Cells
Below are a list of organelles, where they are found and the corresponding fuctions of the organelles.
ORGANELLE |
In
bacteria? |
In plant?
|
In
animal? |
STRUCTURE
& FUNCTION |
Cell
membrane
(Plasma membrane) |
Yes |
Yes |
Yes |
Boundary
between intracellular & extracellular environments. Regulates
entry/exit of substances. |
|
Cell
wall |
Yes,
usually |
Yes |
No |
Rigid
structure providing support for cell. |
|
Cytoplasm |
Yes |
Yes |
Yes |
Jelly-like
substance filling intracellular space contains dissolved substances. |
|
Cyto-skeleton |
No |
Yes |
Yes |
Network
of fine tubes and threads. Provides internal structural support. |
|
Centrioles |
Rarely |
No,
but aster is similar. |
Yes |
Paired
rods, which help organize microtubules during mitosis. |
|
Nucleus |
No |
Yes |
Yes |
Membrane-bound
structure containing cells' genetic information (DNA) and support
molecules. |
|
Nucleolus |
No |
Yes |
Yes |
Small
structure within nucleus. Site of production of ribosomal RNA. |
|
Nuclear
Membrane |
No |
Yes |
Yes |
Boundary
between nucleus and cytoplasm. Regulates passage of materials
between the two. |
|
Flagella,
pili or cilia |
Sometimes
flagella or pili |
Rarely,
but some specialized cells may. |
Only
present in some specialized cells. |
Structures
used to enable movement of cells or sometimes to propel substances
across outer surface of the cell. Predominantly protein in
composition. |
|
Mitochondria |
No |
Yes |
Yes |
Membrane
bound organelles. Folded membranes within contain enzymes for
aerobic respiration. (A little DNA in here too.) |
|
Chloroplasts |
No |
Only
in photosynthetic cells |
No |
Membrane
bound organelles. Folded membranes within contain chlorophyll and
enzymes for photosynthesis. (A little DNA in here too.) |
|
Vacuole |
No |
Yes,
often large |
Unusual,
and small if present. |
Membrane
bound area filled with water and assorted solutes. Role in
maintenance of water balance of the cell. |
|
Ribosomes |
Yes |
Yes |
Yes |
Small
organelles at which protein synthesis occurs. May be free floating
or membrane-bound. |
|
Endoplasmic
reticulum |
No |
Yes |
Yes |
Network
of flattened membranes forming tunnels. Enzymes assisting synthesis
of some lipids and final processing of proteins found here. |
|
Endoplasmic
reticulum |
No |
Yes |
Yes |
Similar
to smooth ER, but with ribosomes embedded in membrane. Proteins to
be exported from cell produced here. |
|
Golgi
apparatus (aka
Golgi Body) |
No |
Yes |
Yes |
Stacks
of saucer shaped membranes where export proteins are modified and
stored prior to entering secretory vesicles for exocytosis. |
|
Lysosomes |
No |
Yes |
Yes |
Membrane
bound structure-containing enzymes, which break down toxic or
unwanted molecules. |
|
Plastids |
No |
Yes |
No |
Membrane
bound structures with varied functions. Leucoplasts - starch
storage. Chromoplasts - colored pigments within (eg flower petals). |
|
Vesicles |
No |
Rare |
Yes |
Packages for storage (eg fat droplets) or temporary transport associated with endocytosis/exocytosis. |