Chapter 4 Functional Anatomy of Prokaryotic and Eukaryotic Cells – Vocabulary Flashcards

Vocabulary-style flashcards covering key terms and definitions from the notes on prokaryotic and eukaryotic cell structure and function.

coccus (cocci)

Spherical-shaped bacterium.

bacillus (bacilli)

Rod-shaped bacterium; plural bacilli.

Bacillus (genus)

A bacterial genus; Bacillus anthracis is the causative agent of anthrax.

bacillus (shape)

Rod-shaped bacterial morphology (not necessarily in reference to the genus).

vibrio

Bacteria that look like curved rods.

spirillum

Spiral-shaped, rigid bacterium with a helical corkscrew shape.

spirochete

Spiral, flexible bacteria moved by axial filaments; typically corkscrew-like and capable of twisting.

axial filament

Endoflagellum; a corkscrew-like filament inside a sheath that enables spirochete movement.

glycocalyx

A sugary coat surrounding a cell; can be organized as a capsule or unorganized as a slime layer.

capsule

A well-organized, tightly attached glycocalyx layer surrounding some bacteria.

slime layer

An unorganized, loosely attached glycocalyx coating.

EPS (extracellular polymeric substance)

Polysaccharide/protein matrix that helps biofilm formation and adherence.

biofilm

Community of cells embedded in a glycocalyx EPS on surfaces.

capsule and virulence

Capsules can protect bacteria from phagocytosis, contributing to virulence.

polyglutamic acid capsule

Capsule of Bacillus anthracis made of p-glutamic acid; protects against phagocytosis.

polysaccharide capsule

Capsule made of polysaccharides (e.g., Streptococcus pneumoniae) contributing to virulence.

phagocytosis

Ingestion and digestion of microorganisms and solids by host cells.

Streptococcus pneumoniae capsule

Polysaccharide capsule enabling pneumonia-causing virulence.

Klebsiella capsule

Capsule that prevents phagocytosis and aids adherence in the respiratory tract.

Streptococcus mutans

Oral bacterium that uses its glycocalyx/capsule to attach to teeth and may utilize capsule as energy source.

Vibrio cholerae glycocalyx

Glycocalyx aiding attachment to intestinal cells.

flagellum

Long, whip-like appendage used for bacterial motility.

axial filament (endoflagellum)

Motility mechanism in spirochetes; flagella inside an outer sheath enabling corkscrew motion.

peritrichous

Flagella distributed around the entire cell.

polar flagellum

Flagellum(s) at one or both ends of the cell.

monotrichous

A single flagellum at one pole.

lophotrichous

Tuft of flagella from one pole.

amphitrichous

Flagella at both poles.

H antigen

Flagellar protein used to distinguish serovars among gram-negative bacteria.

archaeella (archaellum)

Motile structure in Archaea similar to flagella, but distinct evolutionarily.

spirochete movement

Movement by axial filaments producing a corkscrew motion.

fimbriae

Hairlike appendages aiding adhesion to surfaces and other cells; numerous per cell.

Pili (pilus)

Longer than fimbriae; involved in motility (twitching) and DNA transfer (conjugation).

twitching motility

Jerky movement via pilus extension and retraction.

gliding motility

Smooth movement across surfaces, seen in some bacteria like myxobacteria.

conjugation (sex) pilus

Pilus used to transfer DNA between bacteria during conjugation.

gram-positive cell wall

Thick peptidoglycan layer; teichoic and lipoteichoic acids present.

gram-negative cell wall

Thin peptidoglycan layer plus outer membrane containing LPS; periplasmic space exists.

peptidoglycan

Disaccharide NAM-NAG polymer cross-linked by peptides; provides cell wall rigidity.

NAM/NAG

N-acetylmuramic acid and N-acetylglucosamine; backbone units of peptidoglycan.

teichoic acid

Negatively charged polymers in gram-positive cell walls; contribute to wall charge and antigenicity.

lipoteichoic acid

Teichoic acid extending to the plasma membrane; helps anchor wall components.

lipopolysaccharide (LPS)

Outer membrane component in Gram-negative bacteria with lipid A, core polysaccharide, and O polysaccharide.

lipid A

Endotoxin part of LPS; triggers fever and inflammatory responses.

O polysaccharide

O antigen of LPS; serves as serovar/antigen marker in gram-negative bacteria.

porins

Proteins forming channels in the outer membrane to allow molecule passage.

Gram stain

Differential stain; gram-positive retain crystal violet; gram-negative decolorize and take safranin.

Mycoplasma

Bacteria lacking cell walls; membranes contain sterols; resistant to typical cell-wall-targeting antibiotics.

pseudomurein

Cell wall component in some Archaea similar to peptidoglycan but with different sugar acids.

acid-fast cell wall

Mycobacterial cell wall rich in mycolic acids; stained with carbolfuchsin; resistant to Gram stain.

lysozyme

Enzyme that hydrolyzes peptidoglycan bonds; damages bacterial cell walls.

