35 Chapter Flashcards
Fractals
Repetitive patterns
Angiosperms
Flowering plants
Two main groups of flowering plants
Eudicots
Monocots
Organ
Consists of several types of tissues that together carry out particular functions.
Tissue
A group of cells, consisting of one or more cell types that together perform a specialized function.
Vegetative growth
Production of leaves, stems, and roots
Photosynthates
The sugars and the other carbohydrates produced during photosynthesis.
Roots depend on _____
Photosynthates
The shoot system depends on ________
The water and minerals that roots absorb from the soil.
Root system
All of a plant’s roots, which anchor it in the soil.
Absorb and transport minerals and water, and store food.
Root
An organ that anchors a vascular plant in the soil, absorbs minerals and water, and often stores carbohydrates and other reserves.
Primary root
Originating in the seed embryo, is the first root (and the first organ) to emerge from a germinating seed.
Lateral roots
Is formed when the primary root branches out.
Greatly enhances the ability of the root system to anchor the plant and to acquire resources such as water and minerals from the soil.
Tall, erect plants with large shoot masses generally have a ________
Taproot system
Taproot
Usually develops from the primary root and helps prevent the plant from toppling.
Fibrous root system
A thick mat of slender roots spreading out below the soil surface.
-Usually in small plants
Adventitious
A term describing a plant organ that grows from an unusual source, such as roots arising from stems or leaves.
Root hairs
Thin, finger-like extensions of root epidermal cells.
Increase the surface area of the root enormously.
Mycorrhizal associations
Symbiotic interactions with soil fungi that increase a plant’s ability to absorb minerals.
Stem
A plant organ bearing leaves and buds.
Stem main function
To elongate and orient the shoot in a way that maximizes photosynthesis by the leaves.
Another function of stems is to elevate reproductive structures, thereby facilitating the dispersal of pollen and fruit.
True
Nodes
The points at which leaves are attached.
Internodes
The stem segments between nodes.
Apical bud
A bud at the tip of a plant stem; also called a terminal bud.
Axillary bud
A structure that has the potential to form a lateral shoot, or branch. The bud appears in the angle formed between a leaf and a stem.
Examples of modified stems
Rhizomes
Stolons
Tubers
Leaf
Main photosynthetic organ in most vascular plants.
A leaf consists of…
A flattened blade and a stalk, the petiole.
Petiole
Joins the leaf to the stem at a node.
Grasses and many other monocots lack petioles; instead the base of the leaf forms a sheath that envelops the stem.
True
Veins
The vascular tissues of leaves
Most monocots have parallel major veins of equal diameter that run the length of the blade.
True
Eudicots generally have a branched network of veins arising from a major vein (the midrib) that runs down the center of the blade.
True
Simple leaf
Has a single undivided blade.
Compound leaf
The blade consists of multiple leaflets. A leaflet has no axillary bud at its base.
All three basic plant organs—roots, stems and leaves—are composed of dermal, vascular, and ground tissues.
True
Each tissue type forms a tissue system that connects all of the plant’s organs.
True
Dermal tissue system
The plant’s outer protective covering. Forms the first line of defend against physical damage and pathogens.
Epidermis
Example of a Dermal tissue system. A layer of tightly packed cells.
Cuticle
A waxy epidermal coating, helps prevent water loss in leaves and most stems.
Periderm
Replace the epidermis in older regions of stems and roots in woody plants.
The epidermis has specialized characteristics in each organ.
The chief functions of the vascular tissue system are to…
Facilitate the transport of materials through the plant and to provide mechanical support.
Two types of vascular tissues
Xylem
Phloem
Xylem
Conducts water and dissolved minerals upward from roots into the shoots.
Phloem
Transports sugars, the product of photosynthesis, from where they are made (usually the leaves) to where they are needed—usually roots and sites of growth, such as developing leaves and fruits.
The vascular tissue of a root or stem is collectively called the _____
stele
The arrangement of the stele varies, depending on the species and organ.
True
In angiosperms, the root stele is a solid central _________ of xylem and phloem, whereas the stele of stems and leaves consists of _______, separate strands containing xylem and phloem.
Vascular cylinder, vascular bundles
Tissues that are neither dermal nor vascular are part of the ___________
Ground tissue system
Pith
Ground tissue that is internal to the vascular tissue
Cortex
Ground tissue that is external to the vascular tissue
Mature parenchyma cells have primary walls that are relatively thin and flexible, and most lack secondary walls. When mature, parenchyma cells generally have a large central vacuole. Parenchyma cells perform most of the metabolic functions of the plant, synthesizing and storing various organic products. For example, photosynthesis occurs within the chloroplasts of parenchyma cells in the leaf. Some parenchyma cells in stems and roots have colorless plastids that store starch. The fleshy tissue of many fruits is composed mainly of parenchyma cells. Most parenchyma cells retain the ability to divide and differentiate into other types of plant cells under particular conditions—during wound repair, for example. It is even possible to grow an entire plant from a single parenchyma cell.
