Archaea (contains halophiles, thermophiles, and methanogens)

Nucleus: Contains all of the genetic information for the operation and eventual duplication of the cell. The nucleus is contained within the nuclear membrane and within it contains the nucleolus, which is responsible for the synthesis of ribosomal units (for the production of ribosomes). The nucleus also is able to synthesise mRNA, tRNA, and rRNA. The nucleus is also responsible for RNA transcription.
Endoplasmic Reticulum: The rough endoplasmic reticulum is responsible for facilitating protein synthesis with ribosomes and also packaging these proteins into vesicles to be sent to the Golgi apparatus. The smooth endoplasmic reticulum on the other hand has many roles as it is able to convert glycogen into glucose for use as energy, it is able to detoxify the cell from alcohols, and can also synthesise sex hormones and cholesterol.
Golgi Apparatus: The Golgi apparatus is the 'traffic controller' of the cell and is responsible for the packaging and distribution of proteins around the cell. It may add certain functional groups to the protein if necessary to alter their function.
Mitochondrion: The mitochondrion is responsible for the generation of energy for the cell. It contains many cisternae which have the function of generating ATP, and is able to replicate itself independently from the genetic material of the nucleus as it contains some genetic material within itself.
Vacuole: Vacuoles have the function of being places for storage within the cell. The vacuole is also able to maintain homeostasis within the cell as it is able to alter the pH of the cell, and also the concentration of water.
Peroxisome: Peroxisomes have the role of detoxifying the cell. This is through the process of turning free radicals, which may also arise from alcohols, into hydrogen peroxide, which can be later broken down into water.
Lysosome: Lysosomes contain digestive enzymes, stored within an acidic environment, which are able to break down the waste products or foreign contaminants of the cell. These enzymes break down the substance and the organelle is essentially able to consume the waste.

Outer Membrane: The outer membrane is the protective layer of gram-negative bacteria and is encased in lipopolysaccharides, which are molecules responsible for inciting an inflammatory response from the host when in contact. Depending on the cell, the outer-most membrane (peptidoglycan layer in gram-positive bacteria) can contain fimbriae or pili, which are essential for the reproduction and position of prokaryotic cells. Cilia and flagella can also be present as cellular projections to assist in the motility of the cell.
Cell Wall (Peptidoglycan Layer): The peptidoglycan layer is the main protective border more so for gram-positive bacteria than gram-negative bacteria as it is thicker than the one found in gram-negative bacteria, and that gram-positive bacteria do not contain an outer membrane. It is made of inter-weaving n-acetylmuramic acid and n-acetylglucosamine with linking proteins to bind these together. It allows the cell to also interact with its surroundings as gram-positive bacteria also contain teichoic acid channels which allow for the transfer of substances across this layer. Antibiotics such as penicillin are able to specifically target the linking proteins in the peptidoglycan layer, therefore weakening it and allowing for bacteria to be controlled. As the peptidoglycan layer of gram-negative bacteria is sandwiched between the inner and outer membranes, it is said to have endotoxins, whilst as the peptidoglycan layer of gram-positive bacteria is present at the surface, it has exotoxins. Gram-negative bacteria also contain lipoproteins which are responsible for adhesion as well. Both gram-positive and gram-negative bacteria also contain porin proteins which are proteins that are able to pass molecules through the peptidoglycan layer.
Cytoplasmic membrane: The cytoplasmic membrane is the inner-most protective layer of gram-negative and gram-positive bacteria. It is similar to a plasma membrane in a eukaryotic cell in that it is made up of a lipid bilayer that allows for protection and the passage of molecules or solutes through the membrane. This membrane also carries out functions that are done by organelles in a eukaryotic cell such as production of energy and secretion of proteins and enzymes.
Cytoplasm: The cytoplasm is the main medium at which cellular activities take place. Although prokaryotic cells do not contain any true organelles, they do contain a grouping of DNA in the centre of the cell called a nucleoid, and plasmids, which code for the characteristics of the cell such as antibiotic resistance. Prokaryotic cells contain no cytoskeleton.
Nucleoid: The nucleoid contains the genetic material of the prokaryotic cell for its reproduction.
Ribosomes: Ribosomes are responsible for the production of proteins in a prokaryotic cell. These organelles are smaller than the ones in eukaryotic cells (70S compared to 80S).
Storage granules: Storage granules are responsible for the storage of solutes and molecules in the prokaryotic cell. Also just called nutrient reserves.
Fimbriae and Pili: Fimbriae are only present in gram-negative bacteria and are responsible for the bacterial cells' adherence to surfaces. They play a major role in the virulency of bacteria as without this fimbriae, bacteria would not have been able to cause infection (no way to adhere to surfaces). Pili on the other hand are longer than fimbriae but shorter than flagella and can be either used as grappling hooks for the bacterium to move around, or for reproduction in which the bacteria can transfer genetic material to another by docking pili
Flagellum: These are long extensions from the bacterium and are responsible for the motility of the cell.

