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The Chemical Building Blocks of Life
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Raven - Johnson - Biology: 6th Ed. - All Rights Reserved - McGraw Hill Companies
Chemistry of Carbon
•
Organic Molecules are
chemical compounds
containing carbon.
•
Biological
Macromolecules
 Proteins
 Nucleic Acids
 Lipids
 Carbohydrates
Raven - Johnson - Biology: 6th Ed. - All Rights Reserved - McGraw Hill Companies
Macromolecules
Raven - Johnson - Biology: 6th Ed. - All Rights Reserved - McGraw Hill Companies
Building Macromolecules
•
Cells assemble
macromolecules by the
removal of a molecule
of water (Dehydration
Synthesis).
•
Cells disassemble
macromolecules into its
subunits by hydrolysis
(adding a molecule of
water).
Raven - Johnson - Biology: 6th Ed. - All Rights Reserved - McGraw Hill Companies
Protein Functions
•
•
•
•
•
•
Enzyme Catalysis
(speed up reactions)
Defense
Transport
Support
Motion
Regulation
Protein Structure
•
Proteins are polymers
of amino acids.
 Covalent bond
linking two amino
acids is called a
peptide bond.
 There are 20
common amino
acids
Raven - Johnson - Biology: 6th Ed. - All Rights Reserved - McGraw Hill Companies
How Proteins Unfold
•
Alteration of a protein’s environment may
cause denaturation.
 Usually makes the protein biologically
inactive.
 Changes in pH, temperature, salt, etc.
Ex: Salt-curing and pickling food prevents
the growth of bacteria
Ex: A fever of over 106 oF will turn off cell
enzymes and you will die
Raven - Johnson - Biology: 6th Ed. - All Rights Reserved - McGraw Hill Companies
Information Molecules


Nucleic acids are
information storage
devices and produce
precise copies of
themselves.
They contain the
genetic code
- Deoxyribonucleic
acid (DNA)
- Ribonucleic acid
(RNA)
•
•
Made of chains of
nucleotides
Each nucleotide consists of :
 Five carbon sugar
 Phosphate
 Nitrogen base
Raven - Johnson - Biology: 6th Ed. - All Rights Reserved - McGraw Hill Companies
Lipids
•
•
Lipids are a loosely defined
group of molecules
insoluble in water.
Phospholipids form
biological membranes.
 Made of three subunits:
- Glycerol
- Fatty Acids
- Phosphate Group
 Contain a polar head
and non-polar tails.
Raven - Johnson - Biology: 6th Ed. - All Rights Reserved - McGraw Hill Companies
Fats as Food
•
On average, fats yield about 9 kcal of
chemical energy per gram, as compared with
4 kcal per gram for carbohydrates.
 Animal fats are saturated, while most plant
fats are unsaturated.
- Can convert oil into solid fat through
hydrogenation (adding hydrogen).
 Ex: turn cooking oil into margarine
Raven - Johnson - Biology: 6th Ed. - All Rights Reserved - McGraw Hill Companies
Simple Carbohydrates
•
Carbohydrates are a loosely
defined group of molecules that
contain carbon, hydrogen, and
oxygen in a 1:2:1 ratio.
 Monosaccharides (Simple
sugars)
 Disaccharides
- Two monosaccharides
joined by a covalent bond.
 Polysaccharides
- Made of multiple
monosaccharide units.
Raven - Johnson - Biology: 6th Ed. - All Rights Reserved - McGraw Hill Companies
Raven - Johnson - Biology: 6th Ed. - All Rights Reserved - McGraw Hill Companies