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Minerals
MODULE
Biochemistry
Notes
MINERALS
11.1 INTRODUCTION
Minerals are indispensable part of a complete diet of farm animals. In this unit, dietary essential minerals functions, factors affecting the requirements and sources will be discussed. Minerals are essential for the normal growth and maintance of the body. If the daily requirement is more than 100mg/day they are called major elements and if the daily requirements is less than 100mg/day they are called minor elements. The roles of minerals and vitamins in the maintenance of homeostatic balance and mediation of metabolic reactions in the skeleton, tissues, body fluids, digestive juices, etc.
OBJECTIVES
After reading this lesson, you will be able to:
z classify minerals
z describe the functions, Daily requirements of minerals
11.2 CALCIUM
Total calcium in the human body is 1 to 1.5kg, out of which 99% is seen in bone and 1% in extracellular fluid. The main source of calcium is milk. But in India cereals is major source of calcium. The daily requirement of calcium for child is 1200mg/day and for adult it is 500mg/day. During pregnancy /lactation the calcium requirement is 1500mg/day.
The absorption of calcium takes place in 1 st^ and 2 nd^ part of deuodenum. Calcium absorption requires carrier protein, helped by Ca2+^ - dependent ATpase.
Factors responsible for increase in calcium absorption include Vitamin D, Parathyroid hormone, acidity and amino acids. Factors such as phytic acid,oxalates,
MODULE Minerals
Biochemistry
Notes
malabsorption syndromes and Phosphates decreases calcium absorption. The normal calcium level in blood is 9-11mg/dl.
11.2.1 Function of Calcium The major functions of calcium are
(a) Excitation and contraction of muscle fibres needs calcium. The active transport system utilizing calcium binding protein is called Calsequestrin. Calcium decreases neuromuscular irritability. (b) Calcium is necessary for transmission of nerve impulse from presynaptic to postsynaptic region. (c) Calcium is used as second messenger in system involving protein and inositol triphosphate. (d) Secretion of insulin, parathyroid hormone, calcium etc, from the cells requires calcium. (e) Calcium decrease the passage of serum through capillaries thus, calcium is clinically used to reduce allergic exudates. (f) Calcium is also required for coagulation factors such as prothrombin. (g) Calcium prolongs systole. (h) Bone and teeth contains bulk quantity of calcium.
11.2.2 Factors regulating blood calcium level The factors regulating the blood calcium level includes
(i) Vitamin D (a) Vitamin D and absorption of calcium: Active form of calcium is calcitriol. Calcitriol enters intestinal wall and binds to cytoplasmic receptor and then binds with DNA causes depression and consequent transcription of gene code for calbindin. Due to increased availability of calbindin, absorption of calcium increases leading to increased blood calcium level. (b) Vitamin D and Bone: Vitamin D activates osteoblast, bone forming cells & also stimulates secretion of alkaline phosphatase. Due to this enzyme, calcium and phosphorus increase. (c) Vitamin D and Kidney: Calcitriol increase reabsorption of calcium and phosphorus by renal tubules.
MODULE Minerals
Biochemistry
Notes
INTEXT QUESTION 11.
- The total calcium range in human is .................
- Calcium absorption requires ................. dependent ATpase. (a) Ca (b) Mn (c) Mg (d) fe
- Factors responsible for increase in calcium absorption include .................
- When plasma Ca 2+^ level is more than 11mg/dl is called ................. (a) Hypercalcemia (b) Anemia (c) Fluorosis (d) Selenosis
11.3 PHOSPHORUS
Total body content of phosphorus is 1 kg. Bone posses 80 % of total phosphorus and muscle contains 10 % of total phosphorus. Human body requires 500 mg of phosphorus per day. Milk is the good source of phosphorus and it contains about 100 mg/dl of phosphrous. Apart from milk, cereals, nuts and meat are moderate sources of phosprous.
Serum level of phosphate is 3-4 mg/dl for adults and 5-6 mg/dl in children. Consumption of calcitriol increases phosphate absorption.
