A-level Biology Year 1 - Revision pack
1.2 Carbohydrates
You should be able to use and define the following key terms:
Amylopectin: branched polysaccharide of alpha glucose produced in plant cells for energy storage
Amylose: unbranched polysaccharide of alpha glucose produced in plant cells for energy storage
Benedict’s test: a simple biochemical reaction to detect the presence of reducing sugars.
Cellulose: unbranched polysaccharide of beta glucose produced in plant cells to provide strength to cell
walls
Condensation: chemical process in which two molecules combine to form a more complex one with the
elimination of a simple substance, usually water. Many biological polymers, such as polysaccharides and
polypeptides, are formed by condensation. See also hydrolysis.
Disaccharide: two monosaccharides joined by glycosidic bond.
Fructose: hexose monosaccharide.
Galactose: hexose monosaccharide.
Glucose: hexose monosaccharide that comes in two isoforms, alpha and beta.
Glycogen: branched polysaccharide of alpha glucose produced in animal cells for energy storage.
Glycosidic bond: bond formed by condensation reaction between two monosaccharides.
Hexose sugar: a sugar that possesses six carbon atoms. Examples include glucose, fructose and galactose.
Hydrolysis: the breaking down of large molecules into smaller ones by the addition of water molecules. See
also condensation.
Iodine: used to test for the presence of starch, when dissolved in potassium iodide.
Lactose: disaccharide formed from glucose and galactose.
Maltose: disaccharide formed from two molecules of glucose.
Monomer: one of many small molecules that combine to form a larger one known as a polymer.
Monosaccharide: a single carbohydrate monomer.
Pentose sugar: a sugar that possesses five carbon atoms. Two examples are ribose and deoxyribose.
Polymer: large molecule made up of repeating smaller molecules (monomers).
Polysaccharide: carbohydrate formed from many monosaccharides.
Starch: polysaccharide in plant cells formed from amylose and amylopectin
, Sucrose: disaccharide formed from glucose and fructose.
Complete the sentences using the words in bold
alpha amylopectin amylose Benedict’s beta biomass blue branched
branches compact/coiled condensation glycosidic glycosidic helical hexose
hydrolysis iodine insoluble inverted lactose large liver maltose microfibrils
monomers monosaccharides one pentose polymers polysaccharides red
straight strong structure sucrose transport
The majority of the ___________ that makes up organisms is composed of lipids, proteins, nucleic acids and
carbohydrates. Of these, the latter three are all ___________. Polymers are long chains of repeating units
known as ___________. Monomers are joined by ______________ reaction (water is formed as a
byproduct) to form polymers and polymers broken down into constituent monomers by ___________
reaction (water is required to break the bonds).
The monomers in carbohydrates are called ________________. Alpha-glucose, beta-glucose, fructose and
galactose are all ___________ (6 carbon) sugars, while ribose and deoxyribose are both ___________ (5
carbon) sugars. Monosaccharides can be joined together to form disaccharides or ______________. The
bond between the two monosaccharides is called a _____________ bond. The most common disaccharides
are:
Glucose + Glucose = _______________ (used by germinating seeds)
Glucose + Galactose = ______________ (found in mammalian milk)
Glucose + Fructose = _______________ (used to ____________ sugar around plants)
Starch is produced in plants and made of two types of polysaccharide: ____________ and amylopectin.
Amylose is made of a long, _________ chain of ________-glucose molecules joined together through a 1-4
bonds (i.e. carbon 1 on one glucose molecule is bonded to carbon 4 on the next). _______________ is also
made of a chain of glucose molecules but there are also side ___________ as a result of 1-6 bonds. Starch is
an important storage molecule in plants as a result of the following properties:
● ___________: Soluble molecules change the water potential of the solution they are dissolved in. It
is important that starch is insoluble so the water potential remains constant and no water is drawn
into the cell by osmosis.
1.2 Carbohydrates
You should be able to use and define the following key terms:
Amylopectin: branched polysaccharide of alpha glucose produced in plant cells for energy storage
Amylose: unbranched polysaccharide of alpha glucose produced in plant cells for energy storage
Benedict’s test: a simple biochemical reaction to detect the presence of reducing sugars.
Cellulose: unbranched polysaccharide of beta glucose produced in plant cells to provide strength to cell
walls
Condensation: chemical process in which two molecules combine to form a more complex one with the
elimination of a simple substance, usually water. Many biological polymers, such as polysaccharides and
polypeptides, are formed by condensation. See also hydrolysis.
Disaccharide: two monosaccharides joined by glycosidic bond.
Fructose: hexose monosaccharide.
Galactose: hexose monosaccharide.
Glucose: hexose monosaccharide that comes in two isoforms, alpha and beta.
Glycogen: branched polysaccharide of alpha glucose produced in animal cells for energy storage.
Glycosidic bond: bond formed by condensation reaction between two monosaccharides.
Hexose sugar: a sugar that possesses six carbon atoms. Examples include glucose, fructose and galactose.
Hydrolysis: the breaking down of large molecules into smaller ones by the addition of water molecules. See
also condensation.
Iodine: used to test for the presence of starch, when dissolved in potassium iodide.
Lactose: disaccharide formed from glucose and galactose.
Maltose: disaccharide formed from two molecules of glucose.
Monomer: one of many small molecules that combine to form a larger one known as a polymer.
Monosaccharide: a single carbohydrate monomer.
Pentose sugar: a sugar that possesses five carbon atoms. Two examples are ribose and deoxyribose.
Polymer: large molecule made up of repeating smaller molecules (monomers).
Polysaccharide: carbohydrate formed from many monosaccharides.
Starch: polysaccharide in plant cells formed from amylose and amylopectin
, Sucrose: disaccharide formed from glucose and fructose.
Complete the sentences using the words in bold
alpha amylopectin amylose Benedict’s beta biomass blue branched
branches compact/coiled condensation glycosidic glycosidic helical hexose
hydrolysis iodine insoluble inverted lactose large liver maltose microfibrils
monomers monosaccharides one pentose polymers polysaccharides red
straight strong structure sucrose transport
The majority of the ___________ that makes up organisms is composed of lipids, proteins, nucleic acids and
carbohydrates. Of these, the latter three are all ___________. Polymers are long chains of repeating units
known as ___________. Monomers are joined by ______________ reaction (water is formed as a
byproduct) to form polymers and polymers broken down into constituent monomers by ___________
reaction (water is required to break the bonds).
The monomers in carbohydrates are called ________________. Alpha-glucose, beta-glucose, fructose and
galactose are all ___________ (6 carbon) sugars, while ribose and deoxyribose are both ___________ (5
carbon) sugars. Monosaccharides can be joined together to form disaccharides or ______________. The
bond between the two monosaccharides is called a _____________ bond. The most common disaccharides
are:
Glucose + Glucose = _______________ (used by germinating seeds)
Glucose + Galactose = ______________ (found in mammalian milk)
Glucose + Fructose = _______________ (used to ____________ sugar around plants)
Starch is produced in plants and made of two types of polysaccharide: ____________ and amylopectin.
Amylose is made of a long, _________ chain of ________-glucose molecules joined together through a 1-4
bonds (i.e. carbon 1 on one glucose molecule is bonded to carbon 4 on the next). _______________ is also
made of a chain of glucose molecules but there are also side ___________ as a result of 1-6 bonds. Starch is
an important storage molecule in plants as a result of the following properties:
● ___________: Soluble molecules change the water potential of the solution they are dissolved in. It
is important that starch is insoluble so the water potential remains constant and no water is drawn
into the cell by osmosis.
