Vitamin-A Flashcards
(22 cards)
Inactive form of vitamin A?
Beta carotene.
Compounds having vitamin A activity are called?
Retinoids.
Whose trans variety makes vitamin A1?
Retinal.
How can vitamin A1 can be converted to vitamin A2?
By adding extra double bond in vitamin A1.
Major absorption site of vitamin A?
Intestine.
Which form of Vitamin A is absorbed?
Retinal.
Without which substances vitamin A can’t be absorbed?
Fats and bile salts.
In which form vitamin is stored in liver?
Retinal palmitate.
With which substance trans retinal is transported from liver to peripheral tissues?
Retinal binding protein (RBP).
Membrane protein found in photoreceptor cells of retina ?
Rhodopsin.
Which photosensitive cell is for Dim light?
Rods.
What is rhodopsin of rod made up of?
11-cis retinal + opsin.
How many rods are there per eye?
120 million.
Deficiency of 11-cis retinal will cause?
Dark adaptation time increases.
Night blindness.
Which protein is found in cones?
Conopsin .
Which photosensitive cell is responsible for bright light?
Cones.
Deficiency of cones cause?
Colour blindness.
No. of cones per eye?
6 million.
Which synthetic variant of vitamin A prevents acne ?
Isoretinone.
In which case, conjunctiva becomes dry and get keratinised and leads to keratinisation of cornea?
Xerophthalmia.
In which case, grey- whitish plaques are seen adherent to conjunctiva?
Bitot spots.
If xerophthalmia persists for long term, leads to softening of cornea , what is the diagnosis?
Keratomalacia.
