Vitamins And Minerals Flashcards
What are the macrominerals? (6)
Fe2+, Cu2+, Co, Mn, Mg2+, Ni
What are the microminerals? (4)
Na, K, SO4, PO4
What are organic compounds that are required in the diet for normal function but cannot be synthesized?
Vitamins
What are inorganic nutrients?
Minerals
Name the water soluble vitamins (9)
thiamine, riboflavin, niacin, pantothenic acid, biotin, pryidoxine, folate, vitamin C, B12
Name the lipid soluble vitamins.
Vitamins A, D, E, K (they require bile for absorption)
Name some of the reasons for a vitamin deficiency? (7)
Inadequate dietary intake, absorption, use, increased requirements, excretion, loss of microbial synthesis, and drug induced loss.
What is required for carbonyl transfers?
thiamine
What is the active form of B1?
Thiamine pyrophosphate
How long does it take to deplete liver stores of thiamine?
2 weeks
B2 is required for the synthesis of what two things?
FAD and FMN
B2 = riboflavin
Where is FMN formed? Where is FAD formed?
intestinal mucosa; liver
Riboflavin is a coenzyme in what type of reactions?
oxidation-reduction reactions
Why might a riboflavin deficiency be observed in infants who are under phototherapy for jaundice?
B2 breaks down on exposure to visible light.
Name a few metabolic processes that require riboflavin derivatives. (3)
Kreb’s cycle, FA breakdown, phase 1 detox
What amino acid can be converted into niacin, but is very inefficient (60mg > 1mg)?
tryptophan
What is a precurcor of NAD and NADP?
niacin
NAD and NADP are coenzymes in what type of reactions?
Redox reactions
What are the four D’s associated with pellagra (rough skin)?
dermatitis, diarrhea, menentia, death
Corn based diets are associated with niacin deficiency (pellegra). The native people of the americas prepared maize with ashes from their cooking fires and thus, did not have niacin deficiency. Explain.
The alkalinity of the ashes make the niacin available.
How many steps in the conversion of glucose-6-phosphate to CO2 require NAD?
4 - glycolysis, PDH, Kreb’s (2)
What is the name of B3?
Niacin
Pantothenic acid is a constituent of what?
Coenzyme A
What is the name of B5?
pantothenic acid
What is the active form of B6?
Pyridoxal phosphate (PLP)
Where is PLP absorbed?
Upper GI tract
The major breakdown product of PLP, ____, is formed in the liver.
Pyridoxic acid
PLP is a coenzyme for enzymes that use amino acids as substrates. Name for such reactions.
transaminations, decarboxylations, deaminations, racemizations
What is a coenzyme for glycogen phosphorylase?
PLP
What enzyme reaction might account for peripheral neuropathy and epileptic seizures in severe vitamin B6 deficiency?
Conversion of glutamate to GABA
In what type of reaction is biotin a coenzyme?
carboxylation reactions
Most of the water soluble vitamins are synthesized, at least in small quantities by intestinal bacteria. Which is synthesized this way in large quantities?
Biotin
Biotin is covalently attached to enzymes how?
As a prosthetic group
What protein found in raw egg whites has a high affinity for biotin?
Avidin
What do folic acid derivatives facilitate?
One-carbon transfers
What are the three components of folate?
pteridine ring, glutamate, p-aminobenzoate
What vitamin is especially easily destroyed by cooking?
folate
What is the name of B9?
Folic acid
What is the name of B7?
Biotin
Folate exists in what form in food and in cells?
polyglutamate
Folate exists in what form when absorbed?
monoglutamate
How long can the body store folic acid?
4-6 months
Folate acts as one carbon group carrier. What oxidation states can it carry?
Any other than CO2
Pernicious anemia is caused by malabsorption of what vitamin?
B12
What is the name of B12?
Cobalamin
How many rings does B12 have and what is at the center of them?
3 (aka. corrin ring system) carries cobalt
How and where is B12 absorbed?
In the terminal ileum with IF, which is secreted from gastric mucosa
How does B12 get around in the serum?
Bound to transcobalamin or albumin
Where is the active form of B12 prepared?
liver, bone marrow, reticulocytes
What do the use of propionyl CoA and the methylation of homocysteine to methionine have in common?
They both require B12
Why is B12 malabsorbed leading to pernicious anemia?
There is an absense of IF
How long can stores of B12 las in a strict vegetarian?
3-7 years
Which vitamin is a reducing agent and scavenger of free radicals?
Vitamin C
What is the functional cofactor form of vitamin C?
Ascorbic acid
What is required for the hydroxylation of proline and lysine in the biosynthesis of collagen?
Vitamin C
What vitamin is required for the synthesis of NE and EPI? (and Beta-hydroxylase)
Vitamin C
What vitamin acts as an antioxidant and aids in iron absorption?
Vitamin C
Vitamin C is important in what conversion?
Cholesterol to bile acids
Carnitine synthesis requires how many ascorbate-dependent dioxygenases?
2
What structure does Vitamin C resemble?
Glucose
What are the three active forms of Vitamin A?
Retinal, retinol, retinoic acid
90% of Vit A is stored where?
liver
What is converted to retinol in the intestinal cells?
Carotenoids
What is the storage form of Vitamin A?
Retinol esters with fatty acids
What is a principal role of Vitamin A
Absorption of light in the visual system
What does retinoic acid act like?
A lipid-soluble hormone
Beside maintenance of vision what does Vitamin A do?
Maintenance of reproduction, promotion of growth, and differentiation and maintenance of epithelial tissue and gene expression
How is Vitamin A transported from the liver to its target tissue?
Bound to a binding protein
What vitamin is a prohormone?
Vitamin D
What is the name of Vitamin D3?
Cholecalciferol
What is the name of vitamin D2?
Ergocalciferol
Where is D3 synthesized and how?
In the deep layer of the skin in response to ultraviolet radiation (UVB rays 290-315nm)
Cholecalciferol is hydroxylated where?
In the liver
Where is 25-hydroxyVitaminD hydroxylated?
Kidneys
What is the active form of Vitamin D?
1,25-dihydroxyVitaminD
What vitamin is a potent regulator of Calcium metabolism?
D
Active forms of vitamin D are sterol hormones that diffuse through what?
Plasma membranes
What is required for Vitamin D absorption from the GI tract?
Bile
What is the half-life of both 25-hydroxy- and unhydroxylated cholecalciferol?
30 days
What is the half-life of 1,25-dihydroxyVitaminD
4-6 hours
