Biology II plants pt. 2

What are the major functions of plant roots?

The major functions of plant roots are anchorage, absorption of water and minerals from the soil, and food storage.

Carpel

a single pistil, or single member of a compound pistil

Pollen dispersal and seed dispersal accomplish two different and important functions in seed plants. What are these funtions - i.e., what advantage is provided to a plant by widely dispersing its pollen (instead of having the pollen function close to where it is produced) and what advantage is provided to a plant by widely dispersing its seeds (instead of having the seeds germinate close to where they are produced)?

- The functions that pollen dispersal and seed dispersal accomplish are to produce offspring and and to provide additional protection for the embryo. -the advantage of a plant by widely dispersing its pollen is it increases the chance of cross-fertilization. -the advantage provided to a plant by widely dispersing its seeds is increasing the chance of cross-pollination.

What are the functions of the root apical meristerm?

-Acts as an anchor -absorption of water and minerals from soil -food storage (sometimes plants can't photosynthesize water)

What are the three tissue systems that are found in plants? What is the function of each tissue system?

1. Dermal Tissue System: to protect from water loss, bacteria/pathogenic organisms 2.Vascular Tissue System: transport xylem and phloem 3. Ground tissue System: does everything else such as (storing food, producing hormones, etc.)

What are nodes? Internodes? Axillary buds?

1. Nodes-a joint in a stem. (a part of a stem that normally bears a leaf.) 2. Internodes-a space between two nodes 3. Axillary buds (lateral bud)-a bud that is borne at the axil of a leaf and is capable of developing into a branch shoot or flower cluster.

Describe the structure of an angiosperm megagametophyte. Where is this megagametophyte located?

1. Ovules are located in the ovary. -megagametophytes develop within the ovules. 2. Megagametophytes of angiosperms usually have seven cells. -one egg, two synergids, three antipodals. - each with 1n nucleus -one central cell containing TWO 1n nuclei =polar nuclei

What is the function of the pericycle, and where is it located?

A layer of nonvascular tissue that surrounds the vascular tissues in the roots of plants and is in turn surrounded by the endodermis. New lateral roots begin growth from the pericycle.

What are the responsibilities of the shoot apical meristem (i.e., what tissues/organs is it involved in producing?)

1. stem elongation 2. producing new leaves 3. producing new branches -tissues/organs involved are axil, bud primordia, and leaf primordia, nodes

microsporophyll

A leaflike structure that bears microsporangia, such as those of in the strobili of lycophytes or in the male cones of conifers. It forms the stamens of flowering plants which are highly modified microsporophylls

What is a lenticel? Describe its structure and function.

A lenticel is periderm that arent tightly packed and don't have as much suberin. Lenticel helps with gas exchange.

What is double fertilization? What are the products of this process?

2 sperm enters the ovary through the pollen tube. One fertilizes the egg & becomes a diploid zygote. The second combines with the 2 haploid polar nuclei & becomes a triploid nucleus. This becomes the endosperm that will surround & nourish (food) the egg.

What is a companion cell, and what is its function?

A companion cell is a specialized parenchyma cell. Companion cells help sieve tube members by providing nutrients the cell needs.

leaf primordium

A finger-like projection along the flank of a shoot apical meristem, from which a leaf arises.

angiosperm

A flowering plant which forms seeds inside a protective chamber called an ovary.

What is a fruit? What types of plants produce fruit? What benefits are provided by the formation of fruit?

A fruit is a mature ovary with many seeds enclosed. Angiosperms produce fruit. Fruit provides additional protection for the embryo, and aids in seed dispersal because the fruit can either be eaten by an animal and deposited somewhere else or get caught on the fur of an animal and dropped off somewhere else. The seeds can then germinate and not compete for resources with the parent.

Name all of the structures that make up a typical angiosperm seed.

A seed coat, endosperm, and the embryo

How do taproot systems and fibrous root systems differ from one another in structure and function?

A taproot originated from the radicle in the embryo, the taproot goes deeper so it allows for better anchorage and the taproot gets water from deep in the soil. A fibrous root system originated from the radicle but broke off from the taproot, don't provide a lot of anchorage because it doesn't go that deep and it gets water immediately when it rains. It is also seen in most dicots.

There are at least two tissues within an angiosperm seed that serve as storage sites for nutrients. When are these nutrients used, and why is it so important that those nutrients be present within the seed?

Cotyledons and endosperm are used as nutrients. Cotyledons are used in dicots. Endosperm is used in monocots. It's important for the nutrients to be present within the seed because it is the nutrients that allow the plant to germinate and develop before the start to photosynthesize.

What are guard cells? How does the structure of gruard cells differ from the structure of other epidermal cells? What is the function of guard cells?

