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PKM Biochemistry > Vitamins and Minerals > Flashcards

Vitamins and Minerals Flashcards

1
Q

This disease is a result of dietary deficiency of Vitamin C required by prolyl and lysyl hydroxylases.

Symptoms include bleeding gums, swelling joints, poor wound healing and death.

A

Scurvy

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2
Q

This disease is characterized by kinky hair and growth retardation. It is due to dietary deficiency in copper required by ___(enzyme) in cross-linking that strengthens ____ (protein).

A

Menke’s disease

Copper required by lysyl oxidase, which cross links collagen.

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3
Q

Enzymes requiring copper

A

Losers Don’t Take Copper

Lysyl oxidase
Dopamine-b-hydroxylase
Tyrosinase
Cytochrome c oxidase

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4
Q

Deficiency in which vitamin may occur in carcinoid syndrome

A

Niacin.

Shunting of niacin to serotonin synthesis

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5
Q

Deficiency in this mineral along with infection with a virulent strain of Coxsackie virus causes cardiomyopathy

A

Selenium

Disease is called Keshan disease

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6
Q

Deficiency in this vitamin causes spinocerebellar degeneration

A

Vitamin E

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7
Q

Which vitamin is used as a co-enzyme in:
A. Carboxylation reactions
B. Decarboxylation reactions

A

A. Biotin

B. Thiamine

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8
Q

Glutathione peroxidase is an enzyme that contains ___ at the active site

A

Selenocyteine (selenium analogue of cysteine)

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9
Q

This mineral is a component of enzymes, principally oxidases

A

Zinc

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10
Q

Excessive intake of this mineral can interfere with thyroid hormone synthesis

A

Calcium

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11
Q

This mineral is a catalyst in hemoglobin formation; essential in production of RBC and required for absorption of Fe

A

Copper

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12
Q

This mineral is a constituent of enzymes in CO2 exchange and CHON hydrolysis

A

Zinc

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13
Q

This vitamin is essential in the non-oxidative phase of pentose phosphate pathway. It is a co-factor for which enzymes.

A

Thiamine.

Transketolase

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14
Q

This vitamin is part of the fatty acid synthase enzyme complex.

A

Pantothenic acid

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15
Q

Severe burning and aching of the feet, hyperesthesia, and vasomotor changes of the feet that leads to excessive sweating. This syndrome is due to deficiency in ___

A

Pantothenic acid

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16
Q

This vitamin enhances absorption of iron

A

Vitamin C

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17
Q

The earliest sign of Vitamin A deficiency

A

Loss of sensitivity to green light
> Impairment of ability to adapt to dim light
> Night blindness

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18
Q

What is the relationship of Vitamin A with infection?

A

Vitamin A has a role in differentiation of immune cells; deficiency increases susceptibility to infections.

Retinol binding protein is also a negative acute phase protein; lowering vitamin concentration in infection

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19
Q

Calcitriol is able to reduce its concentration by inducing ___ (enzyme) and inhibiting ____.

A

Inducing 24-hydroxylase

Inhibiting 1-hydroxylase

20
Q

Most active of the Vitamin E compounds

A

D-a-tocopherol

21
Q

Vitamin K Quiz

  1. Synthesized by intestinal bacteria
  2. Synthetic compounds
  3. Normal dietary source
A
  1. Menaquinones
  2. Menadione, menadiol
  3. Phylloquinone
22
Q

Thiamine is a coenzyme of which enzymes

A

Pyruvate dehydrogenase
a-ketoglutarate dehydrogenase
Branched chain keto-acid dehydrogenase
Transketolase

23
Q

This vitamin phosphorylates and activates a chloride channel in the nerve membrane

A

Thiamine

24
Q

Accepted index of:

  1. Thiamine nutritional status?
  2. Riboflavin status?
  3. Pyridoxine status?
A

B1:
Activation of apo-transketolase in erythrocyte lysate by thiamine diphosphate.

B2:
Activation of erythrocyte glutathione reductase by FAD added in vitro

B6:
Activation of erythrocyte transaminases

25
Q

Because of its yellow color, it is widely used as an additive

A

Riboflavin

26
Q

What is the formula for the niacin content of foods?

A

mg niacin equivalents = mg preformed niacin + 1/60 (mg tryptophan)

27
Q

The source of ADP ribose for ADP ribosylation of proteins and polyADP-ribosylation of nucleoproteins involved in DNA repair.

A

NAD

28
Q

Carcinoid syndrome is characterized by a relative deficiency in this vitamin.

A

High synthesis of 5-hydroxytryptamine accounts for 60% of body’s tryptophan metabolism; diverting the amino acid from NAD synthesis.

29
Q

Pellagra is more common in women. Why?

A

Estrogen metabolites inhibit tryptophan.

30
Q

Consequences of excessive niacin

A

Dilation of blood vessels and flushing
Skin irritation
Liver damage (>500 mg/day)

31
Q

Most of the Vitamin B6 in the body is in ____.

A

Pyridoxal phosphate in muscle, associated with glycogen phosphorylase (80%)

32
Q

This vitamin is the co-factor of glycogen phosphorylase.

A

B6 (Pyridoxal phosphate)

33
Q

This vitamin is a co-factor in transamination and decarboxylation of amino acids

A

B6

34
Q

In deficiency of this vitamin, there is increased sensitivity to the actions of estrogens, androgens, cortisol, and vitamin D.

A

B6. B6 terminates hormone action by removing hormone-receptor complex from DNA binding.

35
Q

Excess of this vitamin is associated with sensory neuropathy

A

Vitamin B6 (2-7 g/day)

36
Q

There is some evidence that this vitamin is effective in treating premenstrual syndrome.

A

Vitamin B6

37
Q

There are no plant sources of this vitamin, making vegans at risk of developing deficiency.

A

Vitamin B12

38
Q

Describe the absorption of folate?

A
  1. Bound to protein in food
  2. In the stomach, it is released from protein by gastric acid and protein and binds to cobalophilin secreted in saliva.
  3. In the duodenum, cobalophilin is hydrolyzed; and vitamin binds to IF.
  4. IF-vitamin complex absorbed in the ileum.
39
Q

What are the three enzymes dependent on Vitamin B12?

A 
1. Methylmalonyl mutase
(Methylmalonyl CoA > Succinyl CoA)
2. Methionine synthase
(Homocysteine > Methionine converting Methyl- to tetrahydrofolate)
3. Leucine aminomutase
40
Q

Synthetic folic acid

A

Leucovorin

41
Q

How does vitamin B12 deficiency lead to folate deficiency?

A

Methionine synthase is Vitamin B12 dependent. This enzyme converts methyl-tetrahydrofolate to the active tetrahydrofolate while converting homocysteine to methionine. With Vitamin B12 deficiency, folate is stuck in inactive ‘methyltetrahydrofolate’ form.

42
Q

Elevated __ which occurs due to folate deficiency leads to increased risk of atherosclerosis, thrombosis and hypertension.

A

Homocysteine

43
Q

A number of studies suggest that folate supplementation can reduce risk of some cancers. How?

A

Low folate results in impaired methylation of CpG islands in DNA, which is associated with increased risk of colorectal and other CAs.

44
Q

Biotin-dependent enzymes

A
  1. AcetylCoA carboxylase
    Acetyl CoA > malonyl Coa
    2.
45
Q

Vitamin C is the coenzyme for 2 hydroxylases.

A
  1. Dopamine b-hydroxylase

2. Peptidylglycine hydroxylase

46
Q

This vitamin is a cofactor of ALA synthase. Used as treatment in sideroblastic anemia.

A

Pyridoxine

PKM Biochemistry (8 decks)

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