🧪 Biochemistry · Vitamins & Cofactors

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Fat and water-soluble vitamins and deficiency mnemonics — mastered.

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Fat-Soluble Vitamins
Fat-soluble vitamins: ADEK — can accumulate and become toxic
Fat-Soluble Vitamins
Four vitamins stored in body fat — excess can reach toxic levels
A (retinol): vision and immune function. D (calciferol): calcium absorption, bone. E (tocopherol): antioxidant. K (phylloquinone): blood clotting. Stored in liver and adipose tissue.
A
Vision, immune function
D
Calcium absorption, bone health
E
Antioxidant
K
Blood clotting
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🃏 Fat-Soluble Vitamins
Fat-soluble vitamins — which, and why can they be toxic?
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🃏 Answer
Fat-soluble vitamins: ADEK — can accumulate and become toxic
AVision, immune function
DCalcium absorption, bone health
EAntioxidant
KBlood clotting
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Water-Soluble Vitamins
Water-soluble: B vitamins + C — excess is urinated out safely
Water-Soluble Vitamins
Eight B vitamins plus vitamin C — not stored, need regular intake
B1 thiamine, B2 riboflavin (FAD), B3 niacin (NAD⁺), B5 pantothenic acid (CoA), B6 pyridoxine, B7 biotin, B9 folate (DNA synthesis), B12 cobalamin (myelin, RBC). C: collagen synthesis.
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🃏 Water-Soluble Vitamins
Water-soluble vitamins — which, and what happens to excess?
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🃏 Answer
Water-soluble: B vitamins + C — excess is urinated out safely
Water-Soluble Vitamins — B1 thiamine, B2 riboflavin (FAD), B3 niacin (NAD⁺), B5 pantothenic acid (CoA), B6 pyridoxine, B7 biotin, B9 folate (DNA synthesis), B12 cobalamin (myelin, RBC). C: collagen synthesis.
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Vitamin C and Scurvy
Vitamin C deficiency = scurvy: bleeding gums, poor wound healing (collagen fails)
Vitamin C and Scurvy
Vitamin C is essential for collagen hydroxylation
Without vitamin C, proline and lysine residues can't be hydroxylated → unstable collagen → bleeding gums, poor wound healing, bruising, joint pain. Killed sailors on long voyages before citrus was understood.
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🃏 Vitamin C and Scurvy
Vitamin C deficiency — the disease and its signs?
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🃏 Answer
Vitamin C deficiency = scurvy: bleeding gums, poor wound healing (collagen fails)
Vitamin C and Scurvy — Without vitamin C, proline and lysine residues can't be hydroxylated → unstable collagen → bleeding gums, poor wound healing, bruising, joint pain. Killed sailors on long voyages before citrus was understood.
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Vitamin D Deficiency
Vitamin D deficiency: rickets (children — bowed bones), osteomalacia (adults)
Vitamin D Deficiency
Vitamin D is needed for calcium absorption — deficiency weakens bones
Made in skin from UV-B sunlight. Deficiency: rickets in children (soft, bowing bones), osteomalacia in adults (soft bones, pain). Also linked to immune dysfunction and depression. Common in northern latitudes.
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🃏 Vitamin D Deficiency
Vitamin D deficiency — in children vs adults?
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🃏 Answer
Vitamin D deficiency: rickets (children — bowed bones), osteomalacia (adults)
Vitamin D Deficiency — Made in skin from UV-B sunlight. Deficiency: rickets in children (soft, bowing bones), osteomalacia in adults (soft bones, pain). Also linked to immune dysfunction and depression. Common in northern latitudes.
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Folate and B12
Folate (B9): DNA synthesis and repair — deficiency causes neural tube defects and megaloblastic anemia
Folate and B12
Two B vitamins that work together — deficiency in either causes anemia
Folate: required for nucleotide synthesis (DNA building blocks). Deficiency in early pregnancy → neural tube defects. B12: required for myelin synthesis and folate metabolism. Deficiency: megaloblastic anemia, neurological damage.
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🃏 Folate and B12
Folate (B9) — role and deficiency?
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🃏 Answer
Folate (B9): DNA synthesis and repair — deficiency causes neural tube defects and megaloblastic anemia
Folate and B12 — Folate: required for nucleotide synthesis (DNA building blocks). Deficiency in early pregnancy → neural tube defects. B12: required for myelin synthesis and folate metabolism. Deficiency: megaloblastic anemia, neurological damage.
