Cell Structure and Function Chapter 7

Cell Theory  All living things are made of cells.  Cells are the basic units of structure and function in living things.  New cells are produced from existing cells.

Prokaryotic Cells  Bacteria  No Nucleus or membrane bound organelles  Much smaller than Eukaryotes  Cells division occurs rapidly

Eukaryotic Cells  In the Nucleus  Surrounded by nuclear envelope  Chromosomes contain DNA  Nucleolus is the dense region of the nucleus where ribosomes begin.

Eukaryotic Cells  In the Cytoplasm  Ribosomes  Make Proteins  Endoplasmic Reticulum  Rough has ribosomes  Smooth makes lipids for the membrane  Golgi Apparatus  Packages proteins for storage or secretion

 In the Cytoplasm cont..  Lysosomes  Filled with enzymes to “digest” lipids, carbohydrates, and proteins.  Vacuoles  Storage structures for the cell.  Mitochondria  Converts food compounds into ATP (Cell Fuel)  Chloroplasts  Perform photosynthesis in plants to make sugars from sunlight.

Cell Boundaries  Cell Membrane  Flexible barrier made up of a double layered sheet called a lipid bilayer.  Controls what enters and exits the cell.  Protects and supports the cell.  Cell Wall  Supports Plant, Algae, and Fungi cells.  More rigid than cell membrane(fibrous).

Movement across the membrane  Diffusion  Particles are allowed to spread out across the membrane.  Osmosis  Diffusion of water across a semipermeable membrane.  Semipermeable=allows only some things through

Active Transport  Endocytosis  Cell membrane “Swallows” large particles  Phagocytosis  Creation of a food vacuole within the cell  Pinocytosis  Taking up fluids from the environment  Exocytosis  Release of materials from the cell