Q14.1 What are biomolecules ? Give some examples.

Solution

Biomolecules are macromolecules because they are polymers made of hundreds or even thousand of smaller molecules Called monomers

Examples- Carbohydrates, lipids, proteins and nucleic acids.

Q14.2 What are carbohydrates and how are they classified ?

Solution

Carbohydrates→ It as a group of organic Compounds occurring on living tissues and foods in the form of starch , cellulose , sugars . The ratio of Carbon and Hydrogen in Carbohydrates is the same as in water 2:1. It typically breaks down in the animal body to release energy.

Types of Carbohydrates-

Monosaccharides

Disaccharides

Polysaccharides

Q14.3 Discuss the role of glucose as energy source in living organisms

Solution

Through the process of Cellular respiration, the energy in food is converted,into energy that can be used by the body's cells.

During Cellular respiration,glucose and oxygen are converted into CO₂ and H₂O,and the energy is transferred to ATP.

Q14.4 What are polysaccharides ? Give one example.

Solution

A polysaccharide is a Large molecules made of many Smaller monosaccharides . Monosaccharides are simple sugars,like glucose.
A polysaccharides is also called a glycan.A polysaccharides can be homopolysaccharides, in which all the monosaccharides are the same.

Eg-> cellulose and chitin
Glycogen and starch

Q14.5 What is the source of pectin? What is its use ?

Solution

Pectin, a multifunctional constituent of Cell wall is a high value functional food ingredients widely used as getting agent and as stabilizers .

It is produced commercially in form of white to Light brown powder,mainly extracted from citrus fruits and used in food as a gelling agent particularly in jams and jellies.

Q14.6 Distinguish between α-glucose and β-glucose

Solution

-OH group lies below the ring on carbon

α-glucose folds up into a helix

-OH group lies above the ring on carbon

β;-glucose folds up into a plated sheet

Q14.7 Name two carbohydrates which are used as bio-fuels

Solution

Starch and glycogen

Q14.8 Mention two structural differences between amylopectin and cellulose

Solution

Amylopectin Cellulose

It has a branched chain structure It has a linear polymer

It is made of α-glucose units It is made of β-glucose units

Amylopectin	Cellulose
It has a branched chain structure	It has a linear polymer
It is made of α-glucose units	It is made of β-glucose units

Q14.9 Write the structural formula of anomeric form of α-glucose

Solution

structural formulae of anomeric form α-glucose - α-Glucose is a form of glucose that is in a ring shape. Glucose structure occur when the hydroxy I-OH group on the C-6 atom reacts with the -CHO group on the C-1 atom

Q14.10 Write the hydrolysis products of lactose and starch.

Solution

Lactose→
The hydrolysis of lactose gives B-D-galactose and B-D glucose

Starch→
Lactose on hydrolysis gives glucose and fructose

Q14.11 Mention two main functions of carbohydrates in plants

Solution

Carbohydrates are the source of energy in plants.
Their too main function are growth and metabolism.

Q14.12 What is the basic difference between starch and cellulose?

Solution

Cellulose Starch

1 type of β-Glucose 2 types of β-Glucose

Cellulose has β-1,4 linkage Cellulose has α;-1,4 linkage

not dissolve in water dissolves in warm water

cannot be consumed by humans can be consumed by humans

Cellulose	Starch
1 type of β-Glucose	2 types of β-Glucose
Cellulose has β-1,4 linkage	Cellulose has α;-1,4 linkage
not dissolve in water	dissolves in warm water
cannot be consumed by humans	can be consumed by humans

Q14.13 Why are carbohydrates generally optically active ?

Solution

carbohydrates are generally optically active because they have one or more chiral carbon atoms in their molecules.

Eg→ Glucose has 4-chiral Carbon and it is optically active.

Q14.14 What are polysaccharides ? Name two such substances of immense use to us and state their usefulness.

Solution

A polysaccharide is a Large molecules made of many Smaller monosaccharides . Monosaccharides are simple sugars,like glucose.
A polysaccharides is also called a glycan.A polysaccharides can be homopolysaccharides, in which all the monosaccharides are the same.

