TUT 5 Flashcards
(23 cards)
Name the 2 naturally occurring vitamin D forms that are acquired through the diet.
Vitamin D2 and D3
D2= plant-based diet source
D3= animal tissue (cholecalciferol)
Name the active form of vitamin D
1,25-diOH-D3 (cholecalciferol)
Vitamin D & Calcium are important for healthy bones, how do they work together?
Calcium helps build and maintain bones
VItamin D (active form calcitrol) helps body effectively absorb calcium from intestine, reabsorption from kidneys and mobilisation from bone
How safe are antioxidant vitamins
- Safe at an adequate level because they interact at the surface of the membrane to absorb free radicals within their structure
- In excessibe level, may initiate or propagate free radical damage to biomolecules. Can increase iron absorption, trigger inflmmation and can have pro-oxidant effects
- Anti-oxidants safe in short term but not long term
What is beriberi and what causes it?
Beriberi is vitamin B1 deficiency (thiamine deficiency)
- Wet beriberi: cardiovascular, heart failure
- Dry beriberi: nerve damage (paralysis)
What role does Ubiquinol have in the respiratory chain reaction?
Ubiquimol-10 quenches the free radical from sueproxide converting it to oxygen gas
- Also traps free radicals in lipid membranes
- Fat soluble
- Electron carrrier in mitochondria
Describe the structure of glutathione, and outline what is its function?
Glutathione has a 3 amino acid sequences in its reduced form, connected via peptide bonds with an SH group which can form disulphide brdges
- Acts as an intracellular reductant and antioxidant
- Involved in decomposition of hydrogen peroxide into water
- GSH (reduced form) + H202 –> GSSG (oxidized form) + H20
What is the difference between folate and folic acid? Which one is better for human health and why?
Folate= active form
Folate is the naturral form in food and folic acid is the artificial form. >Too much folic acid can can cause cancer
What is Pellagra and how is it caused?
Vitamin B3 deficiency (Niacin deficiency)/ Tryptophan deficiency (tryptophan is a precursor of niacin)
>Dementia, diarrhea, dermatitis
Name 3 macrominerals and 3 microminerals
Macro: Calcium, Phosphorous, Magnesium, Chlorine
Macro: Iron, Copper, Zinc, Manganese
Outline what affects the bioavailability of necessary minerals.
- GI disorders
- Presence of other minerals
- Chelation by other nutrients (fibres)
- Medications interfere with absorption
Name the 3 main ingested antioxidants.
Vitamin C, Vitamin E, Beta carotene (1)
What reaction does superoxide dismutase catalyse and in which compartment in the cell does this occur?
- Occurs in mitochondria
- Superoxide dismutase converts superoxide into hydrogen peroxide and oxygen gas
What does teratogenesis mean? How significant is this when taking vitamins or minerals over the counter and why?
Mother exposes too much harmful vitamins/minerals to the foetus –> cant handle
NOT GENETIC
Which vitamin is the most toxic, considered teratogenic during pregnancy?
Vitamin A – Fat soluble vitamins are more risky.
What is the difference between inorganic and organic arsenic?
Organic form is less toxic than irorganic form of AS
- Inorganic As is found in soils, sediments and ground water
- Organic As forms (As bound to organic molecules) are abundant in seafood (fish and oysters)
How is the bioactivity of retinoic acid different from retinol?
Retinol is converted into retinoic acid
- Retinoic acid PROMOTES growth and differentiation of epithelial cells
- Reitnol can be used for making rhodopsin which is essntial for visual cycle and reproductive system
Give some reacitosn that require vitamin K
- Maturation of blood clotting factos 2,7,9,10
- Chelation of Ca2+
What are the differences between vitamin K1: phylloquinone, vitamin K2: menaquinone and vitamin K3: menadione
K1: phylloquinone, vitamin K2: menaquinone = LIPID SOLUBLE
>K1 from plant deratives (fatty carbon chain)
>K2 from animal derivatives (fatty carbon chain)
K3: menadione = WATER SOLUBLE
>K3 is the synthetic form
Name three major biological functions of Nitric Oxide.
- Vasodilator
- Neurotransmitter
- Promotes exocytosis of insulin
- High levels can cause beta cell destruction and its neurotoxic
What is the role of a macrophage in iron homeostasis?
Phagocytoses dead/injured dead blood cell. Breaks down haemoglobin to haem and globin counterparts. Converts haem to unconjugated billirubin
Ferroportin allows exocytosis of iron
Where in the cell is excess iron stored?
Stored as ferritin proteins in the liver
Where does Hepcidin come from, and what is its role in the body?
- Hepcidin maintains iron homeostasis by regulating the function of ferroportin
- Produced in the liver
- Hepcidin is released from liver in response to inflammatory cytokines namely interleukin-6
- Hepcidin binds to ferroportin –> causes retention of iron in the cell
