The Cell Theory SOL BIO 2a

The Cell  The smallest unit that can perform all life processes

The Cell Theory  The development and refinement of magnifying lenses and light microscopes made the observation and description of microscopic organisms and living cells possible.

The Cell Theory  Many scientists contributed to the cell theory

Microscope/Leeuwenhoek image: Animation from: ___________________________________ a Dutch microscope maker was the first to see LIVING ORGANISMS in pond water. Anton van Leeuwenhoek His observations are now called micro-organisms

Microscope image: Cork image: Hooke image: used a microscope to examine a thin slice of cork and saw “little boxes” He called them “CELLS” because they looked like the small rooms that monks lived in called Cells Robert Hooke

Plant image: Schleiden image: German botanist __________________________ concluded that ALL PLANTS are made of cells Matthias Schleiden

Schwann image: Animals image: German zoologist _________________________ concluded that ALL ANIMALS ARE MADE OF CELLS Theodor Schwann

Virchow: Mitosis: German medical doctor _____________________ saw dividing cells in the microscope and reasoned that cells come from other cells Rudolph Virchow

Review: Biologists and Their Discoveries That Led to The Cell Theory  Robert Hooke  Anton van Leeuvenhoek  Matthias Schleiden  Theodor Schwann  Rudolph Virchow  First light microscope, cork made of “cells”  Simple microscope, living organisms in water  Plants made of cells  Animals made of cells  Cells come from existing cells

CELL THEORY 1. All living things are ________________________. 2. Cells are the basic unit of in an organism. ____________ & _____________ in an organism. (cell = basic unit of _____________) (cell = basic unit of _____________) 3. Cells come from the reproduction of ____________ cells Cell image: MADE OF CELLS other life STRUCTURE FUNCTION

The Cell Theory  Continued advances in microscopy allowed observation of cell organelles and structure.

For centuries people (including scientists)believed that simple living organisms could comeinto being by spontaneous generation.  For centuries people (including scientists) believed that simple living organisms could come into being by spontaneous generation. This was the idea that non-living objects can giverise to living organisms. It was common“knowledge” that simple organisms like worms,beetles, frogs, and salamanders could come fromdust, mud, etc., and food left out, quickly“swarmed” with life.  This was the idea that non-living objects can give rise to living organisms. It was common “knowledge” that simple organisms like worms, beetles, frogs, and salamanders could come from dust, mud, etc., and food left out, quickly “swarmed” with life. Theoryof Spontaneous Generation – FALSE! Theory of Spontaneous Generation – FALSE!

Spontaneous generation – FALSE! Example: Every year in the spring, the Nile River flooded areas ofEgypt along the river, leaving behind nutrient-rich mud thatenabled the people to grow that year’s crop of food. However,along with the muddy soil, large numbers of frogs appeared thatweren’t around in drier times. Example: Every year in the spring, the Nile River flooded areas of Egypt along the river, leaving behind nutrient-rich mud that enabled the people to grow that year’s crop of food. However, along with the muddy soil, large numbers of frogs appeared that weren’t around in drier times. Conclusion: It was perfectly obvious to people back then that muddysoil gave rise to the frogs. Conclusion: It was perfectly obvious to people back then that muddy soil gave rise to the frogs. Back then people made conclusions based on untested observations.

FrancescoRedi Francesco Redi People believed that maggots came from dead meat. Redi’s experiment DISPROVED this theory.

Louis Pasteur – Louis Pasteur –

The Germ Theory by Robert Koch The Germ Theory by Robert Koch Specific types oforganisms causesspecific diseases Specific types of organisms causes specific diseases Those organisms canbe controlled inpeople Those organisms can be controlled in people Those organisms canbe controlled in wine,beer and milk Those organisms can be controlled in wine, beer and milk

Robert Koch Along with Louis Pasteur, Koch is known as one of thefounding fathers of microbiology  Along with Louis Pasteur, Koch is known as one of the founding fathers of microbiology He was the first to state that specific bacteria wereconnected to certain diseases  He was the first to state that specific bacteria were connected to certain diseases Discovered, Bacillus anthracis, Tuberculosis bacillus, andVibrio cholera  Discovered, Bacillus anthracis, Tuberculosis bacillus, and Vibrio cholera Formulated Koch’s Postulates which are still used today  Formulated Koch’s Postulates which are still used today

In order to establish that a specificbacteria is the cause of adisease, the researcher must In order to establish that a specific bacteria is the cause of a disease, the researcher must 1.Find the same pathogen in eachdiseased individual investigated 1. Find the same pathogen in each diseased individual investigated 2.Isolate the culture and pathogen 2. Isolate the culture and pathogen 3.Induce the disease inexperimental animals bytransferring the pathogen fromthe culture 3. Induce the disease in experimental animals by transferring the pathogen from the culture 4.Isolate the same pathogen fromthe experimental animals afterthe disease develops 4. Isolate the same pathogen from the experimental animals after the disease develops Koch’sPostulates Koch’s Postulates

Why is this important? Lead to the discovery of  Lead to the discovery of Vaccines Antibiotics Proper hygiene Example: Childbirth – Doctors would performautopsies on children who had died from childbirthfever, then go and deliver a child without washingtheir hands.  Example: Childbirth – Doctors would perform autopsies on children who had died from childbirth fever, then go and deliver a child without washing their hands.YIKES!!

The Microscope We’ve come a long way!

Simple Microscope

To find total magnification = eye piece x objective Ex: 10X x 4X = 40X total magnification Compound Light Microscope

Electron Microscope

Electron microscope

Light microscope vs. Electron microscope 35 Image EMs show details that are 1000 times smaller than light microscopes can

Electron Microscopy

The Discovery of Cells before nucleus true nucleus

What’s the difference?

Two basic types of cells Prokaryotes Prokaryotes - cells with no nucleus or membrane bound organelles Eukaryotes Eukaryotes – cells with a nucleus and membrane bound organelles

PROKAYOTE   No nucleus   No membrane bound organelles   DNA in a nucleoid region   Simple and smaller   Have a cell wall   Have flagella and cilia   All bacteria are prokaryotes

  Members of the Kingdom Eubacteria and Archaebacteria   Can live in extreme environments (hot, cold, high salt, high acid)   Prokaryotes were probably the first forms of life!   Some eventually gained the ability to photosynthesize which changed the atmosphere? How?   Increase in oxygen allowed aerobic respiration to develop and more efficient energy – created more complex organisms Thank you Prokaryotes!!!!!!!

EUKARYOTE   Eukaryotes arose from prokaryotes   They developed into larger, more complex organisms   Larger and more complex than prokaryotes   Have a true nucleus   Have membrane bound organelles   Kingdoms – Protists, Fungi, Plant, and Animal

ProkaryoticEukaryotic

ProkaryoticEukaryotic Ribosomes (red)

ProkaryoticEukaryotic Ribosomes (red) Nucleus (black)

ProkaryoticEukaryotic Ribosomes (red) Nucleus (black) Cytoplasm (yellow)

ProkaryoticEukaryotic

PROKARYOTIC BOTH EUKARYOTIC Nucleus DNA Bacteria Cytoplasm Ribosomes Complex Basic Oldest Small Organelles Large Cell Membrane

EUKARYOTE Animal vs. Plant Animal Cells: Small vacuoles Lysosomes Centrioles Plant Cells: Large vacuole Chloroplast Cell Wall

52 Plant Cells Cells Animal Cells Cells Cell Membrane Golgi Apparatus Mitochondria Nucleolus Nuclear Envelope Nucleus Ribosomes Endoplasmic Reticulum DNA Large vacuole Cell Wall Chloroplast Centrioles Small vacuole