Eg-> cellulose and chitin
Glycogen and starch

Q14.15 Describe the reaction for release of energy from carbohydrates in human body

Solution

1 mole of Glucose gives CO₂ and H₂O and gives 38 moles of ATP which is converted into ADP producing energy. this energy is used for maintaining body temperature and for doing work.

Q14.16 State two main functions of carbohydratees.

Solution

Two functions of carbohydrates :-

Carbohydrates act as biofuel to provide energy for functioning of causing organisms

They act as constituents of cell walls.

Q14.17 What are chemotrophs ? Where from do they get energy for their cellular activities?

Solution

Chemotrophs- are organisms that obtain energy by the oxidations of e^- donar in their environment. These molecules organic or inorganic. Chematrophs are organisms that obtain their energy from a chemical reaction but their source of carbon is the most oxidised form of Carbon,CO₂.

Q14.18 What is meant by inversion of sugar ?

Solution

sucrose is dextro but on hydrolysis it gives an equimolar mixture of D (+) glucose and D-(-) fructose which is levororatatory. This changes of specific rotation from dextrorotation to laevorotation is known as inversion of sugar.

Q14.19 How do cells derive their need of ATP ?

Solution

Beginning with energy sources obtained from their environment in the form of sunlight and organic food molecules, eukaryotic Cells make energy rich molecules Like ATP and NADH including photosynthesis

Q14.21 What is mutarotation ? Explain occurrence of mutarotation in D-glucose

Solution

The spontaneous change in the specific rotation of an optically active compound with time is called mutarotation. The accepted mechanism of mutarotation of D-glucose involves a simultaneous attack by an acid and a base to yield the open-chain aldehyde form

Q14.22 Write the major classes in which the carbohydrates are divided depending upon whether these undergo hydrolysis, and if so, on the number of products formed.

Solution

The carbohydrates are divided into 3major classes

Monosaccharides

oligosaccharides

polysaccharide

(i) Monosaccharides→ they are polyhydroxy aldehydes or polyhydroxy ketones which cannot be decomposed by hydrolysis to gives simpler carbohydrates

(ii) oligosaccharides→ carbohydrates which yield a definite number of mono (2-19) molecules on hydrolysis.
They include-Disaccharides, Trisaccharides and tetrasaccharides.

(iii) Polysaccharides→ These are carbohydrates of high molecular wt. which yield many monosaccharides molecules on hydrolysis.

Q14.23 The concept of coupling reactions is useful in making the occurrence of a non-spontaneous reaction possible. Explain giving one suitable example.

Solution

The non- spontaneous reaction proceed with an increase in free energy (▵G>0). Such reaction are not feasible.
Such reaction can be made to proceed in the desired direction by coupling with a reaction having large negative ▵G value to that the overall change in free energy becomes (-ve)

Q14.24

Write chemical equations for the reactions of glucose with

acetic anhydride and

ammonical silver nitrate solution

Draw simple Fischer projections of D-glucose and L-glucose. Can these be called enantiomers

Solution

Q14.25 Write reactions to show how glucose separately reacts with

NH₂0H

HNO₃

ammonical AgNO₃

Solution

Q14.26 What are reducing sugars ? Give two examples

Solution

All those carbohydrates which contain a free,-CHO or ketonic group and reduce fenling's solution and Tollen's reagent are referred as a reducing sugar

Eg-> galactose, glucose, fructose etc.

Q14.27 Name the three major classes of carbohydrates and give an example of each of these classes.

Solution

The carbohydrates are divided into 3major classes

Monosaccharides

oligosaccharides

polysaccharide

(i) Monosaccharides→ they are polyhydroxy aldehydes or polyhydroxy ketones which cannot be decomposed by hydrolysis to gives simpler carbohydrates

(ii) oligosaccharides→ carbohydrates which yield a definite number of mono (2-19) molecules on hydrolysis.
They include-Disaccharides, Trisaccharides and tetrasaccharides.

(iii) Polysaccharides→ These are carbohydrates of high molecular wt. which yield many monosaccharides molecules on hydrolysis.