11.3.1 Functions of phosphorus (a) Plays key role in formation of tooth and bone (b) Production of high energy phosphate compounds such as ATP, CTP, GTP etc., (c) Synthesis of nucleotide co-enzymes such as NAD and NADP (d) Formation of phosphodiester backbone structure for DNA and RNA synthesis Hypophosphatemia is the condition which leads to decrease in absorption of phosphorus. Further it leads to hypercalcamia, chronic alcoholism and increased excretion of urinary phosphate. In case of hyperphosphatemia, increase in absorption of phosphate was noticed. Hyperphosphatemia leads to cell lysis, hypocalcemia and thyrotoxicosis.
INTEXT QUESTIONS 11.
- Bone posses ................. % of total phosphorus.
- Serum level of phosphate is ................. mg/dl for adults. (a) 4-8 (b) 3-4 (c) 8-9 (d) 1-
- ................. plays key role in formation of tooth and bone
Minerals MODULE Biochemistry
Notes
11.4 MAGNESIUM
Optimal level of Magnesium for human consumption ranges 300-400 mg/day. The main source of Magnesium includes cereals, beans, leafy vegetables and fish. The normal serum level of Magnesium is 1.8 to 2.2. mg/dl.
11.4.1 Functions of Magnesium
(a) Irritability of neuromuscular tissues is lowered by Magnesium
(b) Magnesium deficiency leads to decrease in Insulin dependent uptake of glucose
(c) Magnesium supplementation improves glucose tolerance
Decrease in Magnesium content leads to the condition called as hypomagnesemia. It causes increase in urinary loss. Causes such as liver cirrhosis, protein calorie malnutrition and hypo para thyroidism leads to hypomagnesemia. Increase in the level of Magnesium is called as hypermagnesemia. The main causes of hypermagnesemia includes renal failure, hyper para thyroidism, rickets, oxalate poisoning and multiple myeloma.
INTEXT QUESTIONS 11.
- Optimal level of ................... for human consumption ranges 300-400 mg/ day.
- Irritability of neuromuscular tissues is lowered by ...................
- Magnesium supplementation improves ................... tolerance
(a) lactose (b) glucose (c) toxin (d) microbial
11.5 IRON
Total body content of iron is 3 to 5 gm out of which 75 % is recorded in blood and rest of them are recorded from liver, spleen, bone marrow and muscle. The normal limit for iron consumption is 20 mg/day for adults, 20-30 mg/day for children and 40 mg/day for pregnant women. The main source of iron is jaggery. Other source of iron includes leafy vegetables and meat etc., Milk is considered as a poor source of iron.
11.5.1 Factors influencing absorption of iron
Iron is absorbed by upper part of duodenum and is affected by various factors
(a) Only reduced form of iron (ferrous) is absorbed and ferric form are not absorbed
Minerals MODULE Biochemistry
Notes
(e) Chronic blood loss
(f) Nephrosis
(g) Lead poisoning
INTEXT QUESTION 11.
- Match the following
Adults 20 - 30 mg/day Children 40 mg/day Pregnant women 20 mg/day
- .................. is the most common nutritional deficiency disease
- The transport form of iron in blood is ..................
11.6 COPPER
Total human body contains about 100 mg of copper and are encountered in muscle, liver, bone marrow, brain, kidney, heart and in hairs. Enzymes such as cytochrome oxidase, tyrosinase, lysyl oxidase, allanine synthase, monoamine oxidase, superoxide dismutase and phenol oxidase contains copper. The normal copper limit for human are 1.5 to 3 mg/day. The main sources of copper are cereals, meat, liver, nuts and green leafy vegetables. From the total dietary copper only 10% are absorbed. Copper are mainly excreated through bile. The normal serum level of copper is 25 to 50 mg/dl.
11.6.1 Functions of copper
(a) Copper is necessary for iron absorption and incorporation of iron into hemoglobin.
(b) It is very essential for tyrosinase activity
(c) It is the co-factor for vitamin C requiring hydroxylation
(d) Copper increases the level of high density lipo protein and protects the heart
11.6.2 Abnormal metabolism of copper
The abnormal metabolism of copper leads to Wilson’s disease and Menke’s kidney hair syndrome.
