The Cell Theory Important Scientists Robert Hooke 1665

The Cell Theory Important Scientists: Robert Hooke – (1665) observed thin slices of cork and saw a lot of little boxes he called “cells” Anton van Leeuwenhoek – (1674) observed live cells in pond water and called them “animalcules”

Mattias Schleiden – (1838) concluded that plants are made of cells Theodor Schwann – (1839) concluded that animals are also made of cells Rudolph Virchow – (1858) determined that cells come only from other cells

The Cell Theory 1. All living things are made of 1 or more cells. 2. Cells are the basic units of structure & function in organisms. 3. All cells arise from existing cells.

The Theory of Abiogenesis & Biogenesis Abiogenesis o Living from nonliving or spontaneous generation o Disproved by Redi and Pasteur’s experiments vs. Biogenesis o Living from living o Proved by Pasteur’s experiment Pasteur’s Experiment Redi’s Experiment

Two Major Types of Cells: v Prokaryotes v Eukaryotes

Prokaryotes NO nucleus NO membrane bound organelles Single celled organisms ex: bacteria Contains a single circular molecule of DNA Many have cell walls that surround the cell membrane; provides support and structure o Some cell walls are surrounded by a capsule which is composed of polysaccharides o Many have flagella which enables it to move o o o

Eukaryotes o Has a nucleus with linear DNA inside o Has membrane bound organelles that carry our specific activities o Single or multicellular organisms ex: plant or animal cells o Have cilia; tiny hair-like structures o Has cytoskeleton (protein fibers) that gives the cells shape and support

Common Cell Features: q cell membrane – outer boundary of a cell that encloses the cell & separates the cell interior from its surroundings; it regulates what enters and leaves the cell. o cytoplasm – the cell’s interior; jelly like substance; contains or holds cell’s structures o ribosomes – cellular structures on which proteins are made o DNA – provides instruction for making proteins; it regulates cellular activities and enables cells to reproduce

Eukaryote vs. Prokaryote (Eukaryotic Cell vs. Prokaryotic Cell)

Eukaryotic Cell

Prokaryotic Cells Eukaryotic Cells

Endosymbiotic Theory The theory of the origin of eukaryotic cells from prokaryotic organisms.