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Thiamine — Vitamin B1
B1 thiamine: energy metabolism cofactor. Deficiency = beriberi (peripheral neuropathy) or Wernicke's (alcoholics)
Thiamine — Vitamin B1
The vitamin that alcoholics most commonly lack
Thiamine pyrophosphate (TPP — the active coenzyme form of B1): cofactor for pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase, transketolase. Beriberi: dry (peripheral neuropathy, muscle weakness), wet (heart failure, edema). Wernicke-Korsakoff syndrome: alcoholics — Wernicke's (confusion, ataxia, eye movement issues) → Korsakoff's (irreversible memory loss).
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🃏 Thiamine — Vitamin B1
Thiamine (B1) — role and deficiency?
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🃏 Answer
B1 thiamine: energy metabolism cofactor. Deficiency = beriberi (peripheral neuropathy) or Wernicke's (alcoholics)
Thiamine — Vitamin B1 — Thiamine pyrophosphate (TPP — the active coenzyme form of B1): cofactor for pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase, transketolase. Beriberi: dry (peripheral neuropathy, muscle weakness), wet (heart failure, edema). Wernicke-Korsakoff syndrome: alcoholics — Wernicke's (confusion, ataxia, eye movement issues) → Korsakoff's (irreversible memory loss).
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Riboflavin — Vitamin B2
B2 riboflavin: component of FAD and FMN — electron carriers in ETC. Deficiency = ariboflavinosis (cracks at corners of mouth)
Riboflavin — Vitamin B2
The vitamin whose deficiency causes characteristic mouth sores
Riboflavin forms FAD (flavin adenine dinucleotide) and FMN (flavin mononucleotide) — electron carriers in the electron transport chain. Deficiency (ariboflavinosis): angular cheilitis (cracks at corners of mouth), glossitis (inflamed tongue), seborrheic dermatitis. Rare in isolation — usually with other B vitamin deficiencies.
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🃏 Riboflavin — Vitamin B2
Riboflavin (B2) — role and deficiency?
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🃏 Answer
B2 riboflavin: component of FAD and FMN — electron carriers in ETC. Deficiency = ariboflavinosis (cracks at corners of mouth)
Riboflavin — Vitamin B2 — Riboflavin forms FAD (flavin adenine dinucleotide) and FMN (flavin mononucleotide) — electron carriers in the electron transport chain. Deficiency (ariboflavinosis): angular cheilitis (cracks at corners of mouth), glossitis (inflamed tongue), seborrheic dermatitis. Rare in isolation — usually with other B vitamin deficiencies.
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Niacin — Vitamin B3
B3 niacin: component of NAD⁺ and NADP⁺. Deficiency = pellagra — 4 Ds: Diarrhea, Dermatitis, Dementia, Death
Niacin — Vitamin B3
The vitamin whose deficiency causes pellagra
Niacin forms NAD⁺ and NADP⁺ — critical electron carriers in metabolism. Pellagra: the 4 Ds — Diarrhea, Dermatitis (sun-sensitive rash on exposed skin), Dementia, Death. Historically common where corn was the dietary staple (niacin in corn is bound form). High-dose niacin: raises HDL (High Density Lipoprotein — good cholesterol), lowers triglycerides.
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🃏 Niacin — Vitamin B3
Niacin (B3) — role, and the 4 Ds of pellagra?
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🃏 Answer
B3 niacin: component of NAD⁺ and NADP⁺. Deficiency = pellagra — 4 Ds: Diarrhea, Dermatitis, Dementia, Death
Niacin — Vitamin B3 — Niacin forms NAD⁺ and NADP⁺ — critical electron carriers in metabolism. Pellagra: the 4 Ds — Diarrhea, Dermatitis (sun-sensitive rash on exposed skin), Dementia, Death. Historically common where corn was the dietary staple (niacin in corn is bound form). High-dose niacin: raises HDL (High Density Lipoprotein — good cholesterol), lowers triglycerides.
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Cobalamin — Vitamin B12
B12 cobalamin: needs intrinsic factor for absorption. Deficiency = pernicious anemia + subacute combined degeneration
Cobalamin — Vitamin B12
The vitamin that requires a specialized carrier for absorption
B12 requires intrinsic factor (from gastric parietal cells) for absorption in ileum. Pernicious anemia: autoimmune destruction of parietal cells → no intrinsic factor → B12 deficiency. Subacute combined degeneration of spinal cord: B12 deficiency damages posterior and lateral spinal columns. Vegans at risk — B12 only in animal products.
