BIOLOGY
Unit 1 Notes:
Characteristics of
Life &
Biomolecules
(1) Characteristics of Life
• All systems classified as “living” must be able to do
the following on their own:
– Reproduce + Pass on genes
– Evolve + Respond + Adapt to their changing
environment
– Metabolize nutrients + Excrete Waste
– Grow + Develop over time
– Maintain Homeostasis
(2) Homeostasis
• Maintaining internal stability / balance.
• What Does This Mean?
– When something changes inside/around an organism,
it must be able to get itself back to a “healthy normal”.
– Examples:
• Shivering when cold
• Making more red blood cells when oxygen levels drop
• Releasing bicarbonate when you eat something acidic
(3) The Cell Theory
• Living things follow the Cell Theory:
– All living things are made of cells.
– Cells are the most basic unit of life.
– Existing cells come from pre-existing cells.
(4) The Biological Elements
• The element that make up all living organisms:
– C (carbon)
– H (hydrogen)
– O (oxygen)
– N (nitrogen)
– P (phosphorus)
– S (sulfur)
(5) The Amazing Carbon Atom
• Carbon is one of the most important elements
found in living systems.
• What Makes Carbon So Special??
– Able to form 4 different bonds.
– Can position and rearrange itself into a lot of different
types of formations and molecules.
– Allows for the wide variety of structures in living
things.
(6) Wonderful Water
• ~70% of a cell is made up of water!
• Water Allows For:
– Special chemical reactions needed to release and store
energy.
– The dissolving of solutes (like sugars and salts).
• What Makes Water So Special??
– Polar Molecule
– Allows for unique interactions with polar and non-polar
molecules in cells.
(7) The Biomolecules
• The molecules that make up all living organisms:
– Carbohydrates
– Lipids
– Proteins
– Nucleic Acids
(8) Carbohydrates
• Function: Provide immediate and intermediate
energy.
• Monomers: Monosaccharides (Glucose, Fructose)
• Polymers: Polysaccharides (Starch, Wheat)
• Draw A Picture:
Monosaccharide
Polysaccharide
Energy Stored In Bonds
Energy Available to
Cells When Bonds
Broken and new bonds
form!
Why Do You Think People
Say Wheat / Multi-Grain
Carbs Are Better For You
Than Simple Sugars?!?
What Are The Pros + Cons
Of Each??
(9) Lipids
• Functions:
– Long term energy storage.
– Make up cell membranes.
• Monomers: Fatty Acids + Glycerol
• Polymers: Triglycerides (aka Fats and Oils)
Phospholipids
Draw A Picture:
Monomers of Triglycerides
Fats and Oils (Saturated vs
Unsaturated fats)
Glycerol
Fatty Acids
Hydrophilic
Head:
-Water Loving
-Polar
Hydrophobic
Tails:
-Water
Fearing
- Non Polar
(10) Proteins
• Functions:
– Provide the expression of the instructions within DNA.
– Catalyze chemical reactions.
• Monomers: Amino Acids
• Polymers: Proteins / Polypeptides
• Draw A Picture:
Amino Acid
Polypeptide
The Amino Acids
Bond Together In
A Very Specific
Order + Structure!
Peptide Bonds
(11) Nucleic Acids
• Function: Provide the genetic instructions for all
cell parts and processes.
• Monomers: Nucleotides
• Polymers: DNA and RNA
• Draw a Picture:
Nucleotide
Phosphate
Nitrogenous
Base
Sugar
DNA
RNA