Exam 3 Bio 2

stages of embryo development in Capsella

1. Globular 2 heart shape 3. torpedo 4 bending 5 mature embryo The young zygote divides uneqaully and is nourished by a suspensor. Then, the root and shoot meristems develop. Next, the endosperm tissue starts to surround the embryo. Finally, the nutrients are fully devoured. The seed coat develops from the integuments.

Explain how the shoot system differs from the root system and identify the various tissues found in each

A SAM produces tissues that increase plant length and generate new organs. Such meristems are known as the primary meristems, and in a process known as primary growth, they ultimately produce primary tissues and organs of diverse types. Secondary growth increases girth of stems and roots.

double fertilization in angiosperms. There are different fates of the two sperm cells transmitted by each pollen tube.

A mechanism of fertilization in angiosperms, in which two sperm cells unite with two cells in the embryo sac to form the zygote and endosperm. Of the two sperm cells, one fertilizes the egg and the other fuses with two polar nuclei to form a 3n endosperm.

List the ways in which plants cope with cellular osmotic stress.

A plant has a mechanism called osmotic adjustment. This means the cell modifies the solute concentration of the cytosol. By increasing the concentration of solutes inside cells, cold-resistant plants prevent water from moving out of their cells when ice crystal formation in intercellular spaces lowers the water potential outside the cells. The cytosol desert plants is typically rich in sugars that bind to phospholipids to form a glasslike structure.helps to stabilize the cellular membranes, preventing them from becoming damaged during plasmolysis. Plant cells under water stress may also increase the number of plasma membrane aquaporins.

Vessel elements

A short, wide, water conducting cell found in the xylem of most angiosperms and a few nonflowering vascular plants. Dead at maturity, vessel elements are aligned end to form micropipes called vessels.

Tracheids

A water-conducting and supportive element of xylem composed of long, thin cells with tapered ends and walls hardened with lignin.

Describe how bulk flow occurs in the xylem and phloem of flowering plants

Bulk flow is the movement of water from one place to another because of pressure or gravity difference. When water amount is high in the roots, then the water pressure will be higher in root xylem than shoot xylem. Water diffuses more readily when the humidity is lower. Pressure gets higher in the phloem sap leaves. Increases in sap causes the water to enter.

Explain how the root endodermis functions as a diffusion barrier

Casparian cells in endodermal cells prevent apoplastic diffusion. The root endodermis prevents harmful solutes from moving to the apoplast to vascular tissues.

Explain how the sexual life cycle of flowering plants differ from that of earlier evolved mosses.

During the evolutionary diversification of land plants, the sporophyte generation has become larger and more complex, while the gametophyte generation has become smaller and less complex. Moss sporophytes are small structures that always grow attached to larger, photosynthetic gametophytes. In contrast, flowering plant sporophytes are notably larger and more complex than gametophytes

Discuss why plant shoots are said to have a modular structure

Each shoot module consists of four parts: a stem node, an internode, a leaf, and an axillary meristem or bud.

Describe how some plants have adapted to light limitations in shady habitats.

Hundreds of plant species have lost their capacity to take in light sources. Other plants take in light in shady places. They have very thin leaves. The shade leaves will have a thin mesophyll layer.

Explain why plants require a source of fixed nitrogen and how they obtain it

Large amounts of nitrogen are required for plant synthesis of amino acids, nucleotide and many other constituents. Soil nitrogen must be in ammonium, ammonia or nitrate form. Nitrate is the fixed form. The nitrogen goes in a cycle throughout the environment and consumed in its various forms. Cyanobacteria fix nitrogen as well to bring to the environment. It uses ATP and nitrogenase to fix the nitrogen/

Explain the importance of several organismal symbionts that plants have.

Mycorrhizal help plants with nutrients. Soil fungi provide plants with nutrients and water. Plant-bacteria symbiosis provide plants with nitrogen. soil bacteria produce plant hormones that affect root structure, others help plants to tolerate drought and other stresses, and some provide plants with nutrients, notably fixed nitrogen.In nitrogen-fixation symbioses, the plants provide organic nutrients to the bacteria, and the bacteria supply the plants with a much higher supply of fixed nitrogen. examples of bacteria:proteobacteria,actinobacteria and cycanobacteria

Describe the phenomenon of double fertilization.

One female gametophyte joins with two male gametophytes. The cell formed by this second fertilization undergoes mitosis, eventually producing a nutritive tissue known as the endosperm 3n

List the major nutritional resources that most plants need for healthy growth

Photosynthetic plants for instance require carbon dioxide and water. But they also require elements such as potassium, nitrogen and calcium. There are more micronutrients and macronutrients that they take in as well.

