FBS 10 - Lecture 2: Structure and Function of Plant Cells and Tissues

A set of practice flashcards covering meristematic tissues, simple permanent tissues (parenchyma, collenchyma, sclerenchyma), complex permanent tissues (xylem, phloem), and plant cell wall structure.

What are the structural and cellular characteristics of meristematic tissues?

Meristematic cells have thin cellulose cell walls, are compact with no intercellular space, contain a large nucleus with abundant cytoplasm, and have very few or no vacuoles.

What type of plant growth is generated by apical meristems, and where are they located in monocots?

Apical meristems generate primary growth (increase in length). In monocot plants, apical meristems are located ONLY in the root tips.

Where are intercalary meristems located in plants, and what is their function in grasses?

Intercalary meristems are located at the base of nodes, internodes, and leaves. In grasses, they allow leaves to grow back after mowing.

What are the four basic metabolic functions performed by parenchyma tissue?

Respiration, photosynthesis, storage, and secretion.

What is aerenchyma, and where is it typically located?

Aerenchyma is a type of parenchyma tissue characterized by large air spaces formed between cells, found in plant stems and leaves.

What chemical compounds make up the crystals found in plant cell vacuoles, and what are their functions?

Vacuolar crystals are made of Calcium oxalate, Calcium carbonate, or silica. They regulate cell pH and Calcium levels, and provide defense against herbivores.

What scientific species name is associated with acridity caused by Calcium oxalate raphide crystals?

Colocasia esculenta (L.) Schott (taro).

What are transfer cells, and how does their structure assist their function?

Transfer cells are modified parenchyma cells with cell wall ingrowths that increase internal membrane surface area to enhance short-distance transport of water and minerals.

Where is collenchyma tissue found in plants, and which plant organ completely lacks it?

Collenchyma is found in the outermost cells of the cortex inside the epidermis in young stems and leaf petioles; it is completely absent in roots.

Which three types of collenchyma tissue are depicted in this diagram?

Lamellar, Angular, and Lacunar collenchyma.

What are the structural features and location of angular collenchyma?

Cells are compactly arranged without intercellular spaces, with hemicellulose and pectin deposited at the angles between cells; it is found in stems forming the hypodermis.

Where is wall deposition located in lamellar collenchyma, and where is this tissue found?

Hemicellulose and pectin are deposited at the cross walls separating adjacent cells; it is usually found in the petiole of leaves.

What are the structural characteristics and location of lacunar collenchyma?

Cells are spherical or oval with small intercellular spaces, with hemicellulose and pectin deposited along the borders of these spaces; it is usually found in the fruit wall.

What structure and main components are shown in this diagram?

Primary cell wall; its three major components are cellulose microfibrils, hemicellulose, and pectin.

How does sclerenchyma differ from parenchyma and collenchyma regarding cell wall composition and vitality at maturity?

Sclerenchyma cells have thick, lignified secondary cell walls and are non-living (dead) at maturity.

What are the two types of sclerenchyma cells and their characteristics?

Fibers (occur as continuous cylinders around stems or in vascular tissue) and Sclereids (stone cells with thicker walls that protect other cells, found in nut shells, drupe stones, and pear fruit).

Which cells are the only living cells present in xylem tissue?

Parenchyma cells.

What are the two water-conducting cell types in xylem, and what is their vitality status when mature?

Tracheids and vessel members; both are nonliving (dead) at maturity.

What are the functional and structural differences between xylem and phloem vessels shown in this diagram?

Xylem vessels carry water and minerals upward in a one-way flow through cells with thick lignified walls and no end walls. Phloem vessels transport water and food in a two-way flow through cells with perforated end walls.

What cell types compose phloem tissue, and which element is primarily responsible for carbohydrate transport?

Phloem consists of sieve-tube elements, companion cells, parenchyma, and sometimes tracheids or fibers; sieve-tube elements are primarily responsible for carbohydrate transport.

How are companion cells connected to sieve-tube elements, and what functions do they perform?

They are connected via plasmodesmata; they regulate the metabolism of adjacent sieve-tube members, provide energy, and assist in phloem loading and unloading.

What dense protein material occupies the central part of mature sieve tubes to assist in transport?

P-protein (slime).

What is the developmental difference between primary and secondary xylem/phloem?

Primary xylem and phloem form early during root and shoot development. Secondary xylem and phloem form later during stem and root development (secondary xylem has lignified secondary walls).