3: Plant cells, Plant tissues, Plant organs Flashcards
(23 cards)
What are three features unique to plant cells?
- Central vacuoles (store water/solutes, provide turgor),
- plastids (e.g., chloroplasts for photosynthesis)
- cell walls (provide structural support and protection).
What is the function of plasmodesmata?
Plasmodesmata are channels between plant cells that allow for cytoplasmic exchange of water, nutrients, and signaling molecules, enabling intercellular communication.
What is the role of the central vacuole?
It stores water, solutes, and pigments, helps maintain turgor pressure, and contributes to cell expansion.
What are the functions of plastids in plants?
Plastids like chloroplasts perform photosynthesis; others store starch, lipids, or pigments.
What are the three main plant cell types and their features?
Parenchyma: thin walls, living; photosynthesis, storage
Collenchyma: uneven thick walls, flexible support
Sclerenchyma: thick, lignified walls, dead; rigid support
Define “organ” and “tissue” in plants.
Organ: a functional unit (e.g., leaf, root);
Tissue: a group of cells with a shared function (e.g., vascular tissue).
What are the three vegetative plant organs and their functions?
Roots (absorb, anchor),
stems (support, transport),
leaves (photosynthesis).
What are the four main tissue types in vegetative organs?
- Dermal,
- vascular (xylem & phloem),
- ground,
- meristematic.
What is primary growth in plants?
Growth in length from apical meristems in shoots and roots; forms primary tissues.
What are the differences in vascular bundles between monocots and dicots?
Monocots: scattered bundles.
Non-woody dicots: ringed.
Woody dicots: ringed with secondary growth.
Describe a non-woody eudicot stem structure.
Includes cuticle, epidermis (with trichomes), cortex, vascular bundles in a ring, pith.
What is secondary growth and who exhibits it?
Increase in girth via lateral meristems; found in woody dicots and conifers.
What are the main xylem cell types and their traits?
Tracheids (long, tapered, pits),
vessel elements (short, wide, open ends).
Both are dead at maturity and conduct water.
How does water move through xylem?
Through transpiration pull and cohesion of water molecules
What are the main phloem cell types and their functions?
Sieve elements (transport sugars, have sieve pores), companion/albuminous cells (support metabolism, alive).
Describe the basic leaf structure.
Upper/lower epidermis (with stomates and guard cells), palisade & spongy mesophyll,
veins (vascular tissue).
What are key structures in a root cross-section?
Root cap,
elongation region,
root hairs,
epidermis, cortex,
endodermis (with Casparian strip),
vascular tissue,
pericycle.
What is the Casparian strip and its function?
The Casparian strip is a specialized, ring-like band found in the cell walls of the endodermis, the inner layer of cells in plant roots.
It acts as a waterproof barrier, controlling which substances can enter the vascular tissues of the plant.
What is the function of stomates and guard cells?
Stomates allow gas exchange; guard cells regulate their opening/closing to balance water loss and CO₂ intake.
What is an apical meristem?
A region of cell division at the tips of shoots and roots, responsible for primary growth.
Define sclerenchyma.
Dead cells with thick lignified walls, providing rigid structural support.
What is the function of the pericycle?
Initiates lateral roots in the root’s vascular cylinder.
What is a vascular bundle?
A strand of xylem and phloem often surrounded by ground tissue in stems and leaves.
