Week 4 - Cell Organelles and Function
Week 4 - Cell Organelles and Function
Week 4 - Cell Organelles and Function
Organelles and
Functions
Prokaryotic and
Eukaryotic Cells
A eukaryote is any
organism whose cells
contain a nucleus and
other organelles
enclosed within
membranes.
Prokaryotes are unicellular
organisms that lack organelles
or other internal membrane-
bound structures. Therefore,
they do not have a nucleus, but,
instead, generally have a single
chromosome: a piece of circular,
double-stranded DNA located in
an area of the cell called the
nucleoid.
Parts and Functions of Prokaryotic cell
Capsule: Found in some bacterial cells, this additional outer covering
protects the cell when it is engulfed by other organisms, assists in retaining
moisture, and helps the cell adhere to surfaces and nutrients.
Pili (Pilus singular): Hair-like structures on the surface of the cell that
attach to other bacterial cells. Shorter pili called fimbriae help bacteria attach
to surfaces.
Plasmids: Plasmids are gene carrying, circular DNA structures that are not
involved in reproduction.
Cell membrane: Surrounds the cell's cytoplasm and regulates the flow of
substances in and out of the cell.
Cell wall: Outer covering of most cells that protects the bacterial cell and gives
it shape.
Nucleoid: Area of the cytoplasm that contains the single bacterial DNA
molecule.
Prokaryotic Cells Eukaryotic cells
plant cells
Eukaryotes
animal cells - organelles
Cell size comparison
Animal cell
Bacterial cell
most bacteria
1-10 microns
eukaryotic cells
10-100 microns