
Vitamin B12 (cobalamin) is required for DNA synthesis in rapidly dividing cells, including the bone marrow's red blood cell precursors. Its deficiency (often due to lack of "intrinsic factor", a stomach glycoprotein needed for its absorption in the small intestine) leads to defective maturation of red blood cells, producing large, immature, dysfunctional red cells — the condition called pernicious anaemia.
Step-by-Step Solution
- Recall the vitamin deficiency diseases: B1 (thiamine) → beriberi; B2 (riboflavin) → cheilosis; B6 (pyridoxine) → convulsions/anaemia (different mechanism); B12 (cobalamin) → pernicious anaemia. …
- AP EAPCET 2022Set eng-2022-07-08-FN1 markMCQQ.Thiamine is (A) Nitrogenous base (B) Amino acid (C) Hormone (D) Vitamin
›Reveal solutionSolution
Thiamine is the common/chemical name of Vitamin B1. Answer: (D) Vitamin.
Concept and Intuition
Vitamins are organic compounds required in small amounts in the diet for normal metabolic function, and each has both a common vitamin-letter name and a specific chemical name. Thiamine is the chemical name given specifically to Vitamin B1, a water-soluble B-complex vitamin. In the body, thiamine is converted into its active coenzyme form, thiamine pyrophosphate (TPP), which plays a central role as a cofactor in carbohydrate metabolism (e.g., in the pyruvate dehydrogenase complex). A deficiency of thiamine/Vitamin B1 causes the disease beriberi, characterized by nerve and cardiovascular problems — a classic NCERT/biomolecules-chapter fact.
Step-by-Step Solution
- Identify what thiamine refers to: it is the chemical/common name for a specific water-soluble vitamin.
- Recall that thiamine = Vitamin B1 (part of the B-complex group of vitamins). …
- AP EAPCET 2021Set ap-2021-09-07-FN1 markMCQQ.Match the following? Vitamin — Source.(a) Vitamin-D —(i) Fish liver oil.(b) Vitamin-E —(ii) Green leafy vegetables.(c) Vitamin-A —(iii) Egg yolk.(d) Vitamin-K —(iv) Sunflower Oil. (A) (a-iii), (b-ii), (c-iv), (d-i) (B) (a-iv), (b-iii), (c-ii), (d-i) (C) (a-iii), (b-iv), (c-i), (d-ii) (D) (a-iv), (b-ii), (c-iii), (d-i)
›Reveal solutionSolution
This tests recall of standard vitamin-source pairings; the correct match is Vitamin-D→egg yolk, Vitamin-E→sunflower oil, Vitamin-A→fish liver oil, Vitamin-K→green leafy vegetables.
Concept and Intuition
Each fat-soluble vitamin has a textbook-associated primary dietary source used in matching-type questions. Vitamin-A (retinol) is classically tied to fish liver oil (cod-liver oil is the iconic vitamin-A supplement). Vitamin-E (tocopherol) is most abundant in vegetable oils, sunflower oil being a prototypical example. Vitamin-K (phylloquinone) is overwhelmingly sourced from green leafy vegetables (spinach, cabbage) — this is the most universally taught pairing ('K for greens'). Vitamin-D, besides being synthesized via sunlight, is dietarily obtained from animal products like egg yolk.
Step-by-Step Solution
- Vitamin-K → green leafy vegetables is the most certain, well-established pairing, which immediately rules out any option pairing K with fish liver oil.
- Vitamin-A → fish liver oil is the other very well-established classic pairing.
- With A and K fixed to (i) and (ii) respectively, the remaining two sources (egg yolk, sunflower oil) must go to D and E.
- Vitamin-E's most emphasized source in nutrition tables is vegetable/seed oils (sunflower oil) — so E → (iv). …
- AP EAPCET 2021Set ap-2021-09-06-FN1 markMCQQ.Deficiency of Riboflavin causes the disease ________ (A) Hemophilia (B) Rickets (C) Beriberi (D) Cheilosis
›Reveal solutionSolution
Riboflavin (B2) deficiency causes cheilosis — cracking at the corners of the mouth. Answer: (D).
Concept and Intuition
Each water-soluble B-vitamin has a signature deficiency disease tied to its metabolic role. Riboflavin (B2) is a precursor of the coenzymes FAD/FMN, central to cellular oxidation-reduction reactions; its deficiency particularly affects rapidly dividing epithelial tissue such as the skin and mucous membranes around the mouth, producing cheilosis (fissuring at the lip corners), angular stomatitis, and glossitis.
Step-by-Step Solution
- Identify riboflavin as Vitamin B2. …
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