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
• Once we know something is living, we also know it must 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 Magical 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 BondsBroken!
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: Fats, Oils, Phospholipids
• Draw A Picture:
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
Peptide Bonds
The Amino Acids Bond Together In A Very Specific Order + Structure!
(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
Sugar
NitrogenousBase
DNA RNA