What is a vitamin and in what amounts are they needed?
Vitamins are essential organic substances needed in minute amounts to activate highly specific metabolic functions in the body
Why are vitamins accessory nutrients?
Because they themselves supply no energy and form no structures but their deficiencies can be dangerous as well as toxic if some are in excess
What are vitamins that must be consumed called?
What are vitamins that may be synthesised by the body using precursors called?
Vitamins can be classified, what are the two sub divisions?
Water soluble vitamins and lipid soluble vitamins
How would you describe water soluble vitamins?
They are not stored in any tissues and excess is removed in urine
Examples of some water soluble vitamins would include?
b1, b2, b3, b5, b6, b9, b12, vitamin c, biotin (vit h)
Where are lipid soluble vitamins stored and can they be removed?
They are stored in the liver and adipose. The body has no way of removing them until they are used.
Give some examples of some lipid soluble vitamins
Vitamins a, d, e and k
Of the vitamins that are ingested, where do the majority originate from?
From plant sources (except b12) as byproducts of photosynthesis
Give two examples of pro vitamins and from what they are synthesised
carotene --> vitamin a ultraviolet light --> vitamin d
What are most vitamins converted into, for use inside the body? What is one of their main roles?
Most vitamins are converted into coenzymes - b12
Some vitamins such as vitamin d and some metabolites of vitamin a have a different role other than coenzymes, what can they do?
They act more like hormones, binding to receptors and controlling gene expression and metabolism
Some vitamins such as vit c and vit e act as ______, not as coenzymes or the control of gene expression and metabolism
What is the role of antioxidants
Preventing or delaying some types of cell damage
What is a coenzyme?
A coenzyme is a non protein compound that is necessary for the functioning of an enzyme
Some coenzymes allow the substrate to react more readily, give some vitamin derivatives that allow this
CoA, pyridoxal phosphate, thiamin diphosphate and vitamin b12
There are some oxidative coenzymes, what are these
NAD+, NADP+, FAD, lipoic acid
What is the function of oxidative coenzymes?
To carry hydrogen atoms or electrons
What is the protein part of the enzyme called?
When the protein part of the enzyme is in combination with the coenzyme the catalytically competent enzyme is known as what?
As the holoenzyme
Apoenzyme + coenzyme =
Vitamin b1 is
vitamin b2 is
vitamin b3 is
vitamin b5 is
vitamin b6 is
vitamin b9 is
vitamin b12 is
vitamin c is