NURSING ANM AND GNM

NURSING EXAM QUESTIONS

BIOCHEMISTRY

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Aldoses are present in nature in
A
pyranose form
B
furanose form
C
Either A or B
D
None of the above
Explanation: 

Detailed explanation-1: -Pyranose is a chemical structure that is comprised of a ring. The ring is made up of six members that contain 5 Carbon and 1 Oxygen atom.

Detailed explanation-2: -furanose-a cyclic form of an aldose or ketose where the ring contains 5 atoms. The fructose ring in sucrose is a furanose. anomers-cyclic sugars that are isomers which differ in configuration only at C-1.

Detailed explanation-3: -For example, glucose is an aldohexose. When it cyclizes, it forms a pyranose ring. The full description of the alpha anomer of cyclized glucose is “alpha-D-glucopyranose”, also called simply “alpha-D-glucose”. Similarly the beta anomer is referred to as “beta-D-glucopyranose”, also called simply “beta-D-glucose.”

Detailed explanation-4: -In the said molecule, there are two aldehyde groups, one in each unit. So that makes 2 aldoses and zero ketose. Both units are six membered rings called pyranose. There are 2 pyranose and 0 furanose rings.

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