The Fluid Mosaic Model of a Cell Membrane

Research Done:

The Fluid Mosaic Model:

-describes the cell membrane of animal cells

-has 2 layers of phospholipids (fats with phosphorous attached), which at body temperature are like vegetable oil. (fluid)

-Phospholid Molecule:

      -Each phospholid molecule has a head that is attracted to water (hydrophilic) and a tail that repels water (hydrophobic).

- Both layers of cell membrane have the hydrophilic heads pointing outwards, with the hydrophobic tails on the inside of the bilayer.

-Proteins and substances such as cholesterol become embedded in the bilayer, giving the membrane the look of a mosaic.

-Because the plasma membrane has the consistency of vegetable oil at body temperature, the proteins and other substances are able to move across it. (fluid)

Resources:

http://www.dummies.com/how-to/content/the-fluidmosaic-model-of-the-cell-plasma-membrane.html

The Fluid Mosaic Model of a Cell Membrane

Picture:

references- http://img.docstoccdn.com/thumb/orig/119157312.png

Drawing of an animal cell

Cells and their Organelles

Other interesting organelles:

Lysosome

• Originated from the GA (golgi apparatus)
• Can be found in most plant and animal cells, especially phagocytic cells.
• Breaks down worn out organelles within the cell. 
• Digests material taken in through endocytosis (e.g. amoeba feeding) or phagocytosis (ingestion of bacteria by white blood cells)
• Produces useful materials for the cell (from the break down of worn out organelles)
• Can fuse with vesicles containing objects that need digesting

Cytoskeleton (Inside Cytoplasm- not a true organelle)

• Provides support for organelles.
• Helps to direct movement of organelles inside the cell
• Provides support for the cell, to maintain the cell shape.

Cilia

• For cell motility (movement)
• Found in sperms

Cells and their Organelles

The Plant Cell

Cell Wall

• Surrounding the cell membrane
• Thick and rigid
• Composed of cellulose
• Function:
• Protects the cell
• Gives the cell a regular shape
• Supports the cell
• Fully permeable

Vacuole

• Large, central vacuole containing cell sap. (sugars, waste, pigments)
• Vacuole membrane is known as tonoplast
• Functions:
• Maintain cell turgidity
• May store various substances
• May be found in animal cells
• Small in size
• Temporary
• Usually stores water and food substances

Chloroplast

• Oval structure
• Is not green
• Contains chlorophyll which is green and makes it green.
• Involved in photosynthesis
• Can be seen under a light micrograph
• Much bigger than the mitochondria, though both organelles are similar in shape
• Contains Thylakoid (1 disc) and Granum (whole stack)

Cells and their Organelles

The Animal Cell

Nucleus

• The largest organelle
• Enclosed by nuclear membrane
• Nuclear membrane has small channels known as the nuclear pores
• Functions: 
• Contains genetic material (DNA)
• Controls cell activity
• Important for cell division

Endoplasmic Reticulum (ER) 

• Rough ER
• for protein secretion
• synthesis of proteins which are to be secreted out of the cell or to be inserted into the cell membrane.
• Smooth ER
• makes non-protein substances such as fats, lipids, steroids which are either secreted (to prevent cell damage) or used by the cell.
• Exists in stomach cells.

Ribosomes

• Bound ribosomes or Free ribosomes.
• Smallest organelle
• It has 2 sub unites
• Involved in protein synthesis
• Free ribosomes synthesize proteins found in protoplasm.

Golgi Body/ Apparatus:

• Consists of membrane-enclosed stacks
• Surrounded by Golgi Vesicles
• Vesicles from ER fuse with the Golgi Apparatus
• Functions:
• Stores and modifies contents
• Packages these substances for secretion

Mitochondrion

• Enclosed by an inner membrane (highly folded) and outer membrane
• It is the site of aerobic respiration 
• Synthesis of ATP (adenosine tri-phosphate)
• Needed for movement
• Found in sperm cells