Vitamins Flashcards
Vitamins are
organic compound
NOT synthesized in the body
Fat soluble vitamins:
Vitamins A.D.E.K
Water soluble
Vitamins B.C
Precursor of Vit A
beta-carotene
Retinol dehydrogenase
convert retinol into retinal/retinaldehyde
Retinal dehydrogenase
convert retinal into retinoic acid
Benefit of vit A:
Vision and retina, skin, mucous, teeth and skeletal
Retinal (aldehyde) are into 2 forms:
cis and trans
Exposure of light/photons alter
structure of retinal (cis–>trans-retinal)
isomerize/change structure
Photoreceptor of the eyes
rods and cones
Rodds and cones interact with
where
the bipolar layer’s cells
In the outer plexiform layer
The bipolar layer communicate with the the ganglion cells in
the inner plexiform layer
Rods cells responsible to
dim light, black and white vision (Dark adaptation)
in the rod cells disks, it contain:
Rhodopsin
Rhodopsin is made of
retinal and opsin
Light cause a
disrupture of the link of retinal to opsin.
Rhodopsin is which type of receptor:
GPCR
When retinal detach from opsin, it activating the secondary messenger system (GPCR mechanism).
The end result of the messenger:
Closure of Na channels –> Cell hyperpolarization
Rod cell normal function is to
inhibit bipolar cells
Hyperpolarization of rod cell result in
less inhibition = stimulation of ganglion cells = allowed vision in dark.
Lack of retinal in the eye:
No retinal to detach from opsin= no 2e messenger= no configuration change.
Deficiency of Vit. A:
Abnormal function epithelial cells
Impaired immune response
Blindness
Vit D make by skin: UV light react with
7-dehydrocholesterol (an enzyme) —> Vit D3 (Cholecalciferol)
Cholecalciferol (vit D3) is
inactive
Prohormone/provitamin
Liver convert in active form by hydroxylation Vit D3 in:
25-hydroxyvitamin D3
Kidney convert in active form by hydroxylation Vit D3 in:
1,25-dihydrovitamin D3 (metabolite form/active form)
The metabolite (Vit D) binds to
Vit D receptor (VDR) –> heterodimerizes with retinoid X receptor (RXR) –> VDRE –> transcriptional
Vit D upregulate: (4)
Calbindins (bind Calcium in GIT for absorption)
Bone matrix proteins (bone strength)
Osteoblast regulation (synthesize bone)
Synthesis of Type I collagen in bones
Vit D downregulate: (1)
Parathyroid hormone –> decrease calcium resorption from bones.
Rickets condition related to:
Deficiency of Vit D –> Weakening and softening of the bones brought by extreme calcium loss
Kiphotic spine is
bending/curvature in the spine (vertebral collase)
Dark skin people are at risk of Vit D deficiency bc
They have less sunlight penetrating through the melanin protection
Non-classical actions of vit D:
anti-hypertensive, Anti-bacterial, anti-inflammatory
deficiency of vit D increase risk of cardiovasc disease/heart attack
Vitamin E is
mixture of antioxidants and free radical scavengers
Benefits of vit E
Protect cell membrane and tissues from damage by oxidation, aids formation RBC and use of vit K
Vit E deciciency:
Neurological damage, hemolytic anemia.
Vit K is made by:
intestinal bacteria
Vitamin C (also know as:)
ascorbic acid
Precursor of vit C (3-ketol-L-glulonolacgone) can be convert into L-ascorbic acid bc
Enzyme required to convert is not present in human.
Why do we need vit C:
bc we dont have the enzyme required to convert the precursor of vit C into L-ascorbic acid.
VIt C is
antioxydant (act as electron donor)
Vit C benefits
Collagen synthesis
Free radicals end result:
DNA damage
Why Vit C cannot be stored?
Bc Vit C in blood is not protein bound (water-soluble vitamins)
Vit B1 (Thiamine) benefits
Help convert food into energy and aid cardiovasc syst and CNS
Thiamine deficiency:
Beriberi
Vit B3 other name
Niacin
Vit B3 deficiency:
Pellagra
Pellagra symptoms is
3Ds: Dermatitis, Diarrhea, Dementia
Vit B9 other name
folate
Folate is essential for
synthesis of DNA
Folate deficiency
Affect Purine and pyrimidine synthesis (Nucleotide synthesis–> DNA)
Folate deficiency
magaloblastic anemia
Fetal malformation
Vit B12 will bind to
Intrinsic factor
B12-IF complex is release into
the intestine
COndition related to the unability to synthesize Intrinsic Factor (IF):
Pernicious anemia
Vit K is necessary for:
the synthesis of thrombin (prothrombin precursor into prothrombin)
