Biology 1108 Test 3 - Definitions

casparian strip

Once the water and solutes reach the endodermis, a continuous waxy barrier called the Casparian strip stops them from entering the xylem via cell walls and forces them to cross the selectively permeable plasma membrane of an endodermal cell to enter the xylem (water-conducting tissue) for transport upward. Figure 36.8.

Endophyte

Plants harbor harmless symbiotic endophytes that live inside leaves or other plant parts. Endophytes make toxins that deter herbivores and defend against pathogens

Zoospores

- Chytrids - Unique among fungi in having flagellated spores, called zoospores.

Root system

- absorb water and minerals, the root system is connected by vascular tissue that is continuous throughout the plant. There are two types of root systems: fibrous and taproot. Taproots grow fast and deep, maximizing support and enabling a plant to use minerals and water deep in soil. Grasses and monocots usually have fibrous root systems. Fibrous roots absorb minerals and water from near the soil surface and prevent erosion.

Shoot system

- produces sugar via photosynthesis. Consist of stem and leaves.

Rhizomes

A rhizome is a horizontal shoot that grows just below the surface. Vertical shoots emerge from axillary buds on the rhizome.

Stem

A stem is an organ consisting of -(1) An alternating system of nodes, the points at which leaves are attached (2) Internodes, the stem segments between nodes

Sink

A sugar sink is an organ that is a net consumer or depository of sugar

Root hairs

Absorption of water and minerals occurs near the root hairs, where vast numbers of tiny root hairs increase the surface area

Tendrils

After it has "lassoed" a support, a tendril forms a coil that brings the plant closer to the support. Tendrils are typically modified leaves, but some tendrils are modified stems.

Pneumatophore

Also known as air roots, pneumatophores are produced by trees such as mangroves that inhabit tidal swamps. By projecting above the water's surface, they enable the root system to obtain oxygen, which is lacking in the thick, waterlogged mud.

Apical dominance

Apical dominance helps to maintain dormancy in most nonapical buds. The inhibition of axillary buds by an apical bud. Inhibits the growth of axillary buds, stimulation of the growth of apical bud.

Bark

Bark consists of all tissues exterior to the vascular cambium. Bark consists of all the tissues external to the vascular cambium, including secondary phloem and periderm.

Protostome

Based on early development, many animals can be categorized as having protostome development or deuterostome development. In general, protostome development begins with spiral, determinate cleavage. Coelom formation begins in the gastrula stage. In protostome development, the coelom forms from splits in the mesoderm. In protostome development, the mouth forms from the blastopore.

Blastula

Cleavage leads to formation of a blastula. A multicellular stage in which cells form a hollow ball.

Guard cells

Each stomatal pore is flanked by two guard cells, which regulate its opening and closing

Mycelium

Fungal hyphae form an interwoven mass called a mycelium that infiltrates the material on which the fungus feeds. This maximizes the surface area-to-volume ratio, making feeding more efficient. Hyphae length is added rather than girth to increase absorptive surface area.

Deuterostome

In general, deuterostome development is characterized by radial, indeterminate cleavage. . In deuterostome development, the coelom forms from mesodermal outpocketings of the archenteron. . In deuterostome development, the mouth forms from a secondary opening.

Heterokaryotic stage

In most fungi, the haploid nuclei from each parent do not fuse right away; they coexist in the mycelium, called a heterokaryon

Cuticle

In nonwoody plants, the dermal tissue system consists of the epidermis, and a waxy coating called the cuticle. . Epidermal cells secrete the cuticle. The cuticle conserves water and protects the plant from predators and infectious agents.

Larva

Many animals have at least one larval stage. A larva is sexually immature and morphologically distinct from the adult; it eventually undergoes metamorphosis.

Chitin

Most fungi have cell walls made of chitin. Chitin is a strong and flexible polysaccharide. Chitin rich walls can enhance feeding by absorption.