Explain how stomata and leaf abscission help reduce transpirational water loss.

Plant stomata close to conserve water under conditions of water stress and open when the stress has been relieved. The guard cells are the reason why they can open and close. In leaf abscissions, it helps plants drop their leaves.

Discuss various plant adaptations that increase the ability to obtain phosphorus.

Plants obtain phosphate by the symbiosis relationships with fungi. Plants that obtain low amounts will also grow longer root hairs to dig in deeper to the ground. Plant secretions also help release the held phosphorus.

Carnivorous plants

Plants that get some or most of their nutrients from trapping and consuming animals.

Explain how sperm production occurs in plants.

Pollen grains will develop in the anther. The anther is part of the stamen. (1) microspore division to produce a young male gametophyte, and (2) development of a tough pollen wall that protects the gametophyte during pollen ransport. Both of these processes are completed before the anthers release pollen. When the pollen is released, the pollen makes its way to the pollen tube. It goes down and connects with female gametophytes.

List ways in which seed plant reproduce and grow

Seeds contain embryos that develop into young plants—seedlings—when seeds germinate. Dispersed seeds may remain dormant in the soil—sometimes for long periods—but germinate when temperature, moisture, and light conditions are favorable. Such conditions activate embryo metabolism, in which stored food is respired for energy needed for cell division and growth.

Discuss how the pistil controls pollen germination

Self-incompatibility helps plants to avoid the combination of gametes that are too genetically similar. It is controlled by interactions between chemical constituents of pollen and the pistil.In gametophytic self-incompatibility, compatibility between pollen and pistil is determined by the haploid genotype of the pollen. In this case, pollen S protein is located in the cytosol.In sporophytic self-incompatibility, compatibility between pollen and pistil is determined by the sporophyte that produced the pollen and contributed S proteins to its coat.

List the four organs found in many flowers and the functions of each organ

Sepal,petal,pistil, stamen. Sepal protect unopen bud. Petal attract insects and animals for pollen transport. Pistil produces female gametophytes. Stamen produce male gametophytes.

List the benefits of soil organic matter for plant growth

Soil provides water and other essential nutrients. Humus is made of dead plant matter that helps it be protected from erosion. Animals wastes also contributes to this protection. The organic matter binds mineral nutrients. This can help plant growth.

Describe how plants transport water, minerals, and organic materials between roots to leaves

Therefore, plants must transport water and minerals upward from roots to shoots and transport organic food from photosynthetic to nonphotosynthetic parts.

Describe the cohesion-tension theory as an explanation for long-distance water movement.

This is the relationship between cohesive forces of water and evaporative tension.Cohensions of water molecules creates a water chain. As they move up the column by evaporation in leaves, more are drawn.

Describe how sieve-tube elements and companion cells work together to form a transport system.

Together, the sieve-tube elements and companion cells form a system for the transport of soluble organic substances made during photosynthesis

List ways that root structure has been modified in different plants in response to different habitats.

Trees grow pneumatopore roots that grow upward in the air. They take in the oxygen rich air better than they would if in soil. Buttress roots help keep trees from toppling over.

List examples of environmental and internal factors that influence seed germination

Water and heat are major factors. The seed must be hydrated and not parched. The plant hormone ethylene, will determine the seedling hook formation.

Describe the differences among turgid, flaccid, and plasmolyzed plant cell.

a plant cell that has absorbed water and has cytoplasm that is pressing outwards on the cell wall is turgid. A plant cell which is limp due to lack of water is flaccid. Plasmolyzed plant cell is the opposite of turgid.

Parasitic plants

absorb water, sugars, and minerals from their living host plant

transmembrane transport

involves the export of a material from one cell via membrane proteins, followed by import of the same substance by an adjacent cell

symplastic transport

is the movement of a substance from the cytosol of one cell to the cytosol of an adjacent cell via membrane-lined channels called plasmodesmata

apoplastic transport

is the movement of solutes along cell walls and the spaces between cells.

complex primary tissues

leaf epidermis, root epidermis,leaf,stem,and root xylem and phloem

Explains why leaves having different shapes and vein patterns exists in nature

leaf flatness facilitates solar energy collection, and thinness helps leaves to avoid overheating. Leaf shape and surface features also reflect adaptation to stressful environmental conditions. eudicots, blades are attached to the stem by means of a stalk known as a petiole, and an axillary bud occurs at the junction of stem and petiole.In contrast, monocots have leaf blades that grow directly from the stem, encircling it to form a leaf sheath

secondary growth

outer bark, secondary phloem and xylem

Simple primary tissues

parenchyma,collenchyma, schlerenchyma,root endodermis,root pericle

plasmolyzed plant cell

the opposite of a turgid plant cell is