Viruses, Prions, Cells & Microorganisms

• Students are expected to learn the distinction between prokaryotes and eukaryotes
• Students are expected to define microbiology and microorganisms
• Students are expected to understand the various sizes and types of microorganisms
• Students are expected to learn the different effects and aspects of microorganisms
• Students are expected to know the differences in major microorganism groups

Prokaryotes vs Eukaryotes

• Organs are composed of specific tissues, which are composed of cells.
• Cells are the structural and functional units of life, containing all necessary infrastructure to perform functions.
• Cells are classified based on cellular structure as prokaryotic or eukaryotic.
• Prokaryotes are mostly single cells, while eukaryotes can be single cells or part of multicellular tissues.
• Prokaryotes have circular DNA, examples include nucleoid, cells, cell membrane, and Ribosomes
• Eukaryotes have linear DNA, examples include nucleus, cells, cell membrane, and Ribosomes
• Prokaryotes are small cells (< 5μm) and always unicellular.
• Prokaryotes lack a nucleus or any membrane-bound organelles. DNA is circular, without introns or proteins.
• Prokaryotes have small 70S ribosomes and divide via binary fission, and reproduction is always asexual.
• Eukaryotes are larger cells (> 10 μm) and can be unicellular or multicellular.
• Eukaryotes have a nucleus and membrane-bound organelles. DNA is linear with introns, associated with proteins to form chromatin.
• Eukaryotes have large 80S ribosomes, divide by meiosis and mitosis; reproduction is sexual and asexual.
• Prokaryotic cells are simpler and smaller (< 5µm) than eukaryotic cells and lack membrane bound organelles
• Structures of prokaryotic cells include the plasma membrane, plasmid, cell wall, pili, nucleoid (DNA), capsule, ribosomes, flagellum, and cytoplasm
• Eukaryotic cells are more complex, containing membrane-bound organelles to perform specific functions.
• Eukaryotic cells contain a nucleus isolated from the cytosol within a double membrane
• Structures of eukaryotic cells include the cell wall, mitochondria, chloroplasts, chromosomes, and nuclear membrane

Microbiology & Microorganisms

• Microbiology is the study of microorganisms including virology, mycology, bacteriology, immunology, microbial ecology, biotechnological microbiology, environmental microbiology, food microbiology, and molecular biology
• Microorganisms are living organisms too small to be seen with the naked eye
• Microorganisms include bacteria, fungi (yeast & molds), viruses, microscopic algae, and protozoa & helminths

Microorganisms Characteristics

• Microorganisms can be unicellular (single cell) or multicellular (more than one cell) and are ubiquitous.
• Microorganisms exist as swimming communities, freely attached to a surface (biofilm)
• Most microorganisms don't cause disease, but some are helpful.

Effects and Aspects of Microorganisms

• Beneficial microorganisms are used in food production (e.g., bread, cheese, yoghurt, wine)
• Beneficial microorganisms are also used in industrial applications (e.g., enzymes, amino acids, vitamins, antibiotic, vaccines, sewage treatment) and agriculture (e.g., recycling of elements, nitrifying bacteria).
• Harmful microorganisms cause food spoilage and diseases (bacterial, viral, fungal) and are known as pathogens

Characteristics of Major Microorganism Groups

• Bacteria are prokaryotic with a simple internal structure and grow on artificial laboratory media.
• Bacteria reproduce asexually (mostly simple cell division – binary fission),
• Some bacteria cause diseases, perform natural cycling, and manufacture valuable compounds in industry.
• Archaea are prokaryotic (initially classified as bacteria) and similar to bacteria in size and simplicity but radically different in molecular organization.
• Archaea is an ancient group intermediate between bacteria and eukaryotes.
• Archaea are obligate anaerobes living in low-oxygen environments and living in extreme environments
• Fungi are eukaryotic, includes Unicellular yeast, multicellular molds, growing on artificial laboratory media
• Reproduction in Fungi is asexual (cell division / budding) or sexual
• Some fungi cause diseases, some are food preparation, and manufacture alcoholic beverages
• Protozoa are Eukaryotic and Unicellular
• Protozoa can be cultivated on laboratory media while some are intracellular parasites
• Reproduction in Protozoa is asexual or sexual
• Some Protozoa types cause dieases, other types are food for aquatic animals
• Algae are Eukaryotic and either Unicellular or Multicellular and Photosynthetic
• Algae mostly occur in aquatic environments
• Reproduction is Algae is asexual or sexual
• Algae produces food in aquatic environments and is a source of food in pharmaceuticals and some algae produce toxic substances
• Viruses are too small to be observed with a light microscope. viruses consist of a DNA/RNA core surrounded by a protein coat.
• Viruses coat may be enclosed in a lipid envelope and are replicated only when they are in a living host cell.
• Bacteriophages are viruses that infect bacteria.
• Prions are proteins that can cause infection, causing neurodegenerative diseases by aggregating extracellularly within the central nervous system.
• Prions aggregation forms plaques, disrupting normal tissue structure, and causes Bovine Spongiform Encephalopathy (BSE) and Creutzfeldt-Jacob Disease (CJD).

Questions about the characteristics and differences between prions, viruses, fungi, protozoa, algae, prokaryotic, and eukaryotic cells. Also includes disease mechanisms and cell structure. Includes novel antibiotics affecting chromatin formation.