Septa

Some fungi have hyphae divided into cells by septa, with pores allowing cell-to-cell movement of organelles

Stolons

Stolons are horizontal shoots that grow along the surface. These "runners" enable a plant to reproduce asexually, as plantlets form at nodes along each runner. Stolon = horizontal shoot that is right above the surface that can grow a new plant. Ex. Strawberries

Sieve-tube elements

Sugar conducting cells of the phloem. In seedless vascular plants and gymnosperms, sugars and other organic nutrients are transported through long, narrow cells called sieve cells. In the phloem of angiosperms, these nutrients are transported through sieve tubes, which consist of chains of cells that are called Sieve-tube elements. They are alive at functional maturity, though they lack organelles, which enables the nutrients to pass through easier.

Gastrula

The blastula undergoes gastrulation, forming a gastrula with different layers of embryonic tissues. Most animals also undergo gastrulation, a process in which one end of the embryo folds inward, expands, and eventually fills the blastocoel, producing layers of embryonic tissue: the ectoderm (outer layer) and the endoderm (inner layer).

Cork cambium

The cork cambium adds secondary dermal tissue. (The secondary plant body consists of the tissues produced by the vascular cambium and cork cambium.) . The cork cambium produces cork cells, which replace the epidermis eith a tougher periderm.

Stomata

The epidermis in leaves has stomata, which allow CO2 exchange. The opening and closing of the stomata is dictated by various environmental conditions, especially those that may cause water loss. When the stomata are closed, plants cannot take in CO2. As a result, photosynthesis will not occur. Open - allows gas exchange to occur - CO2 comes in and O2and water comes out. Water that comes out - transporation Loss of water causes the stoamta to close up because the plant does not want ot loose to much water

Mycosis

The general term for a fungal infection in animals

Mesophyll

The ground tissue in a leaf, called mesophyll, is sandwiched between the upper and lower epidermis

Root cap

The root tip is covered by a root cap, which protects the apical meristem as the root pushes through soil.

Triploblastic

Triploblastic animals also have an intervening (have all three layers) mesoderm layer; these include all bilaterians

Tubers

Tubers are enlarged ends of rhizomes or stolons specialized for storing food. Potatoes = tubers. Stems = store energy underground in this case in the form of starch

Topsoil

it is a soil layer composed of remains of dead organisms and other organic matter

Primary growth

lengthens roots and shoots and arises from cells produced by apical meristems.

Lichen

lichen is a symbiotic association between a photosynthetic microorganism and a fungus in which millions of photosynthetic cells are held in a mass of fungal hyphae. The algae provide carbon compounds, cyanobacteria provide organic nitrogen, and fungi provide the environment for growth. The fungi of lichens can reproduce sexually and asexually.

Mycorrhizae

mutually beneficial relationships between such fungi and plant roots

Root

organ that anchors a vascular plant in the soil, absorbs minerals and water, and often stores carbohydrates and other reserves.

Petiole

petiole attaches the leaf to the stem.

Yeasts

single cellular Fungi. Yeast often inhabits moist environments, including plant sap and animal tissues, where there is a supply of nutrients such as sugars and amino acids.

Haustoria

specialized hyphae which the fungi uses to extract nutrients from or exchange nutrients with their plant hosts

Determinate

stop growing after a certain size ex leaves, thorns and flowers.

Root pressure

the accumulation of water in roots by osmosis, can push xylem sap up a few meters.

Compound leaf

the blade consist of multiple leaflets. A leaflet has no axillary bud at its base. In some plants, each leaflet is further divided into smaller leaflets. Figure 35.6.

Hyphae

the bodies of the fungi typically form a network of tiny filaments called hyphae. They consist of tubular cell walls surrounding the plasma membrane and cytoplasm of the cell.

Cephalization

the development of a head

Sieve plate

the end walls between sieve-tube elements and they have pores that facilitate the flow of fluid from cell to cell along the sieve tube.

Karyogamy

the haploid nuclei contributed by the two parents fuse, producing diploid cells

Blade

the lea consist of a flattened blade and a stalk, the petiole.

Blastopore

the opening of the central cavity of an embryo in the early stage of development.

