Plant Science & Genetics Vocabulary Flashcards

A complete vocabulary flashcard deck covering plant-human utility, molecular genetics, agricultural domestication, biotechnology/GMO methods, photosynthesis pathways, and major plant evolutionary lineages.

Salicin

A biologically active compound found in willow bark that helped lead to the development of modern aspirin.

Digitoxin

A plant-derived compound from foxglove used in the treatment of certain heart conditions.

Paclitaxel

An anticancer drug, also known as taxol, derived from the Pacific yew plant.

Nucleotide

The repeating structural unit of DNA, composed of a sugar, a phosphate group, and one nitrogenous base (adenine, thymine, guanine, or cytosine).

Helicase

An enzyme active during DNA replication that unzips and unwinds the DNA double helix so the strands can be copied.

DNA Polymerase

An enzyme that builds new DNA strands during replication by adding complementary nucleotides to the original template strand.

RNA Polymerase

An enzyme that reads the DNA sequence of a gene during transcription and builds a complementary RNA strand.

Codon

A sequence of three bases on messenger RNA (mRNA) that corresponds to a specific amino acid during translation.

tRNA

Transfer RNA; a molecule that carries a specific amino acid to the ribosome and matches it to the correct mRNA codon during translation.

Cultivation

The intentional management of plants (such as planting, watering, fertilizing, protecting, and harvesting) without necessarily changing them genetically.

Domestication

The process where long-term cultivation and human selection cause genetic changes in a plant population over generations.

Transgenesis

A genetic modification method where a gene is transferred into an organism from a sexually incompatible species.

Cisgenesis

A genetic modification method where an intact, natural gene is transferred from the same species or a sexually compatible relative.

Intragenesis

A genetic modification method where all genetic material comes from the same species or compatible gene pool, but parts of different genes are rearranged.

Agrobacterium tumefaciens

A soil bacterium that naturally transfers DNA into plant cells, exploited by scientists as a gene delivery system for transgenesis.

Bacillus thuringiensis

A soil bacterium that naturally produces insecticidal proteins, commonly sourced for genes used in pest-resistant Bt crops.

Guide RNA

A short single-guide RNA sequence in the CRISPR/Cas9 system designed to match and direct Cas9 to a specific target DNA sequence.

Cas9

A protein enzyme in the CRISPR system that acts as molecular scissors to make a double-strand break at the target DNA location.

Non-Homologous End Joining (NHEJ)

A quick, template-free, and error-prone cellular DNA repair mechanism that often introduces small insertions or deletions, typically resulting in a gene knockout.

Homology-Directed Repair (HDR)

A precise cellular DNA repair mechanism that uses a DNA template to correct mutations, make specific point changes, or insert new sequences.

Gene Flow

The movement of genes between populations, such as when pollen from a genetically modified crop fertilizes a nearby non-GM crop or wild relative.

StarLink Corn

A genetically modified Bt corn variety expressing Cry9C protein approved for animal feed but recalled after trace amounts were detected in human food products.

Thylakoid

A flattened membrane sac inside the chloroplast where the light-dependent reactions of photosynthesis occur.

Stroma

The fluid-filled internal region of the chloroplast surrounding the thylakoids where the Calvin cycle (light-independent reactions) occurs.

Carbon Fixation

The process of converting inorganic carbon ($\text{CO}_2$) into an organic molecule, catalyzed by enzymes like Rubisco in the Calvin cycle.

Photosystem II (PSII)

A pigment-protein complex in the thylakoid membrane that functions first in linear electron flow, absorbing light energy to split water and release oxygen ($\text{O}_2$).

Photosystem I (PSI)

A pigment-protein complex that re-energizes electrons arriving from the electron transport chain to reduce $\text{NADP}^+$ to $\text{NADPH}$.

Linear Electron Flow

The primary pathway of light reactions involving both PSII and PSI that uses electrons from water to produce $\text{ATP}$, $\text{NADPH}$, and $\text{O}_2$.

Cyclic Electron Flow

A light-reaction pathway involving only PSI that cycles energized electrons to produce extra $\text{ATP}$ without generating $\text{NADPH}$ or $\text{O}_2$.

Chemiosmosis

The mechanism in which energy stored in a proton ($\text{H}^+$) gradient drives the synthesis of $\text{ATP}$ as protons flow through $\text{ATP synthase}$.

Rubisco

The enzyme that catalyzes the initial carbon-fixation step of the Calvin cycle by attaching $\text{CO}_2$ to RuBP.

Photorespiration

An energy-wasting metabolic process that occurs when Rubisco binds $\text{O}_2$ instead of $\text{CO}_2$, typically triggered under hot, dry conditions when stomata close.

C4 Photosynthesis

A photosynthetic adaptation that minimizes photorespiration by spatially separating initial carbon fixation in mesophyll cells from the Calvin cycle in bundle sheath cells.

CAM Photosynthesis

A photosynthetic adaptation that temporally separates carbon fixation (taking up $\text{CO}_2$ at night) from the Calvin cycle (occurring during the day when stomata are closed).

Sporopollenin

A highly resistant polymer surrounding plant spores that protects reproductive cells from drying, physical damage, and harsh terrestrial conditions.

Cuticle

A waxy coating on terrestrial plant surfaces that reduces water loss, creating a trade-off by limiting gas exchange.

Stomata

Adjustable pores on plant leaves that allow gas exchange ($\text{CO}_2$ entry and $\text{O}_2$ release) while regulating water loss.

Bryophytes

Non-vascular land plants (mosses, liverworts, hornworts) that lack true vascular tissue, roots, and leaves, are gametophyte-dominant, and require a film of water for swimming flagellated sperm.

Xylem

Lignified vascular tissue responsible for long-distance transport of water and minerals as well as structural support in vascular plants.

Phloem

Vascular tissue responsible for transporting sugars and other organic nutrients throughout the plant.

Megaphylls

Large leaves with branching vascular systems that offer an increased surface area for light capture and internal transport.

Pollen

The microgametophyte (male gametophyte) of seed plants that delivers sperm cells to the ovule via a pollen tube, eliminating the need for environmental water during fertilization.

Gymnosperms

Vascular seed plants whose seeds are "naked" (exposed on cone scales rather than enclosed within a fruit).

Double Fertilization

A unique angiosperm process where one sperm fertilizes the egg to form a diploid ($2n$) embryo, and a second sperm fuses with two polar nuclei to form triploid ($3n$) endosperm.

Carpel

The female reproductive organ of a flower consisting of the stigma, style, and ovary, which encloses the ovules and later develops into fruit.