3.1 Cell Theory
KEY CONCEPT Cells are the Basic unit of life.
3.1 Cell Theory
The cell theory grew out of the work of many scientists
and improvements in the microscope.
• Many scientists contributed to the cell theory.
3.1 Cell Theory
The cell theory grew out of the work of many scientists
and improvements in the microscope.
• Many scientists contributed to the cell theory.
• More was learned about cells
as microscopes improved.
3.1 Cell Theory
The cell theory grew out of the work of many scientists
and improvements in the microscope.
• Many scientists contributed to the cell theory.
• More was learned about cells
as microscopes improved.
• The cell theory is a unifying
concept of biology.
3.1 Cell Theory
Robert Hooke 1665
Observes holes in cork under microsocope.
Names the spaces “cells” as they remind him of the
small rooms found in a religious monastery
Really was observing empty spaces where cells were
before dying
3.1 Cell Theory
Anton von Leeuwonhoek
(just call me Tony)
Dutch lens maker
First to observe and describe
single-celled organisms,
which he originally referred to as
animalcules and cavorting beasties
Today we call what he saw microorganisms – bacteria and
protists
Was also the first to record microscopic observations
of muscle fibers, bacteria, spermatozoa, and blood flow
in capillaries (small blood vessels).
3.1 Cell Theory
Robert Brown
Robby Bobby said –
“That dark structure found
inside many cells should be
called a Nucleus”
3.1 Cell Theory
Theodore Schleiden
Ted said “All plants are composed of cells”
3.1 Cell Theory
Matthias Schwann
Matt knew where it was at when he
declared
“ALL animals (like swans) are made
of cells”
3.1 Cell Theory
Rudolf Virchow
Rejected the concept of
spontaneous generation, which
held that organisms could arise
from nonliving matter
spontaneously.
Rudy’s Rule:
“All cells come from other cells”
3.1 Cell Theory
Early studies led to the development of the cell theory.
• The Cell theory has three principles.
– All organisms are made of cells.
3.1 Cell Theory
Early studies led to the development of the cell theory.
• The Cell theory has three principles.
– All organisms are made of cells.
– All existing cells are produced by other living cells.
3.1 Cell Theory
Early studies led to the development of the cell theory.
• The Cell theory has three principles.
– All organisms are made of cells.
– All existing cells are produced by other living cells.
– The cell is the most basic unit of life.
3.1 Cell Theory
There are thousands of different types of cells that make
up living organisms.
3.1 Cell Theory
All cells share some characteristics
• Most cells are microscopic.
Bacterium
(colored SEM; magnification 8800x)
3.1 Cell Theory
All cells share some characteristics
• Most cells are microscopic
• All cells are enclosed by a membrane
cell membrane
Bacterium
(colored SEM; magnification 8800x)
3.1 Cell Theory
All cells share some characteristics
• Most cells are microscopic
• All cells are enclosed by a plasma membrane
• All cells are filled with cytoplasm
(gel like substance mostly made of water)
cell membrane
cytoplasm
Bacterium
(colored SEM; magnification 8800x)
3.1 Cell Theory
All cells share some characteristics
• Most cells are microscopic
• All cells are enclosed by a plasma membrane
• All cells are filled with cytoplasm
(gel like substance mostly made of water)
• All cells have genetic information
cell membrane
cytoplasm
Bacterium
(colored SEM; magnification 8800x)
3.1 Cell Theory
All cells share some characteristics
• Most cells are microscopic
• All cells are enclosed by a plasma membrane
• All cells are filled with cytoplasm
(gel like substance mostly made of water)
• All cells have genetic information
cell membrane
cytoplasm
Bacterium
(colored SEM; magnification 8800x)
3.1 Cell Theory
Main Idea#2: Cells can be separated into two broad
categories based on their internal structure.
