CELL STRUCTURES PART II

GOLGI Apparatus The GOLGI Apparatus (body) consists of about a dozen large flattened sacs. It acts a bit like a shipping and receiving warehouse. Vesicles from the Smooth and Rough E.R. come in on one side to drop off their contents. The proteins that are dropped off are then slightly modified, sorted, and then re-packaged and shipped to where they need to go. They are either sent to various parts of the cell or they are packaged into secretory vesicles which then empty their contents out of the cell.

The Endoplasmic Reticulum along with the Golgi and the Cell Membrane work together to form the main transport system through the cell.

“Lyse” = Break/Dissolve “Some” = Body/Structure LYSOSOMES One larger special type of vesicle formed off of the Golgi, is a LYSOSOME. Lysosomes contain Hydrolytic Enzymes that break things down. “Lyse” = Break/Dissolve “Some” = Body/Structure

Lysosomes in Action They act to break down incoming macromolecules into their respective monomers, as well as to break down foreign things like germs. They are also used by the cell to break down old cellular components that need to be recycled.

Energy Organelles

Chloroplasts – Don’t need to know their structure, just need to identify them and know that they are found in plants and that they perform PHOTOSYNTHESIS

mitochondria To produce ATP – (energy molecule for the cell) all cells will have Mitochondria to run a special type of reaction called “Cellular Respiration”. The hardest working cells in the body, like muscle, kidney, pancreatic, and sperm cells, will be loaded with mitochondria. Each mitochondrion, will have a double membrane. The inner membrane folds up and down to create more surface area to hold more enzymes. These extra enzymes are required to run all the reactions of “Cellular Respiration”

Cellular Respiration

THE CELL’S CYTOSKELETON Throughout the cytoplasm region of the cell, there is a vast network of microscopic filaments and tubules that give support and structure to the cell. This Cytoskeleton also creates an infrastructure that organelles can fasten onto and move up and down.

The Cytoskeleton can help with: Structure Anchoring Movement One specific type of Microfilament is : ACTIN which has a braided appearance

The other main component of the Cytoskeleton are the MICROTUBULES The other main component of the Cytoskeleton are the MICROTUBULES. These are much larger and have a column-like structure and are used to build bigger structural components of the cell’s cytoskeleton

Microfilaments found throughout the cytoplasm region of a cell Microfilaments found throughout the cytoplasm region of a cell. Like an invisible set of scaffolding

Create track-like pathways that organelles can be pulled along.

Some of the larger cytoskeletal structures in the cell form from special arrangements of microtubules. One of these larger structures is called a CENTRIOLE. Centrioles consist of 27 microtubules arranged in 9 triplets. This formation is known as a “9 +0” arrangement.

A couple other larger cytoskeletal structures include: Basal Bodies, Cilia and Flagella. Basal Bodies – Used for anchoring cilia and flagella into cytoskeleton. They also possess the “9+0” arrangement. Flagellum – Forms long whip-like tail on sperm cell to create locomotion. They consist of 20 microtubules; 9 doublets with 2 central microtubules. This is known as a “9 + 2” Arrangement. Cilia – Are shorter whip-like oars that stick out of a cell. They whip back and forth to push stuff like mucous over the surface of the cell. They possess the same “9 + 2” Arrangement as the Flagellum.

Fig. 3.12

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