Bacteria and Archaea Lecture Flashcards

A set of vocabulary flashcards based on lecture notes covering the biological domains of Bacteria and Archaea, their metabolic diversity, evolutionary history, and the human microbiome.

Bacteria

One of the three monophyletic domains of life, consisting of single-celled organisms with a single circular chromosome, but no nucleus that differs from archaeons in many aspects of the central dogma.

Archaea

One of the three monophyletic domains of life, consisting of single-celled organisms with a single circular chromosome, but no nucleus that differs from bacteria in that aspects of central dogma are more similar to eukaryotes.

Prokaryotes

Single-celled organisms (Bacteria and Archaea) that can evolve in a short amount of time and are notable for their metabolic diversity.

Peptidoglycan (PG)

A network of sugar molecules joined by polypeptides (amino acids) found in bacterial cell walls; targeted by antibiotics like penicillin.

Diffusion

The process by which prokaryotes obtain nutrients from their environment; it requires interior parts to be close to the surrounding environment, which puts constraints on cell size.

Cyanobacteria

Photosynthetic bacteria that began to accumulate oxygen in the atmosphere approximately $2.4$ billion years ago.

Stromatolites

Fossilized structures found in places like Western Australia that provide evidence of early photosynthetic bacteria.

Horizontal gene transfer

The transfer of DNA between cells that promotes genetic diversity in asexual bacteria, often involving DNA pick-up that transforms cells with new traits.

Transformation

Occurs when DNA released into the environment by cell breakdown is taken up by recipient cells, resulting in horizontal gene transfer.

Extremophile

A microorganism that can survive in extreme environmental conditions, such as places too acidic, salty, cold, or hot for most other organisms.

Halophiles

Extremophiles that live in highly saline environments.

Thermophiles

Extremophiles that thrive in very hot environments.

Halobacterium

An archaeon that thrives in extreme salinity and uses red pigments to capture light and convert it into $ATP$.

Photoautotroph

An organism that captures energy from sunlight and uses carbon dioxide as a carbon source.

Chemoautotroph

A microorganism that obtains energy from chemical compounds, not from sunlight, and uses carbon dioxide as a carbon source.

Photoheterotroph

An organism that captures energy from sunlight and obtains its carbon from organic molecules synthesized by other organisms.

Chemoheterotroph

An organism that derives its energy directly from organic molecules such as glucose, and obtains its carbon from organic molecules synthesized by other organisms.

Microbial mats

Densely packed communities of mostly bacteria and archaea organized in layers based on differing levels of light, oxygen, and other chemicals.

Microbiome

A community of microorganisms that can usually be found living together in a given habitat, such as various regions of the human body.

Photosynthesis

The metabolic process summarized as: $\text{Light energy} + H_2O + CO_2 \rightarrow \text{glucose} + O_2$.

Cellular respiration

The metabolic process summarized as: $\text{Glucose energy} + O_2 \rightarrow CO_2 + H_2O + ATP$.

Spontaneous mutation rate (E. coli)

The probability of a mutation occurring in a given gene is $1$ in $10,000,000$ per cell per division.