8. Mitochondria

• are membrane-enclosed organelles found in most eukaryotic cells

• ange from 0.5–10 micrometers in diameter

• described as "cellular power plants" because they generate most of the cell's supply of ATP, used as a source of chemical energy

 Structure 

• contains outer and inner membranes composed of phospholipid bilayers and proteins

• Outer Membrane

  • encloses the organelles

  •  has a protein-to - phospholipid ratio similar to that of the eukaryotic plasma membrane (about 1:1 by weight)

  • contains large numbers of integral proteins called porins

• Inner Membrane contains four types of proteins:

  • (1) Those that perform the redox reactions of oxidative phosphorylation

  • (2) ATP synthase, which generates ATP in the matrix

  • (3) Specific transport proteins that regulate metabolite passage into and out of the matrix

  • (4) Protein import machinery.

 

 

9. Chloroplast

• are organells found in plant cells and other eukaryotic organisms that conduct photosynthesis

• capture light energy to conserve free energy in the form of ATP

Structure 

• contained by an envelope that consists of an inner and an outer phospholipid membrane

• between these two layers is the intermembrane space

• material within the chloroplast is called the stroma

• also contains ribosomes, although most of its proteins are encoded by genes contained in the host cell nucleus, with the protein products transported to the chloroplast

 

10. Vacuole

• membrane-bound organelle which is present in all eukaryotic cells

• enclosed compartments which are filled with fluid such as water or different enzymes, though sometimes they may contain solids

• majority of vacuoles are formed through the fusion of multiple membrane vesicles

 Functions 

• "Isolating materials that might be harmful or a threat to the cell

• Containing waste products

• Maintaining internal hydrostatic pressure or turgor within the cell

• Maintaining an acidic internal pH

• Containing small molecules

• Exporting unwanted substances from the cell"

 

The vacuole is located in the center.

 

 

11. Plasmodesmata

• are microscopic channels which traverse the cells walls of plant cells and enable transport and communication between them

 Structure 

• typical plant cell may have between 10³ and 10⁵ plasmodesmata connecting it with adjacent cells

• are approximately 50-60nm in diameter at the mid-point and are constructed of three main layers, the plasma membrane, the cytoplasmic sleeve, and the desmotubule

• similar in structure to the cellular phospholipid bilayers

  

12. Glycoproteins

• proteins that contain oligosaccharide chains covalently attached to their polypeptide side-chains

• process is known as glycosylation  

13. Cytoskeleton

• cellular "skeleton" contained in the cytoplasm in eukaryotic cells (animal and plant)

Function

• maintains cell shape, protects the cell, enables cellular motion (using structures such as flagella, cilia, and lamellipodia), and plays important roles in both intracellular transport (the movement of vesicles and organelles, for example) and cellular division

  • Microtubules

    • hollow cylinders about 25 nm in diameter, usually made up of 13 protofilaments