Plant versus ztructure

What is photosynthesis?

The process by which plants use sunlight, water, and CO2 to create oxygen and energy in the form of sugar.

What is a chloroplast?

The plant cell organelle where photosynthesis takes place.

What is chlorophyll?

The green pigment in chloroplasts that absorbs light energy for photosynthesis.

What are the inputs (reactants) of photosynthesis?

Light energy, Carbon dioxide (CO2), and Water (H2O).

What are the outputs (products) of photosynthesis?

Glucose (sugar) and Oxygen (O2).

What is the plant cell wall made of?

Cellulose (a structural carbohydrate).

What is the central vacuole in a plant cell?

A large organelle that stores water, nutrients, and waste, and maintains cell turgor pressure.

What is a stomata?

Microscopic pores on the leaf surface used for gas exchange (CO2 in, O2 out).

What are guard cells?

Cells that flank the stomata and control their opening and closing to regulate water loss. [ASSOCIATE WITH A PHOTO]

What is the difference between an Autotroph and a Heterotroph?

Autotrophs make their own food (e.g., plants). Heterotrophs consume other organisms for food.

What is a meristem?

Embryonic plant tissue containing unspecialized cells that actively divide for plant growth.

What is the root system?

All the roots of a plant that anchor it and absorb water and minerals.

What is the shoot system?

The aerial parts of a plant, including stems and leaves (captures light and CO2).

What is the difference between a taproot and a fibrous root system?

Taproot: one main thick vertical root. Fibrous root: a dense mat of thin, shallow roots.

Name 4 types of modified roots.

Prop roots (support), Pneumatophores (oxygen), Buttress roots (stability), Storage roots (store food). [ASSOCIATE WITH A PHOTO]

What is a node and an internode?

Node: point where leaves are attached. Internode: stem segment between two nodes.

Apical bud vs Axillary bud?

Apical: at the shoot tip (causes elongation). Axillary: at the angle of a leaf (forms lateral branches or flowers).

What is apical dominance?

The inhibition of axillary buds by the apical bud (via hormones) to concentrate growth upward.

Rhizome vs Stolon?

Rhizome: horizontal underground stem. Stolon: horizontal surface stem (runners for asexual reproduction). [ASSOCIATE WITH A PHOTO]

What is a tuber?

The enlarged end of a rhizome specialized for storing food (e.g., potato).

What are the two main parts of a standard leaf?

The blade (flattened part) and the petiole (stalk attaching to the stem).

How do veins differ in monocots and eudicots (dicots)?

Monocots: parallel veins. Eudicots: branching/net-like veins.

Name 3 types of modified leaves.

Tendrils (clinging/support), Spines (protection, like on cacti), Bracts (colored to attract pollinators).

What are the 3 plant tissue systems?

Dermal (outer protection), Vascular (long-distance transport), Ground (metabolism, storage, support).

Cuticle vs Periderm?

Cuticle: waxy coating preventing water loss. Periderm: protective tissue (cork) replacing the epidermis in woody plants.

What are the Pith and Cortex?

Ground tissues. Pith: internal to vascular tissue. Cortex: external to vascular tissue.

What are Parenchyma cells?

Living cells with thin primary walls and a large vacuole. Function: photosynthesis, storage, metabolism.

What are Collenchyma cells?

Living cells with unevenly thickened primary walls. Function: flexible support for growing young parts. [ASSOCIATE WITH A PHOTO]

What are Sclerenchyma cells?

Dead cells at maturity with thick, lignified secondary walls. Function: rigid structural support (fibers and sclereids).

What is lignin?

A tough, indigestible polymer that strengthens the secondary cell walls of plants (major component of wood).

What is the function of Xylem?

Transports water and dissolved minerals upward from roots to shoots. (Dead at functional maturity).

Tracheids vs Vessel elements (Xylem)?

Tracheids: long, thin, tapered cells. Vessel elements: wider, shorter, tubular cells with perforation plates. [ASSOCIATE WITH A PHOTO]

What is the function of Phloem?

Transports sugars (organic nutrients) from where they are made to where they are needed. (Alive at functional maturity).

What are the components of Phloem?

Sieve-tube elements (lack a nucleus) and Companion cells (provide metabolic functions for the sieve tube).

What is primary growth?

Growth in length produced by apical meristems (elongates roots and shoots).

What is secondary growth?

Growth in thickness/girth produced by lateral meristems (cambiums) in woody plants.

What is the function of the root cap?

Protects the delicate root apical meristem as it pushes through soil and secretes lubricating slime. [ASSOCIATE WITH A PHOTO]

What are the 3 zones of primary root growth?

1. Zone of cell division. 2. Zone of elongation. 3. Zone of differentiation (maturation).

Where do lateral roots arise from?

The pericycle (the outermost cell layer in the vascular cylinder).

What does the vascular cambium produce?

Secondary xylem (wood) to the inside, and secondary phloem to the outside.

Sapwood vs Heartwood?

Sapwood: younger, outer xylem that still transports water. Heartwood: older, inner xylem that no longer transports water. [ASSOCIATE WITH A PHOTO]

What does the cork cambium produce?

Cork cells to the outside to form the periderm (replaces the epidermis).

What is bark?

All tissues external to the vascular cambium (secondary phloem + periderm).

What is the mesophyll?

The ground tissue of a leaf (parenchyma cells) specialized for photosynthesis, located between the upper and lower epidermis.

What is the preprophase band?

A ring of concentrated microtubules in the cytoplasm that predicts the future plane of cell division.

What is the result of asymmetrical cell division?

It generates daughter cells with different fates (e.g., creating guard cells from an unspecialized epidermal cell).

ABC Hypothesis: What genes form the Sepals?

A genes active alone. [ASSOCIATE WITH A DIAGRAM PHOTO]

ABC Hypothesis: What genes form the Petals?

A and B genes active together.

ABC Hypothesis: What genes form the Stamens?

B and C genes active together.

ABC Hypothesis: What genes form the Carpels?

C genes active alone.

ABC Hypothesis: What is the mutual inhibition rule?

Where A is active, it inhibits C, and vice-versa.

ABC Hypothesis: What happens if gene A is missing?

Gene C spreads to all whorls. Resulting organs: Carpel -> Stamen -> Stamen -> Carpe