Chapter 23 vocabulary Flashcards
apical meristem
found at the tips of all roots and stems and are involved primarily with extension of the pant body (greek, merismos, division)
initials
cells that maintain the meristem as a continuing source of new cells. divide in such a way that one of the sister cells reamins in the meristem as an initial while the other becomes a new body cell.
derivative
sister cells of the intitials that become new body cells
What three overlapping processes make up development?
- growth
- morphogenesis
- differentiation
Development occurs in response to…
instructions contained in the genetic information that an organism inherits from its parents.
in plants, the specific developmental pathway is determined by
position of cells and tissues within the apical-basal and radial patterns. environmental factors (daylength, light quality and quantity, temperature, and gravity.
growth
an irreversible increase in size; a combination of cell division and cell enlargement
most plant growth is brought about by…
cell enlargement.
morphogenesis
(greek, shape and origin) the development of form
The primary event in morphogenesis is…
the expansion of tissue.
Differentiation
the process by which cells with identical genetic constitution become different from one another and form the meristematic cells from which they originated. begins while cell is still enlarging
differentiation depends on…
the control of gene expression.
What is the fate of a plant cell determined by?
the final position in the developing organ.
True or false. Cells communicate positional information to other surrounding cells.
True.
determination
progressive commitment to a specific course of development that brings about a weakening or loss of capacity to resume growth.
competency
the ability of a cell to develop in response to a specific signal, such as light.
What are the simple tissues?
parenchyma, collenchyma, and sclerenchyma
What are the complex tissues?
xylem, phloem, epidermis, and periderm.
True or False. The pith is located only in the stem.
true.
True or False. the pith is located in the leaf.
False. the mesophyll is in the leaf
What processes are parenchymal tissue involved in?
photosynthesis, storage, and secretion
Where are parenchymal cells located?
in the cortex and pith of stems and roots, and in leaf mesophyll, and in the flesh of fruits.
Which basic cell type are most numerous in the body?
parenchymal cells
where else do parenchymal cells reside in the plant? (hard question.)
they occur as vertical strands of cells in the primary and secondary vascular tissues and as horizontal strands called rays in the secondary vascular tissues.
True or False. Parenchymal cells initiate adventitious structures, such as adventitious roots on stem cuttings.
true.
parenchymal cells are totipotent, meaning…
they have the ability to become embryonic cells and to develop into an entire plant.
transfer cells
cell wall ingrowths that serve to increase the surface area of the plasma membrane; helps facilitate movement of solutes over short distances.
True or False. the presence of transfer cells is generally not correlated with the existence of intensive movement of solutes, by uptake or secretion, across the plasma membrane.
False. they are generally correlated to solute movement.
True or False. Collenchyma and parenchymal cells both are living at maturity.
True.
What is the most distinctive structure of collenchyma?
unevenly thickened, nonlignified primary walls
Collenchyma is the typical supporting tissue of…
growing stems, leaves, and floral parts and of most herbaceous (non-woody) organs that undergo little or no secondary growth.
True or false. roots rarely have collenchyma.
true.
True or false. collenchyma is absent in stems and leaves of many monocots that form sclerenchyma early in their development.
True.
True or False. collenchyma support young, growing organs and therefore, tend to elongate.
True.
True or False. Sclerenchyma tissues strengthen and support plant parts that are no longer elongating.
True.
Where can sclerenchyma devleop?
in any or all parts of the primary and secondary plant bodies.
True or false. Schlerenchyma have protoplasts at maturity.
False. they often lack them.
the principal characteristic of schlerenchyma is…
their thick, often lignified, secondary walls.
What are the two types of schlerenchyma cells?
Fibers and schlereids.
What are fibers?
long, slender cells that occur in strands or bundles.
Sclereids are…
variable in shape and often branched.
Sclereids make up….
seed coats of many seeds, the shells of nuts, and the stone (endocarp) of stone fruits, such as olives, peaches, and cherries, and they give pears their characteristic gritty texture.
What is the principal water conducting tissue in the vascular system?
xylem
What three functions, other than water conduction, is the xylem involved in?
conduction of minerals, in support, and in food storage.
What are the principal conducting cells of the xylem?
tracheary elements
What are the two kinds of tracheary elements?
tracheids and the vessel elements.
What do traceids and the vessel elements have in common?
both are elongated cells that have secondary walls and lack protoplasts at maturity, and both may have pits in their walls.
What are pits?
areas lacking secondary walls, in tracheids and the vessel elements.
Unlike tracheids, vessel elements contain what?
perforations, areas lacking in both primary and secondary cell walls.
What is the part of the cell wall bearing the perforation or perforations?
the perforation plate.
