Tag: biomolecules

Quizzes (11) Questions (140)

Questions Related to biomolecules

Multiple choice carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

In fructose and glucose the possible optical isomers are:

  1. 12, 12

  2. 8, 16

  3. 16, 8

  4. 4, 12
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Fructose contains three chiral carbon atom and glucose contain 4 chiral carbon atoms.
The Number of possible Optical isomers for Fructose are ${2}^{3} = 8$
The Number of possible Optical isomers for Glucose are ${2}^{4} = 16$
8, 16 is the Answer
Multiple choice carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

The $\alpha$- D glucose and $\beta$- D glucose differ from each other due to difference in carbon atom with respect to its

  1. Number of $OH$ groups

  2. Size of hemiacetal ring

  3. Conformation

  4. Configuration
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Alpha and beta D-glucose are anomers, which are a type of stereoisomer that differ specifically in the configuration at the anomeric carbon (C-1).

Multiple choice carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

What is the nature of glucose-glucose linkage in starch that males its so susceptible to acid hydrolysis?

  1. Starch is hemiacetal

  2. Starch is acetal

  3. Starch is polymer

  4. Starch contain only few molecules of glucose
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Starch contains acetal linkages (glycosidic bonds) between glucose units. Acetals are acid-labile and readily hydrolyze by acid. Hemiacetals are more reactive but acetals are stable to base but hydrolyzed by acid, making starch susceptible to acid hydrolysis.

Multiple choice carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

${ C } _{ 12 }{ H } _{ 22 }{ O } _{ 11 }\longrightarrow 12C+{ 11H } _{ 2 }{ O }$ in presence of concentrated ${ H } _{ 2 }{ SO } _{ 4 }$.

Which of the following is obtained in the above reaction?

  1. Animal charcoal

  2. Sugar charcoal

  3. Coke

  4. Wood charcoal
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The dehydration of sucrose (C12H22O11) by concentrated sulfuric acid leaves behind a porous black mass of carbon known as sugar charcoal.

Multiple choice carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

Which of the following does not reduce Benedict's solution?

  1. Sucrose

  2. Aldehyde

  3. Glucose

  4. Fructose
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
 Sucrose.. 
Because Sucrose (table sugar) contains two sugars (fructose and glucose) joined by their glycosidic bond in such a way as to prevent the glucose isomerizing to aldehyde, or the fructose to alpha-hydroxy-ketone form. Sucrose is thus a non-reducing sugar which does not react with Benedict's reagent.
Multiple choice carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

In plant glycolipids, the sugar is normally.

  1. oil

  2. wax

  3. glycolipid

  4. phospholipid
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Glycolipids yeild fatty acids, glycerol and carbohydrates on hydrolysis. Monogalactosyldiglycerides are glycolipids which are commonly found in plant leaves and algae. They contain a high proportion of poly unsaturated fatty acids and appear to play a role in photosynthesis.

Multiple choice carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

Carbohydrates may be:

  1. sugars

  2. starch

  3. polyhydroxy aldehyde/ketones

  4. compounds that can be hydrolyzed to sugar
Reveal answer Fill a bubble to check yourself
A,B,C,D Correct answer
Explanation

Carbohydrates are primarily produced by plants and form a very large group of naturally occurring organic compounds. Some common examples are cane sugar, glucose, starch, etc.
The carbohydrates may be defined as optically active polyhydroxy aldehydes or ketones or the compounds which produce such units on hydrolysis.