Q14.28 What is a peptide bond? Explain the primary structure of proteins

Solution

The carbohydrates are divided into 3major classes

Monosaccharides

oligosaccharides

polysaccharide

(i) Monosaccharides→ they are polyhydroxy aldehydes or polyhydroxy ketones which cannot be decomposed by hydrolysis to gives simpler carbohydrates

(ii) oligosaccharides→ carbohydrates which yield a definite number of mono (2-19) molecules on hydrolysis.
They include-Disaccharides, Trisaccharides and tetrasaccharides.

(iii) Polysaccharides→ These are carbohydrates of high molecular wt. which yield many monosaccharides molecules on hydrolysis.

Q14.1 What are biomolecules ? Give some examples.

Solution

Biomolecules are macromolecules because they are polymers made of hundreds or even thousand of smaller molecules Called monomers Examples- Carbohydrates, lipids, proteins and nucleic acids.

Q14.2 What are carbohydrates and how are they classified ?

Solution

Q14.3 Discuss the role of glucose as energy source in living organisms

Solution

Through the process of Cellular respiration, the energy in food is converted,into energy that can be used by the body's cells. During Cellular respiration,glucose and oxygen are converted into CO2 and H2O,and the energy is transferred to ATP.

Q14.4 What are polysaccharides ? Give one example.

Solution

Q14.5 What is the source of pectin? What is its use ?

Solution

Q14.6 Distinguish between α-glucose and β-glucose

Solution

-OH group lies below the ring on carbon α-glucose folds up into a helix -OH group lies above the ring on carbon β;-glucose folds up into a plated sheet

Q14.7 Name two carbohydrates which are used as bio-fuels

Solution

Starch and glycogen

Q14.8 Mention two structural differences between amylopectin and cellulose

Solution

Amylopectin Cellulose It has a branched chain structure It has a linear polymer It is made of α-glucose units It is made of β-glucose units

Q14.9 Write the structural formula of anomeric form of α-glucose

Solution

structural formulae of anomeric form α-glucose - α-Glucose is a form of glucose that is in a ring shape. Glucose structure occur when the hydroxy I-OH group on the C-6 atom reacts with the -CHO group on the C-1 atom

Q14.10 Write the hydrolysis products of lactose and starch.

Solution

Lactose→ The hydrolysis of lactose gives B-D-galactose and B-D glucose Starch→ Lactose on hydrolysis gives glucose and fructose

Q14.11 Mention two main functions of carbohydrates in plants

Solution

Carbohydrates are the source of energy in plants. Their too main function are growth and metabolism.

Q14.12 What is the basic difference between starch and cellulose?

Solution

Cellulose Starch 1 type of β-Glucose 2 types of β-Glucose Cellulose has β-1,4 linkage Cellulose has α;-1,4 linkage not dissolve in water dissolves in warm water cannot be consumed by humans can be consumed by humans

Q14.13 Why are carbohydrates generally optically active ?

Solution

carbohydrates are generally optically active because they have one or more chiral carbon atoms in their molecules. Eg→ Glucose has 4-chiral Carbon and it is optically active.

Q14.14 What are polysaccharides ? Name two such substances of immense use to us and state their usefulness.

Solution

Q14.15 Describe the reaction for release of energy from carbohydrates in human body

Solution

1 mole of Glucose gives CO2 and H2O and gives 38 moles of ATP which is converted into ADP producing energy. this energy is used for maintaining body temperature and for doing work.

Q14.16 State two main functions of carbohydratees.

Solution

Two functions of carbohydrates :- Carbohydrates act as biofuel to provide energy for functioning of causing organisms They act as constituents of cell walls.

Q14.17 What are chemotrophs ? Where from do they get energy for their cellular activities?

Solution

Chemotrophs- are organisms that obtain energy by the oxidations of e- donar in their environment. These molecules organic or inorganic. Chematrophs are organisms that obtain their energy from a chemical reaction but their source of carbon is the most oxidised form of Carbon,CO2.

Q14.18 What is meant by inversion of sugar ?

Solution

sucrose is dextro but on hydrolysis it gives an equimolar mixture of D (+) glucose and D-(-) fructose which is levororatatory. This changes of specific rotation from dextrorotation to laevorotation is known as inversion of sugar.

Q14.19 How do cells derive their need of ATP ?

