Transcript The Cell Theory

BELLRINGER
Please turn in the notes you took over the
virtual investigation we did on Monday (Cell
and Cell Structure App). Even if you didn’t
finish, turn in what you have completed.
Grab cell vocabulary and cell and cell theory
notes from the front table.
LEARNING TARGETS
Explain the 3 main ideas of the cell theory.
Explain the difference between prokaryotic
and eukaryotic cells.
Explain how cells are organized into larger
tissues, organs, organ systems.
THE CELL THEORY

ROBERT HOOKE (1665)
 English scientist.
 Developed the first compound microscope .

ROBERT HOOKE
 In 1665, he used his
microscope to look at cork
cells.
 Hooke coined the term “cell”
 What he saw under the
microscope reminded him of
the living quarters of the
monks (cells).

ANTON VAN LEEUWENHOEK
(1674)
Dutch curtain maker
who ground lenses as a
hobby.
Improved and
perfected the
microscope.
The first to observe
living cells
 (blood cells and bacteria
from his teeth.)

MATHIAS SCHLEIDEN (1837)
 German Botanist
 Observed that all plants are made up of cells .

THEODOR SCHWANN (1837)
 German Zoologist
 Observed that all animals are made up of cells .

RUDOLF VIRCHOW (1858)
 German Doctor
 The first to observe living
cells reproduce.
 Deduced that animal cells
come only from animals,
plant cells come only from
plants.

CELL THEORY SCIENTISTS
 Cell Theory Video

THE CELL THEORY
The observations of these scientists led to the cell theory.

The modern cell theory has 6 parts:
Traditional (Main):
1. Cells are the basic units of life
2. All living things are made of one or more cells.
3. All cells come from preexisting cells.
Additional
o
o
o
energy flow (metabolism and biochemistry) occurs within cells;
cells contain hereditary information (DNA) that is passed from
cell to cell during cell division; and
all cells are basically the same in chemical composition in
organisms of similar species .

ORGANIZATION OF LIFE
 Organisms can be single-celled or multicellular.
 Multicellular organisms are organized into complex structures .
 Multicellular organisms have specialized cells to perform a
single function.
 Ex. Red blood cells carry oxygen; muscle cells provide movement.

MOLECULES
COMBINE TO FORM

CELLS
COMBINE TO FORM
Red blood cells

TISSUES
COMBINE TO FORM
Cardiac muscle

ORGANS
COMBINE TO FORM
Heart

SYSTEMS
COMBINE TO FORM
Circulatory System

ORGANISMS
COMBINE TO FORM

ECOSYSTEMS

WHAT LIMITS CELL SIZE?
 As a cell increases in size, its volume increases faster than its
surface area
 A cell must be able to fill its volume with nutrients and empty
its volume of wastes
 If a cell grows too large, it will not be able to take in enough
food, or get rid of wastes fast enough to survive!
ANOTHER WAY TO LOOK AT IT:
 Each tiny cube
(cell) is better able
to exchange
nutrients and
wastes than the
big cube
ANOTHER WAY TO LOOK AT IT:
TALK IT OVER
 Which cell would be better at exchanging gases (such as oxygen
and carbon dioxide) the red blood cell or the white blood cell and
why?
T YPES OF CELLS
 Prokaryotic cells – primitive cells that have little internal
structure.
 Eukaryotic cells – evolved from prokaryotic cells and contain
numerous internal structures.

 Organelles – structures in the cell responsible for carrying out
specific functions. “cell organs”

PROKARYOTIC CELLS
 Prokaryotic cells do not contain a nucleus or any membrane
bound organelles.
 They are always single-celled organisms.
 Ex. Bacteria
 Very simple structure – cell wall and membrane surrounding
cytoplasm.
 Divide by binary fission

EUKARYOTIC CELLS
 Eukaryotic cells contain a
nucleus and membranebound organelles.
 Can be single-celled or
multicellular organisms.
 Ex. Algae (single), plants
(multi), animals
 Divide by mitosis
 Structure divided into 3
areas: NUCLEUS,
CY TOPLASM, AND CELL
MEMBRANE.
 Eukaryotic cells have
numerous organelles