Question

What is cis-form and trans-form

Answer 1

these are the forms of isomers these type of isomers are called geomatrical isomers in the cis type isomers the two element make angle of 109 and in trans they make 180

Answer 2

Vision involves the isomerization of 11-cis-retinal to all-trans-retinalExplanation:

There are three steps in generating a visual signal.

(a) Isomerization of retinal

When a photon hits a rod or cone cell, a π electron is excited to a higher energy level.

This breaks the  

C=C

double bond between  

C11

and  

C12

and allows rotation to form the all-trans isomer.

(b) Protein conformational changes

The 11-cis-retinal is bound to a protein.

When the 11-cis- retinal isomerizes to the all-trans form, its new shape no longer fits the protein.

It adopts an energetically unfavourable conformation, and this triggers a series of changes to expel it from the protein.

(c) Generation of nerve impulses

One of the intermediates formed during the expulsion of all-trans-retinal activates an enzyme that triggers a series of biochemical reaction, ultimately producing a nerve impulse to the brain.