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.

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 cytoskeleton – microscopic fibers; gives shape & support 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

Prokaryotes Single celled organisms ex: bacteria Lacks a nucleus Lacks membrane bound organelles Contains a single circular molecule of DNA Many have cell walls that surround the cell membrane; it 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 Single or multicellular organisms ex: plant or animal cells o Has a nucleus with DNA inside; linear DNA o Has membrane bound organelles that carry our specific activities o Have cilia; tiny hair-like structures o Has cytoskeleton (protein fibers) that gives the cells shape and support

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

Eukaryotic Cell

What’s different about each cell? DNA (DNA) Membrane-bound