Grouped in strands, collenchyma cells help support young parts of the plant shoot. Collenchyma cells are generally elongated cells that have thicker primary cell walls than parenchyma cells, though the walls are unevenly thickened. Young stems and petioles often have strands of collenchyma cells just below their epidermis. Collenchyma cells provide flexible support without restraining growth. At maturity, these cells are living and flexible, elongating with the stems and leaves they support.
Sclerenchyma cell
A rigid, supportive plant cell type usually lacking a protoplast and possessing thick secondary walls strengthened by lignin at maturity.
Lignin
A relatively indigestible strengthening polymer that accounts for more than a quarter of the dry mass of wood.
Protoplast
Living part of the cell
Two types of schlerenchyma cells
Sclereids
Fibers
Sclereid
A short, irregular sclerenchyma cell in nutshells and seed coats. Sclereids are scattered throughout the parenchyma of some plants.
Fiber
A lignified cell type that reinforces the xylem of angiosperms and functions in mechanical support; a slender, tapered sclerenchyma cell that usually occurs in bundles.
Parenchyma cell
A relatively unspecialized plant cell type that carries out most of the metabolism, synthesizes and stores organic products, and develops into a more differentiated cell type.
Collenchyma cell
A flexible plant cell type that occurs in strands or cylinders that support young parts of the plant without restraining growth.
2 types of water-conducting cells
Tracheids and vessel elements
Tracheid
A long, tapered water-conducting cell found in the xylem of nearly all vascular plants. Functioning tracheids are no longer living.
Vessel element
A short, wide water-conducting cell found in the xylem of most angiosperms and a few nonflowering vascular plants. Dead at maturity, vessel elements are aligned end to end to form micropipes called vessels.
Vessel
A continuous water-conducting micropipe found in most angiosperms and a few nonflowering vascular plants.
Sieve-tube elements (sieve-tube members)
A living cell that conducts sugars and other organic nutrients in the phloem of angiosperms. Connected end-to-end, they form sieve tubes.
Sieve plate
An end wall in a sieve-tube element, which facilitates the flow of phloem sap in angiosperm sieve tubes.
Though alive, sieve-tube elements lack a nucleus, ribosomes, a distinct vacuole, and cytoskeletal elements.
True
Companion cell
A type of plant cell that is connected to a sieve-tube element by many plasmodesmata and whose nucleus and ribosomes may serve one or more adjacent sieve-tube elements.
Intermediate growth
A process of growth that occurs throughout life
Plants can keep growing because they have perpetually dividing, unspecialized tissues called ________ that divide when conditions permit, leading to new cells that elongate and become specialized.
meristems
Meristems
Plant tissue that remains embryonic as long as the plant lives, allowing for intermediate growth
Determinate growth
Stop growing after reaching a certain size
Two types of meristems
Apical meristems
Lateral meristems
Apical meristem
Embryonic plant tissue in the tips of roots and buds of shoots. The dividing cells of apical meristem enable the plant to grow in length.
Primary growth
Growth produced by apical meristems, lengthening stems and roots.
Herbaceous
Nonwoody
Secondary growth
Growth produced by later meristems, thickening the roots and shoots of woody plants.
Lateral meristem
A meristem that thickens the roots and shoots of woody plants. The vascular cambium and cork cambium are lateral meristems.
Vascular cambium
Adds layers of vascular tissue called secondary xylem (wood) and secondary phloem.
Cork cambium
Replaces the epidermis with the thicker, tougher periderm.
Initials/stem cells
Cells that remain sources of new cells
Derivatives
New cells displaced from the meristem
Annuals
Complete their life cycle—from germination to flowering to seed production to death—in a single year or less.
Biennials
Such as turnips, generally require two growing seasons to complete their life cycle, flowering and fruiting only in their second year.
Perennials
Live many years and include tress, shrubs, and some grasses.
Root cap
Protects the delicate apical meristem as the root pushes through the abrasive soil.
Growth occurs just behind the tip in three overlapping zones of cells at successive stages of primary growth. These are the zones of…
Cell division, elongation, and differentiation
The zone of cell division includes…
The root apical meristem and its derivatives
Zone of elongation
A few millimeters behind the tip of the root, where most of the growth occurs as root cells elongate.
Zone of differentiation/zone of maturation
Cells complete their differentiation and become distinct cell types.
The primary growth of a root produces its epidermis, ground tissue, and vascular tissue.
True
Endodermis
The innermost layer of the cortex. A cylinder one cell thick that forms the boundary with the vascular cylinder.
Pericycle
The outermost cell layer in the vascular cylinder, which is adjacent to and just inside the endodermis.
A shoot apical meristem is a dome-shaped mass of dividing cells at the shoot tip.
True
Leaves develop from ________
Leaf primordia
Leaf primordia
Projections shaped like a cow’s horns that emerge along the sides of the apical meristem.
Apical dominance
Tendency for growth to be concentrated at the tip of a plant shoot, because the apical bud partially inhibits axillary bud growth.
Intercalary meristems
Allow damaged leaves to rapidly grow
In most eudicot species, the vascular tissue of stems consists of vascular bundles arranged in a ring.
True
In most monocot stems, the vascular bundles are scattered throughout the ground tissue rather than forming a ring.
