1. The simplest unit of carbohydrate is _________________
Answer: monosaccharide
2. Glycolaldehyde is referred to as aldose. why?
Answer: Because it contains an aldehyde group.
3. Give one example for aldodiose
Answer: Glycolaldyhyde
4. Some authors do not include the compound
glycolaldehyde among the true carbohydrate .Why?
Answer:
Because it is not polyhydroxylic
5. Trioses contain polyhydroxylic groups and they are
considered as _____________
Answer : True carbohydrate
6. Give one
example for ketotriose
Answer : Dihydroxyacetone
7. Glyceraldehyde is an ________________
Answer : Aldotriose ( Because it is
a triose and contains an aldehyde group )
8 . Give one example for ketotetrose
Answer : Erythrulose
9 . Erythrose and threose are _____________
Answer :
Aldotetrose
10 . Pentoses are physiologically important .Why ?
Answer : Because ribose and deoxyribose
are constituents of nucleicacids.
11 . Which carbohydrate is the constituent of the vitamin
riboflavin
Answer : Ribose
12 .What is the molecular formula for hexose ?
Answer : C6 H12O6
13 . What are the
aldohexoses ?
Answer : Glucose, galactose and mannose
14 .Give example for ketohexose .
Answer : Fructose
15 . What are the hexoses present in the plants and
fruits ?
Answer : Glucose and fructose
16 . What is the other name for stereoisomerism ?
Answer : Space isomerism
17 . List out stereoisomers.
Answer : D – Glucose, D –
Galactose, D – Mannose, D – Allose, D – Iodose, D – Talose,
D – Altrose and D
– Gulose.
18 . What is meant by asymmetric carbon atom ?
Answer : A carbon atom is said to be asymmetric when
it bears four different atoms or groups of atoms at the four valancy bonds.
19 . Which carbon atom is asymmetric in glyceraldehydes ?
Answer : Second carbon atom
20 .All sugars having asymmetric carbon atoms exist in
_________ forms .
Answer : Optically active
21 . Give the Vant Hoff formula.
Answer : I =2n (I is
the number of isomers ,n represent the number of asymmetric carbon atoms )
22 . List out monosaccharides containing asymmetric carbon atoms .
Answer : Glucose ,Fructose
,Mannose , Galactose and Glyceraldehyde
.
23 . What is levorotation ?
Answer : When a beam of plane polarized light is passed through a
solution of an optical isomer
, the plane polarized light is found to rotate to the left , it is
described as levorotation
24 . What is dextrorotation ?
Answer : When a beam of plane polarized light is passed through a
solution of an optical isomer , the plane
polarized light rotates to an equal
number of degrees to the right , it is described as dextrorotation .
25 . In which
region the condensation occurs in between two monosaccharide ?
Answer : Union takes place
between C -4 of the first monosaccharide and C – 1 of the
second monosaccharide
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