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Questions and Answers
What classification of minerals is required in amounts greater than 100 mg/day?
What classification of minerals is required in amounts greater than 100 mg/day?
Calcium is absorbed from the first part of the intestine only.
Calcium is absorbed from the first part of the intestine only.
False
What is the daily requirement of calcium for an adult?
What is the daily requirement of calcium for an adult?
500 mg
Calcium is the most abundant mineral in the body, comprising about ______ grams.
Calcium is the most abundant mineral in the body, comprising about ______ grams.
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Match the mineral with its effect or function:
Match the mineral with its effect or function:
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Which of these is NOT a function of calcium?
Which of these is NOT a function of calcium?
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Calcium requires a carrier protein for its absorption.
Calcium requires a carrier protein for its absorption.
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What are the two forms in which plasma calcium is present?
What are the two forms in which plasma calcium is present?
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Which of the following enzymes is NOT activated by calcium through calmodulin?
Which of the following enzymes is NOT activated by calcium through calmodulin?
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Phosphorus is primarily absorbed in the intestines through passive diffusion.
Phosphorus is primarily absorbed in the intestines through passive diffusion.
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What is the normal range of plasma inorganic phosphorus in mg/dl?
What is the normal range of plasma inorganic phosphorus in mg/dl?
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Calcium binds with ___ ions in calmodulin.
Calcium binds with ___ ions in calmodulin.
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Match the following sources of calcium and phosphorus with their corresponding items:
Match the following sources of calcium and phosphorus with their corresponding items:
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Which of the following is a function of phosphorus in the body?
Which of the following is a function of phosphorus in the body?
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The total body phosphorus is approximately 700 gm, with more than 600 gm found in the skeleton.
The total body phosphorus is approximately 700 gm, with more than 600 gm found in the skeleton.
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What is the daily requirement of iron for pregnant and lactating women in mg?
What is the daily requirement of iron for pregnant and lactating women in mg?
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What percentage of dietary iron is usually absorbed by the body?
What percentage of dietary iron is usually absorbed by the body?
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Iron is absorbed in the ferric state (Fe+++) according to the mucosal block theory.
Iron is absorbed in the ferric state (Fe+++) according to the mucosal block theory.
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What condition is characterized by increased iron absorption and can cause bronze discoloration of the skin?
What condition is characterized by increased iron absorption and can cause bronze discoloration of the skin?
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Zinc plays a significant role in ____ and wound healing.
Zinc plays a significant role in ____ and wound healing.
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Match the following minerals with their associated functions:
Match the following minerals with their associated functions:
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What is a common cause of iron deficiency anemia?
What is a common cause of iron deficiency anemia?
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Zinc is not involved in the storage and release of insulin.
Zinc is not involved in the storage and release of insulin.
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List one source of zinc.
List one source of zinc.
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Study Notes
Biochemistry I: Minerals
- Course Title: Biochemistry I
- Course Code: FM 104
- Department: Biochemistry
- Lecturer: Ass. Prof. Dr. Omnia Safwat El-Deeb
- Lecture Title: Minerals
Lecture Objectives
- Know the biochemical classification of minerals
- Recognize the functions of important minerals
- Identify the signs of clinical deficiency and overproduction of important minerals and their absorption mechanisms
Contents
- Classification of minerals
- Calcium (functions and deficiency)
- Phosphorus (functions)
- Iron (absorption, functions, and deficiency)
- Zinc (important enzymes require calcium)
- Fluoride and tooth decay
Definition of Minerals
- Inorganic compounds essential for normal body growth and maintenance
Classification of Minerals
- A-Macrominerals (Bulk Elements): Required in amounts greater than 100 mg/day.
- B-Microminerals (Trace Elements): Required in amounts less than 100 mg/day.
Classification of Minerals List
| Macro Minerals (> 100 mg/day) | Micro Minerals (< 100 mg/day) |
|---|---|
| Calcium | Iron |
| Phosphorus | Zinc |
| Magnesium | Copper |
| Sulfur | Iodine |
| Sodium | Fluoride |
| Potassium | Manganese |
| Chloride | Selenium |
| Chromium | |
| Molybdenum |
I-Calcium
- Sources: Milk, milk products, cheese, almonds, green beans, enriched breads and grains, broccoli, soybeans, sardines, oranges, yogurt, okra, and dried apricots are rich sources of calcium.
- Daily Requirements: Adults need 500 mg/day, children about 1200 mg/day. Requirements increase to 1500 mg/day during pregnancy and lactation.
- Absorption & Excretion: Absorption occurs in the duodenum's first and second parts. Calcium absorption requires a carrier protein and energy (calcium-dependent ATPase). Adults excrete 400 mg in the stool and 100 mg through urine.
- Distribution in the body: 99% of calcium is in bones and teeth, 1% is in body fluids and other tissues. Plasma calcium levels range from 9-11 mg/dL.
