The Endosymbiotic Theory states that the mitochondria and chloroplast in eukaryotic cells were once aerobic bacteria (prokaryote) that were ingested by a large anaerobic bacteria (prokaryote). The aerobic bacteria were initially free-living prokaryotes, before being ingested by anaerobic bacteria.

The Endosymbiotic Theory states that the mitochondria and chloroplast in eukaryotic cells were once aerobic bacteria (prokaryote) that were ingested by a large anaerobic bacteria (prokaryote). This theory explains the origin of eukaryotic cells. Numerous lines of evidence exist, including that mitochondria and chloroplasts have their own circular DNA (prokaryotes also have circular DNA), mitochondria and chloroplasts have a double membrane (the inner membrane would have initially been the ingested prokaryote’s single membrane, and the outer membrane initially would have come from the cell that engulfed it), mitochondria and chloroplasts have 70S ribosomes (prokaryotes 70S have ribosomes, whereas eukaryotes have 80S ribosomes).

Desmosomes are the primary junction that helps keep tissues that are under a lot of stress, like skin, intact. Although tight junctions typically accompany desmosomes, their primary function is to prevent substances from passing between cells. Gap junctions are used for communication between cells, and intercalated discs are only found in cardiac muscle tissue.

The lysosome is an organelle that is used to digest broken cellular machinery or foreign particles. It maintains an acidic environment inside by pumping hydrogen ions in, not out. This environment helps denature the things it needs to digest, and is the most effective pH for the digestive enzymes that are inside.

The other structures do not maintain acidic environments, and would need the capability of removing protons.

The simple answer here is that all of these organelles have a membrane, except for ribosomes. Nuclei, mitochondria, chloroplasts, and cells as a whole have transmembrane proteins spanning the lipid bilayer, which can be used for transport or other purposes. Ribosomes are mostly comprised of rRNA and do not have membranes; thus, they will not bear transmembrane proteins.

The Golgi apparatus is a series of flattened membrane sacs found in the cell. It receives vesicles filled with proteins from the rough endoplasmic reticulum. The Golgi apparatus is responsible for recognizing proteins based on their signal sequences and sending concentrations of similar proteins to various parts of the cell. It can also deliver proteins out of the cell using secretory vesicles. The membrane sacs of the Golgi apparatus are constantly used and regenerated to create vesicles of packaged proteins.

Muscle contraction is accomplished using the function of microfilaments, namely actin and myosin. Microtubules are not a key player in muscle contraction, but are used to create the mitotic spindles, flagella, and cilia. Microtubules are a key element of the cytoskeleton, and are generally involved in structural aspects of the cell.

While free ribosomes are present independently in the cytosol, bound ribosomes are attached to the rough endoplasmic reticulum. Their presence gives this organelle its "rough" appearance and distinguishes it from the smooth endoplasmic reticulum, which does not contain ribosomes. The nuclear envelope, which surrounds and protects the eukaryotic nucleus, is also the site of some bound ribosomes and is connect to the rough endoplasmic reticulum. The Golgi apparatus, lysosomes, and mitochondria have no ribosomes bound to their membranes.

The mitochondria are membrane-bound organelles involved in the process of cellular respiration. Specifically, the Krebs cycle takes place in the matrix of the mitochondria and the electron transport chain takes place along the inner mitochondrial membrane. During aerobic respiration, oxygen is used as the final electron receptor of the electron transport chain and generates water as a byproduct. Without oxygen, the mitochondria cannot perform oxidative phosphorylation, and the cell must rely on glycolysis for energy.

Lysosomes contain hydrolytic enzymes that can digest macromolecules from phagocytosis, endocytosis, and autophagy. When damage occurs to the membrane of the lysosome, these enzymes can be released and cause damage to the cell, leading to apoptosis.

Peroxisomes contain peroxidases, which help to eliminate hydrogen peroxide from the cell and prevent the creation of free radicals. The nucleus houses DNA and would be severely damaged by the introduction of hydrolytic enzymes. The plasma membrane is used to contain the cytoplasm and organelles and the endoplasmic reticulum is used to modify and package proteins.