BIO 123 FINAL EXAM - Exam 1 content

What are the three types of land plants?

Nonvascular Bryophytes, Vascular Seedless Plants, and Vascular Seed Plants

What are the most successful land plants?

Angiosperms (flowering plant) - Vascular Seed Plant

Name the Four things that a Root System does?

Usually below the ground surface, absorbs water and minerals, anchors a plant in the soil, and stores food (carbohydrates)

What is the primary root of a plant?

The taproot- which emerges first from seed

What do Lateral Roots do?

They branch off from other roots and increase stability and absorption

Where does absorption of water and minerals typically occur?

The root hairs

Where do root hairs grow?

Near the root tips

Describe root hairs.

finger-like epidermal cells that increase the absorptive surface area of the root.

What does the shoot system consist of?

Stems and leaves

Where is the shoot system located?

Above ground

What does the shoot system aquire?

Acquires sunlight and Co2 which is important for photosynthesis

What is the main function of the stem?

To elongate and orient shoot to maximize photosynthesis by the leaves and elevate reproductive structures

What is a node?

The point at which leaves are attached to the stem

What is an Internode?

Between two nodes

What are the two types of buds?

Apical bud and axillary bud

Where is the apical bud located?

Always at the tip of the stem

What does an apical bud do?

Drives vertical growth

Where is an axillary bud located?

Side of the stem - where the leaves are

What does an axillary bud do?

Develop into a branch, thorn, or flower

What is the main photosynthetic organ of a plant?

The leaf

What does the leaf do?

Intercepts the leaf, exchanges gasses, utilizes heat, and defends the plant

What does the leaf consist of?

The blade and petiole

What does the petiole join?

The leaf to the stem

What are the two variations of leaves?

Simple and compound leaves

Describe a simple leaf.

Has a single, undivided blade.

Describe a compound leaf.

The blade consists of multiple leaflets.

What is unique about a leaflet?

It does not have an axillary bud at its base.

What are the two types of leaves?

Monocot and Eudicot

How do the veins of monocots and eudicots differ?

Monocot - Veins are parallel

Eudicot - Veins are branched

What is dermal tissue?

A protective outer coating

What is the dermal tissue in a nonwoody plant

It is a single tissue layer called the epidermis

What is the epidermis covered by?

A waxy cuticle that prevents water loss from leaves and stems

What replaces the epidermis in older regions of woody stems and plants?

The periderm - Woody plants outgrow the epidermis which is then replaced by the periderm

What is a guard cell?

A specialized epidermal cell that is important in facilitating gas exchange

What is a trichomes?

A specialized epidermal cell that reduces water loss, reflects light, and is VERY important for defending against pest

What is vascular tissue?

A tissue that facilitates the transport of materials through the plant and provides mechanical support

What does vascular tissue include?

The xylem and phloem

What does the xylem do?

Conducts water and dissolved minerals UPWARD from roots into the shoots

What are the two types of water conducting cells?

Tracheid and vessel elements

Compare the structure of tracheid and vessel elements?

Tracheid -Longer and thinner
Vessel Elements - wider and shorter

Is the xylem dead at maturity?

YES YES YES

What does the phloem do?

Transports sugars from where they are made to actively growing parts of the plant or storage structures IN ANY DIRECTION

What are sugar conducting cells?

Sieve-tube elements - Have a non-conducting cell alongside it. This cell is known as a companion cell

Is the phloem dead at maturity?

NO NO NO

What does ground tissue do?

Function in storage, photosynthesis, support, and short-distance transport

What are the two types of ground tissue?

Pith - Internal to the vascular tissue

Cortex - External to the vascular tissue

What are meristems?

Undifferentiated tissues composed of dividing cells

What do meristems make possible?

Continuous growth

What are the two types of meristems?

Apical and lateral

What type of growth does apical meristems make possible?

primary growth at the tips of shoots and roots

Primary growth leads to what kind of growth?

Growth in length

What type of growth do lateral meristems allow for?

Allows the stems and roots of woody plants to grow in circumference (secondary growth)

What are the two types of lateral meristems?

Vascular cambium and cork cambium

What is a Vascular Cambium?

