Description : Non-protein part of rhodopsin is (A) Retinal (B) Retinol (C) Carotene (D) Repsin
Last Answer : Answer : A
Description : On exposure to light rhodopsin forms (A) All trans-retinal (B) Cis-retinal (C) Retinol (D) Retinoic acid
Description : Retina contains this photo sensitive pigment. (A) Rhodopsin (B) Opsin (C) Retinol (D) Malanin
Description : Retina contains this photosensitive pigment: (A) Rhodopsin (B) Opsin (C) Retinol (D) Melanin
Description : The retinal pigment epithelium cells: a. esterify and store excess retinol b. transport retinol binding protein from blood to subretinal space c. are secured laterally to each other by tight junction d. all above
Last Answer : all above
Description : Which one of the following statements is not correct? (a) Retinal is the light absorbing portion of visual photopigments. (b) In retina the rods have the photopigment rhodopsin while cones have three ... a derivative of vitamin C. (d) Rhodopsin is the purplish red protein present in rods only.
Last Answer : (c) Retinal is a derivative of vitamin C.
Description : One international Unit of vitamin A is the activity present in (A) 0.3 µg of β-Carotene (B) 0.3 µg of retinol (C) 0.6 µg of retinoic acid (D) All of these
Last Answer : Answer : B
Description : Anti-oxidant activity is present in (A) β-Carotene (B) Retinol (C) Retinoic acid (D) All of these
Description : Retinal is reduced to retinol by retinene reductase in presence of the coenzyme (A) NAD+ (B) NADP+ (C) NADH + H+ (D) NADPH + H+
Last Answer : Answer : C
Description : Conversion of all-trans-retinal into alltrans-retinol requires (A) NAD (B) NADH (C) NADP (D) NADPH
Last Answer : Answer : D
Description : Rhodopsin contains opsin and (A) 11-cis-retinal (B) 11-trans-retinal (C) All-cis-retinal (D) All trans-retinal
Description : Retinal is a component of (A) Iodopsin (B) Rhodopsin (C) Cardiolipin (D) Glycoproteins
Description : Retinol and retinal are interconverted requiring dehydrogenase or reductase in the presence of (A) NAD or NADP (B) NADH + H+ (C) NADPH (D) FAD
Description : Retinal is reduced to retinol in intestinal mucosa by a specific retinaldehyde reductase utilising (A) NADPH + H+ (B) FAD (C) NAD (D) NADH + H+
Description : Conversion of β-carotene into retinal requires the presence of (A) β-Carotene dioxygenase (B) Bile salts (C) Molecular oxygen (D) All of these
Description : Good vision depends on adequate intake of carotene rich food. Select the best option from the following statements. (1) Vitamin A derivatives are formed from carotene. (2) The photopigments are embedded in the membrane discs of the inner ... (1) and (3) (c) (2), (3) and (4) (d) (1) and (2)
Last Answer : (b) (1) and (3)
Description : Good vision depends on adequate intake of carotene rich food : Select the best option from the following statements : (a) Vitamin A derivatives are formed from carotene (b) The photopigments are embedded in the membrane discs of the inner segment ... (a) and (c) (3) (b), (c) and (d) (4) (a) and (b)
Last Answer : (1) (a), (c) and (d)
Description : In the chemistry of vision in mammals, the photosensitive substance is called (a) rhodopsin (b) melanin (c) sclerotin (d) retinol.
Last Answer : (a) rhodopsin
Description : The ability of the eye to see in the dark, is due to the production of a purple pigment known as (1) Carotene (2) Rhodopsin (3)Iodopsin (4) Retinene
Last Answer : (4) Retinene Explanation: Retinene-1 is better known as retinaldehyde or simply retinal and is fundamental in the transduction of light into visual signals in the photoreceptor level of the retina (known as the visual cycle). Retinene-2 is more formally known as dehydroretinaldehyde.
Description : The ability of the Eye to see in the dark, is due to the production of a purple pigment known as----? A. Carotene B. Rhodopsin C. Iodopsin D. Retinene (Answer)
Last Answer : D. Retinene (Answer)
Last Answer : (A) β-Carotene
Description : The ability of the eye to see in the dark, is due to the production of a purple pigment known as (1) Carotene (2) Rhodopsin (3) Iodopsin (4) Retinene
Last Answer : Retinene
Description : The following conditions are required for rhodopsin regeneration: a. NADPH b. darkness c. splitting of all trans-retinal from the opsin d. all above
Description : When a photon strikes the rhodopsin: a. bleaching occurs b. retinal molecules are bound to rhodopsin c. the intracellular cGMP is increased d. the sodium ion channels are closed
Last Answer : the sodium ion channels are closed
Description : The retinal pigment epithelium (RPE): a. is sensitive to hypervitaminosis A b. isomerizes all-trans-retinal to 11-cis-retinol c. does not undergo mitosis in response to injury d. secrets the outer layer of the basal lamina that forms the Bruch's membrane.