EDTA

Stabilizes outer membrane disruption to allow lysozyme access in Gram-negative bacteria.

protoplast

A wall-less cell with plasma membrane intact after cell wall removal.

spheroplast

Gram-negative cell after cell wall removal leaving outer membrane intact.

mesosome

Membrane folds in bacteria; now considered an artifact from electron microscopy.

fluid mosaic model

Phospholipid bilayer with embedded proteins; membrane components move laterally.

peripheral vs integral proteins

Peripheral proteins lie on membrane surfaces; integral proteins span the membrane.

selective permeability

Membrane allows some substances to cross while restricting others.

diffusion

Net movement of small, nonpolar molecules from high to low concentration.

facilitated diffusion

Diffusion via membrane transport proteins; no energy expenditure; specificity varies.

osmosis

Net movement of water across a selectively permeable membrane.

isotonic/hypotonic/hypertonic

Isotonic: equal solute concentration; hypotonic: lower outside; hypertonic: higher outside.

active transport

Energy-dependent transport against a concentration gradient.

group translocation

Prokaryote-specific active transport where the transported substance is chemically modified during transit (e.g., glucose phosphorylation by PEP).

endocytosis

Eukaryotic process of taking in material by vesicle formation; includes phagocytosis, pinocytosis, and receptor-mediated endocytosis.

cytoplasm

Cell contents within the plasma membrane, about 80% water; contains cytosol, organelles, and inclusions.

cytoskeleton (prokaryotes)

MreB, ParM, cresetin, and FtsZ proteins providing shape, division, and organization.

nucleoid

Region in prokaryotes containing the circular bacterial chromosome; no membrane around DNA.

plasmids

Small, circular, extrachromosomal DNA molecules that replicate independently and often carry advantageous genes.

70S ribosomes

Prokaryotic ribosomes (30S + 50S subunits) smaller than eukaryotic 80S ribosomes.

80S ribosomes

Eukaryotic ribosomes (60S + 40S subunits) larger than bacterial 70S ribosomes.

carboxysome

Inclusion containing RuBP carboxylase used in CO2 fixation in photosynthetic bacteria.

gas vacuoles

Protein-lined hollow cavities that provide buoyancy in aquatic prokaryotes.

magnetosome

Iron oxide inclusions that act like magnets to orient bacteria and may protect against reactive oxygen species.

endospore

Durable, dormant, highly resistant resting cell formed by some Gram-positive bacteria under nutrient depletion.

sporulation

Formation of endospores inside vegetative cells.

dipicolinic acid (DPA)

Molecule in endospore core aiding dehydration and resistance.

germination

Process by which an endospore returns to vegetative cell under favorable conditions.

nucleus

Membrane-bound organelle in eukaryotes containing most DNA.

nuclear envelope

Double membrane surrounding the nucleus with nuclear pores.

nucleolus

Region where ribosomal RNA (rRNA) is synthesized.

endoplasmic reticulum (ER)

Network of membranes; rough ER has ribosomes; smooth ER lacks ribosomes and functions in lipid synthesis and detoxification.

Golgi complex

Organelle that processes, sorts, and ships proteins via vesicles; cisternae stack.

lysosome

Membrane-bound vesicle with digestive enzymes; digests ingested material.

vacuole

Membrane-bound space used for storage and endocytosis in cells; plant vacuoles can occupy much of the cell.

mitochondrion

Organelle producing ATP via cellular respiration; contains cristae and matrix; has 70S ribosomes and its own DNA.

cristae

Folds of the inner mitochondrial membrane increasing surface area for respiration.

matrix

Central fluid within mitochondria where many enzymes reside.

chloroplast

Plant/algal organelle for photosynthesis; contains chlorophyll, thylakoids, grana, and 70S ribosomes.

thylakoid

Flattened membrane sacs in chloroplasts where light reactions occur.

grana

Stacks of thylakoids in chloroplasts.

peroxisome

Organelle with enzymes for oxidation reactions and detoxification; contains catalase to break down hydrogen peroxide.

centrosome

Cellular region near the nucleus organizing the spindle during mitosis; contains centrioles and pericentriolar material.

centriole

Nine triplet microtubules arranged in a 9+0 array within the centrosome.

endosymbiotic theory

Hypothesis that eukaryotic organelles evolved from free-living prokaryotes living inside larger host cells.

eukaryotic endocytosis

Process of taking in substances by invagination of the plasma membrane; includes phagocytosis, pinocytosis, and receptor-mediated endocytosis.

monomorphic

most bacteria are this, that is, they maintain a single shape

pleomorphic

bacteria that can have multiple shapes