Adds vascular tissue called secondary xylem (wood) and secondary phloem (inner bark)

What is the cork cambium?

Replaces the epidermis with thicker, tougher periderm (outer bark) that protect the stem from water loss and pathogen invasion

What is the difference between primary and secondary growth?

Primary growth - Length

Secondary growth - circumference (width)

What covers the root tip?

A root cap

Where does primary growth occur?

Just behind the tip of the root - three zones

What are the three zones where primary growth occurs?

1. The Zone of cell division

2. Zone of elongation

3. Zone of differentiation, or maturation - Into specialized cells

What is a stele and where is it located?

The collective tissue of a root or stem and it is located in the root cross section

What is the vascular cylinder of the root cross section?

A cylinder that has a solid core of xylem and phloem

What is the vascular cylinder surrounded by?

A cell layer called the pericycle

How does xylem and phloem appear in eudicot roots?

Xylem has a starlike appearance in cross section with phloem which is between the “arms” of the star

What is at the core of monocot roots?

parenchyma cells

How does xylem and phloem appear in monocot roots?

Alternating rings of xylem and phloem

What gives rise to lateral roots?

Pericycle

Why do the roots emerge from the pericycle?

It has to remain connected to the vascular cylinder so that everything remains connected

What is a shoot apical meristem? (primary growth)

A dome shaped mass of dividing cells at the shoot tip

What protects the meristem? (primary growth)

The leaves of the apical bud

How are vascular bundles arranged in eudicots

In a ring

How are vascular bundles arranged in monocots

They are scattered throughout the ground tissue

What do leafs develop from?

The leaf primordia

What is the stomata

Pores in the epidermis of the leaf that allows exchange of gases for photosynthesis

What is a stoma?

Singular for stomata (plural)

What is on each side of the every stoma in a leaf?

Two guard cells that regulate its opening and closing to reduce water loss

What is mesophyll

The ground tissue in a leaf, sandwiched between the upper and lower epidermis

What are the two layers of mesophyll in eudicots?

Palisade mesophyll and spongy mesophyll

What is palisade mesophyll?

Upper layer and is rich in chloroplasts to maximize light capture

What is spongy mesophyll?

Lower layer and loosely packed to create air spaces for gas exchange

What are leaf veins?

The leaf’s vascular bundles

What is a bundle sheath?

Protects and regulates movement of substances between the vascular tissue and the mesophyll

What is the purpose of stems?

To serve as support structures and conduits for long distance transport of water and nutrients

What do shoot adaptations represent?

Compromise between enhancing photosynthesis and minimizing water loss

Why do roots respond to local changes in soil conditions?

In order to maximize nutrient uptake

Explain competition between roots

More competition - Roots from different plants

Less competition - Roots from the same plant

What type of association do roots and hyphae of soil fungi have?

Mutualistic - Mycorrhizae

Why do roots and hyphae of soil fungi have a mutualistic association?

The mycorrhizal fungi increase the surface area for absorbing waters and minerals - Plant is getting minerals, while the fungi is getting organic compounds that the plants produce

What are nodules?

Swellings along the roots of legume which is composed of the plant cells that are infected by Rhizobium bacteria

What type of relationship does plants have with nitrogen-fixing Rhizobium?

Symbiotic because legumes make fixed nitrogen which means it makes into a form that is usable by the plant

How are sugar molecules transported?

Upward or downward from where they are made or broken down to various parts of the plant body

What is osmosis?

Diffusion of water from higher to lower

What is water potential?

Measure of the cell’s ability to absorb water by osmosis

Is water potential higher or lower in the root compared to soil?

Lower - Water moves by osmosis into the root

What is bulk-flow?

The movement of liquids in response to a pressure gradient (higher to lower)

How does bulk-flow occur?

Tracheids and vessel elements of the xylem and sieve tube elements of phloem

What is the endodermis?

The last checkpoint for selective passage of minerals from cortex to vascular tissue

What is the Casparian strip?

A waxy barrier that minerals that reach the endodermis encounter

What is the tension-cohesion model?

Explains the rise of water in a plant

What is transpiration?

Evaporation of water from plant that causes tension at the top of the plant