Plant Biology Flashcards

Flashcards covering key concepts in plant adaptations, characteristics, life cycles, ecological importance, and tissue organization.

What are Apical Meristems?

Growth regions at root and shoot tips, allowing upward and downward growth.

What are Multicellular Dependent Embryos?

Embryos that develop within tissues of the female parent providing protection and nutrients.

What are Walled Spores Produced in Sporangia?

Durable spore walls containing sporopollenin to resist harsh environments.

What are Multicellular Gametangia?

Organs that produce gametes (archegonia for eggs, antheridia for sperm).

What is Alternation of Generations?

Life cycle with both multicellular haploid (gametophyte) and diploid (sporophyte) stages.

What are examples of Nonvascular Plants (Bryophytes)?

Mosses, liverworts, and hornworts.

What is a key characteristic of Nonvascular Plants (Bryophytes)?

Lack vascular tissue (no xylem or phloem), hence small and found in moist environments.

What does it mean when it is said that bryophytes have a Gametophyte-dominant life cycle?

The green leafy part of bryophytes is the haploid stage.

Why do Bryophytes require water for fertilization?

Flagellated sperm swim to egg. This is why water is needed for fertilization.

What are the Life Cycle Phases of Bryophytes?

The gametophyte produces gametes in archegonia/antheridia, fertilization occurs (needs water), diploid sporophyte grows from zygote and remains attached to gametophyte, sporophyte produces haploid spores via meiosis, and spores disperse and grow into new gametophytes.

Why are mosses considered Pioneer species?

They colonize bare, disturbed environments (e.g., after volcanic eruptions).

What is the Ecological Importance of Mosses?

Help prevent erosion and retain soil moisture, contribute to peat formation, and provide habitat and food for microfauna.

What are examples of Seedless Vascular Plants?

Ferns, horsetails, and club mosses (lycophytes).

What is a key characteristic of Seedless Vascular Plants?

Vascular tissue (xylem and phloem) allows larger size and structural support.

What does it mean when it is said that Seedless Vascular Plants have a Sporophyte-dominant life cycle?

The sporophyte is the dominant life cycle stage, unlike bryophytes.

Why do Seedless Vascular Plants still rely on water for fertilization?

Flagellated sperm, so they rely on water for fertilization.

What kind of structures do Seedless Vascular Plants hold?

Have true roots, stems, and leaves (often with microphylls in lycophytes or megaphylls in ferns).

What are the Life Cycle Phases of Seedless Vascular Plants?

The sporophyte produces spores in sori (on fern fronds); spores germinate into independent gametophytes; gametophytes produce gametes; water allows sperm to swim to egg; and fertilization forms a new diploid sporophyte.

What is the Ecological Importance of Seedless Vascular Plants?

Major contributors to carbon fixation in ancient ecosystems, formed vast coal deposits during the Carboniferous period, help stabilize soil and support biodiversity in modern ecosystems, and some are used in horticulture and medicine (e.g., ferns).

What is the purpose of Seeds in Seed Plants?

Protect and nourish the embryo, can remain dormant during unfavorable conditions, and aid in dispersal (via wind, animals, etc.).

What are Reduced Gametophytes?

Microscopic and protected within sporophyte tissue, reducing vulnerability to environmental damage.

What is Heterospory?

Two types of spores: microspores (male gametophytes) and megaspores (female gametophytes), increasing efficiency and specialization in reproduction.

What is an Ovule?

Structure that develops into a seed after fertilization and contains the female gametophyte and egg cell.

What is Pollen?

Male gametophyte carried by wind or animals, eliminating the need for water in fertilization.

What does it mean for Gymnosperms to have 'naked seeds'?

Gymnosperms (like conifers) have seeds that are not enclosed in fruit.

What is the Gymnosperm Life Cycle?

Sporophyte (2n) is the dominant, visible tree; produces cones (pollen and ovulate); pollination occurs; fertilization occurs inside ovule; seed forms from ovule and disperses; and seed germinates into new sporophyte.

What is the major adaptation of Angiosperms: Flowers?

Specialized reproductive structures that attract pollinators (insects, birds, etc.).

What is the major adaptation of Angiosperms: Fruits?

Develop from ovaries and protect/disperse seeds.

What is the major adaptation of Angiosperms: Double Fertilization?

One sperm fertilizes the egg; another forms endosperm (nutritive tissue).

What is the major adaptation of Angiosperms: Efficient Vascular Tissue?

Advanced xylem (vessels) for better water transport.

What is the major adaptation of Angiosperms: Co-evolution with Pollinators?

Increases reproductive success and genetic diversity.

What is the Angiosperm Life Cycle?

Sporophyte (2n) produces flowers; anthers produce microspores → pollen; ovary contains ovules → megaspores → female gametophytes; pollination occurs; double Fertilization take place; ovule becomes seed, ovary becomes fruit; and seed disperses, germinates → new sporophyte.

