mnsr 32

Question 1

geometric isomers can be

Answer 1

• cycloalkanes
• substuited alkenes
• square planer or octahedral complexes

Question 2

geometric isomers in alkenes is due to

Answer 2

no free rotation around the c-c double bond , the pi bond would break if rotation occurred

Question 3

the creation of c-c double bond can create 2 possible structure

Answer 3

cis and trans and they must have 2 different groups

Question 4

geometric isomers of alkene can be inter-converted by

Answer 4

• breaking the c-c pi bond
• rotating the omega bond
• reforming the pi bond
• can be done photochemically aka w/ light or thermally aka heat

Question 5

we use the — system if we don’t have 2 identical substuients

Answer 5

E.Z by assigning the highest prioerty
Z: same/ together
E: opposite

Question 6

light enters the — and focused on the — and strikes the —–

Answer 6

pupil, lens, light sensitive detector aka retina located along the inner surface at the back of the eye.

Question 7

cells on the retina responds to light and sends a msg through —- to the —

Answer 7

optic nerve, brain

Question 8

very sensitive to white light and provides night vision

Answer 8

rods

Question 9

provides color information and sharpness

Answer 9

cones

Question 10

11-cis-retinal is a —-

Answer 10

chromophore ( light absorbing group ) consist of penta-ene and aldehyde

Question 11

11-cis- retinal combines w — to give —

Answer 11

opsin protein to produce rhodopsin pigment

Question 12

the primary isomerisation events occurs in

Answer 12

C 11 and C 12 double bond

Question 13

the aldehyde reacting w/ amino group gives
aldehyde is the 11-cis-retinal and the amino group is from the opsin protein

Answer 13

imine/ schiff base

Question 14

when rhopsin absorbs a photon it isomeizes to

Answer 14

all trans configuration without any changes in the protein structure at first

Question 15

rhosodpsin containing all trans configuration is called

Answer 15

bathorhopsin

Question 16

all trans isomers don’t fit in the protein bc of the

Answer 16

rigid elongated structure

Question 17

all trans chromophore adopts a twisted configuration which is

Answer 17

energetically unfavourable, so series of changes occurs to expel the chromophore from the protein

Question 18

when rhodopsin changes its conformation

Answer 18

we’ll have different absorbance characterstics
rhodospsin -> bathrodospin -> lumirdopsin (longest wavelength ) -> metradopsin 1 -> metradospin 2 -> trans retinal ( free and the shortest )

Question 19

when lumirphson undergoes hydrolysis that’ll produce

Answer 19

opsin protein + 11-trans-retinal

Question 20

11-trans-retinal is converted to 11-cis-retinal by

Answer 20

retinal isomerase

Question 21

is a precursor of retinal and is 11-trans-rtinol

Answer 21

vitamin a

Question 22

How is the vitamin a converted to rhodopsin

Answer 22

vitamin a ( retinol dehydrogenase ) -> 11-trans retinal ( retinal isomerase ) -> 11-cis-retinal (+opsin) -> rhodopsin

Question 23

vitamin a can be found in

Answer 23

cod liver oil, eggs, green veggies and carrots that contains b-carotene

Question 24

how to convert b-carotene into vitamin a

Answer 24

b- carotene ( b-cartotene dixogenase ) -> vitamin a

Question 25

b-carotene is converted to vitamin a in

Answer 25

walls of the small intestine ( intestinal mucosa )

Question 26

the retinol formed is stored in the

Answer 26

liver as retinol ester , this is why we take cod liver oil for vitamin a supplement