Lesson 4: Prokaryotic Structures

What are the three domains of life?

Bacteria, Archaea, and Eukarya.

What is a key characteristic of prokaryotic cells?

They lack a nucleus and membrane-bounded organelles.

What type of cell wall do Archaea lack?

Peptidoglycan.

What are extremophiles?

Organisms that thrive in extreme environmental conditions.

Name one type of extremophile.

Methanogens, extreme halophiles, or thermoacidophiles.

What is the shape of a bacillus?

Rod-shaped.

What is the shape of a coccus?

Spherical.

What is the term for bacteria that occur in pairs?

Diplococci or diplobacilli.

What structures do all bacterial cells possess?

A cell membrane, cytoplasm, ribosomes, and one or a few chromosomes.

What is the function of plasmids in bacteria?

They carry nonessential genes, such as those for antibiotic resistance.

What is the role of the prokaryotic ribosome?

Protein synthesis.

What is the composition of the bacterial cell wall?

Peptidoglycan, a framework of glycan chains cross-linked by peptide fragments.

What distinguishes Gram-positive bacteria from Gram-negative bacteria?

Gram-positive bacteria have a thick peptidoglycan layer, while Gram-negative bacteria have a thin peptidoglycan layer and an outer membrane.

What is the purpose of the Gram stain?

To differentiate between Gram-positive and Gram-negative bacteria based on their cell wall structure.

What is a glycocalyx?

A sticky, extracellular polysaccharide that allows cells to attach.

What are the two types of glycocalyx?

Capsule (organized) and slime layer (unorganized).

What is the function of flagella in bacteria?

To provide motility.

What are the different arrangements of bacterial flagella?

Monotrichous, lophotrichous, amphitrichous, and peritrichous.

What are fimbriae?

Short, hair-like structures that allow for attachment to surfaces.

What is the function of pili in bacteria?

To facilitate the transfer of plasmid DNA between cells.

What are endospores?

Dormant bodies formed by some bacteria that are resistant to harsh conditions.

What is the cytoplasm of a bacterial cell primarily composed of?

70-80% water, along with soluble proteins, salts, and carbohydrates.

What are inclusions in bacterial cells?

Non-membrane bound granules that store nutrients or building blocks.

What is the significance of the nucleoid in bacterial cells?

It is the area where the single, circular chromosome is aggregated.

What does the term 'virulence' refer to?

A pathogen's capacity to inflict harm on its host.