Botany Exam 1 Improved

What problems did plants face when transitioning from water to land?

Desiccation/water loss, obtaining and transporting water and minerals, gas exchange, structural support against gravity, and reproduction without surrounding water.

What structure helps terrestrial plants reduce water loss?

The cuticle.

What structures allow plants to exchange gases while regulating water loss?

Stomata.

What tissue transports water and minerals in vascular plants?

Xylem.

What tissue transports sugars in vascular plants?

Phloem.

What are the three groups of bryophytes?

Mosses, liverworts, and hornworts.

What is Plant Awareness Disparity (PAD)?

The tendency for people to notice, recognize, and pay less attention to plants than to animals.

How can Plant Awareness Disparity be addressed?

Increase plant education, plant identification, exposure to plants, interaction with plants/nature, and awareness of plant importance.

When did crop cultivation begin?

About 10,500 years ago.

Where is the Fertile Crescent?

The ancient Near East, including the region around the Tigris and Euphrates Rivers.

Why was agriculture important to human societies?

Crop cultivation supported growing populations and contributed to towns, cities, specialization, and cultural diversification.

What is the Urban Heat Island Effect?

The tendency for urban areas to be warmer than surrounding rural or less-developed areas.

Why do cities experience the Urban Heat Island Effect?

Pavement, buildings, and other built surfaces absorb and retain heat, while cities often have less vegetation and evapotranspiration.

How can plants reduce the Urban Heat Island Effect?

Trees and vegetation provide shade and cool the environment through evapotranspiration.

What neighborhood/city attributes can affect tree cover?

Historical land use and investment, development patterns, available planting space, neighborhood conditions, and social and physical characteristics.

What did Burghardt et al. (2022) examine?

The relationship between historic redlining and present-day urban street-tree communities.

What pattern was associated with historically better-rated neighborhoods in Burghardt et al. (2022)?

They tended to have more vegetation/tree canopy, cooler temperatures, and greater ecosystem-service values.

What pattern was associated with historically D-graded/redlined neighborhoods?

Fewer large/older trees, lower alpha diversity, different community composition, and greater homogenization were predicted.

What are ecosystem services?

Benefits that humans receive from ecosystems.

What is a provisioning ecosystem service?

A product provided by an ecosystem, such as food, timber, fibers, or medicines.

What is a regulating ecosystem service?

A benefit from regulation of environmental processes, such as temperature, climate, water, air quality, or erosion.

What is a cultural ecosystem service?

A nonmaterial benefit such as recreation, aesthetics, education, or cultural value.

What is a supporting ecosystem service?

An ecosystem process that supports ecosystem functioning, such as nutrient cycling and primary production.

What are the major types of plastids?

Chloroplasts, chromoplasts, and colorless plastids such as amyloplasts.

What is the main function of chloroplasts?

Photosynthesis.

What is the main function of chromoplasts?

Accumulation of pigments that contribute to plant coloration.

What is the main function of amyloplasts?

Storage of starch.

How do primary and secondary cell walls differ?

Primary walls form during cell growth and are relatively flexible; secondary walls are deposited inside primary walls and are generally thicker, stronger, and often lignified.

What are the functions of plant cell walls?

Support, protection, maintaining cell shape, and resisting excessive cell expansion.

What is the cell cycle?

The sequence of events through which a cell grows, duplicates its DNA, prepares for division, and divides.

What happens during G1?

The cell grows and performs normal metabolic activities while producing cellular components.

What happens during S phase?

DNA is replicated.

What happens during G2?

The cell continues preparing for division and checks/repairs DNA.

What happens during M phase?

Mitosis and cytokinesis occur.

What is the order of mitosis?

Prophase, metaphase, anaphase, telophase (PMAT).

What happens during prophase?

Chromatin condenses into chromosomes and the mitotic spindle develops.

What happens during metaphase?

Chromosomes align at the equatorial plane.

What happens during anaphase?

Sister chromatids separate and move toward opposite poles.

What happens during telophase?

Chromosomes reach the poles, decondense, and new nuclear envelopes form.

What is cytokinesis?

Division of the cytoplasm to form two daughter cells.

How does plant cytokinesis differ from animal cytokinesis?

Plant cells form a cell plate rather than dividing primarily by a cleavage furrow.

What is the phragmosome?

A cytoplasmic sheet that helps establish the future division plane in plant cells with large vacuoles.

What is the phragmoplast?

A structure containing microtubules and actin that directs vesicles to the division plane during cell-plate formation.

What is the cell plate?

The developing partition between daughter plant cells that forms from vesicles and expands outward until it joins the parent cell wall.

What is the preprophase band?

A band of microtubules that marks the future plane of cell division.

What are plasmodesmata?

Channels connecting neighboring plant cells that allow intercellular transport and communication.

What is a desmotubule?

An endoplasmic-reticulum-derived tube running through a plasmodesma.

What are major roles of plant vacuoles?

Storage, water balance and turgor, cell enlargement, sequestration, degradation, and recycling.

What is water potential?

A measure of the potential energy of water used to predict the direction of water movement.

In what direction does water move based on water potential?

From higher water potential to lower water potential.

What is the water-potential equation?

Ψw = Ψs + Ψp.

What is solute potential?