Pericycle

the outermost cell layer of the cortex is called the endodermis

Indeterminate

the plant never stops growing

Node

the point at which leaves are attached

Internode

the stem segments between the nodes. Internodes may be extremely long or short. Growing, healthy plants tend to have longer internodes.

Phloem

transports organic nutrients, sugars - the product from photosynthesis, from where they are made (usually the leaves) to where they are needed (usually roots and sites of growth.

Taproot

type of root system. tall, erect plants with large shoot masses generally have a taproot system, consisting of one main vertical root, the taproot, which usually develops from the primary root and which prevent the plant from falling. Taproots grow fast and deep, maximizing support and enabling a plant to use minerals and water deep in soil. One main vertical root that gives rise to lateral roots, or branch roots.

Tracheid

type of water-conducting cells of the xylem. Tracheids are found in the xylem of all vascular plants. Tracheids only move small amounts of water. Tracheids are long, thin cells with tapered ends, water moves from cell to cell mainly trough the pits, where it does not have to cross thick secondary walls.

Vessel elements

type of water-conducting cells of the xylem. Vessel elements align end to end to form long micropipes called vessels. Most of the water movement occurs in the vessel elements. Think of them as straws in the plant (stack of hollow cells). Vessel elements are common to most angiosperms and a few gymnosperms

plasmogamy

union of two parent mycelia. Two haploid mycelia of different mating types undergo plasmogamy.

Xylem

vascular tissue, Xylem conducts water and dissolved minerals upward from roots into the shoots.

Cleavage

cell division. After a sperm fertilizes an egg, the zygote undergoes rapid cell division called cleavage.

Coenocytic

coenocytic fungi consist of a continuous cytoplasmic mass having hundreds or thousands of nuclei

Meristem

continuously embryonic tissue and allow for indeterminate growth. Apical meristems add primary growth- growth in length. In woody plants, lateral meristems add secondary growth, increasing the girth of roots and stems.

Transpiration

drives the transport of water and minerals from roots to shoots via the xylem. The loss of water by evaporation from leaves (and other aerial parts of a plant).

Cortex

ground tissue that is external to the vascular tissue.

Pith

ground tissue that is internal to the vascular tissue.

Molds

growth of filamentous fungi that produce spores by mitosis and form visible mycelia

Simple leaf

has a single undivided blade. Some simple leaves are deeply lobed. Figure 35.6.

Leaf

in most vascular plants, the leaf is main photosynthetic organ. In addition to intercepting light, leaves exchange gases with the atmosphere, dissipate heat, and defend themselves from herbivores and pathogens.

Secondary growth

increases the diameter of stems and roots in woody plants. The growth in thickness produced by lateral meristems.

Metamorphosis

is a developmental transformation that turns the animal into a juvenile, which resembles an adult but is not yet sexually mature.

Adhesion

is the sticking together of molecules of different kinds.

Cohesion

is the sticking together of molecules of the same kind.

Coelom

a characteristic of body plants. Coelomates such as earthworms have a true coelom, a body cavity completely lined by tissue derived from mesoderm.

Vascular cambium

a cylinder of meristematic cells only one cell thick, is wholly responsible for the production of secondary vascular tissue. It is located outside the pith and primary xylem and to the inside of the primary phloem and the cortex. The vascular cambium adds layers of vascular tissue called secondary xylem (wood) and secondary phloem.

Source

a sugar source is a plant organ that is a net producer of sugar, by photosynthesis or by breakdown of starch,

Companion cell

alongside each sieve tube element is a nonconducting cell called a companion cell, which is connected to the sieve tube element by numerous plasmodesmata.

Apical (terminal) bud

an apical bud, or terminal bud, is located near the shoot tip and causes elongation of a young shoot. Primary growth.

Axillary bud

an axillary bud is a structure that has the potential to form a lateral shoot, or branch. Axillary or lateral buds are found in leaf axils and contribute to lateral growth of the plants. Axillary buds develop from meristematic cells left at the bases of leaf primordial. Areas where another branch can develop- potential growth of branch.

Diploblastic

animals have only have the ectoderm and endoderm layers