Trace Elements

Question 1

List the structures of iron and describe where they’re found

Answer 1

Iron exists in 2 forms:
i) essential or functional iron and ii) in the storage form.
Essential or function iron.
It is found in:
1. hemoproteins such as myoglobin and hemoglobin.
2. Enzymes that use iron as a cofactor such as xanthine oxidase in purine catabolism, and Acyl CoA dehydrogenase in beta oxidation
ii) Storage.
There are 2 types ferritin and hemosiderin
1. Ferritin is found in the blood liver, spleen and bone marrow. Ferritin is made up of the protein apoferritin to which is bound the iron.
2. Hemosiderin. This is seen in iron overload when there is excess iron in the body

Question 2

Describe the metabolic role of iron

Answer 2

Dietary Iron is absorbed from the small intestines and it transported through the blood bound to the glycoprotein transferrin

Question 3

State the recommended daily requirements and sources of iron

Answer 3

Recommended Daily requirements.
10 to 20mg/day.
Sources
Animal source: meat, fish, liver, spleen, red marrow.
Plant source: cereals, legumes and nuts.

Question 4

Describe the clinical conditions associated with iron deficiency

Answer 4

Iron deficiency: it causes a hypochromic microcytic anemia.
It is commonly seen in women due to loss of blood during menstruation, in people with tape worms, in pregnant women and children. These groups of populations require more in in the diet. The pregnant women are given iron supplements to prevent them from getting iron deficiency anemia.

Question 5

Describe the clinical conditions associated with iron overload

Answer 5

Iron overload. There are 2 types hemochromatosis and hemosiderosis..
Hemochromatosis: There is accumulation of ferritin and hemosiderin in the liver and skin due to defect in regulation of iron absorption.
Hemosiderosis: this is seen in areas where food is prepared in rusty iron pots and it leads to increased intake of iron in the body. Common among the Bantu speaking populations in Africa hence the name Bantu hemosiderosis.

Question 6

Describe the chemical structure and metabolic role of copper

Answer 6

Chemical nature: Mainly in the form of copper oxide
Metabolic role: copper is absorbed from gut and is bound to celuroplasmin. Copper is a cofactor in enzymes such as cytochrome oxidase in the ETC, catalase ,mono amino oxidase( MAO). It also plays a role in iron metabolism by facilitating its incorporation in transferrin

Question 7

State the recommended daily requirements and sources of copper

Answer 7

Recommended daily requirements: 2 -4 mg/day
Sources: Animal: meat Plant: Legumes, nuts, cereals

Question 8

What clinical conditions are associated with copper?

Answer 8

1. Deficiency causes a hypochromic microcytic anemia due to its role in the incorporation of iron to transferrin.
2. Wilson disease. This is an autosomal recessive inherited disease condition . There is retention of copper in the liver, brain, kidney which can cause hepatic cirrhosis.

Question 9

List the trace elements used as cofactors and their corresponding enzymes

Answer 9

ZINC: It is a cofactor for alcohol dehydrogenase, glutamate dehydrogenase, lactate dehydrogenase, carbonic anhydrase, carboxypetidase.
MAGNESIUM: It is a cofactor in kinases, ribonucleases.
MANGANESE: It is a cofactor for pyruvate carboxylase and acetyl CoA carboxylase.
COBALT: It is found in the structure of vitamin B12 in the prosthetic group
SELENIUM: It is a cofactor in glutathione peroxidase