4-2 Parts of the Eukaryotic Cell

Part 1

Cell Biology or Cytology

Cyto = cell ology = study

Uses observations from

several types of microscopes

to create a total picture of

how a cell is put together.

The Plasma Membrane

Separates the cell from the environment.

Is “semi-permeable” and regulates the movement of materials in/out of a cell.

ALL cells have a plasma membrane.

The Plasma membrane is a Bilayer Phospholipid

The Fluid Mosaic ModelThe Fluid Mosaic ModelThe individual phospholipids are constantly shifting back

and forth creating small openings…..

The motion of these “shifting” lipids is referred

to as a “fluid” motion.

In addition to the phospholipids, the plasma membrane contains:

• proteins, • cholesterol,• and carbohydrates. Together they make up the

“mosaic” portion of the “fluid mosaic” model.

The Membrane has several Protein “Groups”

Peripheral Proteins - are attached loosely to the inner or outer membrane.

Integral Proteins – extend into, or through the membrane.

Transmembrane Proteins – appear at both the inner and outer surface.

The Proteins, found in the Plasma Membrane, have

several functions…. They are: Channel Proteins Transport Proteins Recognition Proteins Adhesion Proteins Receptor Proteins Electron Transfer Proteins

Channel Proteins are passageways for certain substances

through the plasma membrane

Transport Proteins

use energy (ATP) to transfer materials across the membrane

Recognition Proteinsdistinguish the identity of neighboring cells.

are also called “glycoproteins” because they have short sugar or carbohydrate chains attached.

the sugar chains stick out from the surface like antennae. Glycoproteins

Adhesion Proteins

attach cells to other cellsor

provide anchors for filaments

Receptor Proteins

act as binding sites for hormones or other trigger molecules

Electron Transfer Proteins are involved in transferring electrons from one molecule to

another during chemical reactions

Glycocalyx

is a carbohydrate “coat” covering the outer face of the

plasma membrane…. the glycocalyx provides recognition markers for cell

to cell recognition

Organelle is a term meaning "small

organ”. is a part or body in a cell with

a specialized function. is an important organizational

structure of cells.

Organelles

are a way to form compartments in cells to separate chemical reactions.

they keep various enzymes separated in space.

In other words, they are bags of enzymes!

Cytoplasm

is an Area (not stuff) between the cell membrane and the nuclear envelope.

It contains the cytosol, and nucleus and cell organelles

(if it’s a eukyote).

Cytosol

is the Semi-fluid portion of the cytoplasm (the gooey stuff inside the cell)….

It is composed mostly of water and nutrients.

Animal Cell

Plant Cell

To be continued…….go to

4-2, Part 2