8. Cytoplasmic Functions and Organelles

Cytoplasm: Everything inside the plasma membrane but outside of the nucleus.
Contains organelles and inclusions.
Each cell has a specific shape, determined by its structural skeleton known as the cytoskeleton.

Collection of protein fibers providing the inner working and skeleton to the cell.
Assists in maintaining the specific shape of the cell.
Interacts with the extracellular matrix and neighboring cells.
Cell shapes vary (flat, skinny, tall, thin, long, round) based on inner structures, organization, and interactions with the extracellular matrix and neighboring cells.
Formed of microfilaments (smaller) and microtubules (thicker, hollow).
Arrangement affects cell shape.
Microfilaments are typically located towards the plasma membrane edge.
Microtubules spread out within the cell.

Microtubules facilitate intracellular movement along with other proteins.
Different amounts of proteins used to make microfilaments and microtubules result in various cell shapes and features.
Microfilaments can attach to proteins that cross the plasma membrane, anchoring the cell to the extracellular matrix or neighboring cells.
This results in different cellular junctions, important in different tissue structures and functions.
Microtubules are important in both movement and shape.
Microfilaments facilitate shape and anchoring.

Microtubule structures can be used on the outer surface of cells to move things around.
Cilia in airways move mucus along the surface.
Bacterial cells use flagella (microtubule structure) to propel themselves through fluid.
Sperm cells use microtubules in their tails to propel them through the female reproductive tract.
Microtubules facilitate movement both inside and outside of cells.

Important in protein synthesis and translation due to attached ribosomes, giving it a rough appearance.
Closely associated with the nucleus, providing a passageway for mRNAs to go straight from the nucleus.
Proteins are synthesized, folded, and modified inside the rough ER.
Modifications include adding carbohydrates, removing amino acids, and joining polypeptides.

Lacks ribosomes, so it is not involved in protein production.
Involved in lipid production, detoxification, and calcium ion storage.
Cells that produce lipids or detoxify substances have more smooth ER.
All cells need some smooth ER for membrane lipid production.
Liver cells have large amounts of smooth ER due to their role in detoxification.

Proteins from the rough ER are packaged into vesicles and shipped to the Golgi.
Vesicles fuse with the Golgi, where proteins are further packaged and modified.
Proteins undergo exocytosis to be secreted out of the cell.
Vesicles can also fuse with the plasma membrane, embedding proteins in it.
The Golgi is involved in packaging and shipping for secretion and embedding within the membrane.
The Golgi does not make proteins.
Golgi sits more towards the plasma membrane edge of our cell further away from our nucleus.

Small vesicles containing enzymes and a low pH (around $pH = 5.5$ ).
Break down structures found in the cytoplasm.
Internalize structures, break them down using enzymes, and release components back into the cytoplasm for reuse.
Act as waste disposal centers, breaking down large organic molecules (lipids, proteins, complex carbohydrates), and worn-out organelles.
Bacteria brought in through phagocytosis can be safely destroyed by fusing with the lysosome.
This process is regulated and controlled to prevent damage to other cellular components.
Organelles are like different rooms in a house, each with a specific function.
Lysosomes are spread throughout the cell so that we can remove and, deal with large worn out organic molecules and organelles.