(a) Wilson’s disease
In case of Wilson’s disease ceruloplasmin level in blood is drastically reduced. The incidence of Wilson’s disease is noticed for 1 in 50,000 populations. The
MODULE Minerals
Biochemistry
Notes
defect in a gene encoding copper binding ATPase of liver cells leads to Wilson’s disease. Wilson’s disease leads to
(i) Accumulation of copper in liver leads to hepatocellular degeneration and cirrhosis (ii) Deposition of copper in brain basal ganglia leads to leticular degeneration (iii) Copper deposits as green pigmented ring around cornea and the condition is called as Kayser-Kleischer ring Over accumulation of copper can be treated by consumption of diet containg low copper and injection of D-penicillamine, which excretes copper through urine.
(b) Menke’s kidney hair syndrome It is X-linked defect. In this condition copper is absorbed by GI tract, but cannot be transported to blood. The defect in transport of copper to blood is due to absence of an intracellular copper binding ATPase, which is due to mutation in gene encoding them.
INTEXT QUESTIONS 11.
- Total human body conatins about ................. mg of copper (a) 100 (b) 200 (c) 300 (d) 400
- Menke’s kidney hair syndrome is ................. linked defect.
- Deposition of copper in ................. leads to leticular degeneration
11.7 ZINC
The daily requirement of Zinc for human consumption ranges 10mg /day. The major sources of Zinc includes grains, beans, nuts cheese, meat and shellfish. The normal serum level of Zinc in human is 100mg/day. In the human total body the content of Zinc is 2gm, out of which 60 % is encountered in skeletal muscle and 30% in bones highest concentration is seen in hippocampus area of brain and prostatic secretion.
More than 300 enzymes in human body are zinc-dependent; some of them are carboxypeptidase, carbonic anhydrase, alkaline phosphatase, lactate dehydrogenase, alcohol dehydragenase. The enzyme RNA polymerase, which is required for transcription, contains zinc and it is essential for protein bio synthesis.
MODULE Minerals
Biochemistry
Notes
highest in adult. It is very necessary for normal development and maturation of sperm.
Selenium toxicity could be termed as selenosis. The toxicity symptoms include hair loss, falling of nails, diarrhea, weight loss and garlicky odor in breath.
INTEXT QUESTIONS 11.
- The normal limit of Selenium for human consumption is ............... mg/day
- Glutathione peroxides is a .................. dependent enzyme
11.10 MANGANESE
The normal limit of Manganese for human is 5mg/day. The major source of Manganese are nuts. In metabolism, its absorption is inhibited by iron. In blood, it binds with transmanganin and excreted through bile.
INTEXT QUESTIONS 11.
- The major source of Manganese is ..................
- Manganese are excreted through ..................
WHAT HAVE YOU LEARNT
z In this lesson you have learnt about the importance and types of clinically significant mineral elements. z Mineral elements are solid crystalline, chemical elements that cannot be decomposed and synthesized by ordinary chemical reactions. z They are present in both plants and animals to execute specific functions and the amount to be required is largely determined by certain inherent factors. z Minerals although nutritionally required in smaller amounts are essential for maintenance and production purposes. However the major and trace minerals are needed by the body in large and small amount respectively. z Generally, deficiencies of most minerals are shown by a reduced appetite and production, slow growth and occasionally death.
Minerals MODULE Biochemistry
Notes
TERMINAL QUESTIONS
- Write a short note on minerals?
- What are the elements of major and minor minerals?
- Write a note on calcium and its finctions?
- What are the functions of phosphorous?
- Narrate the importance of iron?
ANSWERS TO INTEXT QUESTIONS
- 1 to 1.5 kg
- Ca
- Vitamin D
- Hypercalcemia
- Phosphorus
11.
- 300 to 400
- Magnesium
- Glucose
11.
- Adults 20 mg/day
Children 20 – 30 mg/day Pregnant women 40 mg/day
- Anemia
- Transferin
