Viruses and Prokaryotes Flashcards

Flashcards on Viruses and Prokaryotes

Microbes

Microscopic organisms not grouped by evolutionary relatedness, including viruses and organisms in all three domains: Bacteria, Archaea, and Eukaryote.

Capsid

An outer protein coat of a virus.

Enveloped Virus

A virus enclosed in the plasma membrane derived from a host cell.

Non-enveloped (naked) Virus

A virus enclosed only by its capsid.

Host Range

The limited number of host species that a virus can infect.

Viral Vectors

Medical and commercial uses of viruses - gene therapy, creating GMOs, cancer treatments and drug delivery to cells

Bacteriophages

Viruses that infect and kill bacteria species.

Hemagglutinin

Proteins on the influenza virus that attach to host cells.

Neuraminidase

Proteins on the influenza virus that are used to release the virus from host cells.

Zoonotic Disease

Infectious and transmitted between animal species.

Coronaviruses

Viruses named for the crown-like spikes on their surface.

HIV (Human Immunodeficiency Virus)

A retrovirus that uses reverse transcriptase to transcribe RNA onto DNA.

Vertical Transmission

Inheriting the virus from a parent through asexual propagation or by infected seeds

Horizontal Transmission

Entering through damaged cell walls and by vectors, such as insects

Prions

Infectious proteins that cause degenerative brain tissue diseases.

Domains

The largest, most inclusive groups in the classification hierarchy of organisms (Bacteria, Archaea, Eukaryota)

Nucleoid

The loop structure of DNA in prokaryote cells.

Bacterial Shapes

Typical bacteria shapes are cocci, bacilli, and spiral, and are used for identifying species.

Endospores

Metabolically inactive form of bacteria with an outer protective coat which provides protection, and can remain viable in harsh conditions for centuries

Fimbriae

Short hair-like extensions that allow prokaryotes to stick to their substrate or other individuals in a colony.

Pili (or sex pili)

Longer than fimbriae and allow prokaryotes to touch and exchange DNA.

Plasmids

Smaller rings of independently replicating DNA in prokaryotes.

Peptidoglycan

Glycoprotein network of sugar polymers cross-linked by polypeptides found in bacterial cell walls.

Taxis

The ability to move toward or away from a stimulus.

Flagella

The most common external structures used by prokaryotes for movement.

Transduction

Movement of genes between bacteria by virus bacteriophages.

Transformation

Occurs when a prokaryotic cell takes and incorporates foreign DNA from the surrounding environment.

Conjugation

Transfer of genetic material between prokaryotic cells and the DNA transfer is always one way.

F factor (fertility factor)

A piece of DNA that is required for the production of pili, cells with this are DNA donors during conjugation; cells without this factor are DNA recipients.

High-frequency recombination cell (Hfr cell)

A bacterium with the F factor integrated into its nucleoid DNA.

R plasmids

Carry antibiotic resistance and can be transferred from cell-to-cell.

LUCA (Last Universal Common Ancestor)

A microbe that was the beginning of all life on Earth

Extremophiles

Archaea able to live in extreme environments such as hot springs or saline waters

Methanogen

Archaea that live inside the digestive system of organisms

Bioremediation

Some species can digest or break-down pollutants in the environment

Palindrome

A palindrome in genetics is a DNA or RNA nucleotide sequence that reads the same in both directions.

Exotoxins

Secreted and cause disease even if the prokaryotes that produce them are not present.

Endotoxins

Released only when the bacteria die and their cell walls break down.

Phototrophs

Obtain energy from light.

Chemotrophs

Obtain energy from chemicals.

Heterotrophs

Cannot make its own food by carbon fixation, and requires a nutrient source from other sources of organic carbon; obtains energy from “eating” other organisms to get the organic compounds.

Autotrophs

Organisms that can synthesize their own food from inorganic compounds using heat or light as the energy source, such as a plant, algae, or photosynthetic bacteria

Obligate aerobes

Require O2 for cellular respiration

Obligate anaerobes

Are poisoned by O2 and live by fermentation or use substances other than oxygen for respiration.

Facultative anaerobes

Can use O2 if it is present or carry out fermentation or anaerobic respiration if it is not present

Biofilms

Surface-coating colonies where metabolic cooperation can occur between prokaryotic species.

Symbiosis

Any type of a close and long-term biological interaction between two different biological organisms; the organisms, each termed a symbiont, must be of a different species.

Mutualism

Both species benefit.

Commensalism

One species gets a benefit, but no harm or benefit to the other species

Parasitism

Using an organism as its host source of nutrition; very few bacteria species are BLANK

Nitrogen Fixation

Converting atmospheric nitrogen (N2) to ammonia (NH3) and supply nitrogen to plants