True
Stomata
Pores in the epidermis
Guard cells
Regulate the opening and closing of the pore.
Mesophyll
The leaf’s ground tissue. Consists of mainly parenchyma cells specialized for photosynthesis.
Two distinct layers of mesophyll
Palisade mesophyll
Spongy mesophyll
Palisade mesophyll
Consists of one or more layers of elongated parenchyma cells on the upper part of the leaf.
Spongy mesophyll
Is below the palisade mesophyll.
The vascular tissue of each leaf is continuous with the vascular tissue of the stem.
True
Bundle sheath
A layer of cells that regulates the movement of substances between the vascular tissue and the mesophyll.
All gymnosperm species and many eudicot species undergo secondary growth, but it is unusual in monocots.
True
As primary growth adds leaves and lengthens stems and roots in the younger regions of a plant, secondary growth increases the diameter of stems and roots in older regions where primary growth has ceased.
True
In a typical woody stem, the vascular cambium is located outside the pith and primary xylem and to the inside of the primary phloem and the cortex. In a typical woody root, the vascular cambium forms exterior to the primary xylem and interior to the primary phloem and pericycle.
True
Vascular rays
Radial files of mostly parenchyma cells that connect the secondary xylem and phloem.
Researchers can estimate a tree’s age by counting growth rings.
True
Dendrochronology
The science of analyzing tree growth ring patterns.
Since a thick ring indicates a warm year and a thin ring indicates a cold or dry one, scientists use ring patterns to study climate changes.
True
Xylem sap
Water and minerals transported through the xylem.
Heartwood
Layers of secondary xylem that no longer transport xylem sap.
Sapwood
The newest, outer layers of secondary xylem that transport xylem sap.
The cork cambium gives rise to cork cells that accumulate to the exterior of the cork cambium.
True
As cork cells mature, they deposit a waxy, hydrophobic material called _______ in their walls and then die.
suberin
Suberin
Is a waxy substance found in the cell walls and functions as a barrier that helps protect the stem or root from water loss, physical damage, and pathogens.
Dotting the periderm are small, raised areas called ______, in which there is more space between cork cells, enabling living cells within a woody stem or root to exchange gases with the outside air.
Lenticels
Bark
Includes all tissues external to the vascular cambium.
-Secondary phloem and all layers of periderm
Development
The specific series of changes by which cells form tissues, organs, and organisms
Developmental plasticity
The ability to alter form in response to local environmental conditions.
The three overlapping processes involved in the development of a multicellular organism are :
Growth
Morphogenesis
Cell differentiation
Growth
An irreversible increase in size
Morphogenesis
Is the process that gives a tissue, organ, or organism its shape and determines the positions of cell types.
Cell differentiation
Is the process by which cells with the same genes become different from one another.
Arabidopsis thaliana
A tiny weed in the mustard family.
Is a favored model organism of plant geneticists and molecular biologists.
Transgenes
Genes from different organisms.
Knock-out mutant
An insertion of transforming DNA that destroys the function of the disrupted gene.
____________ precede leaf elongation, and _____________ precede leaf broadening.
Transverse divisions, longitudinal divisions
Symmetry of cell division
The distribution of cytoplasm between daughter cells.
Asymmetrical cell division
One daughter cell receives more cytoplasm than the other during mitosis.
Polarity
The condition of having structural or chemical differences at opposite ends of an organism.
Pattern formation
The development of specific structures in specific locations.
Lineage-based mechanisms
Hypothesis on morphogenesis which proposes that cell fate is determined early in development and that cells pass on this destiny to their progeny.
Position-based mechanisms
Hypothesis which proposes that the cell’s final position in an emerging organ determines what kind of cell it will become.
Examples of transcription factors
KNOTTED-1
MADS-box
KNOTTED-1
Gene important in the development of leaf morphology, including the production of compound leaves.
MADS-box
Affects the number or placement of plant organs.
Cell differentiation depends, to a large degree, on the control of gene expression—the regulation of transcription and translation, resulting in the production of specific proteins.
True
Plants develop from a juvenile stage to an adult vegetative stage to an adult reproductive stage.
True
Phases
Plant developmental stages
Phases occur only within the shoot apical meristem.
True
Phase changes
The morphological changes that arise from transitions in the shoot apical meristem activity.
Flower formation involves a phase change from vegetative growth to reproductive growth.
True
Unlike vegetative growth, which is indeterminate, floral growth is usually determinate.
True
Meristem identity genes
A plant gene that promotes the switch from vegetative growth to flowering.
Floral organs
Sepal (first, outermost whorl)
Petal (second whorl)
Stamen (third whorl)
Carpel (fourth, innermost, whorl)
- Form a circle when viewed from above
Organ identity genes
A plant homeotic gene that uses positional information to determine which emerging leaves develop into which types of floral organs.
ABC hypothesis of flower formation
Proposes that three classes of genes direct the formation of the four types of floral organs.
A genes are switched on in the two outer whorls (sepals and petals); B genes are switched on in the two middle whorls (petals and stamens); and C genes are switched on in the two inner whorls (stamens and carpels).
True
