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.