Viruses, Bacteria, Archaea, Protozoa, and Fungi Lecture Notes

A collection of vocabulary flashcards covering the characteristics, classification, reproduction, and diseases associated with viruses, bacteria, archaea, protozoa, and fungi.

Capsid

A protein coat encasing the genetic information of a virus, made up of smaller units called capsomeres.

Lipid envelope

A coat protecting the capsid of some viruses, featuring spikes made of glycoproteins for attaching to a cell.

Bacteriophage

A type of virus that infects bacteria, typically having a complex structure including a capsid head, sheath, and tail fibers.

Retroviruses

RNA viruses, such as HIV, that transfer their RNA into DNA and then to mRNA after entering a host cell.

Restricted host range

A condition where a virus is specific to one host, such as HIV only infecting human white blood cells ($T$-lymphocytes).

Adsorption

The first stage of viral reproduction where the virus attaches to a cell membrane.

Lytic cycle

A viral reproduction cycle that involves attachment, penetration, biosynthesis of viral components, maturation, and lysis of the host cell to release new phages.

Lysogenic cycle

A cycle in which phage DNA integrates into the bacterial chromosome as a prophage and is replicated along with the host's DNA.

Viroid

A short, single strand of RNA with no surrounding capsid that interferes with cell function and causes diseases in crops like potatoes and coconuts.

Prion

A glycoprotein particle containing about $250$ amino acids and no DNA or RNA, responsible for diseases such as BSE (mad cow disease).

Peptidoglycan

The specific substance found in bacterial cell walls, also referred to as murein.

Plasmids

Small, closed circles of extra DNA in bacteria containing genes responsible for toxins and antibiotic resistance.

Gram positive bacteria

Bacteria that appear purple after staining due to their cell wall composition.

Gram negative bacteria

Bacteria that appear pink after staining due to their cell wall composition.

Chemoautotrophic bacteria

Bacteria that obtain organic compounds using energy from chemical bonds, such as the oxidation of $NH_3$, $H_2S$, or $Fe^{2+}$.

Binary fission

The primary method of bacterial reproduction where one cell divides into two.

Conjugation

The transfer of genetic material between bacterial cells through a pilus.

Transformation

A process of genetic reproduction where a bacterium takes up DNA fragments or plasmids from its environment.

Transduction

The transfer of portions of DNA from one bacterium to another by bacteriophages.

Methanogens

Archaea that live in anaerobic environments, such as sewage treatment ponds, and use $CO_2$ and $H_2$ to produce methane ($CH_4$).

Halophiles

Archaea that prefer high salt concentrations, found in locations like the Great Salt Lake or the Dead Sea.

Thermoacidophiles

Archaea that live in acidic hot springs with temperatures from $80-116^{\circ}C$ and a pH less than $2$.

Pseudopodia

Cytoplasmic extensions used for movement and feeding (phagocytosis) by Sarcodina protists like the Amoeba.

Trypanosoma

A parasitic flagellate transmitted by the tsetse fly that causes sleeping sickness.

Plasmodium

A parasitic sporozoan that causes malaria and has no special organs for locomotion.

Hypha

The vegetative filament of a fungus, which may be divided into cells by perforated cross walls called septa.

Mycelium

A mat of interwoven hyphae that constitutes the body of a fungus.

Mycorrhiza

A symbiotic mutualistic relationship between fungi and plant roots.

Lichen

A hybrid colony consisting of algae or cyanobacteria living symbiotically among the filaments of fungus species.