Реферат: The Plant Cell Essay Research Paper Cell

The Golgi Apparatus is a series of stacked membranes in the cytoplasm that packages proteins for

secretion or storage in vesicles. Inside the membranes are sacs of fluid or gel-like substances. The Golgi

Apparatus takes proteins in transport sacs from the endoplasmic reticulum and sends it through a series of

these membranes. The proteins are then “modified”‘ as they pass from membrane to membrane. After the

vesicle of proteins has finished its trip through the Golgi Apparatus, it buds off the organelle in a Golgi sac,

ready to be stored or transported to other parts of the body.

Cell Membrane

Size: 7 to 8 NM (nanometers)

Basic Function:

* Controls what enters and exits the cell.

* Separates cell from outer environment.

On the outside of all cells, there is a layer of protein and lipid (fat) called the cell membrane or the

plasma membrane. This membrane is found in ALL cells. The membrane is selectively permeable, meaning

it allows some molecules to enter and some not to. The membrane allows molecules in through two forms

of transport, active and passive. Passive transport consists of simple diffusion through the pores in the

membrane or carrier molecules. Active transport consists of endocytosis, exocytosis, and the sodium-

potassium pump. The membrane also protects the cell from the outside environment, keeping the cytoplasm

and its organelles in, and all of the stuff outside out.

Mitochondria

Size: 2 to 3 ?m

Basic Function:

* Serves as “respiration” center” for cell.

* Makes energy for the cell.

Floating inside the cytoplasm are a series of fairly large organelles called Mitochondria. These

organelles, the size of some bacteria, serve as the cell’s respiration centers, the place where energy for the

cell is produced. Since the Mitochondria serves as a center for energy production, there are varying

numbers of mitochondria in different cells. Muscles have many mitochondria due to the amount of energy

they need, but skin cells have very few. The mitochondria (singular: mitochondrion) have two membranes.

The outer membrane protects the organelle, and the inner membrane is folded into a series cristae or long