Plant Biology Lecture Review

Flashcards created to review key concepts from the plant biology lecture notes.

What are plants as carbon sinks?

They absorb CO2 and incorporate it into their tissues.

What medicine is derived from willow trees?

Aspirin for pain relief.

Was heroin originally intended to be less addictive?

Yes, it was meant to replace morphine.

Why is California a biodiversity hotspot?

It has exceptionally high species richness and endemism.

What deficiency leads to childhood blindness?

Vitamin A deficiency; golden rice helps prevent this.

What structures are in plant cells?

Nucleus, mitochondria, chloroplasts, plasmodesmata.

How do plasmodesmata differ from animal junctions?

They are not homologous; they are unique plant cell connections.

Is multicellularity shared between plants and animals?

No, it evolved independently.

Why can't plant cells move?

The rigid cell wall restricts movement.

What is the primary cell wall made of?

Cellulose, hemicellulose, and pectin.

What is the secondary cell wall made of?

Lignin; thick, strong, non-flexible.

What does lignin do to cells?

Reduces metabolic space, eventually killing the cell.

What separates plant cells?

The middle lamella, a jello-like layer.

What are the plant body’s two vegetative parts?

Root system and shoot system.

What is the SAM?

Shoot apical meristem; source of all above-ground tissues.

What is the RAM?

Root apical meristem; source of root tissues.

What is primary growth?

Lengthening growth at SAM and RAM.

What are the three plant tissues?

Dermal, vascular, ground.

What does dermal tissue do?

Forms epidermis and prevents desiccation.

What are stomata?

Pores controlling gas exchange via guard cells.

What are trichomes?

Hair-like structures for defense, reflection, and metabolites.

What are root hairs?

Water-absorbing extensions of epidermal cells.

What does xylem transport?

Water and minerals upward.

What does phloem transport?

Sugars and nutrients throughout the plant.

What are parenchyma cells?

Ground tissue, thin-walled, living, metabolic.

What are collenchyma cells?

Ground tissue, thick primary walls, flexible support.

What are sclerenchyma cells?

Ground tissue, lignified secondary walls, dead support cells.

What are the main parts of a leaf?

Petiole, midrib, blade.

Where are stomata located?

On the underside of the leaf.

What is palisade mesophyll?

Chloroplast-dense photosynthetic layer.

What is spongy mesophyll?

Gas exchange layer.

What are nodes?

Stem points where leaves attach.

What are internodes?

Stem sections between nodes.

What is the axillary meristem?

Meristem at nodes that forms branches or flowers.

What are the main root parts?

Root cap, RAM, root hairs.

Who produces flowers?

Angiosperms.

What are carpels?

Female reproductive organs.

What are stamens?

Male reproductive organs.

What is algae as a group?

A paraphyletic set of early divergent aquatic plant lineages.

Where did plants first evolve?

In water, later moving to land.

What were benefits of land colonization?

More sunlight and CO2.

What were challenges on land?

Desiccation, structural support, reproductive dispersal.

Why are glaucophytes important?

Their chloroplasts retain peptidoglycan from cyanobacteria.

Why are red algae red?

Different photosynthetic pigments.

Which pigments do green plants use?

Chlorophyll a, b, and carotenoids.

How do green plants store sugar?

As starch in chloroplasts.

What are the 7 groups of land plants?

Liverworts, mosses, hornworts, lycophytes, monilophytes, gymnosperms, angiosperms.

What are synapomorphies of land plants?

Waxy cuticle, protected embryo, sporophyte, airborne spores.

What does meiosis produce?

Four haploid cells.

How do plants make gametes?

By mitosis.

What is a haplontic life cycle?

Multicellular haploid stage; only zygote is diploid.

What is alternation of generations?

Alternating gametophyte (n) and sporophyte (2n).

What do gametophytes produce?

Gametes.

What do sporophytes produce?

Spores.

What are bryophytes?

Paraphyletic non-vascular plants.

What do bryophytes lack?

Xylem, phloem, true leaves, true roots.

How do bryophytes absorb water?

Ectohydrically over whole surface.

What are hydroids?

Water-conducting cells in mosses.

What are leptoids?

Nutrient-conducting cells in mosses.

What is dominant in bryophytes?

Gametophyte.

Why do bryophyte sperm need water?

They must swim to the egg.

What is sporopollenin?

A protective, waterproof coating on spores.

What characterizes liverworts?

Flat, spongy gametophytes, tiny sporophytes.

What characterizes mosses?

Upright gametophyte, elongated sporophyte.

What characterizes hornworts?

Large green sporophyte that photosynthesizes.

What are vascular plants?

Plants with xylem and phloem.

What are seedless vascular plants?

Ferns and lycophytes.

What are tracheids?

First xylem type; lignified, dead at maturity.

What do roots do?

Anchor plant, absorb water/minerals, store nutrients.

How do monocots and eudicots differ in stem bundles?

Monocots: scattered; eudicots: ordered ring.

What does phloem consist of?

Sieve tube elements and companion cells.

How does water move in xylem?

Cohesion and adhesion pull water upward.

What is phloem loading?

Sugar moved into sieve tubes; may require ATP.

What are microphylls?

Single-veined leaves of lycophytes.

What are strobili?

Cone-like clusters of sporangia.

What is heterospory?

Production of two spore sizes: micro + mega.

What are megaphylls?

Large, highly vascularized leaves.

What is overtopping?

Dominant branch outgrowth forming megaphylls.

What are monilophytes?

Ferns, horsetails, whisk ferns.

Where are sori located?

On the underside of fern leaves.

What is a rhizome?

Underground stem of fern.

What characterizes horsetails?

Hollow stems, reduced leaves, strobili.

What characterizes whisk ferns?

Dichotomous branching, tiny leaves, synangia.

What are synapomorphies of seed plants?

Seeds, pollen, heterospory, secondary growth.

What is the microgametophyte?

Pollen.

What is the megagametophyte?

Egg-producing female gametophyte.

What do seeds contain?

Embryo, nutritive tissue, seed coat.

What nutritive tissue do gymnosperms have?

Haploid megagametophyte tissue.

What nutritive tissue do angiosperms have?

Triploid endosperm via double fertilization.

Do gymnosperms make fruit?

No; only angiosperms do.

Are seed-plant sperm motile?

No; delivered via pollen tube.

What makes pollen tough?

Sporopollenin coating.

What is auxin?

Primary growth hormone produced in SAM.

What does auxin do?

Stimulates cell expansion; causes phototropism; suppresses axillary buds (apical dominance).

What is cytokinin?

Hormone from RAM promoting axillary growth.

What is secondary growth?

Increase in width via vascular cambium producing wood.

What are gymnosperm cones?

Seed cones: megasporangia; pollen cones: microsporangia.

What is the gymnosperm nutritive tissue?

Megagametophyte (n).