AP Biology Exam Review

Plant Anatomy and Physiology

Angiosperm divisions

Dicot

2 cotyledons: storage tissue for embryoNetted veins4X 5X petalsRing of vascular bundlestaproot

Monocot

1 cotyledon

Parallel veins3X petalsScattered vas. BundleFibrous root

Plant tissue Ground tissue: parenchyma,

collenchyma, sclerenchyma

Dermal tissue: lower and upper epidermis, cuticle

Vascular tissue: xylem and phloem

Vascular tissue Xylem: primary and secondary cell

wall, pits vs. perforations, tracheids vs. vessel elements

Phloem: sieve tube members, pores, sieve plants, companion cells, plasmodesmata

Xylem

Phloem

Meristems Shoot Lateral Root

Seed Embryo: epicotyl (shoot tip),

plumule (young leaves), hypocotyl (young shoot), radicle (root), coleoptile (sheath of monocot)

Seed coat Endosperm or cotyledons Remains dormant until ABA

washed away

Seed Plumule Radicle Endosperm Seed coat Cotyledon Hypocotyl: dicot Coleoptile:

monocot

Germination: breaking dormancy Imbibition: absorb water, removing

ABA, gibberellin promotes germination

Meristamtic cells: actively dividing cells (primary growth)

Root: zone of cell division, zone of elongation, root cap, zone of maturation

Seed germination

Primary vs. secondary growth Primary growth: primary xylem

and phloem (still living)

Secondary growth: increases girth (width), occurs at vascular cambium and cork cambium, VC wood, CC periderm (cork)

Root structure Epidermis with root hairs Cortex Endodermis Vascular cylinder (stele)

Root

Stem structure Epidermis with cutin Cortex Vascular cylinder (xylem, phloem,

pith)

Secondary growth in stems: sapwood heartwood (annual rings)

Secondary stem growth – vascular cambium

Cell plates – plant mitosis

Tree stem

Leaf structure Epidermis with cuticle Palisade mesophyll Spongy mesophyll Vascular bundle Guard cells with stomata

Leaves

Transport Transpiration

– water transport

Bulk flow/source to sink – sugar transport

Plasmodesmata: connects two plant cells

Symplast vs. apoplast

Transport types

Water transwport Apoplast: within cell walls or

between cells

Symplast (within cells, plasmodesmata)

Requires osmosis, capillary action, cohesion-tension

Root and H2O

Leaf water potential

Controlling stomata

Factors causing stomata to close

high temperature CO2

concentrations low Night diffusion of K+ out of guard cells

Stomata control

Sugar transport

Sieve tube:pressure flow

Mineral uptake

Symbiotic bacteria

Double fertilization

Auxin

Signaling

Hormoneoverview Auxin Abscisic acid Brassinoid Cytokinin Ethylene Gibberellin