Quest #3: 2.1 Molecules to
Metabolism & 2.3 Carbohydrates &
Lipids
Compounds containing carbon that
occur in living organisms are
regarded as organic.
Exceptions: carbonates and oxides of
carbon (e.g. CO2)
Biological Macromolecules:
• Major molecular components of an E. coli cell
• Component Percentage weight
•
•
•
•
•
•
•
•
Water
Nucleic Acids
Protein
Carbohydrate
Lipid
Building Blocks
and intermediates
Organic Ions
70
7
15
3
2
2
1
Organic
Macromolecules
27%
Biological Macromolecules
• Synthesized from smaller subunits or
building blocks
– building block = monomer
– macromolecule = polymer
Formation of Macromolecules
Monomers
Polymers
Formation and Breakdown of Organic
Macromolecules
• Condensation
–Joins monomers to form polymers
- water is removed
• Hydrolysis
–Breaks down polymers to form
monomers – water is added
Classes of Organic
Macromolecules in Cells
Carbohydrates
Lipids
Proteins
Nucleic Acids
Carbohydrates
• Building blocks (monomers) are simple
sugars called monosaccharides.
• Function in energy storage and cell structure
Glucose – a common monosaccharide (Be
able to ID glucose from a diagram)
H
Three examples of disaccharides –
maltose, lactose, and sucrose
- The disaccharide (two monosaccharides
linked) is the beginning of a carbohydrate
polymer.
- A carbohydrate polymer with more than two
monosaccharides is a polysaccharide.
Three examples of disaccharides –
maltose, lactose, and sucrose
First example of polysaccharide - cellulose
Second example of polysaccharide - starch
Third example of polysaccharide - glycogen
Some functions of carbohydrates in
animals
• Glucose: broken down in cellular respiration
to release energy
• Lactose: the sugar in the milk produced by
mammals
• Glycogen: energy store in liver and skeletal
muscles
Some functions of carbohydrates in plants
• Fructose: energy source and component of
sucrose
• Sucrose: unreactive, and so a good way to
transport sugar throughout the plant
• Cellulose: main component of the cell wall
Lipids
• Biological molecules that are non-polar and thus
insoluble in water. Lipids include fats,
phospholipids, steroids and waxes.
• FATS
– are the main energy storage molecule in cells, and
– are composed of fatty acids and glycerol, and
– are technically known as triglycerides.
Triglyceride – three fatty acid molecules
joined to glycerol by condensation
reactions
Glycerol
3 Fatty acids
Condensation reactions resulting in
formation of a triglyceride
Condensation
Functions of Lipids
• Energy storage in plants and animals
• Thermal insulation in animals as
subcutaneous fat
• Cushioning of organ systems
• Cuticle on leaf to prevent water loss
• Oil on feathers for waterproofing
• Buoyancy in aquatic animals
• Major component of plasma membrane