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🃏 Cobalamin — Vitamin B12
Cobalamin (B12) — absorption and deficiency?
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🃏 Answer
B12 cobalamin: needs intrinsic factor for absorption. Deficiency = pernicious anemia + subacute combined degeneration
Cobalamin — Vitamin B12 — B12 requires intrinsic factor (from gastric parietal cells) for absorption in ileum. Pernicious anemia: autoimmune destruction of parietal cells → no intrinsic factor → B12 deficiency. Subacute combined degeneration of spinal cord: B12 deficiency damages posterior and lateral spinal columns. Vegans at risk — B12 only in animal products.
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Vitamin A
Vitamin A (retinol): vision (rhodopsin), immune function, epithelial integrity. Deficiency = night blindness.
Vitamin A
Fat-soluble vitamin essential for vision and epithelial health
Retinal (from retinol): component of rhodopsin — visual pigment in rod cells. Retinoic acid: regulates gene expression, epithelial differentiation. Deficiency: night blindness (earliest sign), xerophthalmia (dry eyes), increased infection susceptibility. Toxicity: teratogenic in pregnancy (liver, isotretinoin).
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🃏 Vitamin A
Vitamin A — roles and deficiency?
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🃏 Answer
Vitamin A (retinol): vision (rhodopsin), immune function, epithelial integrity. Deficiency = night blindness.
Vitamin A — Retinal (from retinol): component of rhodopsin — visual pigment in rod cells. Retinoic acid: regulates gene expression, epithelial differentiation. Deficiency: night blindness (earliest sign), xerophthalmia (dry eyes), increased infection susceptibility. Toxicity: teratogenic in pregnancy (liver, isotretinoin).
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Vitamin K
Vitamin K: essential for blood clotting factors II VII IX X. Warfarin works by blocking vitamin K recycling.
Vitamin K
The clotting vitamin — and the target of anticoagulant drugs
Vitamin K: cofactor for gamma-carboxylation of clotting factors II (prothrombin), VII, IX, X, and anticoagulant proteins C and S. K1 (phylloquinone): green leafy vegetables. K2 (menaquinone): bacteria, fermented foods. Warfarin: inhibits vitamin K epoxide reductase → can't recycle vitamin K → reduced clotting factor activity.
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🃏 Vitamin K
Vitamin K — role, and how warfarin affects it?
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🃏 Answer
Vitamin K: essential for blood clotting factors II VII IX X. Warfarin works by blocking vitamin K recycling.
Vitamin K — Vitamin K: cofactor for gamma-carboxylation of clotting factors II (prothrombin), VII, IX, X, and anticoagulant proteins C and S. K1 (phylloquinone): green leafy vegetables. K2 (menaquinone): bacteria, fermented foods. Warfarin: inhibits vitamin K epoxide reductase → can't recycle vitamin K → reduced clotting factor activity.
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Essential Mineral Cofactors
Mineral cofactors: zinc (wound healing, immune, taste), iron (hemoglobin, ETC), iodine (thyroid hormones), calcium (bones, signaling)
Essential Mineral Cofactors
Four essential minerals and their key biochemical roles
Zinc: 300+ enzymes, wound healing, immune function, taste and smell, DNA synthesis. Deficiency: growth retardation, impaired immunity, hypogeusia. Iron: hemoglobin (O₂ transport), myoglobin, cytochromes. Iodine: thyroid hormones T3 (triiodothyronine) and T4 (thyroxine) — deficiency causes goiter, hypothyroidism, cretinism. Calcium: bones/teeth, muscle contraction, nerve signaling, second messenger.
Zinc
300+ enzymes, immunity, wound healing
Iron
Hemoglobin, ETC
Iodine
Thyroid hormones T3/T4
Calcium
Bones, muscle, nerve signaling
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🃏 Essential Mineral Cofactors
Mineral cofactors — zinc, iron, iodine, calcium?
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🃏 Answer
Mineral cofactors: zinc (wound healing, immune, taste), iron (hemoglobin, ETC), iodine (thyroid hormones), calcium (bones, signaling)
Zinc300+ enzymes, immunity, wound healing
IronHemoglobin, ETC
IodineThyroid hormones T3/T4
CalciumBones, muscle, nerve signaling
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