Biochemistry — Vitamins, Minerals & Trace Elements
⚙ Minerals & Trace Elements
The building blocks your enzymes actually need. Calcium contracts, magnesium phosphorylates, copper wires your mitochondria, and the trace elements keep glycolysis from grinding to a halt.
🔬 A 35-year-old presents with tremor, personality changes, and liver cirrhosis. Slit-lamp exam reveals golden-brown corneal rings. What is the most likely diagnosis?
Section I
🪛 The Minerals
Click any element to expand its full profile. These are the heavy hitters your enzymes, muscles, and bones depend on.
20
Ca
Calcium
12
Mg
Magnesium
30
Zn
Zinc
29
Cu
Copper
26
Fe
Iron
What It Does
Intracellular calcium is needed for all muscle contraction
Smooth muscle uses extracellular calcium for second messenger systems
Atrium and thalamus are the only membranes that use calcium to depolarize
🔑A-T for Atrium-Thalamus: the two rebels that depolarize with Ca²⁺ instead of Na⁺
Cardiac ventricle depends on extracellular Ca²⁺ to trigger intracellular Ca²⁺ release —
"calcium-induced calcium release"A little extracellular Ca²⁺ enters through L-type channels during the plateau phase, then triggers massive Ca²⁺ release from the sarcoplasmic reticulum via ryanodine receptors
Used for axonal transport
Presynaptic influx of calcium is necessary for release of all neurotransmitters
Needed for normal bone and teeth development
Clinical Pearl
Babies in utero need calcium for neurotransmitter release — deficiency can cause developmental delay
What It Does
Cofactor for ALL kinases(why?)Kinases use negatively charged ATP. Mg²⁺ has a positive charge that holds onto those negative charges, stabilizing ATP for the kinase to work
Cofactor for PTH — so low Mg can mimic hypoparathyroidism
Interacts with potassium in the early distal convoluted tubules of the kidneys
Cotransport protein for both K⁺ and Mg²⁺
Board Trap
Can't fix hypokalemia until you fix hypomagnesemia — they share a cotransporter in the DCT. If Mg is low, K keeps leaking out no matter how much you replace
What It Does
Needed by hair, skin, sperm, and taste buds🔑Zinc = the vanity mineral. Hair, skin, taste, and swimmers. Everything you'd notice on a date.
Deficiency
Dysgeusia (altered/loss of taste)
May turn hair color red
What It Does
Needed by lysine oxidase in the formation of collagen
(why it matters)Lysine oxidase crosslinks collagen and elastin fibers. Without copper, connective tissue falls apart
Needed by Complex IV of the electron transport chain (cytochrome c oxidase)
🔴 Excess — Wilson's Disease
Autosomal recessive
Ceruloplasmin deficiency (the protein that carries copper)
Causes drug-induced lupus; can't use if patient has penicillin anaphylaxis
🔵 Deficiency — Menke's Kinky Hair Syndrome
Orange colored hair because copper gets stuck in the hair
Hair feels like copper wire
What It Does
Needed for formation of heme and hemoglobin
Ferrous iron (Fe²⁺) binds oxygen — the useful form
Ferric iron (Fe³⁺) has been oxidized — can't carry O₂
🔑Fe2+ = ferr-OUS = use-ful. Fe3+ = ferr-IC = is cr*p. The 2 is the one you want.
Needed by Complex III and IV of the electron transport system
Clinical Pearl
Vitamin C protects iron from being oxidized in the GI tract — that's why we tell patients to drink orange juice when taking iron supplements
Board Favorite
Movement Disorder in a Middle-Aged Person
Wilson's and Huntington's both cause movement disorders with psychiatric symptoms. The board loves to make you pick between them.
Feature
Huntington's (90%)
Wilson's Disease
Inheritance
Autosomal dominant
Autosomal recessive
Mechanism
Trinucleotide repeats (CAG)
Ceruloplasmin deficiency
Brain lesion
Caudate nucleus atrophy
Lenticular nucleus (basal ganglia)
Movement
Chorea
Tremor, dystonia
Liver?
No
Yes — cirrhosis
Eyes?
No
Kayser-Fleischer rings
Anticipation?
Yes
No
Treatment
Antipsychotics (dopamine blockers)
Penicillamine (chelation)
MCC of death
Suicide
Liver failure
💡 Trinucleotide Repeat Diseases
5 diseases that COULD have trinucleotide repeats: Huntington's, Fragile X, Friedreich's Ataxia, Prader-Willi Syndrome, Myotonic Dystrophy
Section II
🔬 Trace Elements
Tiny amounts, massive consequences. Each one is a potential board question.
24
Cr
Chromium
34
Se
Selenium
42
Mo
Molybdenum
25
Mn
Manganese
9
F
Fluoride
What It Does
Enhances insulin action — therefore delays progression of diabetes
Deficiency
Causes diabetes (impaired glucose tolerance)
🔑Chromium = Chrome = shiny like insulin receptors. Without the chrome, your receptors are dull and can't respond.
What It Does
Needed primarily by the heart
Excess
Breath smells like garlic (arsenic does this too!)
🔑Se-licious garlic breath. Selenium and arsenic both give you garlic breath — think of a vampire who can't be repelled.
Deficiency
Dilated cardiomyopathy (Keshan disease)
What It Does (+ Manganese)
Needed by many enzymes in glycolysis
Xanthine oxidase needs BOTH molybdenum and manganese
(why it matters)Xanthine oxidase is the enzyme that makes uric acid. This is why allopurinol (blocks xanthine oxidase) treats gout
What It Does
Needed by many enzymes in glycolysis
Partners with molybdenum for xanthine oxidase (uric acid production)
What It Does
Needed for teeth and bone growth
Excess
Blocks enolase of glycolysis → causes low energy state
(connection!)Enolase converts 2-phosphoglycerate to PEP in glycolysis. Block it and you choke off ATP production. Full circle back to Chapter 1!🔑Fluoride = Floor-ride. Too much fluoride and your energy hits the floor because enolase is blocked.
Test Yourself
🎮 Match the Mineral
Drag each mineral to its signature finding. Don't overthink it.
Minerals
Findings
Final Boss
🎯 Quiz Time
10 random questions from a pool of 16. Answers shuffle every load.