Bacterial Cell Structure and Function

Flashcards on Bacterial Cell Structure and Function

Filamentous Bacteria

Bacteria that make hyphae leading to mycelium formation, resembling fungi but are distinct. Examples include cyanobacteria and Streptomyces.

Complex Bacteria

Bacteria that create fruiting bodies. An example is Myxococcus, a predator.

Arrangement of Bacteria

Determined by the plane of division and whether separation occurs after division.

Smallest Bacteria Size

0.3 μm, exemplified by Mycoplasma.

Average Rod Bacteria Size

1.1 - 1.5 x 2 – 6 μm, such as E. coli.

Very Large Bacteria Size

600 x 80 μm, like Epulopiscium fishelsoni.

SA/V Ratio Effect on Nutrient Transport

Larger SA/V ratios facilitate easier nutrient movement.

FtsZ

A tubulin homologue in bacteria that helps identify the middle for binary fission.

MreB

An actin homologue in many rod-shaped bacteria, providing shape.

CreS

An intermediate filament homologue that maintains the curve shape in some bacteria.

Glycogen

A storage inclusion used for glucose storage in bacteria.

Poly-β-hydroxybutyrate (PHB)

A storage inclusion for carbon storage in bacteria.

Polyphosphate Granules (Volutin)

A storage inclusion for phosphate storage in bacteria.

Sulfur Globules

A storage inclusion for sulfur storage in bacteria.

Cyanophycin Granules

A storage inclusion for amino acids (nitrogen) storage in bacteria.

Gas Vacuoles

Inclusions that help cells become lighter for photosynthesis.

Magnetosomes

Inclusions that orient bacteria toward magnetic fields, aided by cytoskeletal protein MamK.

Plasmids

Extrachromosomal DNA that replicates independently of chromosomes, carrying extra information.

Episomes

Plasmids that can integrate into the chromosome of the host.

Conjugate Plasmids

Plasmids that facilitate the sharing of plasma between two bacteria.

R Plasmids

Plasmids that confer resistance against antibiotics.

Virulence Plasmids

Plasmids that help bacteria carry information to make toxins.

Col Plasmids

Plasmids that enable bacteria to produce molecules to kill neighboring bacteria for competition.

Plasma Membrane Functions

Encompassing the cytoplasm and selectively controlling interactions with the external environment.

Fluid Mosaic Model

Describes the structure of the plasma membrane with amphipathic lipids and various proteins.

Peripheral Proteins

Membrane proteins not embedded in the membrane and easily movable.

Integral Proteins

Membrane proteins attached and embedded in the membrane, having hydrophobic/hydrophilic regions.

Transmembrane Proteins

Proteins that cross the membrane.

Hopanoids

Bacterial membrane components that affect fluidity and rigidity.

Macronutrients

Essential elements for bacterial survival, represented by 'N-CHOPS': nitrogen, carbon, hydrogen, oxygen, phosphorous, sulfur.

Passive Diffusion

The movement of substances from high to low concentration without energy expenditure. Examples include water, oxygen, and carbon dioxide.

Facilitated Diffusion

The movement of substances from high to low concentration using permeases.

Active Transport

The movement of molecules against the concentration gradient, requiring energy.

Group Translocation

A transport mechanism where the substance is chemically altered during transport.

ABC Transporters

Primary active transporters found in all three domains of life, using ATP as an energy source.

MFS

Secondary active transporters that use ion gradients as an energy source.

Symport

A type of cotransport where two substances move in the same direction.

Antiport

A type of cotransport where two substances move in opposite directions.

Bacterial Cell Wall Functions

Provides shape, protection, and plays a role in pathogenicity.

Peptidoglycan

A unique component of bacterial cell walls, targeted by Gram staining.

Gram-Positive Cell Wall

Characterized by a thick peptidoglycan layer and teichoic acids.

Gram-Negative Cell Wall

Characterized by a thin peptidoglycan layer and an outer membrane containing LPS.

Teichoic Acids

Polymers in Gram-positive cell walls that provide an overall negative charge.

LPS

Lipopolysaccharide, found in the outer membrane of Gram-negative bacteria, containing lipid A.

Lipid A

An endotoxin present in LPS that can cause septic shock.

Mycolic Acid

A waxy substance in Mycobacteria that prevents Gram staining.

Acid-Fast Staining

A staining technique used for Mycobacteria due to the presence of mycolic acid.

Atypical Bacteria

Bacteria that cannot be stained by Gram-stain procedures or lack a cell wall.

Lysozyme

An enzyme that breaks down peptidoglycan.

Penicillin

An antibiotic that inhibits cell wall synthesis.

Protoplasts

Cells that have lost their cell wall in Gram-positive bacteria.

Spheroplasts

Cells that have lost their cell wall in Gram-negative bacteria.

L-Form

Bacteria that can shut down the production of peptidoglycan.

Glycocalyx

A polysaccharide layer outside the cell wall for surface attachment and protection.

Capsules

A thick, well-organized layer of glycocalyx that is resistant to phagocytosis.

Slime Layer

A loosely attached and less organized layer of glycocalyx that facilitates gliding motility.

S Layers

Self-assembling protein or glycoprotein layers for protection and stability.

Pili and Fimbriae

External structures used for attachment.

Sex Pili

Pili that allow for horizontal gene transfer through conjugation.

Type IV Pili

Pili that facilitate twitching motility.

Flagella

Structures used for motility, attachment, and virulence.

Chemotaxis

Movement due to chemical attractants or repellents.

Phototaxis

Movement to light.

Magnetotaxis

Movement due to magnetic fields.

Bacterial Endospore

A complex, dormant structure resistant to environmental conditions.

Sporulation

The process of forming a spore from a living cell.

Germination

The process of a spore returning to a living cell.

Schaeffer-Fulton Method

An Endospore staining technique that stains endospores green and vegetative cells red.