Chapter 4: Functional Anatomy of Prokaryotic and Eukaryotic Cells

A comprehensive set of practice flashcards covering core concepts from Chapter 4: Functional Anatomy of Prokaryotic and Eukaryotic Cells, including cell types, cell walls, membranes, organelles, transport, nucleic acids, ribosomes, shapes, appendages, glycocalyx, endospores, and Gram staining.

What is the main feature that distinguishes prokaryotes from eukaryotes?

Prokaryotes lack a membrane-bound nucleus; eukaryotes have a nucleus and internal organelles.

Name the three basic shapes of bacteria.

Bacilli (rods), cocci (spheres), and spirals.

What is the glycocalyx and what functions does it serve?

A capsule or slime layer outside the cell wall; it aids in adherence, protects against dehydration and nutrient loss, and contributes to biofilm formation and immune evasion.

Differentiate the following bacterial surface structures: flagella, axial filaments, fimbriae, and pili.

Flagella propel movement; axial filaments (in spirochetes) are long coiled filaments around the cell; fimbriae are hair-like structures for attachment; pili are rigid tubes used for conjugation and gene transfer.

Compare Gram-positive and Gram-negative bacterial cell walls.

Gram-positive walls have a thick peptidoglycan layer with teichoic acids and no outer membrane; Gram-negative walls have a thin peptidoglycan layer, an outer membrane with LPS, and a well-developed periplasmic space.

How do acid-fast bacteria differ from other bacteria in terms of cell wall?

Acid-fast bacteria (e.g., Mycobacterium) have waxy mycolic acid in their cell walls and stain red with acid-fast stains; non-acid-fast bacteria stain blue.

How do archaea and mycoplasmas differ in terms of cell walls?

Archaea often lack peptidoglycan (may have pseudopeptidoglycan); mycoplasmas lack a cell wall altogether.

Describe the primary functions of the prokaryotic plasma membrane.

A phospholipid bilayer that acts as a selective barrier, controlling material transport; hosts membrane transport proteins.

Define simple diffusion, facilitated diffusion, osmosis, and active transport.

Simple diffusion moves substances down a concentration gradient without energy; facilitated diffusion uses transport proteins; osmosis is diffusion of water across a selectively permeable membrane; active transport moves substances against their gradient and requires energy.

What are the functions of ribosomes in cells?

Ribosomes are the sites of protein synthesis, made of RNA and protein, and consist of two subunits; they occur in both prokaryotes and eukaryotes.

What are endospores and what are sporulation and endospore germination?

Endospores are dormant, tough structures formed under stress to protect DNA; sporulation is their formation; germination is the return to vegetative growth when conditions improve.

How do prokaryotic and eukaryotic flagella differ?

Prokaryotic flagella rotate to propel the cell; eukaryotic flagella beat in a whip-like, undulating manner.

What are the components and functions of the glycocalyx capsule?

The capsule is a rigid outer layer composed of glycocalyx; it protects from dehydration and nutrient loss, aids adherence, and contributes to immune evasion and biofilm formation.

What is the role of the capsule in biofilm formation and pathogenesis?

Capsules aid adherence to surfaces and immune evasion, facilitating biofilm formation on tissues and implanted devices.

What are endospores and why are they important?

Endospores are dormant, highly resistant structures that protect the genome under harsh conditions, ensuring survival until conditions improve.

What is peptidoglycan and where is it located?

Peptidoglycan is the rigid mesh-like polymer forming the bacterial cell wall that provides structural support.

How does Gram staining differentiate bacteria?

Differentiates bacteria into Gram-positive (purple) and Gram-negative (red/pink) based on cell wall structure and alcohol permeability.

List the four steps of Gram staining and what each step accomplishes.

Crystal violet (primary stain) stains all cells; iodine (mordant) forms a complex with crystal violet; alcohol (decolorizer) dehydrates Gram-positive walls to retain dye and decolorizes Gram-negative walls; safranin (counterstain) colors the decolorized Gram-negative cells pink.

What is the periplasmic space and which bacteria have it?

The space between the outer membrane and inner plasma membrane in Gram-negative bacteria; contains enzymes and transport proteins.

What distinguishes Gram-positive from Gram-negative envelopes in terms of layers?

Gram-positive: thick peptidoglycan with teichoic acids; Gram-negative: thin peptidoglycan, outer membrane with LPS, and a well-developed periplasmic space.

What are teichoic acids and where are they found?

Teichoic acids are polymers in the Gram-positive cell wall that help draw materials into the cell and aid in identification.

What changes color during Gram staining for Gram-positive vs Gram-negative bacteria?

Gram-positive retain the purple crystal violet stain after alcohol; Gram-negative become colorless and are counterstained pink by safranin.

What is an atypical cell wall and which organisms have it?

Atypical cell walls include Mycobacterium (with mycolic acid) and Nocardia (partial acid-fast features); they resist standard staining and require acid-fast staining methods.

What are the main differences in Gram-negative envelopes in terms of outer membrane components?

Outer membrane contains lipopolysaccharides (LPS) and lipoproteins; it contributes to the periplasmic space and barrier function.

Where is DNA located in a eukaryotic cell versus a prokaryotic cell?

In eukaryotes, DNA is housed in the nucleus; in prokaryotes, DNA is in the nucleoid region in the cytoplasm (no true nucleus).

What are plasmids?

Extrachromosomal genetic elements that carry non-crucial genes (e.g., antibiotic resistance) and can be transferred between bacteria.

What is the typical size range of a bacterial cell?

Approximately 0.2 to 2.0 micrometers in diameter and 2 to 8 micrometers in length.

Which domains of life consist of unicellular organisms and include bacteria, archaea, and eukarya?

Domains Bacteria and Archaea are prokaryotic; Domain Eukarya includes unicellular and multicellular eukaryotes.

What structures increase bacterial adherence to surfaces or to each other?

Fimbriae (and capsules) increase adherence; pili can also aid in attachment during conjugation.

What is the function of mitochondria?

Mitochondria are the energy-producing organelles in eukaryotic cells (ATP production).

Which organelles are unique to eukaryotic cells?

Membrane-bound organelles such as the nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus, lysosomes, etc.

What is the difference between a nucleus and a nucleoid?

The nucleus is a membrane-bound organelle containing DNA in eukaryotes; the nucleoid is an irregular region in prokaryotic cells where DNA is located, not separated from the cytoplasm.

Which cells contain ribosomes, and where are they located?

Ribosomes are the sites of protein synthesis and are present in both prokaryotic and eukaryotic cells; located in the cytoplasm and, in eukaryotes, also on the rough endoplasmic reticulum.

What is the function of the cytoskeleton?

Provides structural support and helps maintain cell shape.

What is endocytosis and phagocytosis?

Endocytosis is the process of taking materials into the cell; phagocytosis is the ingestion of particles via pseudopods.

What is exocytosis?

The process of releasing materials from the cell by vesicle fusion with the cell membrane.

What are vacuoles and inclusions?

Vacuoles store materials in eukaryotes; inclusions store materials in prokaryotes.

What is the role of LPS in the Gram-negative outer membrane?

LPS (lipopolysaccharide) contributes to outer membrane structure and can trigger immune responses; it is a component of the Gram-negative outer membrane.

Name the main organelles involved in protein synthesis and processing in the cell.

Ribosomes synthesize proteins; rough endoplasmic reticulum synthesizes membrane-associated and secreted proteins; Golgi apparatus processes and packages proteins.