Minerals

Question 1

B9 Functions

Answer 1

• Folate

- Precursor of tetrahydrofolate, coenzyme involved in generating precursors for DNA and protein synthesis

Question 2

B9 Deficiency

Answer 2

• Folate
• Neural tube defects
• Macrocytic anemia
• Hyperhomocysteinemia
• Decreases availability of purines and dTMP inhibiting DNA synthesis

Question 3

B12 Function

Answer 3

• Cobalamin
• Coenzyme in methionine synthesis and in conversion of methylmalonyl CoA to succinyl CoA
• Folate metabolism

Question 4

B12 Deficiency

Answer 4

• Cobalamin
• Pernicious anemia (megaloblastic anemia with demyelination
• Can arise from deficiency in intrinsic factor
• Can be stored efficiently in liver

Question 5

Absorption of B12

Answer 5

• Released from protein by acid hydrolysis in stomach

- Then binds to intrinsic factor to be absorbed by ileum

Question 6

B9/B12 connection

Answer 6

-In the absence of vitamin B12, B9 becomes trapped in a form that cannot be used for purine and dTMP synthesis

Question 7

Cause of macrocytic anemias

Answer 7

• Deficiency in nucleotides leads to decreased DNA and RNA synthesis
• Cells increase in size without dividing
• Do not carry sufficient oxygen

Question 8

Pernicious anemia

Answer 8

-Lack of intrinsic factor

Question 9

Macrominerals important for fluid homeostasis

Answer 9

-Potassium, sodium, chloride

Question 10

Calcium function

Answer 10

-Bone, signaling, coagulation, muscle contraction, neurotransmission

Question 11

Calcium deficiency

Answer 11

-Muscle cramps, osteoporosis, rickets

Question 12

Calcium distribution in the body

Answer 12

• 98% is in bone and teeth in the form of hydroxyapatite
• Bone is the body’s calcium reservoir
• 2% is in the rest of the body

Question 13

Magnesium functions

Answer 13

• Essential for enzymes that use MgATP as substrate

- Present at high levels in bone, required for formation

Question 14

Magnesium deficiency

Answer 14

• Weakness, tremors, cardiac arrhythmia

- Required for many transporters that requires MgATP or MgADP as substrate.

Question 15

Phosphorus functions

Answer 15

• Mostly present in phosphates
• Major component of bone (hydroxyapatite)
• Part of nucleic acids, membrane lipids
• Required in all energy-producing reactions

Question 16

Phosphorus deficiency

Answer 16

• Rare

- Rickets, muscle weakness, muscle breakdown, seizure

Question 17

Iron functions

Answer 17

• O2/CO2 transport in hemoglobin
• Oxidative phosphorylation
• Cofactor in several nonheme iron proteins and cytochromes

Question 18

Iron deficiency

Answer 18

• Microcytic anemia

- Decreased immunity

Question 19

Reduction of iron

Answer 19

• Fe3 reduced to Fe2 by vitamin C
• Low pH released Fe3 from ligands
• Usually bound to carriers

Question 20

Two major barriers of iron absorption

Answer 20

• Release of Fe3 from food

- Availability of reducing agent to convert Fe3 to Fe2

Question 21

Transferrin

Answer 21

-Iron transport

Question 22

Ferritin

Answer 22

-Iron storage

Question 23

Hepcidin

Answer 23

• Signals iron sufficiency

- Prevents export of Fe2 from the duodenal mucosal cell by downregulating the exporter

Question 24

Iron toxicity

Answer 24

• Long term: hemochromatosis- iron overload leads to iron deposits in tissues and lactic acidosis due to compromised mitochondrial function
• Acute: iron overdose in children
• Can replace other metals in reactions

Question 25

Copper functions

Answer 25

- Assists iron absorption through ceruloplasmin - Cofactor for enzymes required in collagen synthesis, FA metabolism, and elimination of ROS - Helps iron bind transferrin for distribution

Question 26

Copper deficiency

Answer 26

- Rare - Anemia, hypercholesterolemia, fragility of large arteries, bone demineralization, demyelination - Menkes' syndrome or consuming zinc makes patients more susceptible

Question 27

Menkes disease

Answer 27

- Mutations in Cu transporter ATP7A - Presents as a copper-deficiency disorder - Many enzymes secreted without copper

Question 28

Wilson's disease

Answer 28

- Mutations in ATP7B - Results in copper overload - Liver failure and liver cancer

Question 29

Zinc function

Answer 29

- Cofactor for over 300 metalloenzymes | - Structural role in many proteins (zinc fingers)

Question 30

Zinc deficiency

Answer 30

-Poor wound healing, dermatitis, reduced taste acuity, poor growth, impaired sexual development in children

Question 31

Chromium function

Answer 31

-Component of chromodulin: facilitates insulin binding to its receptor

Question 32

Chromium deficiency

Answer 32

-Impaired glucose tolerance

Question 33

Iodine function

Answer 33

- Incorporated into T3 and T4 | - Regulates basal metabolic rate

Question 34

Iodine deficiency

Answer 34

- Goiter | - Hyperthyroidism or hypothyroidism

Question 35

Selenium function

Answer 35

- Component of antioxidant enzymes (glutathione peroxidase) | - Component of deiodinase enzymes involved in T3 and T4 metabolism

Question 36

Selenium deficiency

Answer 36

-Keshan disease: in areas with little selenium in soil