The Cell
Cell Theory and Structure
Scientists Contributing to The Cell
Theory
Anton van
Leeuwenhoek– one of
the first people to
study nature with a
microscope– he made
detailed drawings of
little creatures he
found in pond water
Cell scientists
Robert HookeCoined the term “cell”.
He looked at cork
through the
microscope and said
the compartments
looked like the rooms
that monks lived in
“cells”
Cell scientists
Rudolph Virchow –
cells come from
preexisting cells
Cell Scientists
Schleiden - all plants
are made of cells
Schwann – all
animals are made of
cells
The Cell Theory
All the scientists previously mentioned
contributed to the Cell Theory which
states:
– All living things are composed of cells
– Cells are the basic unit of structure and
function in living organisms
– New cells are produced from pre-existing cells
Basic Cell Structures
Cell membrane- thin, flexible barrier around the
cell. It is semi-permeable, meaning some things
are let through and others are not
Cell Wall- thick outer covering found in plant,
bacteria and algae cells. Not found in animal
cells
Cytoplasm- A mixture of salt and water that
contains all the cell’s inner parts
Nucleus- The control center of the cell,
otherwise known as the “brain”. It controls cell
activities and contains the DNA
Prokaryotes and Eukaryotes
Prokaryotes- simple cells with no nucleus
or membrane-bound organelles.
Examples are bacteria
Eukaryotes- complicated cells with a
control center (nucleus) and other
organelles (means little organ) Animals
and plants have Eukaryotic cells
Images
Prokaryote
Eukaryote
Cell Structures
Cell Wall- Made from
fibers such as
cellulose
Main function is to
provide support and
structure for cell
Found in plants,
almost all bacteria
(prokaryotes), fungi
and algae
Not found in animals
The Nucleus
Discovered by Scottish botanist Robert Brown
Controls most of the cell’s activities and carries their
heredity
Chromatin is DNA in a granular mass inside the
nucleus
Chromosomes form when the chromatin wraps tightly
around proteins and condense
Nucleolus- Small, irregular structure inside the
nucleus- the first step towards making proteins
happens here
Nuclear Envelope- thin, flexible barrier that seperates
the nucleus from the rest of the cell
Cytoskeleton
A network of protein filaments that provide
support and movement for the cell
Microtubules- hollow tubes of protein that
maintain cell shape and act as “tracks”
that organelles move around on
Microfilaments- Long, thin fibers that
function in movement and support, makes
up cilia and flagella
Cilia and Flagella
Cytoplasmic Organelles
Ribosome- Proteins are made here in the
Ribosome-home
Endoplasmic Reticulum- (ER)- two types,
smooth and rough (studded with ribosomes).
Components of the cell membrane are made
here and proteins are modified
Golgi Apparatus (UPS center), proteins, carbs
and lipids are packaged and shipped all over the
cell
Cytoplasmic Organelles
Lysosomes- (Clean Up Crew) Little pac-man like
organelles that munch through the cell “eating”
trash and dead organelles
Vacuoles- (Mini-Warehouse Storage Center)stores food and water for the cell to use later
Chloroplast- Makes food in plant cells
“Mighty” Mitochondria- breaks down food and
makes energy for the cell, has its own DNA that
you get from your mother