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 : Rhodopsin contains opsin and (A) 11-cis-retinal (B) 11-trans-retinal (C) All-cis-retinal (D) All trans-retinal
Last Answer : Answer : A
Description : The non-protein part of rhodopsin is (A) Retinal (B) Retinol (C) Carotene (D) Repsin
Description : Non-protein part of rhodopsin is (A) Retinal (B) Retinol (C) Carotene (D) Repsin
Description : When light falls on rod cells (A) All-cis-retinal is converted into all-trans-retinal (B) 11-cis-retinal is converted into 11-trans-retinal (C) 11-trans-retinal is converted into all-transretinal (D) 11-cis-retinal is converted into all-trans-retinal
Last Answer : Answer : D
Description : Conversion of all-trans-retinal into alltrans-retinol requires (A) NAD (B) NADH (C) NADP (D) NADPH
Description : Prosthetic group in cone cell phototreceptors is (A) Iodine (B) Opsin (C) 11-cis-retinal (D) all-trans-retinal
Last Answer : Answer : C
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
Last Answer : all above
Description : The following form of vitamin A is used in the visual cycle: (A) Retinol (B) Retinoic acid (C) Retinaldehyde (D) Retinyl acetate
Description : Retinoic acid is involved in the synthesis of (A) Rhodopsin (B) Iodopsin (C) Porphyrinopsin (D) Glycoproteins
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 : Retinoic acid participates in the synthesis of (A) Iodopsin (B) Rhodopsin (C) Glycoprotein (D) Cardiolipin
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 : Retinal is converted into retinoic acid in the presence of (A) Retinal oxidase (B) Retinal carboxylase (C) Retinene reductase(D) Spontaneously
Last Answer : (A) β-Carotene
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 : Retinal is reduced to retinol by retinene reductase in presence of the coenzyme (A) NAD+ (B) NADP+ (C) NADH + H+ (D) NADPH + H+
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 : What is the name given to the non-superimposable mirror image forms of chiral compounds? w) cis-trans x) enantiomers y) functional isomers z) diasteriomers
Last Answer : ANSWER: X -- ENANTIOMERS
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 : 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 : Rod cells possess a trans-membrane protein which is (A) Adenylate cyclase (B) Transducin (C) Rhodopsin (D) B as well as C
Description : Inducers and repressors are (A) Enhancer and silencer elements respectively (B) Trans-acting factors (C) Cis-acting elements (D) Regulatory proteins
Description : Besides structural genes that encode proteins, DNA contains some regulatory sequences which are known as (A) Operons (B) Cistrons (C) Cis-acting elements (D) Trans-acting factors
Description : Folding of newly synthesized proteins is accelerated by (A) Protein disulphide isomerase (B) Prolyl cis-trans isomerase (C) Chaperonins (D) All of these
Description : Which of the statements is false regarding chiral compounds? (a) rotate the plane of polarized light (b) have cis and trans isomers (c) exist as enantiomers (d) can be detected with a polarimeter
Last Answer : have cis and trans isomers
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 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
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 : Which can show the cis-trans isomerism:
Last Answer : Which can show the cis-trans isomerism: A. `CICH_(2)CH_(2)CI` B. `CI_(2)C=C=CH_(2)` C. `CH_(2)C=CCI_(2)` D. CICH=C=CHCI
Description : Which of the following combination of axial & equitorial bonds show Cis or Trans orientation in Dimethyl cyclohexane. (i) 1e, 2e (ii) 1e, 3e (iii) 1e,
Last Answer : Which of the following combination of axial & equitorial bonds show Cis or Trans orientation in Dimethyl cyclohexane. ... 3a (vi) 1e, 4a (vii) 1a, 3a
Description : In which compound, Cis-Trans nomenclature cannot be used?
Last Answer : In which compound, Cis-Trans nomenclature cannot be used? A. `CH_(3)-CH=CH-CH_(3)` B. `CH_(3)-CH=CH-COOH` C. D. `C_(6)H_(5)-CH=CH-CHO`
Description : Cis-trans isomerism is found in square planar complexes of molecular formula: (a and b are monodentate ligands)
Last Answer : Cis-trans isomerism is found in square planar complexes of molecular formula: (a and b are monodentate ligands) A. ` ... . `Ma_(2)b_(2)` D. `Mab_(3)`
Description : Why cis isomers are polar and trans are not?
Last Answer : Need answer
Description : what is indicated by the prefixes cis- and trans-?
Last Answer : The type of stereoisomer
Description : Among Cis and Trans structure of Hex-2-ene which has higher boiling point and why?
Last Answer : Ans: The dipole moment of a molecule depends upon dipole-dipole interactions. Since cis-isomer has higher dipole moment, therefore it has higher boiling point.
Description : Two dominant nonallelic genes are 50 map units apart. The linkage is (a) cis type (b) trans type (c) complete (d) absent/incomplete.
Last Answer : (d) absent/incomplete.
Description : When two genetic loci produce identical phenotypes in cis and trans position, they are considered to be (a) multiple alleles (b) the parts of same gene (c) pseudoalleles (d) different genes
Last Answer : (c) pseudoalleles
Description : What is the term used for isomers that are in rapid equilibrium? (a) keto-enol tautomers (b) constitutional isomers (c) conformational isomers (d) cis-trans isomers
Last Answer : keto-enol tautomers
Description : Predict which of the following alkenes reacts the fastest with HCl? (a) CH3CH2CH2CH2CH=CH2 (b) cis-CH3CH2CH=CHCH2CH3 (c) trans-CH3CH2CH=CHCH2CH3 (d) (CH3)2C=CHCH2CH3
Last Answer : (CH3)2C=CHCH2CH3
Description : What is(are) the product(s) in the Pd-catalyzed hydrogenation of 1,2- dimethylcyclopentene? (a) trans-1,2-dimethylcyclopentane (b) cis-1,2-dimethylcyclopentane (c) a mixture of trans and cis-1,2-dimethylcyclopentane (d) 1,1-dimethylcyclopentane
Last Answer : cis-1,2-dimethylcyclopentane
Description : What is the product when 3-heptyne reacts with the Lindlar catalyst? (a) 2-methyl-2-heptene (b) trans-3-heptene (c) cis-2-methyl-3-hexene (d) cis-3-hexene
Last Answer : cis-3-hexene
Description : Rank the following dienes in order of increasing stability : trans-1, 3-pentadiene, cis-1,3-pentadiene, 1,4-pentadiene and 1,2-pentadiene
Last Answer : 1,2-pentadiene < 1,4-pentadiene < cis-1,3-pentadiene < trans-1,3-
Description : Which of the following is the most stable alkene? (a) trans-3-hexene (b) cis-3-hexene (c) 1-hexene (d) (Z)-3-hexene
Last Answer : trans-3-hexene
Description : Which of the following statements about propene, CH3CH=CH2, is correct? (a) All nine atoms lie in the same plane. (b) The compound has a cis and trans isomer. (c) There is a total of eight sigma bonds. (d) All the carbon atoms are sp2 hybridized
Last Answer : There is a total of eight sigma bonds.
Description : Which of the following compounds will have zero dipole moment? (a) cis-1,2-dibromoethylene (b) 1,1-dibromoethylene (c) trans-1,2-dibromoethylene (d) all of these
Last Answer : trans-1,2-dibromoethylene