Seed Plants and Plant Structure: Key Concepts for Biology

Alternation of Generations (Seed Plants)

Seed plants are sporophyte-dominant; gametophytes are reduced and inside cones/flowers.

Microspores develop into what?

Pollen, the male gametophyte.

Megaspores develop into what?

Female gametophyte inside the ovule.

Pollination vs Fertilization

Pollination = pollen arrival. Fertilization = sperm and egg fuse inside ovule.

Where does pollination occur in angiosperms?

On the stigma of the flower.

Where does fertilization occur?

Inside the ovule.

Male (staminate) cones produce

Pollen (male gametophyte).

Female (ovulate) cones contain

Ovules, where eggs develop.

Gymnosperm seed coat comes from

The integument (2n).

Gymnosperm embryo ploidy

2n (fertilized egg).

Gymnosperm food source in seed

Female gametophyte tissue (n).

Angiosperm male structure

Stamen (anther + filament).

Angiosperm female structure

Carpel/Pistil (stigma + style + ovary).

Where are ovules located in flowers?

In the ovary.

Double Fertilization Result #1

Sperm + Egg → Embryo (2n).

Double Fertilization Result #2

Sperm + Polar nuclei → Endosperm (3n) food supply.

Fruit develops from what part of the flower?

The ovary.

Seeds develop from

Ovules.

Function of pollen tube

Delivers sperm to the egg inside ovule.

What is dispersed in gymnosperms?

Seeds (not spores).

What is dispersed in angiosperms?

Seeds (often inside fruit).

Primary Growth does what?

Lengthens plant (gets taller/longer).

Where is the root apical meristem located?

Just behind the root cap.

Root: Zone of Cell Division

Cells are actively mitotic.

Root: Zone of Elongation

Cells stretch → root length increases.

Root: Zone of Maturation

Root hairs form → water absorption.

Three Tissue Systems

Ground, Dermal, Vascular.

Ground Tissue

Includes Parenchyma, Collenchyma, Sclerenchyma.

Dermal Tissue

Includes Epidermis + Guard Cells.

Vascular Tissue

Includes Xylem + Phloem.

Parenchyma Cell Traits

Thin walls, large cells, alive, storage/photosynthesis.

Collenchyma Cell Traits

Uneven cell walls, alive, flexible support (celery strings).

Sclerenchyma Cell Traits

Thick lignin secondary walls, dead, rigid support.

Xylem transports what?

Water and minerals upward.

Are xylem cells alive?

No — dead at maturity.

Phloem transports what?

Sugars.

Are phloem cells alive?

Yes — sieve tube cells are alive with companion cells.

Leaf: Palisade Parenchyma

Tightly packed; major photosynthesis.

Leaf: Spongy Parenchyma

Loose; gas exchange.

Stomata Function

Gas exchange + water regulation.

Guard Cells' Role

Open/close stomata.

Monocot Leaf Venation

Parallel veins.

Dicot Leaf Venation

Branched veins.

Monocot Stem

Vascular bundles scattered.

Dicot Stem

Vascular bundles in a ring.

Monocot Root

Vascular tissue in ring.

Dicot Root

X-shaped xylem in center.