Microbiology Lecture: Cell Structure, Transport, and Bacterial Classification

Comprehensive vocabulary flashcards covering membrane transport mechanisms, prokaryotic and eukaryotic cell structures, symbiotic relationships, flagellar arrangements, and bacterial classifications based on the provided lecture notes.

Hypertonic

A solution characterized by a high solute concentration.

Hypotonic

A solution characterized by a lower solute concentration.

Isotonic

Two solutions separated by a porous membrane where water or solvent molecules can pass through equally.

Fluid Mosaic Model

A model describing the plasma membrane structure consisting of a fluid phospholipid part and a mosaic part composed of proteins.

Peripheral proteins

Proteins located on the top layer of the cell membrane.

Transmembrane proteins

Transverse bilayer proteins that span across the cell membrane.

Integral proteins

Proteins that are integrated directly into the membrane phospholipids.

Plasma membrane

A thin membrane that separates internal cellular activities from outside events.

Active transport

A transport mechanism where substances move from low to high concentration against a gradient, requiring energy (ATP) and transporter proteins.

Passive transport

A transport mechanism where substances move from high to low concentration down a gradient without requiring energy (ATP).

Crenation

The shrinking of cells without a cell wall when placed in a hypertonic solution as they lose water.

Lysis

The swelling and bursting of cells without a cell wall when placed in a hypotonic solution as they gain water.

Plasmolysis

The shrinking or collapse of the cellular content in a cell with a cell wall when placed in a hypertonic solution.

Turgid

The swollen condition of a cell with a cell wall when placed in a hypotonic solution.

Endospores

Resistant resting cells produced by bacteria such as Bacillus and Clostridium.

Mycolic acids

Waxy acids produced exterior to the peptidoglycan layer by Mycobacteriaceae.

Peptidoglycan

A bacterial cell wall polymer made of two major sugar polysaccharides, NAG and NAM, cross-linked by tetrapeptide and pentapeptide linkages.

Glycocalyx

An external sugar coat surrounding cells consisting of a capsule and a slime layer.

Fimbriae

Short, thin, hair-like external structures (several 100 per cell) used primarily for attachment rather than mobility.

Pili

Longer and fewer hair-like filamentous structures used for attachment, mobility, and sexual reproduction.

Facilitated diffusion

A passive transport process where solutes combine with transporter proteins in the membrane to move along a concentration gradient.

Group Translocation

An active transport process exclusively in prokaryotes requiring a transporter protein and energy to alter substances during transport.

Flagella

Chains of protein (flagellin) consisting of a filament, hook, and basal body that propel bacteria.

Chemotaxis

Bacterial movement towards or away from chemical stimuli.

Phototaxis

Bacterial movement towards light.

Osmotaxis

Bacterial movement in response to salt levels or osmotic pressure.

Aerotaxis

Bacterial movement in response to oxygen concentrations.

Thermotaxis

Bacterial movement in response to temperature differences.

Monotrichus

Having a single flagellum at one end of the bacterial cell.

Lophatrichus

Having a tuft or multiple flagella on one side of the bacterial cell.

Amphitrichus

Having flagella on two opposite sides of the bacterial cell.

Peritrichus

Having flagella distributed all over the bacterial cell surface.

Cytoskeleton

A structure composed of microfilaments, intermediate filaments, and microtubules that provides structural support and transports cellular materials.

Chloroplasts

Organelles unique to algae and green plants containing thylakoids with chlorophyll and enzymes required for photosynthesis.

Rough Endoplasmic Reticulum (Rough ER)

Endoplasmic reticulum studded with ribosomes, involved in protein synthesis.

Smooth Endoplasmic Reticulum (Smooth ER)

Endoplasmic reticulum lacking ribosomes, involved in synthesizing fats and hormones.

Golgi Apparatus

An organelle that sorts and packages transport proteins.

Lysosomes

Membrane-bound organelles containing digestive enzymes that break down molecules and bacteria.

Chitin

The primary component of fungal cell walls.

Cellulose

A polysaccharide component found in plant and algal cell walls.

Symbiosis

Any interaction between different species living within a community.

Mutualism

A symbiotic interaction where both populations benefit from each other.

Amensalism

A symbiotic interaction in which one population harms or kills another while remaining unaffected itself.

Commensalism

A symbiotic interaction where one population benefits and the other is unaffected.

Neutralism

A symbiotic interaction defined by the coexistence of metabolically active populations where neither affects the other.

Parasitism

A relationship where one organism benefits by invading and harming a host organism.

Microbiome

All prokaryotic and eukaryotic microorganisms associated with a specific organism.

Resident microbiota

Microorganisms that constantly live in or on our bodies.

Transient microbiota

Microorganisms that are only temporarily found in or on the human body.

Oligotrophs

Organisms capable of growth in environments with very low levels of nutrients.

Eutrophs

Organisms (also known as copiotrophs) that require copious amounts of organic nutrients to grow.

Coliforms

Gram-negative enteric bacteria that ferment lactose completely into acid and gas.

Non-coliforms

Gram-negative enteric bacteria that cannot ferment lactose completely.

Actinobacteria

A phylum of Gram-positive bacteria characterized by high G+C content (more than 50% guanine and cytosine nucleotides in their DNA).

Bacilli (Phylum Low G+C)

A class/group of Gram-positive bacteria characterized by low G+C content (less than 50% guanine nucleotides in their DNA).

Archaea

Harmless, highly diverse microorganisms with pseudomurein cell walls that live in every habitat and produce methane.