Where do perforations generally occur?
on the end walls, with the vessel elements joined end-to-end, forming vessels.
What are vessels?
long, continuous columns or tubes created by perforations.
What is the principal water-conducting cell in angiosperms?
the vessel elements.
What is the only type of water conducting cell found in seedless vascular plants and gymnosperms?
tracheids.
True or False. the xylem of many angiosperms contain both vessel elements and tracheids.
true.
What are more efficient water conductors? Tracheids, or vessel elements?
vessel elements.
Which type of water conducting cell is better at containing air bubbles?
tracheids.
What makes it possible for the tracheids to stretch or extend after cells have differentiated?
annular/helical thickenings.
True or False. the primary xylem’s wall thickening is greatly influenced by the amount if elongation.
True. little elongation results in nonextensible, rather than extensible elements.
In the metaxylem and secondary xylem, the secondary cells walls of the tracheids and vessel elements cover the entire primary walls, except…
at the pit membranes and at the perforations of the vessel elements, which are called pitted elements, and are rigid and cannot be stretched.
What is programmed cell death?
the outcome of genetically programmed processes that result in cell death.
What is an example of programmed cell death?
tracheary element differentiation
What is the principal food conducting tissue in vascular plants?
the phloem.
Other than sugars, what does the phloem transport?
amino acids, lipids, micronutrients, hormones, the floral stimulus, (florigen) and numerous proteins and RNAs, some of which serve as signaling molecules.
True or false. short-distance signaling in plants occurs predominantly through the phloem.
False. Long-distance signaling does.
True or False. the phloem is the route for movement of a range of plant viruses.
True.
What are the principal conducting cells of the phloem?
sieve elements
What are sieve elements?
the cells of the phloem that are involved in the long-distance transport of food substances.
what are sieve areas?
clusters of pores through which the protoplasts of adjacent sieve elements are interconnected.
what are the two types of sieve elements found in seed plants?
sieve cells, and sieve-tube elements.
What is the only food conducting cell in gemiosperms?
sieve cells
Which sieve element occurs in angiosperms?
sieve-tube elements.
In sieve cells, the sieve area pores are…
narrow and the sieve areas are uniform in structure on all walls.
In sieve-tube elements, the sieve areas…
on some walls have larger pores than those on other walls of the same cell.
What is a sieve plate?
the part of the wall bearing the sieve areas with larger pores.
Where are sieve plates generally located?
on end walls
True or False. The presence of sieve plates is a defining characteristic of…
sieve elements, and are not found in sieve cells.
What is callose?
a polysaccharide composed of spirally wound chains of glucose residues.
Most of the callose seen in the pores of conducting sieve elements are deposited there in response to…
injury during preparation of the tissue for microscopy.
True or False. callose also shows in the form of platelets beneath the plasma membrane around each plasmodesma at the site of developing sieve-plate pores.
True.
True or False. unlike tracheary elements, sieve elements have living protoplasts at maturity.
True.
The protoplasts of the sieve-tube elements of angiosperms, are characterized by the presence of…
P protein (once called slime.)
What is a forisome?
a single, nondispersive P-protein body found in legumes, that undergo rapid and reversible calcium-controlled changes in which they occlude the sieve-plate pores.
Sieve-tube elements are usually associated with specialized parenchyma cells called…
companion cells.
What is the life support cell of sieve-tube elements?
companion cells
in gymnosperms, sieve-tube elements are associated with a different cell that serves the same function as companion cells. What are these cells called?
Albuminous cells/Strasburger cells
What is the difference between companion and albuminous cells?
companion cells come from the same mother cells, whereas albuminous cells (Strasburger cells) do not.
The epidermis contains…
guard cells, many types of appendages, or trichomes and other types of specialized cells.
What is responsible for the whitish or bluish “bloom” on the surface of some leaves and fruits?
epicuticular wax
This is the site of light perception involved in circadian leaf movement and photoperiodic induction.
epidermis
Guard cells contain….
chloroplasts.
Guard cells regulate stomata, in the aerial parts of the plants and thus…
control the exchange of gases, including water vapor, into and out of those pores.
Where are stomata most abundant?
leaves
true or false. Guard cells are often associated with subsidiary cells.
True.
What is the periderm?
it commonly replaces the epidermis in stems and roots that undergo secondary growth.
What cells in the periderm are loosely arranged and provide for aeration of the internal tissues of roots and stems?
lenticels
The periderm consists of these three parts:
phellem (protective, non-living cork)
phellogen or cork cambium
phelloderm (a living parenchyma-like tissue)
Look at the chart on page 556-557 and practice memorizing it.
ok.
