Fundamentals of Cell Signaling – Bacterial Structures and Functions

These flashcards cover essential vocabulary and key concepts related to bacterial cell structures, membrane functions, transport systems, and cell walls.

Flagella

Long, whip-like structures that aid in bacterial motility.

Pili

Hair-like appendages that facilitate attachment and transfer of genetic material between bacteria.

Capsule

A protective, gelatinous layer surrounding some bacteria.

Plasma Membrane

A biological membrane that separates and protects the interior of the cell from the external environment.

Cytoplasm

The jelly-like substance within the cell membrane containing organelles and cytosol.

Cell Wall

Rigid outer layer providing structural support and protection to bacterial cells.

Inclusions

Storage granules within the bacterial cytoplasm that store nutrients or materials.

Spores

Highly resistant structures formed by some bacteria to survive adverse conditions.

Ribosomes

Molecular machines that synthesize proteins in the cell.

Nucleoid

Region in a bacterial cell containing the circular DNA chromosome.

Prokaryotic Structural Components

Composed of macromolecules such as DNA, RNA, proteins, polysaccharides, and phospholipids.

Macromolecules

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

Proteins

Macromolecules made up of amino acids; perform a variety of functions within the cell.

Polysaccharides

Carbohydrates consisting of long chains of sugar units; play roles in structure and energy storage.

Phospholipids

Molecules that form the bilayer of cell membranes, consisting of a hydrophilic head and two hydrophobic tails.

Nucleic Acids (DNA/RNA)

Biomolecules composed of nucleotides that store and transmit genetic information.

Fluid Mosaic Model

A model describing the structure of the plasma membrane as a mosaic of different components that move fluidly.

Amphoteric Molecules

Molecules that can act as both acids and bases, such as phospholipids.

Hydrophobic

Repelling water; refers to molecules that do not interact favorably with water.

Hydrophilic

Attracting water; refers to molecules that interact favorably with water.

Membrane Proteins

Proteins embedded in the lipid bilayer that assist in various cell functions.

Integral Membrane Proteins

Proteins that span the entire membrane and are involved in transport and communication.

Peripheral Membrane Proteins

Proteins that are loosely attached to the membrane surface and play roles in signaling.

Peptidoglycan

A polymer that makes up the cell wall of bacteria, providing strength and rigidity.

Teichoic Acid

Acidic polysaccharides found in the cell walls of Gram-positive bacteria.

Endotoxin

A toxic component of lipopolysaccharides found in the outer membrane of Gram-negative bacteria.

Bacterial Secretion Systems

Mechanisms that transport proteins out of the bacterial cell.

Facilitated Diffusion

A process where substances cross membranes with the assistance of carrier proteins, without energy use.

Active Transport

The movement of substances against their concentration gradient, requiring energy.

Ion-Driven Transport

A form of active transport using ions to move substances across membranes.

Group Translocation

A transport process where a substrate is chemically modified during its translocation across membranes.

Sec Pathway

A bacterial secretion system that transports unfolded proteins across the cytoplasmic membrane.

Tat Pathway

A bacterial secretion system that transports fully folded proteins across the cytoplasmic membrane.

Bacterial Cell Wall

A protective layer surrounding the cell membrane of bacteria, typically composed of peptidoglycan.

Gram-positive Bacteria

Bacteria that have a thick peptidoglycan layer in their cell walls.

Gram-negative Bacteria

Bacteria with a thinner peptidoglycan layer and an outer membrane containing lipopolysaccharides.

Lipopolysaccharide (LPS)

A large molecule found in the outer membrane of Gram-negative bacteria composed of lipids and polysaccharides.

Hydrophobic Environment

The internal environment of the membrane created by the orientation of fatty acid tails.

Transport Systems

Proteins that mediate the passage of solutes through membranes.

Cytoplasmic Membrane

A selective barrier surrounding the cytoplasm of the cell.

Energy Conservation Functions

Functions of the membrane that are crucial for directing energy usage within the cell.

Transport of Solutes

Methods bacteria use to move solutes across their membranes, including uniport, symport, and antiport.

Outer Membrane

The outer layer of Gram-negative bacteria containing lipopolysaccharides.

Periplasmic Space

Space between the inner and outer membranes in Gram-negative bacteria.

ATP-binding Cassette (ABC) Transporters

A type of active transport system that utilizes ATP to transport various substrates across membranes.

MFP (Membrane Fusion Protein)

A component of Type I secretion systems that helps transport substrates between membranes.

OMF (Outer Membrane Factor)

Protein that forms pores in the outer membrane of Gram-negative bacteria for protein export.

Twin Arginine Translocation (Tat)

A system allowing translocation of folded proteins across the membrane in bacteria.

Phosphotransferase System (PTS)

A group translocation system used primarily for carbohydrate transport in bacteria.