The component of water potential caused by dissolved solutes; increasing solute concentration makes it more negative.

What is pressure potential?

The component of water potential resulting from physical pressure on water.

What is turgor pressure?

The pressure of the cell contents against the cell wall.

What happens to turgor pressure when a plant cell loses water?

Turgor pressure decreases.

What is plasmolysis?

The condition in which water leaves a plant cell and the protoplast/plasma membrane pulls away from the cell wall.

What are the two types of tracheary elements?

Tracheids and vessel elements.

How do tracheids differ from vessel elements?

Tracheids are elongated conducting cells that conduct through pits; vessel elements are generally wider, join end-to-end, and have perforations between elements.

What is transpiration?

Loss of water vapor from a plant, especially through stomata.

Why is transpiration called an "unavoidable evil"?

Plants need stomata for CO2 uptake and photosynthesis, but open stomata also allow water to escape.

What is cohesion?

Attraction between water molecules.

What is adhesion?

Attraction between water and another surface.

How does cohesion-tension theory explain water movement to the tops of tall trees?

Evaporation from leaves creates tension in the xylem; cohesion keeps water molecules connected in a continuous column, allowing the tension to pull water upward.

What is a source in phloem transport?

A plant organ or tissue that supplies sugars such as sucrose to the phloem.

What is a sink in phloem transport?

A plant organ or tissue that uses or stores sugars delivered by the phloem.

Give an example of a sucrose source.

A mature, highly photosynthetic leaf.

Give an example of a sucrose sink.

A developing fruit, seed, root, or other growing/storage tissue.

How does the osmotically generated pressure-flow mechanism move sugars from source to sink?

Sugar loading at the source draws water into the phloem and generates high pressure; sugar unloading at the sink changes pressure, producing bulk flow from source toward sink.

What is the water pathway from a root hair to the atmosphere?

Root hair → epidermis → cortex → endodermis → vascular tissue/xylem → stem xylem → leaf xylem → mesophyll → leaf air spaces → stoma → atmosphere.

What are the two types of vessel elements based on perforation pattern?

Scalariform and simple vessel elements.

How do scalariform and simple vessel elements differ?

Scalariform vessel elements have multiple elongated openings in the perforation plate; simple vessel elements have one large opening.

What is a meristem?

Plant tissue containing cells capable of continued division and contributing to plant growth.

What are the three tissue systems of the plant body?

Dermal, ground, and vascular.

What are the three major ground tissues?

Parenchyma, collenchyma, and sclerenchyma.

What is parenchyma?

Usually living, relatively thin-walled cells involved in photosynthesis, storage, secretion, repair, and other functions.

What is collenchyma?

Living cells with unevenly thickened primary walls that provide flexible support.

What is sclerenchyma?

Cells with thick, often lignified secondary walls that provide strong, rigid support; many are dead at maturity.

What are the principal conducting cells of xylem?

Tracheids and vessel elements.

What are the principal conducting cells of phloem?

Sieve cells and sieve-tube elements.

What is a perforation plate?

An opening or set of openings in the end wall of a vessel element that allows water to pass between vessel elements.

What is a pit?

A thin or unthickened region of a cell wall that allows movement between adjacent conducting cells.

What is a sieve cell?

A conducting phloem cell generally associated with seedless vascular plants and gymnosperms.

What is a sieve-tube element?

A specialized phloem conducting cell found in angiosperms that joins with other sieve-tube elements to form sieve tubes and is associated with companion cells.

What is callose?

A carbohydrate deposited around sieve-plate pores that can help regulate or block the pores.

What is P-protein?

A phloem protein associated with sieve-tube elements that can help seal damaged phloem.

What is an annual?

A plant that completes its life cycle in one growing season or year.

What is a biennial?

A plant that completes its life cycle over two years.

What is a perennial?

A plant that lives for multiple years.

What is secondary growth?

Increase in thickness or girth of a plant body.

What produces secondary growth?

Lateral meristems, especially vascular cambium and cork cambium.

How does secondary growth affect the primary body of a stem?

It adds secondary vascular tissues and protective tissues, increases stem thickness, and causes original outer tissues to be displaced or replaced.

What does vascular cambium produce?

Secondary xylem toward the inside and secondary phloem toward the outside.

What does cork cambium produce?

Cork (phellem) toward the outside and phelloderm toward the inside; together with cork cambium these form the periderm.

What is periderm?

A secondary protective tissue that replaces the epidermis in plant parts undergoing substantial secondary growth.

What is bark?

The tissues external to the vascular cambium.

How does bark change during the life of a woody plant?

New periderm can form deeper within the plant while older outer tissues become part of the outer bark and may die or be shed.

If a nail is driven into a tree 5 feet above ground and the tree grows 2 feet taller per year, where is the nail after 10 years?

Approximately 5 feet above ground because height growth occurs primarily at apical meristems rather than by moving existing trunk tissue upward.

Why can't tree age always be accurately estimated by counting growth rings?

Environmental conditions and unusual growth patterns can produce indistinct, missing, or multiple growth rings.

What is a remnant prairie?

A surviving portion of original/native prairie vegetation that was not completely converted or destroyed.

What is a restored prairie?

A prairie established or managed through human efforts to restore native prairie characteristics to a degraded or altered site.