CARBOHYDRATES
Key Terms
Monomers
3.1 BIOLOGICAL MOLECULES Polymers
Condensation reaction
MISSESTRUCH 2020
Hydrolysis reaction
Monomers and Polymers
Monomers (mono meaning one, think monobrow!)
Small, single units that act as the building blocks to create
larger molecules.
Polymers (poly meaning more than two)
Made up of many monomers, usually thousands, chemically
bonded together.
Condensation and Hydrolysis Reactions
For monomers to bond together a chemical reaction occurs; this is a condensation reaction.
Condensation reactions involve the removal of a water molecule. This removal of water from
monomers enables a chemical bond to form between the monomers.
A hydrolysis reaction is the opposite of this- hydro (water) lysis (to split). A water molecule is added
between two bonded monomers (within a dimer or polymer) to break the chemical bond.
1 MISSESTRUCH 2020
,CARBOHYDRATES
Key Terms
Monosaccharides
3.1 BIOLOGICAL MOLECULES Disaccharides
Polysaccharides
MISSESTRUCH 2020
Glucose
Carbohydrates Galactose
Fructose
Carbohydrates are key biological molecules that store energy
and can provide structural support to plant cells.
Carbohydrates can be classified into three groups determined by how many units they are made of,
as seen in the flow diagram below.
Fructose
Larger carbohydrates, such as sucrose and starch, are made from monosaccharides.
The monomers of carbohydrates are known as monosaccharides and glucose, galactose and
fructose are three common examples. Monosaccharides are sugars and are soluble in water.
Their function is either to provide energy or to be a building block to create larger molecules.
All carbohydrates contain three elements: carbon, hydrogen and oxygen (CHO).
The general formula for a monosaccharide is CnH 2nOn, where n = the number of carbon atoms it
contains.
2 MISSESTRUCH 2020
,CARBOHYDRATES
Key Terms
Monosaccharides
3.1 BIOLOGICAL MOLECULES Glucose
Isomer
MISSESTRUCH 2020
α glucose
Glucose β glucose
Glucose, C 6H12O6 , is a very important monosaccharide that can
provide energy or be polymerised to form a structural support
molecule (cellulose) or energy storage molecule (glycogen and
starch).
Glucose has two structural isomers. Isomers are
compounds that have the same formula, but the
atoms are arranged differently.
The diagram on the left shows the isomer α
glucose.
β glucose is the second isomer. There is only one difference in the structural arrangement
between these isomers. The hydrogen (H) and hydroxyl group (OH) on carbon 1 swap position.
α glucose β glucose
This small change has a significant impact on the bonding and final structure of the polymers
that they form.
3 MISSESTRUCH 2020
,CARBOHYDRATES
Key Terms
Monosaccharides
3.1 BIOLOGICAL MOLECULES Disaccharides
Glycosidic Bond
MISSESTRUCH 2020
Maltose
Disaccharides
Lactose
Disaccharides are two monosaccharides bonded together by Sucrose
a glycosidic bond, that is formed by a condensation reaction.
There are three key disaccharides that you need to remember, and these are made from the three
key monosaccharides you learned.
glucose + glucose --> maltose
glucose + galactose --> lactose
glucose + fructose --> sucrose
Condensation and Hydrolysis Reactions
The diagram below demonstrates how a condensation reaction creates a disaccharide. A water
molecule is being removed (highlighted in red) from the hydroxyl group (OH) on carbon 1 and carbon
4 on the two monosaccharides. The bond that forms is known as a glycosidic bond (highlighted in
blue). This diagram shows a 1-4, glycosidic bond because it is located between carbon 1 and
carbon 4.
Disaccharides can be broken down back into monosaccharides via a hydrolysis reaction. Hydrolysis
is when a water molecule is added in to break a bond, as shown in the diagram below.
MISSESTRUCH 2020
4
, CARBOHYDRATES
Key Terms
Polysaccharides
3.1 BIOLOGICAL MOLECULES Condensation reaction
Energy store
MISSESTRUCH 2020
Structural support
Polysaccharides
Starch
Polysaccharides are polymers made up of many Glycosidic bonds
monosaccharides. A polysaccharide is created in the same way
as a disaccharide, via condensation reactions. There are three
key polysaccharides that you need to learn the structure and
function of: starch, glycogen and cellulose.
Starch and glycogen are both energy stores, whereas cellulose provides structural support.
Starch
Starch is found in plants, not in animal cells, and it is the major carbohydrate store. Starch is made
from the excess glucose created during photosynthesis. Glucose is used in respiration, but if more
glucose is created in photosynthesis than is needed, it is converted into the polymer starch for
storage.
Structure of starch
Starch is a polymer made up of α-glucose. These α-glucose monomers are joined together via
condensation reactions and are held in place by 1,4 and 1,6 - glycosidic bonds (The numbers refer
to which carbon atoms the bond forms between).
