1. Cell Theory What have we learned about cells over time?
What do we currently know about cells?

2. The 3 Main points of CELL THEORY
ALL ORGANISMS ARE COMPOSED OF 1 or MORE CELLS (Schwann, 1839) THE CELL IS THE BASIC UNIT OF LIFE IN ALL LIVING THINGS (Schwann, 1839) ALL CELLS COME FROM EXISTING CELLS (Virchow, 1858)

3. Who was the first person to see single-celled organism?
Anton Von Leuwenhoek – the guy who is credited with inventing the microscope
Saw ‘beasties’ (bacteria) under 200x magnification
He observed bacteria in pond water- bacteria which couldn’t be seen with the naked eye

4. Who named cells? Robert Hooke (1665)
He observed slices of cork under a microscope and called the box-like structures “cells”

5. Plant and Animal Cells
In 1838, Matthias Schleiden proposed that all plants are made of cells
In 1839, Theodor Schwann proposed that all animals are made of cells

6. All organisms are made of 1 or more cells
Sometimes there are organisms made of only 1 cell: single celled organisms; unicellular creatures Prokaryotic cells do not contain a nucleus (ex/ Archaebacteria & Eubacteria) Eukaryotic cells contain a nucleus (ex/ Protozoa (Paramecium), gametes) We and many other creatures are made of more than one cell: multicellular organisms (ex/ Protozoa (Kelp), Fungi, Plants, Animals)

7. The cell is the basic unit of life in all living things
Living things must reproduce (sexually or asexually)
Living things contain genetic material (DNA)
Living things utilize energy (Metabolism, cell transport)
Living things grow and develop (get larger and change as they grow)
Living things respond to stimuli (the environment affects the activity of an organism. The organism tries to maintain homeostasis
Vocab:
Homeostasis: maintaining a stable internal environment

8. All cells come from existing cells
In 1858 Rudolf Virchow observed cellular reproduction (asexual)
Theorized that cells all come from other cells
Well, how did the first cells come to be?
Scientists are still trying to find this out...
ENDOSYMBIONT THEORY: mitochondria and chloroplasts descended from ancient prokaryotes, and developed a symbiotic (mutual benifiting) relationship; they “live” inside eukaryotic cells

9. NOW… How do we define a ‘typical’ cell?
Kinda Tough…. There is no typical cell We can group them as prokaryots/eukaryots Uni- or Multi- cellular Plants or Animal Cells Identify Organelles

10. PROKARYOTES vs EUKARYOTES
Fun fact: Karyot = Kernel
There are no typical cells, but we divide them into two sub categories.
Prokaryotes are mainly bacteria
Eukaryotes are mostly higher plants and animals
They have many similarities:
They contain DNA (genetic material)
They have a cell membrane
They have ribosomes
They have cytoplasm
They MAY have flagella or cilia
They have mechanisms for creation of ATP (energy)
They contain many similar structures and mechanisms

11. PROKARYOTES vs EUKARYOTES
IMAGES
Fun fact: Karyot = Kernel

12. Can be uni- or multi-cellular Have a sticky capsule
PROKARYOTES
EUKARYOTES
Contain no nucleus
Have a nucleus
Contain no organelles
Have organelles
Are all unicellular
Can be uni- or multi-cellular
Have a sticky capsule
Covered in a n extracellular matrix outside of the plasma membrane
All contain cell walls
Have cytoskeletons
Were likely the very first cells (2.5 bya)
Likely evolved from prokaryotes (~1by after prokaryotes)
They can live in a variety of environments
May need to have adapted to it’s environment
All are bacteria
Includes everything which is not bacteria
Smaller in size
Much larger in size
DNA is in a ring formation
DNA is in a linear (chromosomal) form
Reproduce asexually
May reproduce sexually or asexually

13. Unicellular Organisms Multicellular organism
May be prokaryotic or eukaryotic
Must be eukaryotic
Made of only 1 cell
Made of 1 or more cells
Can do all functions required for life (reproduce, produce waste… etc)
Cells are specialized and work together (skin cells, digestive tract lining cells, etc…)
Likely the first type of cell
Likely evolved from unicellular