Download Water, Carbohydrates, Lipids, Proteins, Nucleic Acids

Chapter 3: Water,
Carbohydrates,
Lipids, Proteins,
Nucleic Acids
Dr. Amy Rogers
• Human body is 2/3 water by weight
• On Earth, life first appeared in water
What is it about WATER???
Properties of Water
n  Solvent: Polar & charged solutes
n  Specific
Heat:
great insulator
n  Temperature/Density: Ice floats!
n  Surface
Tension:
Walk on water? Sure!
Water as a Solvent
Hydrophilic:
“water loving”
interacts with water
Polar or Ionic Solute
Hydrophobic molecules
• Do not dissolve in water
• Crucial for maintaining
biological
“compartments”
Water is a good insulator
Imagine you are winter camping in the Rocky Mountains.
To keep warm, you can take one of these items into your
sleeping bag with you:
Water bottle heated to 100oF
vs.
Aluminum brick heated to 100oF
Specific Heat:
The amount of energy required to raise the
temperature of a substance by 1o C
Heat buffering
by water maintains (relatively) stable
temperatures on earth
and in animals’ bodies
The important macromolecules for
cells:
n  Carbohydrates
n  Lipids
n  Proteins
n  Nucleic
Acids
Polymers
n  Many
complex organic molecules are
polymers
(large molecules made up of
many similar or identical subunits)
Simple Carbohydrates
n  Monosaccharides
(Simple sugars)
e.g, glucose, fructose, deoxyribose
• Note ending of sugar names is usually ose
Complex Carbohydrates
n  Polysaccharides
e.g., starch, glycogen, cellulose, chitin
n  Polymers
n  Bread,
of thousands of sugars
cereal, pasta
Complex Carbohydrates:
Starch
• Massive polymer of
glucose
• Energy storage in many
plants
• When energy is needed,
starch is degraded back
into glucose
Complex Carbohydrates:
Glycogen
• Main form of
carbohydrate storage
in animals
• In humans, kept
primarily in liver and
muscle
Complex Carbohydrates:
Cellulose
• Rigid
• Cell walls of many
organisms:
• Trees, cotton, grasses…
• Easily the most abundant
carbohydrate on earth!
• Mammals cannot digest it
• Major source of insoluble
fiber
Lipids
n 
Fats, oils, cholesterol, hormones
n 
Made of C, H, O like carbohydrates but
relatively much more H than O
n  Relatively
n  Not
insoluble in water
all are polymers
Lipids
n  Uses:
Long-term energy storage
n  Insulation
n  Hormones
n  Separation of biological compartments
(membranes)
n 
Energy Storage
n  Carbohydrates
& Lipids are both used by
cells to store energy for future use
Lipids (fats)
n  All
n 
membranes are made of lipids
Cell membrane, nuclear membrane
Proteins:
Workers of the world, united
n  Need
something done? Call a protein!
n  About
½ dry weight of a cell
n  Enzymes:
n 
mediate chemical reactions
Messengers, transporters, defenders, movers, structure
builders, poisons, communicators…….
Proteins are Polymers
n 
Proteins are long chains of smaller subunits
called amino acids
n 
Like letters of the alphabet, they can be strung
together in any sequence or length to create a
spectacular variety of proteins
Amino Acids
make polypeptides
Proteins:
3D is key
n 
A long straight chain of amino acids is
energetically unstable: BONDS will form
n 
Polypeptides fold into a specific conformation
n 
Unique 3D shape of proteins is CRUCIAL for
their function
Nucleotides & Nucleic Acids
n  Subunit:
nucleotides
Nucleotide ATP is vital energy carrier
n  You will learn much more about ATP soon
n 
Phosphate group
Sugar
“Base”: A, T, G, C
Nucleotides & Nucleic Acids
n  Nucleotide
polymer: Nucleic acid (DNA,
RNA)
n  Information
molecule
Blueprint for protein manufacture
n  Cell’s “hard drive”
n