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Carbohydrates
Grade 10 Biology
Your Assignment
Your Carbohydrate Assignment
1. What defines a carbohydrate and what is its
function in both plant and animal cells?
2. Monosaccharides (-oses): structure, and the
ratio of C:H:O
3. Disaccharides: reaction used to join them,
removal of water, sucrose, maltose and lactose.
4. Polysaccharides: starches (glycogen & cellulose)
5. What are the main uses of carbohydrates in cells
(plants and animals)?
Additional Resources (1)
• The Tree of Life, lipids and Carbohydrates topic
Additional Resources (2)
Carbohydrate Website links
• http://www.s-cool.co.uk/alevel/biology/biological-molecules-andenzymes/revise-it/carbohydrates
• http://www.sciencemag.org/site/feature/data/
carbohydrates.xhtml
• Molecular Workbench Carbohydrates Module:
Polymerization
 Organic compounds are formed by polymerization
 Large carbon compounds are built up from
smaller simpler molecules called MONOMERS
 Monomers can bind to one another to form
complex molecules known as POLYMERS
 Macromolecules are very large polymers
Polymerization
Building and Breaking Polymers
 Monomers link to form polymers through a chemical reaction
called a CONDENSATION REACTION or Dehydration
Synthesis
 Water is released during the formation of polymers
 The BREAKDOWN of some complex molecules, such as
polymers, occurs through a process known as HYDROLYSIS
 Hydrolysis is the reversal of a condensation reaction
Dehydration Synthesis
Hydrolysis
4 Groups of Organic Compounds Found in Living Things
Carbohydrates (C-H-O 1:2:1 ratio)
Lipids (C-H-O)
Proteins (C-H-O-N)…sometimes S
Nucleic Acids (C-H-O-N-P)
Carbohydrates
 MONOSACCHARIDES are simple sugars in a 1:2:1
ratio
 GLUCOSE
 GALACTOSE = sugar found in milk
 FRUCTOSE = fruit sugar
 Chemical composition (C6 H12 O6)
Simple carbohydrates:
monosaccharides
• Monosaccharides
(simple/single sugars) have
the empirical molecular
formula of CH2O
– Glucose: C6H12O6 is the most
common monosaccharide
• Can exist in linear or ring
form
• Carbohydrates can be
simple sugars (fructose,
galactose, glucose etc.) or
polymers made from these
simple sugars
Glucose
Important Monosaccharides
ISOMERS
Carbohydrates
Simple carbohydrates: Disaccharides
Disaccharides are made up of 2 monosaccharides that have
undergone a dehydration reaction (e.g. sucrose, maltose,
lactose); formula is C12H22O11
Disaccharides consist of 2 monosaccharides covalently bonded
together by a glycosidic linkage which forms by dehydration
synthesis (condensation reaction)
Carbohydrates
DISACCHARIDES consist of two single
sugars(monosaccharides) linked together
by glycosidic linkage (Dehydration
synthesis)
Lactose = Milk sugar
Sucrose = Table sugar
Carbohydrates
Polysaccharides
• Polysaccharides provide
• Consist of 3 or more
energy storage and
monosaccharides
structural material
joined together (may be
• 2 energy storage
100’s or 1000’s)
• The function of a
polysaccharide is
determined by its
sugar monomers and
the position of the
glycosidic linkages
17
polysaccharides are starch
(plant) and glycogen
(animal)
• 2 structural
polysaccharides are
cellulose (plants) and chitin
(animals - exoskeleton)
22
Carbohydrates
 Starch - Plants convert excess sugars into starches for long-term
storage (Alpha linkage)
 Glycogen -Animals store glucose in the form of polysaccharide
glycogen in the liver and muscles to be used as quick energy
 Cellulose -a structural polysaccharide contained in the cell walls
of plants (ß linkage)
 Chitin – a polysaccharide found in the cell walls of fungi and the
exoskeletons of insects and arthropods
Storage Polysaccharides: Starch
Found in plants (organelle plastids), made of glucose
monomers joined by a 1-4 glycosidic linkage. Bond
angles make the molecule helical
– Amylose: simplest unbranched form
– Amylopectin: more complex, branched form
Storage Polysaccharides: Glycogen
Found in animals, stored in liver and muscle cells.
Extensively branched
• In humans, glycogen banks do not last longer
than a day
Structural Polysaccharides:
Cellulose
• major component of
plant cell walls
• Plants produce 1011 ton
of cellulose per year
• Cellulose is a polymer
of glucose, however it
uses the β form, which
gives it a different
3-dimensional shape
• Cellulose forms straight
unbranched chains
Cellulose
• Because of the different structure, very
few organisms have the enzymes
necessary to break down cellulose
• Makes it a very
strong and resistant
“insoluble fiber”
Chitin
• Carbohydrate used by arthropods
(insects, spiders, crustaceans, and
related animals) to build their
exoskeletons
• Also used for cell walls in fungi
• Feels leathery and can become hardened
when encrusted with calcium
carbonate (shells)
• Similar to cellulose molecules
except the glucose has a
nitrogen-containing side group
Beta glucose
Variation in
Carbohydrates
Alpha glucose
Condensation reaction
Disaccharides
Starch
Cellulose
Glycogen
Polysaccharides:
Structure and
function