AP Review

Chapters 29-31,

Fast Facts

There are four main groups of land plants: bryophytes, pteridophytes, gymnosperms, and angiosperms

Bryophytes: mosses; distinguished from algae by advances that allow for life on land

Pteridophytes: ferns; contain vascular tissue (transport water and food); “seedless plants”

Fast Facts

Gymnosperms:conifers; “naked seed” (seeds are not enclosed in a special chamber)

Seed: consists of a plant embryo packaged with food and a protective coat

Angiosperms: flowering plants; “container seed”; most modern-day plants

algal ancestors bryophytes vascular plants the origin of seeds the evolution of flowers

Fast Facts

Charophyceans are the green algae most closely related to land plants

Several terrestrial adaptations distinguish land plants from charophycean algae

- growth in length is from apical meristems

- multicellular, dependent embryos

- alteration of generations: gametophyte and sporophyte

Fast Facts

Fast Facts

Fast Facts

Adaptations for water conservation:

- formation of a cuticle

- stomata contain guard cells

Adaptations for water transport:

- xylem: carry water and minerals up from root

- phloem: distribute sugars and amino acids throughout the plant

Fast Facts

The gametophyte is the dominant generation in the life cycle of bryophytes

Modern vascular plants include ferns (pteridophytes), gymnosperms, and flowering plants (angiosperms)

Differ from bryophytes

- contain phloem and xylem

- dominant sporophyte generation

Fast Facts

Fast Facts

Seed plants are vascular plants that produce seeds

The developing embryo is encased in a protective seed coat and supplied with its own source of food (endosperm or cotyledons)

Fast Facts

Fast Facts

Seeds allow the embryo to be moved away from the parent by wind, water, and animals

Seed plants are not tied to water for fertilization; pollen grains do not need to be transported by liquid

Fast Facts

Gymnosperms lack enclosed chambers in which seeds develop; instead, seeds develop on the surfaces of specialized leaves called sporophylls.

Phylum Anthophyta:

- all angiosperms are placed in one phylum

Two classes: monocots and dicots

Fast Facts

- have vessel elements for water transport instead of tracheids; speed water transport through the plant

Fast Facts

Fast Facts

All fungi are eukaryotic; most are multicellular

mycete = fungi

Fungi differ from plants in nutritional mode, structural organization, growth, and reproduction

Fungi are heterotrophs that acquire their nutrients by absorption

Fast Facts

The bodies of fungi are constructed of tiny filaments called hyphae

- the hyphae are divided into cells by cross-walls, or septa

- cells walls are made of chitin

Fast Facts

Lichens

- symbiotic relationship of millions of photosynthetic microorganisms held in a mesh of fungal hyphae

- the alga provides the fungus with food. The fungus provides a suitable environment for growth

Fast Facts

Fast Facts

Mycorrhizae

- mutualistic association of plant roots and fungi

- responsible for making nutrients able to be absorbed

Sample Questions

Discuss the adaptations that have enabled flowering plants to overcome the following problems associated with life on land. a) The absence of an aquatic environment for reproduction. b) The absence of an aquatic environment to support the plant body c) Dehydration of the plant

Fast Facts

Plants are made up of two main systems: the root system and shoot system

Monocots have fibrous roots: mat of thin roots that spread out below the soil surface

Dicots have a taproot: one large vertical root that produces lateral branch roots

Fast Facts

Stem

- an alternating system of nodes (place where leaves are attached) and internodes (the stem between the nodes)

- apical dominance: growth focuses on the terminal bud; inhibits the axillary bud

Fast Facts

Leaves

- main photosynthetic organ of plants

- consist of a flattened blade and a petiole (stalk that join to the node of the stem)

- monocots have parallel veins in leaves

- dicot leaves have a multi-branched network of veins

Fast Facts

Plant organs are composed of three tissue systems: dermal, vascular, and ground

Dermal tissue

- single layer of tightly packed cells that covers and protects all young parts of the plants

