Exam Unit 1a Study Guide Spring 2022

Vocabulary flashcards covering key terms from cell types, cell structures, Gram staining, metabolism, transport, acid-fast concepts, bioenergetics, and taxonomy.

Prokaryotic cell

Cell lacking a true nucleus and membrane-bound organelles; contains a nucleoid and circular chromosome.

Eukaryotic cell

Cell with a true nucleus and membrane-bound organelles; contains linear chromosomes.

Nucleoid

Region in prokaryotic cells where the circular chromosome resides; not membrane-bound.

Nucleus

Membrane-bound organelle in eukaryotes that houses genetic material (DNA).

Circular chromosome

Double-stranded circular DNA typical of prokaryotes.

Linear chromosomes

DNA organized into linear chromosomes typical of eukaryotes.

Ribosome

Molecular machine for protein synthesis; 70S in prokaryotes, 80S in eukaryotes.

Membrane-bound organelles

Organelles surrounded by membranes (e.g., nucleus, mitochondria) found in eukaryotic cells.

Pilus

Hair-like projection used for attachment and DNA transfer (conjugation) in bacteria.

Plasma membrane

Phospholipid bilayer surrounding the cell; controls transport in both prokaryotic and eukaryotic cells.

Vacuole

Membrane-bound storage compartment; large central vacuole in plant cells; rare in bacteria.

Inclusions (storage)

Storage granules for nutrients (e.g., glycogen, polyphosphate) found in some cells.

Capsule

External polysaccharide layer that protects bacteria from host defenses and aids adhesion.

Gram-positive cell wall

Thick peptidoglycan layer with teichoic acids; no outer membrane; retains crystal violet.

Gram-negative cell wall

Thin peptidoglycan layer plus outer membrane containing LPS; has periplasm; decolorizes with alcohol.

Teichoic acid

Polysaccharide-rich molecules in Gram-positive cell walls; contribute to charge and rigidity.

Lipopolysaccharide (LPS)

Molecule in the outer membrane of Gram-negative bacteria; endotoxin component.

Peptidoglycan

Polymer forming the bacterial cell wall; thickness differs between Gram-positive and Gram-negative.

Gram stain reagents in order

Crystal violet → Iodine → Alcohol → Safranin.

Crystal violet

Primary stain; colors all cells purple; typically retained by Gram-positive cells.

Iodine (mordant)

Forms a crystal violet–iodine complex to trap dye in thick cell walls.

Alcohol (decolorizer)

Decolorizes cells; removes dye from Gram-negative cells, leaving Gram-positive purple.

Safranin

Counterstain that colors decolorized Gram-negative cells pink/red.

Acid-fast bacteria

Bacteria with waxy, mycolic acid–rich cell walls; not well stained by Gram stain; require acid-fast stain.

Acid-fast cell wall difference

Waxy, lipid-rich wall (mycolic acids) that resists decolorization.

Mycobacterium tuberculosis

Acid-fast bacterium with a waxy cell wall; not easily seen with Gram stain.

Final electron acceptor in aerobic respiration

Oxygen (O2).

Final electron acceptor in anaerobic respiration

Varies; commonly nitrate, sulfate, or other inorganic molecules depending on organism.

Final electron acceptor in fermentation

An organic molecule (e.g., pyruvate) that accepts electrons; no external inorganic acceptor.

Total NADH yield in aerobic respiration (per glucose)

Approximately 10 NADH produced from glycolysis and Krebs to enter the ETC.

FADH2 yield in aerobic respiration (per glucose)

2 FADH2 produced during the Krebs cycle per glucose.

Active transport

Movement of substances against their gradient using energy and transport proteins.

Passive diffusion

Movement of substances down their gradient without energy input.

Osmosis

Diffusion of water across a selectively permeable membrane.

Catabolism

Metabolic pathways that break down molecules to release energy (degradative).

Anabolism

Metabolic pathways that build larger molecules from smaller units (biosynthetic).

Exergonic reaction

Releases energy; negative delta G.

Endergonic reaction

Requires energy input; positive delta G.

Biogenesis

Living matter arises from preexisting life; opposed to spontaneous generation.

Spontaneous generation

Idea that life can arise from nonliving matter; disproved by experiments (Pasteur).

Genetic engineering

Direct manipulation of an organism's genes to modify traits.

Bioremediation

Use of microorganisms to degrade environmental pollutants.

Pilus and conjugation

Pilus forms a bridge to transfer DNA between bacteria during conjugation.

Conjugation

Horizontal gene transfer via a pilus; transfer of DNA between bacteria.

Archaea extremophiles

Archaea that thrive in extreme conditions (extremophiles).

Pathogenic microbe

Microorganism capable of causing disease.

Capsule main function

Protects against phagocytosis and aids adherence to host tissues.

Endospore

Durable, dormant cell form that survives harsh conditions; formed under stress.

Sporulation

Process of endospore formation in response to nutrient limitation.

Cocci

Spherical bacterial cells.

Bacilli

Rod-shaped bacterial cells.

Flagella (five styles)

Different patterns of flagellar placement on bacteria (e.g., monotrichous, lophotrichous, amphitrichous, peritrichous, etc.).

Binomial nomenclature

Genus species naming; genus capitalized, species lowercase; both italicized.

Genus (in binomial name)

First part of a scientific name; capitalized.

Species epithet (in binomial name)

Second part of a scientific name; lowercase.

Path of light in a compound microscope

Light from the source -> condenser -> stage/specimen -> objective lens -> tube -> ocular lens -> eye.