Biology: Ch. 29 (1-2) Short Answer

What are the differences between a taproot, a fibrous root system, and an adventitious root?

A taproot systems has one large primary root. A fibrous root system has many small, branched roots. Adventitious roots grow from unusual places, such as stems or leaves.

Distinguish between primary growth and secondary growth in a tree.

An increase in a plant's length (height) is called primary growth. An increase in a plant's diameter is called secondary growth.

What kind of meristems do monocots and dicots have in common?

Both have apical meristems at the tips of stems and roots.

How do the structures of parenchyma cells, collenchyma cells, and sclerenchyma cells differ?

Parenchyma cells have thin walls and cube- shaped or elongated cells. Collenchyma cells have thick walls and are irregular in shape. Sclerenchyma cells have thick, even, rigid cell walls.

Suggest an environmental condition in which the regulation of water movement by endodoermal cells might help ensure a plant's survival.

Plants growing in low nutrient soil can hold higher concentrations of nutrients than the soil, because the endodermal cell can actively transport minerals into the vascular tissue against a concentration gradient.

Describe some factors that may influence the transport of water through xylem tissue.

Plants with predominantly vessel elements in the xylem could transport water more quickly; the amount of sunlight, the air temperature, humidity, and amount of water in the soil would influence water transport.

Describe how the plant kingdom would be different if plant growth only occurred in lateral meristems.

Plants would only grow in diameter, not in length. There would be no tall plants.

What is the difference between primary growth and secondary growth in roots?

Primary growth is an increase in root length that occurs in apical meristems. Secondary growth is an increase in root diameter that occurs in lateral meristems.

State one function of a root cap.

Root caps help the root to move more easily through the soil as it grows.

Explain how root hairs increase the ability of a plant to absorb water from the soil the plat grows in.

Root hairs greatly increase the root surface area in contact with the soil.

What are the major functions performed by the root systems of plants?

Roots anchor the plant, absorb water and mineral nutrients, and store carbohydrates or water.

How are the roots of most plants adapted to perform the major root functions?

Roots have a cap at each tip that protects it as it grows through soil. Root hairs, extensions of the epidermis, increase the root surface area used for water and mineral uptake. Parenchyma stored carbohydrates and carries out metabolic activities. Roots have vascular tissue that transports water and minerals to stems, and stems transport these materials to leaves.

Why might a taproot be an advantage to some plants, whereas a fibrous root system might be an advantage to others?

Taproots offer large plants support and enable plants to reach water deeper in the ground. Fibrous roots offer support in shallow soils and maximize water collection.

Describe the structures of the three major plant tissue systems.

The dermal tissue system is composed of flat parenchyma cells that form the outer layer of a plant. The ground tissue system is composed mainly of parenchyma cells but also includes some collenchyma and sclerenchyma cells; ground tissue forms between dermal and vascular tissue in non- woody plant parts. The vascular tissue system is composed of elongated sclerenchyma cells with some parenchyma cells. The cells of vascular tissue are connected end-to-end and have openings between adjoining cells.

What vertebrate animal structures have cells that carry out functions similiar to those of sclerenchyma?

The skeletal system provides structure and support.