Solution

Beginning with energy sources obtained from their environment in the form of sunlight and organic food molecules, eukaryotic Cells make energy rich molecules Like ATP and NADH including photosynthesis

Q14.21 What is mutarotation ? Explain occurrence of mutarotation in D-glucose

Solution

The spontaneous change in the specific rotation of an optically active compound with time is called mutarotation. The accepted mechanism of mutarotation of D-glucose involves a simultaneous attack by an acid and a base to yield the open-chain aldehyde form

Q14.22 Write the major classes in which the carbohydrates are divided depending upon whether these undergo hydrolysis, and if so, on the number of products formed.

Solution

Q14.23 The concept of coupling reactions is useful in making the occurrence of a non-spontaneous reaction possible. Explain giving one suitable example.

Solution

The non- spontaneous reaction proceed with an increase in free energy (▵G>0). Such reaction are not feasible. Such reaction can be made to proceed in the desired direction by coupling with a reaction having large negative ▵G value to that the overall change in free energy becomes (-ve)

Q14.24 Write chemical equations for the reactions of glucose with acetic anhydride and ammonical silver nitrate solution Draw simple Fischer projections of D-glucose and L-glucose. Can these be called enantiomers

Solution

Q14.25 Write reactions to show how glucose separately reacts with NH20H HNO3 ammonical AgNO3

Solution

Q14.26 What are reducing sugars ? Give two examples

Solution

All those carbohydrates which contain a free,-CHO or ketonic group and reduce fenling's solution and Tollen's reagent are referred as a reducing sugar Eg-> galactose, glucose, fructose etc.

Q14.27 Name the three major classes of carbohydrates and give an example of each of these classes.

Solution

Q14.28 What is a peptide bond? Explain the primary structure of proteins

Solution

Biomolecules are macromolecules because they are polymers made of hundreds or even thousand of smaller molecules Called monomers

Examples- Carbohydrates, lipids, proteins and nucleic acids.

Through the process of Cellular respiration, the energy in food is converted,into energy that can be used by the body's cells.

During Cellular respiration,glucose and oxygen are converted into CO₂ and H₂O,and the energy is transferred to ATP.

-OH group lies below the ring on carbon

α-glucose folds up into a helix

-OH group lies above the ring on carbon

β;-glucose folds up into a plated sheet

Amylopectin Cellulose

It has a branched chain structure It has a linear polymer

It is made of α-glucose units It is made of β-glucose units

Lactose→
The hydrolysis of lactose gives B-D-galactose and B-D glucose

Starch→
Lactose on hydrolysis gives glucose and fructose

Carbohydrates are the source of energy in plants.
Their too main function are growth and metabolism.

Cellulose Starch

1 type of β-Glucose 2 types of β-Glucose

Cellulose has β-1,4 linkage Cellulose has α;-1,4 linkage

not dissolve in water dissolves in warm water

cannot be consumed by humans can be consumed by humans

carbohydrates are generally optically active because they have one or more chiral carbon atoms in their molecules.

Eg→ Glucose has 4-chiral Carbon and it is optically active.

1 mole of Glucose gives CO₂ and H₂O and gives 38 moles of ATP which is converted into ADP producing energy. this energy is used for maintaining body temperature and for doing work.

Two functions of carbohydrates :-

Carbohydrates act as biofuel to provide energy for functioning of causing organisms

They act as constituents of cell walls.

Chemotrophs- are organisms that obtain energy by the oxidations of e^- donar in their environment. These molecules organic or inorganic. Chematrophs are organisms that obtain their energy from a chemical reaction but their source of carbon is the most oxidised form of Carbon,CO₂.

The non- spontaneous reaction proceed with an increase in free energy (▵G>0). Such reaction are not feasible.
Such reaction can be made to proceed in the desired direction by coupling with a reaction having large negative ▵G value to that the overall change in free energy becomes (-ve)

Q14.24

Write chemical equations for the reactions of glucose with

acetic anhydride and

ammonical silver nitrate solution

Draw simple Fischer projections of D-glucose and L-glucose. Can these be called enantiomers

Q14.25 Write reactions to show how glucose separately reacts with

NH₂0H

HNO₃

ammonical AgNO₃

All those carbohydrates which contain a free,-CHO or ketonic group and reduce fenling's solution and Tollen's reagent are referred as a reducing sugar

Eg-> galactose, glucose, fructose etc.