Phytochemistry and Plant Physiology - Lecture Notes Flashcards

Question-and-answer flashcards covering key concepts from the lecture notes: plant structure, tissue types, plastids and chloroplasts, nutrient transport, acclimation vs adaptation, niche theory, plant hormones, and abiotic stress strategies.

What are the ecological and evolutionary drivers of chemical diversity in plants, and how do they impact plant-biotic interactions?

Ecological and evolutionary factors shape the diversity of plant secondary metabolites and their effects on interactions with biotic partners (pollinators, herbivores, microbes).

What is acclimation?

An adjustment in physiology within an individual during a single lifetime in response to environmental stress, involving changes in gene expression that alter phenotype; may be adaptive.

What is adaptation?

An adjustment in physiology within a population over generations via natural selection; heritable variation; phenotypic changes that increase fitness under a given environment.

What is the difference between a fundamental niche and a realized niche?

Fundamental niche is the potential range of conditions a species can persist in the absence of interactions; realized niche is the actual conditions under which it exists given interactions like competition.

What is a plastid and what is its origin?

A plastid is an organelle derived from endosymbiotic cyanobacteria; all plastids share this lineage, with chloroplasts specialized for photosynthesis.

Describe the chloroplast genome in terms of size and gene content.

A circular genome of about 150,000 base pairs containing 30–50 RNA genes and roughly 100 protein-coding genes; transcribed in both directions and housing photosynthetic genes.

What are thylakoids and why are they important?

Membrane-bound compartments inside chloroplasts where the light reactions of photosynthesis occur, creating the proton gradients used to synthesize ATP and NADPH.

What is the primary function of the chloroplast?

To carry out photosynthesis and carbon fixation; houses chlorophyll and the machinery for the light reactions and Calvin cycle.

Name the three tissue types in plants.

Dermal tissue, vascular tissue, and ground tissue.

What are the components of dermal tissue in leaves?

Pavement cells, guard cells, and trichomes (epidermal cells); also includes root hairs and the cuticle.

What is the function of phloem?

Transports sugars and other solutes through sieve-tube elements and companion cells (mass flow).

What is the function of xylem?

Transports water and minerals; composed of dead vessel elements and tracheids with primary and secondary walls and pits for lateral movement.

Define parenchyma tissue and its role.

Ground tissue with thin primary walls; metabolically active and often totipotent; involved in metabolism, storage, repair, and secretion (chlorenchyma when containing chloroplasts).

Define collenchyma and its role.

Ground tissue with elongated cells and irregularly thickened primary walls; provides flexible support, especially along the vasculature.

Define sclerenchyma and its role.

Ground tissue with thick secondary walls (often lignified); cells are usually dead at maturity and provide rigid support; includes fibers and sclereids.

What tissue forms the outer protective covering of leaves and includes guard cells and pavement cells?

Dermal tissue (epidermis).

What tissue makes up the bulk of the leaf interior and contains chlorenchyma?

Ground tissue, specifically the mesophyll (palisade and spongy mesophyll).

Differentiate between palisade mesophyll and spongy mesophyll.

Palisade mesophyll contains tall, tightly packed chloroplast-rich cells near the upper surface; spongy mesophyll has loosely arranged cells with air spaces to facilitate gas exchange.

What controls stomatal opening and closing?

Guard cells regulate stomatal aperture in response to environmental and hormonal signals.

What are plasmodesmata?

Cytoplasmic channels between plant cells that enable symplastic transport, linking cytosol without crossing cell walls.

What are sieve-tube elements and companion cells?

Sieve-tube elements conduct phloem sap; companion cells assist and regulate sieve-tube element function and loading/unloading of sugars.

What are vessel elements and tracheids?

Xylem water-conducting cells; both are dead at maturity; vessel elements form vessels in angiosperms, while tracheids are common in gymnosperms; both have pits for lateral water movement.

What is the origin and significance of plastids in plants?

Plastids originated from a single endosymbiotic event with cyanobacteria; they differentiate into chloroplasts and other plastids, possessing their own genomes and replicating independently.

What are the zinc-like basics of the vascular cambium and cork cambium?

Vascular cambium is a lateral meristem producing secondary xylem and secondary phloem; cork cambium (phellogen) produces the periderm (cork) contributing to secondary growth.

What is the difference between primary and secondary cell walls?

Primary cell walls form during growth; secondary cell walls are deposited after growth and are often lignified, providing extra strength and support.

What is an endosymbiotic origin relevant to chloroplasts and mitochondria?

Chloroplasts originate from cyanobacteria; mitochondria originate from proteobacteria; both are derived from ancient endosymbiotic events and contain their own genomes.

What is the focus of the abiotic stress chapter in this course according to the notes?

Understanding how plants interact with the environment to maintain homeostasis through acclimation-based responses or pre-existing adaptations.

What is homeostatic compensation in the context of acclimation and adaptation?

The total increase in plant activity resulting from both acclimation (within a lifetime) and adaptation (across generations), reflecting in situ performance under stress.

What time scales are associated with acclimation versus adaptation in plants?

Acclimation occurs within days to months in an individual; adaptation occurs over generations through evolutionary time.

What is totipotency in plants and why is it important?

Most plant cells can dedifferentiate into totipotent stem cells, enabling regeneration and tissue culture; plants are highly modular with distributed stem cells.

What is cuticle and its function in plants?

A waxy layer on the epidermis that reduces water loss and provides protection against environmental stress.

Name two key plant hormones involved in stress responses and development.

Auxin and Abscisic acid (ABA) are central; others include Gibberellin, Cytokinin, Ethylene, Jasmonic acid, Salicylic acid, Brassinolide, Strigolactone.