CELL STRUCTURE AND FUNCTIONS

Cell Types Eukaryotic: has a nucleus and membrane bound organelles Prokaryotic: has no nucleus Important: Both types have DNA

Common factors in all cells! Cell Membrane Cytoplasm DNA (the genetic code)

Organelle “little organs” A subunit in a cell that has a special function

Cell Structure and Function Plasma membrane (cell membrane) Surrounds and protects cells Selectively permeable Maintains cellular homeostasis

Structure of the Plasma Membrane Phospholipid Bilayer Hydrophobic tails Hydrophilic heads Embedded and surface proteins Transport Cell cell identification Cholesterol Prevents fatty acid chains from sticking together

Plasma membrane Phospholipid bilayer Outermost layer and inner most layer are water-soluble Middle layer is water-insoluble

Structure of the Plasma Membrane Embedded and surface proteins Transport Cell to cell identification Cholesterol Prevents fatty acid chains from sticking together

Structure of the plasma membrane Cholesterol Prevents the layers from sticking together Helps the cell membrane hold its form Cholesterol

Cytoplasm Clear gelatinous fluid in which organelles and other cell parts are held

Animals vs. Plants Both are eukaryotic plant cell animal cell

How do plant and animal cells differ? Plant cells have a cell wall and contain chloroplasts- animal cells lack these structures Cell Wall Chloroplasts

Cell Wall Found in plant cells, fungi, and most bacteria Made of cellulose

Cell wall Function Provides added protection and structure Is porous and allows any molecule that is not too big to pass (is not selectively permeable)

Plants maintain their basic structure because of the cell wall. Turgid Placid