Biology Exam 3: Ch 28

Plant Organs: Roots

Below ground

Which of the following are the parts of a typical leaf?

Blade and petiole

Meristems

Areas of dividing cells that allows growth in all plants -Undifferentiated (unspecialized) cells that divide frequently, generating new cells and tissues. -Apical Meristems: Occur at the tips of roots and shoots & enable primary growth, growth in length

Vascular Cambium

Ring of dividing cells -Between the primary xylem and primary phloem -Uneven activity of the vascular cambium causes a visible ring each year

Where would you find the mesophyll?

In the leaf

What is the movement in the xylem?

One way

Stomata Regulate Transpiration

Open during the day, which allows CO2 to enter the leaf from the atmosphere for photosynthesis when light is available -At night, there is no light for photosynthesis, therefore no need for CO2, and the stomata are closed

What cell type is responsible for the bulk of photosynthesis in a typical leaf?

Parenchyma

How do cells in a meristem differ from other cells in a plant?

They are undifferentiated and continue to divide and generate new cells and tissues

Collenchyma Cells

Unevenly thickened primary walls; support for actively growing parts

Angiosperms

"The flowering plants" -90% of the plant kingdom -Organs are composed of different tissues (roots, shoots=stems, leaves, flowers) -Tissues composed of cells of different types

Functions of a Plant's Roots

1. Anchor the plant in the soil 2. Store food in the form of carbohydrates such as starch 3. Absorb and transport minerals and water 4. Root hairs increase the surface area of the root

Primary growth in a root is achieved by:

1. Cell division 2. Cell elongation (mainly by taking up water)

Process of Secondary Growth

1. The epidermis is sloughed off 2. It is replaced with a new outer called cork (produced by cork cambium) 3. Mature cork cells are dead (thick waxy walls to protect underlying tissues) 4. Bark consists of everything external to the vascular cambium -Secondary phloem, cork cambium, cork

Plant Organs: Shoots

Above ground -Stems, leaves, flowers

Food-conducting Cells

Arranged end to end, forming tubes. -Remain alive at maturity -Phloem sap moves in various directions: from a sugar source (where sugar is produced) to a sugar sink (where sugar is stored or consumed)

Vascular Bundles

Arranged vascular tissue systems in the stem -The center of the stem is often important in food storage

What is meant by the term "indeterminate growth?"

Continued growth of an organism as long as it lives

The primary function of guard cells is to __________.

Control the rate at which a plant loses water and takes in CO2

Dermal Tissue

Covers and protects leaves, stems, and roots -Helps prevent water loss with the cuticle (a waxy coating)produced by epidermal cells

What are the 3 types of plant tissues?

Dermal, Vascular, & Ground

What is not a function of the root system?

Food production

Ground Tissue

Functions in photosynthesis, storage, support

Stems

Generally grow above ground -Support the leaves and flowers -Have nodes, the points at which leaves are attached, and attached, the portions of the stem between nodes internodes bud, at the apex (tip) of the stem -Terminal buds, at angles formed by a leaf and the stem phenomenon of apical dominance

Plant Tissues

Group of cells that form organs of plants -3 types (dermal, vascular, ground)

Determinate Growth

Growth ends after reaching a certain size (animals)

A major role of root hairs is to __________.

Increase the root surface area for absorption

Primary growth produces ____ whereas secondary growth produces ____?

Increased length; increased thickness

How does transpiration play a role in the functioning of plant organs?

It creates tension that pulls water up through the xylem

Parenchyma Cells

Most abundant cell type; variety of functions -Located inside Sclerenchyma (aka ground tissue)

Which of the following is correct when considering the function of primary and secondary growth?

Primary growth adds height, and secondary growth adds girth.

Secondary Growth

Process which the stems and roots of many plant species thicken over time (annual growth rings) -Woody vs. Nonwoody (herbaceous) plants -Adds cells on either side

Lateral Meristems

Produce secondary growth

Importance of Plants

Provide shelter, food, and breeding areas for other organisms -Humans depend on plants for food, fuel, and clothing

Vascular Tissue

Provides support and long-distance transport -Phloem: transports sugars from leaves or storage tissues to other parts of the plant. -Xylem: conveys water and dissolved minerals upward from the roots to the stems and leaves.

Sclerenchyma Cells

Secondary strengthened with light in, main chemical in wood; support -Located inside the epidermis

Which of the following is the main component of wood?

Secondary xylem

What is not a plant tissue?

Stoma

Which of the following best describes the daily cycle of stomata in most plants?

Stomata are open during the day and closed at night.

Indeterminate Growth

The ability for plants to grow throughout life -The life span of plants varies greatly

Cells that contain the most chloroplasts are found in what region of a typical leaf?

The mesophyll

Which of the following best describes the region on a plant stem where one typically finds leaves?

The node

Leaves

The primary sites of photosynthesis; consist of: 1. A flattened blade 2. A stalk, or petiole, which joins the leaf to the stem -Leaves are highly varied in their arrangements & shapes -Epidermis contains stomata (tiny pores between two specialized guard cells that regulate the size of the stomata) -Ground tissue = mesophyll, the main site of photosynthesis. -Vascular tissue system is made up of a network of veins

Plant's Roots

The root is pushed through the soil by primary growth -The root cap protects the actively dividing cells

Where would you find a node?

The stem

Angiosperms: 2 Types of Water-conducting Cells

Tracheids & vessel elements -They are dead with only their cell walls remaining; arranged in chains of hallow tubes with overlapping ends

Which one of the following describes the loss of water through the stomata in a plant's leaves?

Transpiration

Thinking about our circulatory system, which tissue system in a plant would be most analogous?

Vascular tissue

Cross Section of a Root

Vascular tissue system: forms a cylinder in the center Ground tissue system: forms the cortex where cells store food -Innermost layer is endodermis, selective barrier that regulates the passage of substances between the cortex and the vascular tissue.

Xylem Transport

Water, dissolved ions from the roots to the tips of the leaves through vertical Xylem tubes. -Transpiration: loss of water by evaporation, occurs through pores in the leaves called stomata; pulls water up the plant against gravity