Unit 2 – Part 1 Review *Cell Theory *Prokaryote vs. Eukaryote Cells *Plant vs. Animal Cells *Cell Organelles *Function of Organelles *Cell Membranes *Cell Transport

Cell Theory Scientists Hooke – coined the term “cells” after observing cork under a microscope Leeuvenhoek – said cells were like little animals “animacules” Shleiden – discovered all plants are made up of cells Schwann – discovered all animals are made up of cells Virchow – discovered that all cells come from other cells

3 Tenets of the Cell theory The Cell Theory has THREE principles. 1. All living things are composed of one or more cells. 2. The cell is the most basic unit of structure of all living things. Unicellular organisms- one cell Multicellular – specialized regions called tissues. Cells Tissues Organs Organ Systems Organisms 3. All existing cells come from previously existing cells. The ability of cells to divide to form new cells is the basis for all reproduction and for the growth and repair of all multicellular organisms.

2 types of Cells Prokaryote & Eukaryotes Prokaryote Both Eukaryote No Nucleus Have DNA Nucleus Present Small in size Have Ribosomes Larger Size All Unicellular Have Cytoplasm Unicellular or Multicellular Evolved First Have a Cell Membrane Came after Prokaryotes All Bacteria Can have a Flagella Everything that’s NOT Bacteria No Membrane Bound Organelles Membrane Bound Organelles

Prokaryote & Eukaryote

2 main types of eukaryotic cells Plant & Animal Cells

Cell membranes Semi-Permeable or Selectively Permeable Helps cell to maintain HOMEOSTASIS Functions Controls what enters and exits cell Support Protection Made up of PHOSPOLIPIDS Phosphate Head (Water Loving) Fatty (Lipid) Tail (Water Fearing)

Cellular Transport Active Transport- Requires ENERGY low  high concentrations Endocytosis Exocytosis Protein Pumps Passive Transport- No ENERGY high low concentrations Diffusion Facilitated Diffusion Osmosis

Directions of Osmosis