Cell Biology and Structure

The Endoplasmic Reticulum (ER) is a large network of membrane-bound tubes and sheets. It appears as long tubules or round or oblong bags (vesicles) and is involved in protein and lipid synthesis.

Vacuoles are membrane-bound organelles found in the cytoplasm of cells, serving as storage sacs for solid or liquid contents such as water, nutrients, or waste products. Golgi apparatus is involved in packaging, endoplasmic reticulum in synthesis and transport, and plastids in photosynthesis and pigment storage.

Vacuoles are typically small and temporary in animal cells, whereas they are large and permanent in plant cells. They help in maintaining osmotic pressure and storing nutrients in animals.

The Golgi apparatus is involved in the formation of lysosomes, which are the cell's waste disposal system. It packages digestive enzymes into membrane-bound vesicles that become lysosomes.

Plastids are similar to mitochondria in their external structure, as both have a double membrane and contain their own DNA and ribosomes. This similarity supports the endosymbiotic theory of organelle origin.

The Rough Endoplasmic Reticulum (RER) has particles called ribosomes attached to its surface, giving it a 'rough' appearance. These ribosomes are the sites of protein synthesis.

Cisterns (or cisternae) are the flattened, membrane-bound sacs that make up the Golgi apparatus. They are stacked in a parallel fashion and are involved in the processing of proteins.

Vacuoles are very large in plant cells, often occupying 50% to 90% of the cell volume. They provide structural support and maintain turgor pressure within the cell.

The stroma is the fluid-filled internal space of a plastid (specifically chloroplasts) surrounding the thylakoids. It contains the enzymes necessary for the dark reactions of photosynthesis.

The Endoplasmic Reticulum (ER) is responsible for the synthesis of essential biomolecules. Rough ER, which has ribosomes attached, manufactures proteins, while Smooth ER is the primary site for lipid and fat molecule production.

The Golgi apparatus is functionally and often physically connected to the endoplasmic reticulum. It receives proteins and lipids synthesized in the ER via transport vesicles for further processing, packaging, and distribution.

Plastids, specifically leucoplasts, serve as storage organelles in plant cells. Amyloplasts store starch, elaioplasts store oils, and aleuroplasts store protein granules.

The membrane of the endoplasmic reticulum is a phospholipid bilayer that is structurally similar to the plasma membrane. This similarity allows for the exchange of membrane components through vesicle budding and fusion.

Plastids are unique to plant cells and some algae; they are not found in animal cells. While large central vacuoles are characteristic of plants, small vacuoles can exist in animal cells, making plastids the most distinctive answer.

Plastids (like chloroplasts) and mitochondria are semi-autonomous organelles. They possess their own circular DNA and ribosomes, allowing them to produce some of their own proteins independently of the nucleus.