The five modes of action for antibiotics: Inhibition of cell wall synthesis, inhibition of protein synthesis, inhibition of nucleic acid replication and transcription, injury to plasma membrane, and inhibition of the synthesis of essential metabolites.

Common Features for All Cells: Enclosed in a lipid bilayer, require ATP for energy, cell blueprints stored as genes and DNA, there is constant genetic code, cell structure and function is controlled by proteins, and DNA can be converted into RNA and then proteins.

The shape and arrangement can differentiate between different types of cells. For example, staphylococcus denotes the formation of a v-shaped cell structure made up of circular cells, whilst streptococcus contains circular cells connected one after the other.

Gram-positive bacteria stain purple and gram-negative bacteria stain pink.

Normal flora are defined as those who are present in the body, but do not cause any negative affects to it. This flora (also referred to as normal microbiota) is commensal, meaning that it can benefit from the host, but the host does not, or only benefits minimally from the flora. Some flora are resident and are present permanently and some are transient and only present for short periods of time.

Sites that do not contain normal flora are called sterile sites. Internal sides such as the blood, internal organs, and peritoneal cavity are sterile as they are inaccessible, and external sides such as the bladder and stomach are sterile as they are unsuitable for bacteria.

Organisms can be commensal, mutualistic, or parasitic. Commensal organisms have one organism that benefits from the interaction, and one that does not or only does to a small extent. Mutualistic relationships have both organisms benefiting equally from the relationship. Parasitic relationships only have one organism that is thriving, and the other acts as a host which can have very detrimental outcomes. Either the relationship can end when the host dies, and thus the parasite dies as well, or the host can kill off the parasite.

Opportunistic organisms on the other hand may start off as either commensal or mutualistic relationships, however if there is a change in the environment or one organism proliferates and greatly increases in number due to a lower immune response or change in the balance of antagonism, then it can become a pathogen. This has negative effects on the relationship.

Koch's Postulates state that in determining whether a micro-organism causes a particular disease, it must be present in each case, then it must be grown in an isolated culture, it must cause disease when introduced to a healthy host, and the same micro-organism must be isolated again from the diseased host.

There are multiple layers of cells but the cells on the top layer are dead (contain no nuclei) and are desiccation resistant.

Lining epithelial tissue is avascular, polarised, has a sparse intercellular matrix, a basal lamina and basement membrane, and a limited lifespan.

Cilia are cellular projections that allow for the unidirectional movement of objects across the surface of the cell. They are present in some places such as the respiratory tract and in conjunction with goblet cells and mucus work to rhythmically beat and remove cell debris and other foreign contaminants from the cell.

Microvilli on the other hand are present in the gastrointestinal tract and have the role of increasing the surface area of this tract dramatically in order to maximise the ability of the tract to consume nutrients. They collectively form a brush border.

Stereocilia, analogous to elongated microvilli have the role of concentrating spermatozoa and the absorption of water in the epididymis to ensure for the movement of spermatozoa through it and to the seminal vessel.

Desmosomes are strong adhesions between cells with intermediate filaments and intercellular plaques.

Gap junctions allow for rapid communication between cells and contain connecting mechanisms are called connexons.

Hemidesmosomes attach cells to the basal lamina with integrins which are transmembrane receptor proteins.

Tight junctions seal off the basolateral compartment from the apical compartment with strands of transmembrane proteins.

The basement membrane is a combination of the basal lamina and the reticular lamina.

Its main function is diffusion, and is therefore found in the alveoli of the lungs in the lining of blood vessels. Simple squamous epithelium appears to be shaped like pavement when viewed from the top and has bulging nuclei as the cell is very thin.

Simple cuboidal epithelium is a single layer of cuboidal epithelial cells that are found in places such as the kidney tubules. Their main role is structural, but they can play absorptive roles such as ion transfer in the kidney tubules.

This epithelium is present inside the body and is in places where friction resistance is needed. It is non-keratinised meaning the top layers are not hardened and therefore there are nuclei present iin the top layers of these cells.

This epithelium is rare and can serve an absorptive, secretory, and structural purpose. It is present in the lining of the stomach and in exocrine glands and allows for nutrients to diffuse through it. It is cuboidal as it must contain the mechanism for mucus release. The ciliated version of this epithelium is present in the Fallopian tubes.

This epithelium is usually ciliated and is present in the respiratory tract. Cells of this epithelium originate from the basal lamina, but not all are able to reach the apical surface. This gives the image that it is stratified, when it is actually not. It can play secretory, absorptive (in epididymis), and movement roles. It is present in the prostate and seminal vesicle.

This epithelium is not common and only serves a structural purpose. It is present in the conjunctiva as well as excretory ducts of glands and the middle-sized ducts of salivary glands.

This epithelium is not common and contains two or more layers of cuboidal cells. It is present in large ducts of salivary glands.

Transition epithelium has columnar-like cells on the bottom, and these cells eventually become flatter. This epithelium is stratified (by definition) and has the ability to stretch. There are specialised 'umbrella cells' on the apical surface that do not allow the toxic urine from passing through to the cells below. This epithelium can alter its appearance based on the distension of the bladder and is also present in parts of the urethra.