- for the cuticle

Fast Facts

Vascular tissue

- involved in the transport of materials between the root and the shoot

- xylem: moves water and dissolved minerals upward from roots

- tracheids and vessel elements are elongated cells that are dead

at functional maturity

Fast Facts

Fast Facts

- phloem: moves food made by leaves to the roots

- sieve-tube members transport sucrose and other organic

materials

- sieve plates help move fluid from cell to cell

- companion cell: assist the STM

Fast Facts

Ground tissue

- tissue that is neither dermal nor vascular

- in dicots, divided into the pith (internal to the vascular tissue) and the cortex (external to vascular tissue)

- photosynthesis, storage, and support

Fast Facts

Plant tissues are composed of three basic cell types: parenchyma, collenchyma, and sclerenchyma

Parenchyma cells

- have 1o cell walls, but lack 2o

- typical plant cell; least specialized

- perform most metabolic functions of the plant

Fast Facts

Collenchyma cells- thicker 1o cell walls - support young parts of the plant shoot- provide support without restraining growth

Sclerenchyma cells- support; form thick 2o cells that are strengthened by lignin- dead at functional maturity- ex. xylem cells

Fast Facts

Vascular tissue runs through the stem in strands called vascular bundles

- surrounded by ground tissue

In dicots, the vascular bundles are arranged in a ring, with the pith inside the ring, the cortex is outside

In monocots, the vascular bundles are scattered throughout the ground tissue

Fast Facts

Fast Facts

Tissue organization of leaves

The epidermis is composed of tightly interlocked cells

- stomata: tiny pores that allow for gas exchange w/ the help of guard cells

The ground tissue is sandwiched between the upper and lower epidermis in the mesophyll

Fast Facts

- the mesophyll consists of parenchyma cells w/ chloroplasts

The vascular tissue also flows through the leaf from the stem

- contains the xylem and phloem

Fast Facts

Differences in water potential drive water transport in plant cells

Osmosis: the net uptake or loss of water by a cell

Water potential: the combined effect of solute concentration and pressure.

- psi (Y)

- water will move from the solution with the higher water potential to the solution with the lower water potential

Fast Facts

Bulk flow: the movement of fluid driven by pressure

Root pressure: water flows in from the root cortex, generating a positive pressure that forces fluid up the xylem

Root pressure causes guttation: when more water enters leaves than is transpired and the excess is forced out

Fast Facts

Pulling up xylem sap: Transpiration-Cohesion-Tension Theory

Transpiration

-when stomata open water exits the leaf

- move from [high] to [low]

Cohesion

- water molecules will bond to each other with hydrogen bonds

Fast Facts

Hormones: chemical signals that coordinate the parts of an organism

Tropism: any growth response that results in curvatures of whole plant organs toward or away from stimuli

Phototropism: the growth of a shoot toward light

Fast Facts

Auxin (IAA)

- any chemical substance that promotes the elongation of coleoptiles

- moves from the shoot tip down to the base of the plant

Cytokinins

- stimulate cytokinesis, or cell division

Fast Facts

Gibberellins

- stimulate growth in the stems and leaves, but not in the roots

- stimulates cell elongation and division

Abscisic Acid

- slows down growth

- seed dormancy: high levels of ABA inhibit germination; only when the ABA is inactivated will the seed germinate

Fast Facts

Ethylene

- produced by plants in response to environmental stresses

- also occurs in fruit ripening and programmed cell death

Sample QuestionsAngiosperms (flowering plants) and vertebrates

obtain nutrients from their environment in different ways: (A) Discuss the type of nutrition and the nutritional requirements of angiosperms. (B) Describe 2 structural adaptations in angiosperms for obtaining nutrients from the environment. Relate structure to function. (C) Interdependence in nature is evident in symbiosis. Explain two symbiotic relationships that aid in nutrient uptake, using examples from angiosperms.