- Forms: Diffusible Calcium (50% of total serum calcium) is ionized (essential for blood clotting). Non-diffusible calcium is combined with albumin and cannot cross the cell membrane.
-
Functions:
- Strong bones and teeth.
- Aids in muscle contraction.
- Cellular metabolism.
- Neural transmission.
- Plays a key role in blood clotting.
- Normalizes heart rhythm.
- Calcium and Enzymes Activity: Calmodulin is a calcium-binding regulatory protein that binds to 4 calcium ions. Calcium binding activates enzymes, including various regulatory kinases. Other enzymes (e.g., pancreatic lipase, coagulation enzymes, rennin) can be directly activated by calcium without calmodulin's involvement.
-
Factors affecting calcium absorption:
- Enhancers: High protein diet, acidic pH, high dietary lactate or citrate, vitamin D (calcitriol), parathormone
- Inhibitors: Excess fat in the diet, alkalinity, high phosphate, oxalate, and phytates in the diet, vitamin D deficiency, parathormone.
- Regulation: A complex regulatory system maintains normal calcium and phosphate levels in the body. Key hormones include parathyroid hormone (PTH), 1,25-dihydroxycholecalciferol (calcitriol), and calcitonin. These hormones act on the intestinal tract, bone, and kidneys.
II-Phosphorus
- Sources: Milk, milk products, fish, meat, liver, kidney, leafy vegetables, and egg yolks are good sources. Phospho-proteins (e.g., casein in milk, vetillin in eggs).
- Daily Requirements: Adults: 800-1000 mg/day. Pregnant women: 1500-2000 mg/day.
- Absorption: Absorbed by active transport as phosphate.
- Absorption Function: Helps filter waste in the kidneys and stores/releases energy.
- Distribution in the body: 600g of phosphorus is in skeletons (bones/teeth)
- Plasma Phosphorous levels: Normal range is 3-5 mg/dL.
- Relationship with Calcium: Phosphorus and Calcium have an inverse relationship. High phosphorus can cause calcium excretion by the kidneys.
-
Function:
- Bone formation
- Phosphate buffers
- Cellular components (nucleic acids, phospholipids, phosphoproteins, coenzymes, high-energy phosphate compounds).
III-Sodium & Potassium
- Sodium: Affects cardiac muscle activity, maintains heart beat, maintains acid-base balance of the body
- Potassium: Maintains intracellular osmotic pressure, plays a role in protein biosynthesis, transmits nerve impulses.
IV-Iron
- Source: Meat, liver, kidney, nuts, beans, and dates are good sources of iron.
- Requirements: Adults: 10 mg/day. Pregnant/lactating women: 30 mg/day.
- Absorption: Iron absorption occurs in the duodenum and upper jejunum. Diet contains approximately 10-20 mg of iron per day. Only about 10-20% is absorbed.
- Mechanism (Mucosal Block theory): Absorbed as ferrous (Fe++), oxidized to ferric (Fe+++), and combines with apoferritin to form ferritin. Ferritin releases ferrous ions to capillaries, and apoferritin is regenerated based on body needs. Intestinal apoferritin gets saturated with iron, absorption is blocked.
- Iron-containing proteins: Hemoglobin, myoglobin, cytochromes, catalase, peroxidase, Ferritin, transferrin, hemosiderin
-
Factors affecting iron absorption:
- Enhancers: Vitamin C (ascorbic acid), meat, poultry & fish (amino acids), gastric acid, cooking in iron vessels, low body stores of iron.
- Inhibitors: Calcium, some antacids, oxalate (spinach), animal products(milk, egg), tannins (tea, coffee), Zn/Cu containing foods.
Clinical Abnormalities
- Iron Deficiency Anemia: Causes: Decreased intake/absorption, increased loss (hemorrhage, menstruation), increased requirements (pregnancy, lactation), parasitic worm infestations
- Iron Overload: Causes: Repeated blood transfusions, intravenous iron administration. Hemochromatosis: a hereditary disease characterized by abnormal iron absorption. Iron is deposited as hemosiderin in the liver (causing cirrhosis), pancreas (fibrosis, diabetes), and skin (bronze discoloration).
II-Zinc
- Sources: Meat, liver, eggs, seafood, milk, whole-grain cereals
- Absorption: Primarily in the small intestine
- Functions: Essential for growth, reproduction, tissue repair, wound healing; forms a complex with insulin for storage/release in the pancreas
Questions
- Classify minerals
- Enumerate factors affecting calcium absorption
- Function of phosphorus
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Description
Test your knowledge on the classification and functions of minerals in biochemistry. This quiz covers essential topics such as macrominerals and microminerals, their roles in the body, and the signs of deficiency and overproduction. Gain insight into the biochemical significance of minerals for growth and maintenance.