Guard cells are epidermal cells that surround and regulate the opening of the stomata. Guard cells have a thickened primary cell wall and have chloroplasts while other epidermal cells have a normal primary or secondary cell wall, no chloroplasts and are tightly packed. Guard cells function is to prevent water loss by increasing turgor pressure to allow more water uptake.

What does the term gymnosperm mean, and why is this an appropriate name for this group of organisms?

Gymnosperm means 'naked seed,' the seeds are not enclosed thus naked. Angiosperm means "vessel seed."

In general, what is meant by the term "meristem"? What is the difference between apical meristems, primary meristems, and lateral meristems, with respect to their function and their location?

Meristem is the growth that occurs in specialized regions. Apical meristem produce primary meristem. Primary meristem produce protoderm, ground meristem and procambium. Lateral meristem produce vascular cambium and cork cambium which is secondary growth. Apical and and primary meristems provide growth at the top and bottom of the plant which help add growth in length. Lateral meristems provide growth on the sides of the plant which help add width.

bud primordium

Meristematic tissue that gives rise to an axillary bud

What are root hairs, and what is their major contribution to root function?

Outgrowths of the dermal tissue in the root system that increases surface area and allows greater absorption of water in dry soil pockets.

Where are the ovules of angiosperms located? Where are the microsporangia located?

Ovules are located in the ovaries of angiosperms or part of the overall carpel.

Parenchyma tissue, collenchyma tissue, and sclerenchyma tissue are all types of ground tissue. How do these tissues differ from one another with respect to the characteristics of the cells that are found in each, and their functions?

Parenchyma cells have a thin primary cell wall, are active in metabolic activities and are the least specialized. Collenchyma tissue has unevenly thickened primary cell walls, no important metabolic role, provides flexible support and not lignified. Sclerenchyma tissue has primary AND secondary cell walls (thick, rigid and lignified), cells undergo apoptosis, and provide support to older organs.

cross pollination

Pollen from the flower of a plant is moved to the flower of another plant and results in a new generation of offspring in the form of seeds.

Where does angiosperm pollen germinate? Describe the path of pollen tube growth

Pollen germinates on the stigma. The pollen tube grows through the style and releases two sperm in the ovule.

What are the major differences between primary cell walls and secondary cell walls with respect to when they are formed, where they are located, and their chemical composition?

Primary cell walls are formed when new cell is produced. Primary cell walls are located on the outside of the cell. Primary cell walls are made up of mainly cellulose. Secondary cell walls are formed by adding to the primary cell wall. Secondary cell walls are located between primary cell wall and plasma membrane. Secondary cell walls are made up of cellulose, lignin and/or suberin.

What is the difference between a primary tissue and a secondary tissue? What is the difference between the primary growth of a plant and the secondary growth of a plant?

Primary tissue adds to the length of the organ. Secondary tissue adds to the width of the organ. The primary growth occurs at root tips and shoot tips, from apical meristems and primary meristems. The secondary growth occurs only in some species and can occur in areas other than shoot/root tips.

Describe the general structure of a flower. What is the function of each of the following types of floral appendages - sepals, petals, stamens, carpels? Which of these are sterile appendages? Explain. Which are fertile appendages? Explain.

Sepals and petals are sterile, while the carpels and stamens are fertile as stamens carry the pollen and carpels is the location for the egg to be contained.

Sieve tube members are the conducting cells of phloem, specialized for the transport of metabolites within a plant. In what way do sieve tube members differ from a "typical" plant cell? How do these differences improve the ability of seive tube members to serve as efficient metabolite-conducting cells?

Sieve tube members only have the protoplast but are missing organelles (lose vaculoe, nucleus, and mitochondria). This allows sieve tube members to have more room to transport metabolites.

Describe the structure of a stamen. Describe the structure of a pistil.

Stamen contains the anther located at the top, and the filament being the stalk like structure.

What are the major functions of a typical plant stem?

The major functions include support and positioning of leaves, support and positioning of flowers/fruits and transport.

What additional structures are part of the embryo in grasses (a type of monocot), but are not present in the embryos of other types of plants?What is the function of these additional structures? How do other plants compensate, in part, for the absence of these additional structures?

The coleoptile and the coleorhiza are part of the embryo in monocots but not in other types of plants. The coleoptile covers the young shoot (plumule). The coleorhiza covers the young root (radicle). Other plants use the hypocotyl to protect the young plant from the harmful minerals in the soil.

Both the epidermis and the periderm need to perform the same basic functions. What are those functions? How does the structure of the epidermis contribute to those functions? How does the structure of the periderm contribute to those functions?