2 Basic Cell Types: Eukaryotic cells and Prokaryotic cells.
1. Prokaryotic Cells
These cells DO NOT have a nucleus or organelles
2. Eukaryotic Cells
These cells DO have a TRUE nucleus and organelles
3.1 Cell Theory
Eukarytic Cells
• Eukaryotic cells have a
nucleus.
nucleus
cell membrane
3.1 Cell Theory
Two major cell types: Eukaryotic cells and Prokaryotic cells
•
•
Eukaryotic cells have a nucleus.
nucleus
Eukaryotic cells have
membrane-bound organelles.
organelles
cell membrane
3.1 Cell Theory
Two major cell types: Eukaryotic cells and Prokaryotic cells
nucleus
organelles
•
Prokaryotic cells do not
have a nucleus.
cell membrane
3.1 Cell Theory
Two major cell types: Eukaryotic cells and Prokaryotic cells
nucleus
organelles
•
Prokaryotic cells do not
cell membrane
have a nucleus.
•
Prokaryotic cells do not
have membrane-bound
cytoplasm
3.1 Cell Theory
Eukaryotes are organisms made of Eukaryotic cells
Organisms that have Eukaryotic cells include:
• Protists
• Fungi
• Plants
• Animals
3.1 Cell Theory
Organisms are made of either prokaryotic or eukaryotic cells
Prokaryotes are organisms made of Prokaryotic cells
Organisms that have Prokaryotic cells include:
• Bacteria (2 groups: Archaea, Bacteria)
•
•
•
•
Eukaryotes are organisms made of Eukaryotic cells
Organisms that have Eukaryotic cells include:
Protists
Fungi
Plants
Animals
3.1 Cell Theory
Prokaryotic Cells
No Nucleus
Eukaryotic Cells
Nucleus
No membrane surrounded
organelles
Membrane surrounded
organelles
Smaller
Larger
Single celled/ Unicellular
Single or Multicellular
Found in bacteria, archaea Found in protists, fungi, plant
and animals
Circular DNA
DNA + proteins=Chromosomes
3.1 Cell Theory
Fossil Evidence of Prokaryotic and Eukaryotic Cells
PROKARYOTES
EUKARYOTES
Photosynthetic marine bacteria Evolved 1.5 billion yrs ago
3.5 Billion Years Ago
First ones were unicellular
Later cells became
multicellular
3.1 Cell Theory
Endosymbiotic Theory
Developed in the 1970’s
Endosymbiosis- a relationship in which one organism lives
within the body of another and both benefit from relationship.
Early mitochondria and chloroplasts were once simple
prokaryotic cells that were taken up by larger prokaryotes
around 1.5 bya. Some of the smaller prokaryotes may have
survived inside the larger ones. Both strutures helped the
larger cell get energy.
Mitochondria and Chloroplasts have their own DNA &
ribosomes, can copy themselves
3.1 Cell Theory
Endosymbiosis
3.1 Cell Theory
Parts of a Prokaryotic Cell
3.1 Cell Theory
Prokaryotic Cell Structures and their Functions
A. Plasma Membrane –
Protective coating surrounding the cytoplasm that
regulates(controls) what enters/leaves cell.
Archaea have special lipids in their membranes not found
in any other type of organism on Earth.
B. Cell Wall –
Covering outside the cell membrane.
Bacteria have peptidoglycan molecules, Archaea don’t
C. Capsule – Made of polysaccharides and located outside
cell wall. Helps bacteria not dry out and avoid being
attacked. Bacteria with capsules are often disease causers.
3.1 Cell Theory
D. Cytoplasm
Fluid filled space inside cell membrane. Mostly water.
E. Ribosomes
Site where amino acids join together through
dehydration synthesis to form protein molecules.
F. Nucleoid
Location where DNA is found in prokaryotes
G. Plasmid
Small piece of DNA separate from main chromosome
3.1 Cell Theory
I. Flagella
Long, whiplike structure used for moving.
J. Pili
Thinner, shorter, more numerous than flagella.
Allows prokaryotes to stick to surfaces and other
prokaryotes.
3.1 Cell Theory
3.1 Cell Theory
Helpful Animations and Videos
Prokaryotic vs. Eukaryotic Cells: Comparison and Contrast
http://science.howstuffworks.com/life/28732-assignmentdiscovery-elements-of-cells-video.htm
http://www.youtube.com/watch?v=y623clAREHI
http://www.youtube.com/watch?v=yWy4o_UfZ4A
http://www.youtube.com/watch?v=WRO-DPyB9Bk