Lab #2: Prokaryotes

cell wall

Rigid outer layer surrounding the cell membrane in most bacteria that gives the cell shape and protects it from bursting.

flagella

Tendril-like appendages that rotate to propel a bacterial cell through its environment.

capsule

A sticky outer layer (made of polysachharides & proteins) outside the cell wall that protects the cell and helps it adhere to surfaces.

cytoplasm

The gel-like substance inside the cell membrane where cellular components and reactions are contained.

microbial communities

Groups of different microorganism populations living and interacting together in the same environment.

agar plate

A petri dish containing a solid agar-based growth medium used to culture microorganisms.

artificial media

Nutrient preparations made in the lab to grow microorganisms outside their natural environment.

enrichment media

Media containing specific nutrients that favor the growth of a particular organism over others in a mixed sample.

selective media

Media containing agents that inhibit the growth of certain organisms while allowing others to grow.

pure culture

A population of microorganisms containing only one species, with no other organisms present.

culture characteristics

Observable traits of a microbial culture, such as shape, arrangement, and colony appearance, used to help identify it.

cell shape

The basic geometric form of an individual bacterial cell.

coccus

A spherical or round-shaped bacterial cell.

bacillus

A rod-shaped bacterial cell.

spirillum

A spiral or corkscrew-shaped bacterial cell.

arrangement

The pattern in which bacterial cells group together after division.

cocci (arrangement)

Plural form of coccus; round bacterial cells arranged in groups such as single, diplo- (pairs), strepto- (chains), and staphylo- (clusters)

bacilli (arrengement)

Plural form of bacillus; rod-shaped bacterial cells arranged in groups such as single, diplo- (pairs), strepto- (chains), and palisades (columnar)

spirilla

Plural form of spirillum; spiral-shaped bacterial cells.

pleiomorphic

Describing an organism that can vary in shape or size rather than having one fixed form.

bacterial chains

Bacterial cells that remain attached end-to-end after division, forming a chain-like arrangement.

gram stain

A staining technique used to classify bacteria based on differences in their cell wall structure.

gram negative

Bacteria with a thin peptidoglycan layer and an outer membrane, which stain pink/red in a Gram stain.

gram positive

Bacteria with a thick peptidoglycan layer and no outer membrane, which stain purple in a Gram stain.

peptidoglycan

A mesh-like polymer of sugars and amino acids that forms the structural component of the bacterial cell wall.

colony culture morphology

The visible characteristics of a bacterial colony growing on a plate, such as color, shape, and texture.

biological macromolecules

Large molecules essential to life, including carbohydrates, lipids, proteins, and nucleic acids.

carbohydrates

Macromolecules made of sugar units that serve as a primary energy source and structural component.

lipids

Fatty macromolecules that make up cell membranes and serve as energy storage.

proteins

Macromolecules made of amino acids that perform structural, enzymatic, and functional roles in the cell.

adenosine triphosphate (atp)

The molecule cells use to store and transfer energy for cellular processes.

energy harvesters

Organisms classified by the energy source and carbon source they use to grow.

phototroph

An organism that obtains energy from light.

chemotroph

An organism that obtains energy from redox reactions

autotroph

An organism that obtains carbon from inorganic sources such as carbon dioxide.

heterotroph

An organism that obtains carbon from organic compounds made by other organisms.

photoautotroph

An organism that uses light for energy and carbon dioxide as its carbon source.

photoheterotroph

An organism that uses light for energy but obtains carbon from organic compounds.

chemoautotroph

An organism that obtains energy from inorganic chemicals and carbon from carbon dioxide.

chemoheterotroph

An organism that gets both its energy and carbon from eating or absorbing organic compounds

metabolism

The sum of all chemical reactions occurring within an organism to sustain life.

morphology

The study of the form and structure of an organism, such as cell shape and arrangement.

saprophyte

An organism that obtains nutrients by feeding on dead or decaying organic matter.

decomposition

The breakdown of dead organic material into simpler substances, often by microorganisms.

parasite

An organism that lives on or in a host organism and benefits at the host's expense.

pathogen

A microorganism capable of causing disease in a host.

cyanobacteria

Photosynthetic bacteria, sometimes called blue-green algae, that produce oxygen as a byproduct.

photosynthesis

The process by which organisms convert light energy into chemical energy, typically producing oxygen and organic compounds.

pigment

A colored substance in an organism that can absorb light, often involved in processes like photosynthesis.

extremophile

An organism adapted to survive and thrive in extreme environmental conditions.

aerobic

Requiring oxygen to survive and carry out metabolism.

anaerobic

Able to survive and grow without oxygen, and sometimes harmed by its presence.

acidophile

An organism that thrives in highly acidic environments.

thermophile

An organism that thrives in high-temperature environments.

osmophile

An organism that thrives in environments with high solute (sugar) concentrations.

hypersaline

Describing an environment with a very high salt concentration.