SBI4U - Biochemistry
Macromolecules
Carbohydrates & Lipids
Organic Chemistry
• originally the chemistry of compounds
produced by living organisms
• in general organic compounds contain
carbon and hydrogen, and usually other
elements such as nitrogen, sulfur and
oxygen
Macromolecules
• macromolecules are large molecules
that are often composed of repeating
sub-units
• some of the biologically important
macromolecules are:
– carbohydrates
– proteins
-lipids
-nucleic acids
Functional Groups
• specific clusters of atoms attached to
the carbon backbone
• functional groups react in characteristic
ways, giving chemical properties to
macromolecules, and are involved in
most reactions in living organisms
Functional Groups
Image from: http://www.bothbrainsandbeauty.com/academic-discussions/chemistry-academicdiscussions/functional-groups-429
Electronegativity
(Image from: http://www.britannica.com)
Polar vs. Non-Polar
• molecular polarity is determined by:
– polarity of bonds within molecule
– symmetry of molecular structure
• polarity of molecules or functional
groups determines characteristics such
as solubility
Carbohydrates
Image from: http://www.lifetime-fitness.ca/pages/meet-our-trainers/trainer-tips--nutritional
• carbohydrates are
the most important
energy source
• animals cannot
synthesize
carbohydrates; they
must be consumed
in plant material
Structure of Carbohydrates
• carbohydrates are made up of either
single sugar molecules, or chains of
many single sugar molecules
– monosaccharides
– disaccharides
– oligosaccharides
– polysaccharides
Monosaccharides
Image from: http://www.phschool.com/science/biology_place/biocoach/bioprop/glucose.html
• single sugars in
straight chain or ring
form
• C:H:O usually in
1:2:1 ratio (glucose
is C6H12O6)
• examples: fructose,
galactose, ribose,
deoxyribose
Monosaccharides
Image from: http://course1.winona.edu/sberg/241f08/Lec-note/Biochem.htm
• some
monosaccharides
are isomers, e.g.,
glucose, fructose,
and galactose
Find the sugars…
Image from: http://amerthehammer.com/2010/12/04/understanding-ingredient-labels-todays-tip/
Disaccharides
Image from: http://mansfield.osu.edu/~sabedon/biol1020.htm
• sugar molecules
made from 2 single
sugars
• formed by a
dehydration
synthesis
(condensation)
reaction
•
See animation:
http://www.youtube.com/watch?v=UyDnn
D3fMaU
Polysaccharides
• oligosaccharides are shorter-chain
sugars with 3-10 single sugars
• longer chain carbohydrates are called
polysaccharides
• examples: starch, cellulose, glycogen,
chitin
Polysaccharides
Image from: http://www.yellowtang.org/chemistry.php
Lipids
Image from: http://www.herdaily.com/health/892/the-effects-of-food-additives-and-preservatives.html
• 3 groups:
– fats, oils, waxes
– phospholipids
– steroids
• Functions:
– energy storage
– insulation
– absorption of
vitamins
– raw materials
Triglycerides
Image from: http://homepage.smc.edu/wissmann_paul/anatomy2textbook/phospholipids.html
• most common type
of fat
• glycerol + 3 fatty
acid molecules
• saturated and
unsaturated fatty
acid chains
•
See animation:
http://www.youtube.com/watch?v=3xF_L
K9pnL0
Phospholipids
Image from: http://www.bioteach.ubc.ca/Bio-industry/Inex/
• key component of
cell membranes
• 1 glycerol + 2 fatty
acid chains + 1
phosphate group
• phosphate end is
polar and watersoluble, fatty acid
end is non-polar
Phospholipids
Image from: http://micro.magnet.fsu.edu/cells/plasmamembrane/plasmamembrane.html
Waxes
Image from: http://igiwax.com/wax-basics/overview/
• long-chain fatty
acids linked to
alcohols/carbon
rings
• suitable as waterproof coating for
plant leaves, animal
feathers, etc.
Steroids (Sterols)
Images from: http://en.wikipedia.org/wiki/File:Cholesterol_structure.png and
http://commons.wikimedia.org/wiki/File:Testosterone_structure.png
• carbon-based
multiple-ring
structure
• used to make
hormones such as
estrogen and
testosterone