What is the function of Roots?

Anchor plant in soil, absorb water and minerals, and store carbohydrates.

What is the purpose of Root hairs?

Increase surface area for absorption.

What is the structure of a Taproot system (in dicots)?

One main root.

What is the structure of a Fibrous root system (in monocots)?

Many small roots.

What is the function of a Stem?

Support leaves and flowers; transport fluids via xylem and phloem; and store nutrients and sometimes perform photosynthesis.

What are Nodes?

Points where leaves attach.

What are Internodes?

Stem segments between nodes.

What are Axillary buds?

Can form lateral shoots (branches).

What are Apical buds?

Found at stem tip and responsible for vertical growth.

What is the function of Leaves?

Main site of photosynthesis and gas exchange (via stomata).

What is the Blade of a leaf?

Broad, flat surface of the leaf.

What is the Petiole of a leaf?

Connects leaf to stem.

What are the Veins of a leaf?

Transport water and nutrients (vascular tissue).

What are the Components of the Dermal Tissue System?

Epidermis (non-woody plants) and Periderm (replaces epidermis in woody plants).

What is the Functions of the Dermal Tissue System?

Protection; prevent water loss (via cuticle); contain guard cells (regulate stomata); and may have trichomes (hairs for protection or absorption).

What are the Components of the Vascular Tissue System?

Xylem transports water and minerals upward; and Phloem transports sugars and organic nutrients.

What is the Function of the Vascular Tissue System?

Long-distance transport of materials and structural support.

What are the Components of the Ground Tissue System?

Pith (inside vascular tissue) and Cortex (outside vascular tissue).

What is the Function of the Ground Tissue System?

Photosynthesis, storage, and support.

What are Parenchyma cells?

Thin, flexible walls; alive at maturity and responsible for photosynthesis, storage, wound repair, and can differentiate into other cell types.

What are Collenchyma cells?

Unevenly thickened walls; alive at maturity and responsible for flexible support.

What are Sclerenchyma cells?

Thick, rigid walls with lignin; dead at maturity and responsible for rigid structural support (fibers and sclereids).

What is Primary Growth?

Originates from apical meristems at root and shoot tips; responsible for vertical (lengthwise) growth; produces primary tissues; and occurs in all plants.

What is Secondary Growth?

Originates from lateral meristems; responsible for horizontal (thickness) growth; produces secondary xylem (wood) and secondary phloem (part of bark); and occurs mainly in woody plants.

What are Short-Range Transport Routes in Plant Tissues?

Apoplast route (movement through cell walls and intercellular spaces), Symplast route (movement through the cytoplasm via plasmodesmata), and Transmembrane route (movement across cell membranes and cytoplasm repeatedly).

How does Water Move via Xylem?

Driven by transpiration; water moves up due to cohesion and adhesion; and this creates a negative pressure (tension) in the xylem, pulling water upward (Cohesion-Tension Mechanism).

How is Water Flow Regulated by Stomata?

Stomata are pores on the underside of leaves controlled by guard cells; when guard cells take up water, they swell and open stomata; and when water is scarce, guard cells lose turgor, closing stomata to conserve water.

How does Sugar Transport via Phloem (Translocation)?

Sugar is actively loaded into phloem at source → water follows by osmosis → high pressure builds; at sink, sugar is removed → water leaves → pressure drops; and this pressure gradient pushes sugar from source to sink.

What are the different categories of Soil texture?

Sand (large particles → good drainage, poor nutrient retention), Silt (medium particles → moderate retention), and Clay (tiny particles → holds water and nutrients well, but may have poor drainage).

What are the Components of Soil?

Inorganic particles (sand, silt, clay), organic matter (humus), air and water, and living organisms (microbes, fungi, earthworms, etc.).

What are the Characteristics of Australian Soils?

Generally old and weathered with low fertility; often acidic or nutrient-poor, particularly in phosphorus; some areas have saline or sodic soils; and low organic matter and poor water-holding capacity in many regions.

What are the key Macronutrients Plants require?

Nitrogen (N), Phosphorus (P), and Potassium (K).

What benefit does Mycorrhizal fungi provide in Mutualistic Relationships in Soil?

Increase nutrient and water uptake for plants, and in turn, plants provide sugars to fungi.

How can Soils be damaged and what are ways to improve soil?

Soil Damage Causes: Overgrazing, deforestation, and poor agricultural practices, erosion, salinization, compaction, and nutrient depletion, excessive use of chemical fertilizers and pesticides. Soil Improvement Techniques: Composting and adding organic matter, crop rotation and cover cropping, reduced tillage to maintain structure, contour plowing and terracing to prevent erosion, use of biofertilizers and mycorrhizal inoculants.