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LO: SWBAT explain how the cell theory was developed
Do Now: What instrument was vital for scientists to discover and learn about cells? How does this instrument work?
HW: Read pages 169-172, page 172 # 1-5
What instrument was vital for scientists to discover and learn
about cells?
Light Microscope
A light microscope can magnify objectsup to 1000 times.
This instrument allows scientists to see larger parts of a cell (cell membrane, nucleus, chromosomes, etc…)
Anton van Leeuwenhoek 1600’s
Spiral Bacteria
Human Sperm
Developed simple light microscopes that allowed him to examine tiny living organisms he called “animacules”
Robert Hooke(1665)
CORK CELLSWhat is this?
First Compound Microscope
First person to use the word “cell”
Matthias Schleiden (1838)ALL PLANTS ARE MADE OF
CELLS
Theodor Schwann (1838)ALL ANIMALS ARE MADE UP OF
CELLS
Rudolf Virchow (1858)
CELLS COME FROM
PRE-EXISTING CELLS
Cell theory• All living things are made of cells
• Cells are the basic unit of structure and function (metabolism)
• New cells come from pre-existing cells
What are some problems with the Cell Theory?
• Are viruses living?
• Where did the first cell come from?
Viruses
They are not made up of cells, but are
they living?
What do you know about viruses?
•They can make you very sick
•They can be transmitted
from person to person
•There are different types
of viruses
HOW BIG IS A VIRUS?
They are microscopic and
smaller than cells!
Too small to be seen with a light microscope
How can we determine if a virus is living or non-living?
• Is it made of cells?
• Does it maintain homeostasis?
• Does it carry out metabolism?
• Does it reproduce?
Is a virus living or non living?
Introduction to Viruses Video
How are cells classified?
How do these cells compare?
SIMPLE
COM
PLEX
Cells are broken down into two main classes:
Cells
Prokaryotic Eukaryotic
Prokaryotes:
Were probably the first life forms to appear on earth 3.5 billion years ago
Harsh Early Earth
What were the conditions on Earth at this time?1)Hot2)Little Oxygen3)Abundant Lightning4) Volcanic Activity
Why do you think Prokaryotes were the first life forms on earth?
1)Simple Structures
2) Their ability to tolerate harsh environments
3) Their ability to adaptto changing
environments
What are some features of prokaryotes?
1)Prokaryotes have NO NUCLEUS!!2) Have few organelles (mini-organs)3) PROKARYOTES = BACTERIA
** Although prokaryotes do not have nuclei, theydo have DNA.
What organisms are made up of eukaryotic cells?
Plants Animals Fungi Protists
All other living things are made up of Eukaryotic Cells
What are some features of typical eukaryotic cells?
1) They are more complex
2) Appeared later on earth
3) They have nuclei4) They are larger5) Have more organelles6) Have membrane
boundorganelles
Eukaryotes
CELL TYPES
• PROKARYOTIC
• HAVE only a few ORGANELLES
• HAVE NO NUCLEUS
• PRIMITIVE CELLS
• Only Bacteria
• EUKARYOTIC
• HAVE ORGANELLES
• HAVE NUCLEUS
• MODERN CELLS
• All other living things: animals, plants, fungi, protist (unicellular organisms)
What do all cells have in common?
• Cell membrane – gives shape to the cells and allows things in and out.
• The cytoplasm – the jelly like material where all cell parts are found
Compare and contrast these two cars?
SIMPLE
COMPLEX
How Do These Cells Compare?
SIMPLE
COM
PLEX
Eukaryotes evolved from prokaryotes