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