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18 Nov 2019
The structure of beta-carotene is given below. Compare it to the structure of vitamin A shown in the Introduction section. a. What is the difference between beta-carotene and vitamin A? b. Vitamin A can be derived from B-carotene by cleavage of a double bond. Indicate on the structure which double bond would be cleaved. How many units of vitamin A can you get from one beta-carotene? Why are beta-carotene, retinol, and retinal characterized as conjugated systems? Going from 11-cis-retinol to all-trans-retinal is an isomerization. a. What brings about this conversion? b. What kind of bond is isomerized? c. Propose a mechanism that would allow for the isomerization to take place. Fats in this experiment are hydrolyzed by saponification with base. Why do you hydrolyze with KOH and not with an acid like HCl? In the Procedure section, you are cautioned to use petroleum ether and diethyl ether in the hood and not to have any flames in the laboratory. Why must you exercise these precautions?
The structure of beta-carotene is given below. Compare it to the structure of vitamin A shown in the Introduction section. a. What is the difference between beta-carotene and vitamin A? b. Vitamin A can be derived from B-carotene by cleavage of a double bond. Indicate on the structure which double bond would be cleaved. How many units of vitamin A can you get from one beta-carotene? Why are beta-carotene, retinol, and retinal characterized as conjugated systems? Going from 11-cis-retinol to all-trans-retinal is an isomerization. a. What brings about this conversion? b. What kind of bond is isomerized? c. Propose a mechanism that would allow for the isomerization to take place. Fats in this experiment are hydrolyzed by saponification with base. Why do you hydrolyze with KOH and not with an acid like HCl? In the Procedure section, you are cautioned to use petroleum ether and diethyl ether in the hood and not to have any flames in the laboratory. Why must you exercise these precautions?
Collen VonLv2
14 Jun 2019