Last Answer : isomerizes all-trans-retinal to 11-cis-retinol
Description : Photosensitive compound in human eye is made up of (a) opsin and retinol (b) transducin and retinene (c) guanosine and retinol (d) opsin and retinal.
Last Answer : (d) opsin and retinal.
Description : Retinol and Retinol binding protein are bound with this protein: (A) Albumin (B) Prealbumin (C) α-globulin (D) β-globulin
Description : Retinol and retinol –binding protein (RBP) bound with this protein: (A) Albumin (B) Prealbumin (C) α2-globulin (D) β-globulin
Description : Rod cells possess a trans-membrane protein which is (A) Adenylate cyclase (B) Transducin (C) Rhodopsin (D) B as well as C
Description : Retinol is transported in blood bound to (A) Aporetinol binding protein (B) α2-Globulin (C) β-Globulin (D) Albumin
Description : cAMP is so called because it is formed during (A) TCA cycle (B) Urea cycle (C) Rhodopsin cycle (D) It has a cyclic structure
Description : The following form of vitamin A is used in the visual cycle: (A) Retinol (B) Retinoic acid (C) Retinaldehyde (D) Retinyl acetate
Description : Which of the following statements regarding Vitamin A is true? (A) It is not an essential Vitamin (B) It is related to tocopherol (C) It is a component of rhodopsin (D) It is also known as Opsin
Description : Dictary deficiency of this vitamin leads to night blindness: (A) Retinol (B) Niacin (C) Ascorbic acid (D) Cholecalciferol VITAMINS 125
Description : Retinol is transported to the blood as retinol attached to (A) α1-globulin (B) α2-globulin (C) β-globulin (D) γ-globulin
Description : Retinoic acid is involved in the synthesis of (A) Rhodopsin (B) Iodopsin (C) Porphyrinopsin (D) Glycoproteins
Description : Retinol isomerase is present in (A) Retina (B) Liver (C) Both (A) and (B) (D) None of these
Description : Both Wernicke’s disease and beriberi can be reversed by administrating (A) Retinol (B) Thiamin (C) Pyridoxine (D) Vitamin B12
Description : Dicoumarol is antagonist to (A) Riboflavin (B) Retinol (C) Menadione (D) Tocopherol
Description : Retinoic acid participates in the synthesis of (A) Iodopsin (B) Rhodopsin (C) Glycoprotein (D) Cardiolipin
Description : Milk is poor in (A) Cholesterol (B) Retinol (C) Calcium (D) Iron
Description : Milk is a good source of (A) Proteins, calcium and iron (B) Proteins, calcium and ascorbic acid (C) Proteins, lactose and retinol (D) Proteins, lactose and essential fatty acids
Description : Sodium fluorescein: a. has a higher affinity for plasma protein than indocyanine green. b. does not leak from the choroidal vasculature. c. does not leak from normal retinal vasculature. d. emits light of longer wavelengths than the one it absorbs
Last Answer : does not leak from normal retinal vasculature.
Description : During phototransduction: a. hyperpolarisation occurs due to closure of the sodium channels b. 11-cis-retinal molecules are converted to all-trans-retinal c. transducin, a G protein converts GDP to GTP d. all above
Description : The following are true about dark adaptation: a. only regeneration of rhodopsin is responsible b. adaptation usually takes about 20 minutes c. dilatation of pupil plays a part in dark adaptation d. it is better with the fovea than the peripheral retina
Last Answer : dilatation of pupil plays a part in dark adaptation
Description : Which is a pro vitamin or vitamin that has antioxidant properties? (A) Beta carotene (B) Vitamin E (C) Vitamin C (D) Vitamin D
Description : Two molecules of vitamin A can be formed from 1 molecule of (A) α-Carotene (B) β-Carotene (C) γ-Carotene (D) All of these
Description : Precursor of Vitamin A is (A) α-Carotene (B) β-Carotene (C) γ-Carotene (D) All of these VITAMINS 121
Description : The molecule of vitamin A1 contains (A) Benzene ring (B) β-Ionone ring (C) β-Carotene ring (D) None of these
Description : β-Carotene, precursor of vitamin A, is oxidatively cleaved by (A) β-Carotene dioxygenase (B) Oxygenase (C) Hydroxylase (D) Transferase