Prokaryotic Microbes Study Guide

A comprehensive set of flashcards covering the key concepts and details related to prokaryotic microbes and their characteristics.

What do all prokaryotes have?

Cell wall, cell membrane, nucleoid, cytoplasm, ribosomes.

What is the structure of the cell membrane in prokaryotes?

Made of a phospholipid bilayer, serves as a selectively permeable barrier and an anchor for proteins.

What is peptidoglycan?

A polymer that forms the cell wall made of alternating sugars NAG and NAM with peptide connectors.

What are lysozymes?

Enzymes that cut the alternating sugars in peptidoglycan, causing bacterial cell lysis.

What two types of cell walls do bacteria have?

Gram-positive and Gram-negative.

What makes up the Gram-positive cell wall?

Composed of 90% peptidoglycan and includes teichoic acid and lipoteichoic acid.

What characterizes Gram-negative bacteria?

Contains an outer membrane and has a thinner peptidoglycan layer.

What is the function of lipopolysaccharides in Gram-negative bacteria?

Serves as an endotoxin and is part of the outer membrane.

How do antibiotics affect Gram-positive and Gram-negative bacteria?

Gram-positive bacteria allow most antibiotics to enter, whereas Gram-negative bacteria have a barrier that can prevent antibiotics from entering.

What is a Gram stain?

A process used to distinguish between Gram-positive and Gram-negative bacteria.

What color do Gram-positive bacteria appear after a Gram stain?

Purple.

What color do Gram-negative bacteria appear after a Gram stain?

Pink.

What external appendages do bacteria have?

Pili, fimbrae, and flagella.

What is the function of flagella in bacteria?

Provides motility and allows bacteria to self-propel.

How do prokaryotic flagella differ from eukaryotic flagella?

Prokaryotic flagella are simpler in structure.

What is chemotaxis?

The tendency of cells to move in response to a chemical signal.

What are the two types of chemotaxis?

Positive (towards an attractant) and negative (away from a repellent).

What are periplasmic flagella?

Also known as axial filaments, they are found in Gram-negative spirochetes.

What is the function of fimbrae?

Provides attachment sites for bacteria to cells and surfaces.

What is the role of pili?

Facilitates attachment and genetic transfer through conjugation.

What is the S-layer?

A protective layer made of S-layer proteins that helps with attachment and cell integrity.

What is the function of bacterial capsules?

Prevent immune cell attachment and engulfment, and aid in adhesion.

What does the slime layer do?

Provides protection from dehydration and helps with adhesion.

What is the nucleoid?

The area where chromosome aggregation occurs in bacteria.

What are plasmids?

Small circular pieces of DNA that are not essential for survival but can be shared between cells.

What are ribosomes made of in bacteria?

Composed of protein and rRNA; the whole ribosome is 70S.

What is the cytoskeleton in prokaryotes?

Protein fibers that help maintain cell shape and assist in cell division.

What are endospores?

Dormant bacteria cells that help bacteria survive under limited nutrient conditions.

What is sporulation?

The process of forming endospores in response to environmental signals.

What does germination refer to?

The process where endospores break dormancy in the presence of water and specific agents.

What are the shapes of bacteria classified as?

Coccus, bacillus, spirillum, coccobacillus, vibrio, and spirochete.

What shape are cocci?

Spherical or dot-shaped bacteria.

What shape are bacilli?

Rod-shaped bacteria.

What is spirillum?

Helical, comma-shaped bacteria.

What is coccobacillus?

Short, plump bacteria that resemble both cocci and bacilli.

Describe vibrio bacteria.

Gently curved bacteria categorized as bacillus.

What is a spirochete?

Tightly coiled, spring-like bacteria classified as spirillum.

What is bacterial arrangement based on?

The pattern of division and how cells remain attached after division.

What is a diplococcus?

Two cocci together.

What is a staphylococcus?

Groups of cocci in clusters.

What is a streptococcus?

Cocci arranged in a chain.

What is a diplobacillus?

Two bacilli attached to each other.

What is a streptobacillus?

Multiple bacilli lined up in a chain.

What are archaea?

Another group of prokaryotes more closely related to eukarya than bacteria.

What are extremophiles?

Organisms that live in extreme habitats, adapted to extreme conditions.

What is microscopic morphology?

Observation of shapes under a microscope.

What is macroscopic morphology?

Observation of colony appearance at a larger scale.

What does bacterial physiology encompass?

Growth and metabolism of bacteria.

What is serological analysis?

Determining a pathogen by antibody interactions.

What is genetic and molecular analysis in bacteria?

Techniques like ribosomal RNA sequencing for classification.

What is a bacterial species defined by?

A collection of bacterial cells with similar traits.

What is a subspecies or strain?

Variations within a species where relatedness is below 97% in rRNA.

What is a serotype?

Different surface molecules or antigens in bacteria.

What are the main types of eukaryotic microbes?

Fungi, algae, helminths, and protozoa.

What defines macroscopic fungi?

Fungi that are visible to the naked eye.

What is chitin?

The main composition of fungal cell walls.

What is ergosterol?

A component of the fungal cell membrane that maintains fluidity.

What does heterotrophic saprobe mean?

Fungi that obtain nutrients from dead organic matter.

What is microscopic fungi?

Fungi that require a microscope to be seen, such as yeast and molds.

What are hyphae?

Thread-like cells that make up molds and other filamentous fungi.

What are spores in fungi?

Reproductive structures that can be asexual or sexual.

What does dimorphic mean in fungi?

Fungi that can exist as yeast in the heat and mold in the cold.

What are primary pathogens?

Pathogens that affect the general population.

What are opportunistic pathogens?

Pathogens that affect individuals with compromised immune systems.

What is the difference between superficial and systemic infections?

Superficial infections are not deeply invasive, while systemic infections are deep and can affect organs.

What defines protists?

Eukaryotes that are not fungi, animals, or plants.

What is the role of algae?

Photosynthetic protists that contribute to aquatic food webs and oxygen production.

What are microscopic algae?

Unicellular algae that are small and often seen under a microscope.

What are protozoa?

Animal-like, unicellular eukaryotes that live in moist habitats.

How do protozoa move?

Using pseudopods, flagella, or cilia.

What is a trophozoite?

The active, motile feeding stage of protozoa.

What is a cyst?

The dormant phase of protozoa that can enter hosts via contaminated food or water.

What are helminths?

Parasitic worms, including roundworms and flatworms.

What are roundworms also known as?

Nematodes.

What are flatworms?

Helminths with thin, flat bodies, including cestodes and trematodes.

What does hermaphroditic mean in relation to helminths?

Having both female and male reproductive organs.

What is the life cycle of helminths?

Includes fertilized egg, larval, and adult stages.

How do helminths typically infect humans?

Through contaminated food, soil, or water.

What are common routes of helminth transmission?

Oral intake, skin penetration, or vector transmission.