Campbell Biology Chapters 26, 27, 29, 30, 35, 37, and 39 Review Flashcards

Vocabulary practice flashcards generated from Campbell Biology 12e Chapters 26, 27, 29, 30, 35, 37, and 39 review notes.

Monophyletic Group (Clade)

A group of species that consists of an ancestral species and all of its descendants.

Paraphyletic Group

A group of taxa that consists of an ancestral species and some, but not all, of its descendants.

Polyphyletic Group

A group of taxa that includes distantly related organisms but does not include their most recent common ancestor.

Sister Taxa

Groups of organisms that share an immediate common ancestor not shared by any other group.

Outgroup

A species or group of species from an evolutionary lineage known to have diverged before the lineage containing the species being studied (ingroup).

Convergent Evolution

The independent evolution of similar features in different evolutionary lineages due to similar environmental pressures rather than shared ancestry.

Homology

Similarity in traits among different species resulting from shared ancestry.

Analogy

Similarity between two species due to convergent evolution rather than descent from a common ancestor with the same trait.

Principle of Maximum Parsimony

An approach in phylogenetics stating that when evaluating multiple hypotheses, one should prefer the tree requiring the fewest evolutionary events.

Paralogous Genes

Homologous genes that arise from gene duplication within a single species' genome and diverge within the same gene pool.

Orthologous Genes

Homologous genes derived from a common ancestor that diverge only after a speciation event occurs.

Horizontal Gene Transfer

The transfer of genes from the genome of one organism to another through mechanisms like plasmid exchange, viral infection, or fusion of organisms.

Molecular Clock

A method for measuring the absolute time of evolutionary change based on the observation that certain genes or genomic regions accumulate mutations at constant rates.

Peptidoglycan

A polymer of modified sugars cross-linked by short polypeptides found in the cell walls of most bacteria.

Endospore

A resistant, thick-walled cell produced inside a bacterium that allows it to survive harsh conditions, such as boiling.

Fimbriae

Short, hair-like protein appendages on prokaryotic cells used for attachment to substrates or other cells.

Pili (Sex Pili)

Structures on prokaryotes that pull two conducting cells together prior to DNA transfer during conjugation.

Nucleoid

A non-membrane-enclosed region in a prokaryotic cell containing its concentrated chromosomal DNA.

Plasmid

A small, circular, double-stranded DNA molecule carrying accessory genes separate from those of a bacterial chromosome.

Transformation

A mechanism of genetic recombination in prokaryotes wherein a cell takes up foreign extracellular DNA from its surrounding environment.

Transduction

A process of horizontal gene transfer in which phages (viruses) carry bacterial DNA from one host cell to another.

Conjugation

The direct transfer of DNA between two prokaryotic cells that are temporarily joined.

F Factor

A DNA segment or plasmid in bacteria that carries genes required for the formation of pili and the transfer of DNA during conjugation.

R Plasmid

A bacterial plasmid carrying resistance genes that confer protection against specific antibiotics.

Photoautotroph

An organism that uses light as an energy source and carbon dioxide ($\text{CO}_2$) as a carbon source.

Chemoautotroph

An organism that obtains energy from inorganic chemicals and uses carbon dioxide ($\text{CO}_2$) as a carbon source.

Chemoheterotroph

An organism that must consume organic compounds for both energy and carbon sources.

Biofilm

A surface-coating colony of one or more species of prokaryotes that engage in metabolic cooperation.

Exotoxin

A toxic protein secreted by a living bacterium into its environment that causes disease symptoms.

Endotoxin

A toxic component of the outer lipopolysaccharide membrane of certain gram-negative bacteria, released only upon bacterial cell death.

Sporopollenin

A durable polymer that prevents exposed zygotes of charophytes and plant spores from drying out.

Apical Meristem

A localized region at a growing tip of a plant root or shoot where cell division takes place.

Cuticle

A waxy covering on the epidermis of plant shoots that reduces water loss.

Stomata

Microscopic pores in leaf and stem epidermis flanked by guard cells that regulate gas exchange and transpiration.

Archegonia

Female gametangia in non-flowering plants that produce non-motile egg cells and site fertilization.

Antheridia

Male gametangia in non-flowering plants that produce and release flagellated sperm cells.

Microphylls

Small, unbranched, spine-shaped leaves with a single strand of vascular tissue, unique to lycophytes.

Megaphylls

Leaves with a highly branched vascular system, characteristic of monilophytes and seed plants.

Pollen Grain

In seed plants, a protective structure containing the male gametophyte enclosed within a sporopollenin-rich wall.

Ovule

A plant structure consisting of a megasporangium, megaspore, and protective integuments that develops into a seed after fertilization.

Endosperm

A triploid ($3n$) nutrient-rich tissue formed by double fertilization in angiosperms that nourishes the embryonic plant.

Root Hair

A tiny extension of a root epidermal cell that vastly increases surface area for the absorption of water and minerals.

Parenchyma Cells

Relatively unspecialized plant cells with thin primary walls that conduct metabolic functions like photosynthesis and storage.

Collenchyma Cells

Living plant cells with unevenly thickened primary cell walls that offer flexible support to growing shoot regions.

Sclerenchyma Cells

Rigid support cells with thick secondary cell walls containing lignin, typically dead at functional maturity.

Tracheids and Vessel Elements

Elongated, water-conducting xylem cells with lignified walls that are dead at functional maturity.

Sieve-Tube Elements

Living cells of phloem organized end-to-end to form channels for sugar transport, lacking a nucleus at maturity.

Vascular Cambium

A cylinder of lateral meristematic tissue in woody plants that produces secondary xylem inwardly and secondary phloem outwardly.

Cork Cambium

A cylinder of lateral meristematic tissue that produces tough cork cells to replace the epidermis during secondary growth.

Cation Exchange

A process where plant roots secrete hydrogen ions ($\text{H}^+$) to displace positively charged mineral ions from soil clay particles for absorption.

Chlorosis

The yellowing of plant leaves due to reduced chlorophyll synthesis, often caused by mineral deficiencies like nitrogen or magnesium.

Mycorrhizae

Mutualistic associations between plant roots and fungi that enhance water and mineral absorption for the plant.

Rhizobium

A group of soil bacteria that establish nitrogen-fixing symbioses within root nodules of legume host plants.

Epiphyte

A plant that grows physically anchored upon another plant without drawing nutrients or water directly from the host.

Etiolation

Plant shoot growth adaptations for darkness, featuring unexpanded leaves, pale stems, and minimal root elongation.

De-etiolation

The greening process and structural modifications shoot systems undergo when exposed to light, mediated by phytochromes.

Auxin

A plant hormone (such as IAA) that promotes cell wall acidification, cell elongation, apical dominance, and phototropism.

Cytokinins

Plant hormones produced in roots that promote cell division (cytokinesis) and delay leaf senescence.

Gibberellins

Plant hormones that stimulate rapid stem elongation, seed germination, and fruit growth.

Abscisic Acid (ABA)

A plant hormone that inhibits growth, maintains seed dormancy, and closes stomata during drought stress.

Ethylene

A gaseous plant hormone that promotes fruit ripening, leaf abscission, and triple responses to mechanical stress.

Statoliths

Dense starch-storing plastids located in root cap cells that settle downward in response to gravity, mediating gravitropism.

Systemic Acquired Resistance

A long-lasting plant-wide defense response against pathogens triggered in uninfected organs distant from the infection site.