Lesson 1 Biological Organization - Plant Tissues and Structures

Flashcards based on Lesson 1 Biological Organization lecture notes covering plant tissues including xylem, phloem, epidermis, cuticle, guard cells, stomata, and meristematic tissues.

What is the primary transport function of xylem in plants?

Xylem transports water and dissolved minerals from the roots to the rest of the plant.

What are the main conducting cells of xylem?

Vessel elements and tracheids.

What are the cellular characteristics of mature xylem conducting cells?

They are dead at maturity and have lignin-strengthened secondary walls.

What is the function of lignin in xylem cell walls?

Lignin makes the walls strong and water-resistant.

Which plant vessel tissue is shown in this diagram featuring one-way flow, thick walls stiffened with lignin, and no end walls between cells?

Xylem vessel

What substances does phloem transport throughout the plant?

Sugars and other organic substances produced during photosynthesis.

What are the main conducting cells of phloem, and do they remain alive at maturity?

Sieve-tube elements, which remain alive at maturity.

How are sieve-tube elements connected to form continuous tubes?

They are connected by sieve plates.

What is the role of companion cells in phloem tissue?

Companion cells, which are a specialized type of parenchyma cell, help load sugars into the sieve tubes.

Which plant vascular tissue is shown in this diagram with two-way flow and perforated end walls?

Phloem vessel

What is the plant epidermis?

A single layer of protective cells found on the surface of plant leaves and young stems.

What waxy substance is produced by epidermal cells to form the cuticle?

Cutin.

What are the two primary functions of the plant cuticle?

Reduces water loss and protects the plant from pathogens.

What tissue replaces the epidermis in woody stems and roots?

The periderm.

What are guard cells?

A pair of specialized epidermal cells that surround a stoma (plural: stomata).

How do changes in guard cell state affect the opening and closing of stomata?

When guard cells become turgid, the stomata open; when guard cells become flaccid, the stomata close.

What processes do stomata enable in plants?

Gas exchange ($\text{CO}_2$ enters and $\text{O}_2$ exits) and water vapor release through transpiration.

What mechanism controls the opening and closing of stomata?

Changes in turgor pressure within the guard cells.

In this cross-section diagram of a leaf, which specialized epidermal structures regulate gas exchange and transpiration?

Guard cells and stomata

From where do all plant tissues originate?

Meristems (meristematic tissues).

What kind of cells are found within meristematic tissue?

Actively dividing, undifferentiated cells.

What is the primary role of meristems in plants?

Meristems are responsible for plant growth by dividing and differentiating into specialized plant tissues.