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MISSESTRUCH 2020
Key Terms
Monomers
3.1 BIOLOGICAL MOLECULES Polymers
Condensation reaction
MISSESTRUCH 2020
Hydrolysis reaction
Monomers and Polymers
Monomers (mono meaning one, think monobrow!)
Small, single units that act as the building blocks to create
larger molecules.
Polymers (poly meaning more than two)
Made up of many monomers, usually thousands, chemically
bonded together.
Condensation and Hydrolysis Reactions
For monomers to bond together a chemical reaction occurs; this is a condensation reaction.
Condensation reactions involve the removal of a water molecule. This removal of water from
monomers enables a chemical bond to form between the monomers.
A hydrolysis reaction is the opposite of this- hydro (water) lysis (to split). A water molecule is added
between two bonded monomers (within a dimer or polymer) to break the chemical bond.
1 MISSESTRUCH 2020
,CARBOHYDRATES
Key Terms
Monosaccharides
3.1 BIOLOGICAL MOLECULES Disaccharides
Polysaccharides
MISSESTRUCH 2020
Glucose
Carbohydrates Galactose
Fructose
Carbohydrates are key biological molecules that store energy
and can provide structural support to plant cells.
Carbohydrates can be classified into three groups determined by how many units they are made of,
as seen in the flow diagram below.
Fructose
Larger carbohydrates, such as sucrose and starch, are made from monosaccharides.
The monomers of carbohydrates are known as monosaccharides and glucose, galactose and
fructose are three common examples. Monosaccharides are sugars and are soluble in water.
Their function is either to provide energy or to be a building block to create larger molecules.
All carbohydrates contain three elements: carbon, hydrogen and oxygen (CHO).
The general formula for a monosaccharide is CnH 2nOn, where n = the number of carbon atoms it
contains.
2 MISSESTRUCH 2020
,CARBOHYDRATES
Key Terms
Monosaccharides
3.1 BIOLOGICAL MOLECULES Glucose
Isomer
MISSESTRUCH 2020
α glucose
Glucose β glucose
Glucose, C 6H12O6 , is a very important monosaccharide that can
provide energy or be polymerised to form a structural support
molecule (cellulose) or energy storage molecule (glycogen and
starch).
Glucose has two structural isomers. Isomers are
compounds that have the same formula, but the
atoms are arranged differently.
The diagram on the left shows the isomer α
glucose.
β glucose is the second isomer. There is only one difference in the structural arrangement
between these isomers. The hydrogen (H) and hydroxyl group (OH) on carbon 1 swap position.
α glucose β glucose
This small change has a significant impact on the bonding and final structure of the polymers
that they form.
3 MISSESTRUCH 2020
,CARBOHYDRATES
Key Terms
Monosaccharides
3.1 BIOLOGICAL MOLECULES Disaccharides
Glycosidic Bond
MISSESTRUCH 2020
Maltose
Disaccharides
Lactose
Disaccharides are two monosaccharides bonded together by Sucrose
a glycosidic bond, that is formed by a condensation reaction.
There are three key disaccharides that you need to remember, and these are made from the three
key monosaccharides you learned.
glucose + glucose --> maltose
glucose + galactose --> lactose
glucose + fructose --> sucrose
Condensation and Hydrolysis Reactions
The diagram below demonstrates how a condensation reaction creates a disaccharide. A water
molecule is being removed (highlighted in red) from the hydroxyl group (OH) on carbon 1 and carbon
4 on the two monosaccharides. The bond that forms is known as a glycosidic bond (highlighted in
blue). This diagram shows a 1-4, glycosidic bond because it is located between carbon 1 and
carbon 4.
Disaccharides can be broken down back into monosaccharides via a hydrolysis reaction. Hydrolysis
is when a water molecule is added in to break a bond, as shown in the diagram below.
MISSESTRUCH 2020
4
, CARBOHYDRATES
Key Terms
Polysaccharides
3.1 BIOLOGICAL MOLECULES Condensation reaction
Energy store
MISSESTRUCH 2020
Structural support
Polysaccharides
Starch
Polysaccharides are polymers made up of many Glycosidic bonds
monosaccharides. A polysaccharide is created in the same way
as a disaccharide, via condensation reactions. There are three
key polysaccharides that you need to learn the structure and
function of: starch, glycogen and cellulose.
Starch and glycogen are both energy stores, whereas cellulose provides structural support.
Starch
Starch is found in plants, not in animal cells, and it is the major carbohydrate store. Starch is made
from the excess glucose created during photosynthesis. Glucose is used in respiration, but if more
glucose is created in photosynthesis than is needed, it is converted into the polymer starch for
storage.
Structure of starch
Starch is a polymer made up of α-glucose. These α-glucose monomers are joined together via
condensation reactions and are held in place by 1,4 and 1,6 - glycosidic bonds (The numbers refer
to which carbon atoms the bond forms between).
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MISSESTRUCH 2020