The epidermis and periderm have to provide an effective barrier at the plant surface to prevent water loss and infection from pathogens. The epidermis has guard cells that prevent water loss and protection from pathogens. Periderm have lenticels that allow for gas exchange because the lenticels are not tightly packed and do not have too much suberin.

Stamen

The male reproductive organ of a flower, consisting of a stalk (filament) bearing an anther which produces pollen.

The epidermis is a primary dermal tissue and the periderm is a secondary dermal tissue. Describe the most common cell types found in each of these tissues.

The most common cell types are epidermal cells, guard cells, and periderm. Epidermal cells have primary cell walls, no chloroplasts, cutin on the cell wall that creates a cuticle, and the cells are tightly packed. Guard cells surround, and regulate the opening of the stomata, have thickened primary cell walls, and do have cholorplasts. Guard cells change shape to cause stomates to open or close. Periderm is secondary dermal tissue which are composed of cork cells that are box-shaped, tightly packed, and have suberized secondary cell walls that undergo apoptosis.

filament

The part of a stamen that supports the anther of a flower; the stalk of a stamen.

how are the pollen grains of gymnosperms usually dispersed?

The pollen grains are dispersed through wind dispersal.

Which structures are a part of the embryo? What is the function of each of these parts of the embryo? Describe how these structures are arranged in the embryo.

The root-shoot axis and one or two cotyledons. The root shoot axis consists of the radicle, the plumule, the hypocotyl, and one or two cotyledons. The radicle becomes the primary root. The plumule includes the epicotyl and embryonic leaves, which are the stem-like portion above the cotyledons. The hypocotyl is the stem-like portion below the cotyledons. The cotyledons are food-storage organs. The structures are arranged like the plant they will grow to be.

Describe the components that are present in an angiosperm seed, and the function of each. How does this differ from a typical gymnosperm seed?

The seed coat (2n), an embryo (2n), and the endosperm (3n). The seed coat protects the embryo. The embryo germinates to become another sporophyte generation. The endosperm provides nutrients. A typical gymnosperm seed has a seed coat and an embryo but the nutrients are gametophyte tissue (n).

Which structures are present that are NOT a part of the embryo? What is the function of each of these?

The seed coat and the endosperm are not apart of the embryo. The seed coat protects the embryo and the endosperm provides food for the embryo.

What are the types of lateral meristems, and what tissues does each of these produce?

The types of lateral meristem are vascular cambium and cork cambium. Vascular cambium produces vascular tissue. Cork cambium produces dermal tissue.

What are the types of primary meristem, and what primary tissues does each primary meristem produce?

The types of primary meristem are protoderm, ground meristem, and procambium. Protoderm produces dermal tissue. Ground meristem produces ground tissue. Procambium produces vascular tissue.

How is the structure of both tracheids and vessel members related to their ability to serve as efficient water-conduction cells?

Tracheids allow for slower water movement while vessel members allow for rapid water movement. Rapid water movement can be damaging so having a mix of both is an evolutionary success.

To what tissue system does each of the following belong-tracheids, vessel members, sieve tube members, and companion cells?

Tracheids and vessel members belong to the vascular xylem tissue system. Sieve tube members and companion cells belong to the vascular phloem tissue system.

How is the structure of tracheids similar to the structure of vessel members?

Tracheids and vessel members both have primary and lignified secondary cell walls, undergo apoptosis (with no protoplast), and have pits in the secondary cell wall.

How is the structure of tracheids different from the structure of vessel members?

Tracheids are narrower, longer and have pits distributed on all walls. Vessel members are wider, shorter, stack into vessels, and have pits on the side walls but perforations in end walls which allow for rapid water flow.

What are trichomes? What functions might trichomes perform?

Trichomes are epidermal appendages composed of one or more individual epidermal cells which include root hairs and leaf hairs. Root hairs help water absorption. Leaf hair protect from pathogens. Leaf hairs also reflect light so the plant doesn't take too much light in.

What mechanisms of pollination are common in angiosperms?

Wind dispersal in some but the most common are insects that carry the pollen from flower to flower. Birds and bats pollinate also.

megasporaphyll

a leaf that bears megasporangia. compared to carpel of a flowering plant.

sporophyll

a modified leaf that bears sporangia

apoptosis

a programmed cell death that secondary lignified cells undergo to leave behind the cell wall.

microstrobilus

in conifers, male pollen-bearing cone

megastrobilus

in conifers, the female (seed-bearing) cone

What is the major function of typical plant leaves?

photosynthesis

cross fertilization

process by which sperm from one flower's pollen fertilizes the eggs in a flower of a different plant

axil

the angle between the upper side of a leaf or stem and the supporting stem or branch.

pistil

the ovule-bearing or seed-bearing female organ of a flower, consisting when complete of ovary, style, and stigma.