Exam 2 Study Guide: Lectures 11 - 20Lecture 11Learning objectives2-1. Review the general features of plant cells and thefunctions of the following: chloroplasts, mitochondria, centralvacuole, cell wall. What are plasmodesmata? Chloroplasts: convert solar energy to chemical energy-photosynthesis Mitochondria: generate the majority of the cell’s energyCentral vacuole: stores water and ions; a structural componentCell wall: cell structure, prevents the cell membrane fromburstingPlasmodesmata: microscopic channels, which traverse the cellwalls of, plant cells and some algal cells, enabling transport andcommunication between them.2-2. What modern group of the kingdom Protista is closest tothe ancestors of the Plant Kingdom? Therefore, in making a cladogram/phylogeny of Plants, whatis the best group to use as outgroup?Green algae  compare cell walls, etc. 2-3. Name three major challenges faced by ancestral plants as they successfully colonized land.- Lack of water- UV radiation (too hot)- Predators - Changes in weather2-4. What adaptations (plant derived traits) did plants eventually evolve for greater success on land?- Apical meristems: localized regions of cell division at the tips of shoots and roots- Alternation of generations: result in both haploid and diploid stages that exist as multicellular bodies—two multicellular body forms alternate - Multicellular embryo that is dependent on the parent plant: parent provides nutrients to the embryo – develop from zygotes that are retained within tissues of the female parent- Sporangia that produce walled spores: makes the walls of spores very tough and resistant to harsh conditions; protect the developing spores until they are ready to be released into the air- Gametangia that produce gametes: produce gametes within multicellular organs called gamentangia 2-5. Tell a characteristic feature (e.g., a new trait in the group) of each of the following divisions of the Plant Kingdom: ferns, gymnosperms, angiosperms.Ferns: living seedless vascular plants BIO 311D 2nd EditionGymnosperms: a vascular plant that produces seeds those are not protected by fruit but are hidden in a woodycone. They do not have flowers, but most retain their leaves year round.Angiosperms: vascular plants that produce flowers and fruit with one or more seedsLecture 122-6. The three main vegetative (non-reproductive) organs of plants are leaves, stems, and roots. Tell the main general functions of each, and be able to pick out these structures in different plants (including vegetable foods). Leaves: photosynthesisStems: support and transportRoots: anchor and absorb 2-7. Give some examples of evolutionarily modified stems, roots & leaves, e.g., cactus spine, and tell what specialized functions they serve that allow that particular type of plant to be adapted for a certain habitat or way of life. Modified ShootsThese are examples of shoots (including both the stem and leaves) that have become secondarily modified.Bulbs: These shoots are an adaptation for interrupted life... for existence in environments with a dormant season due to annual rainfall variations or to life in the temperate climates.Thorns: The thorns of Hawthorne are modified dwarf shoots.Tendrils: Tendrils of grape are modified flowering shoots. Modified StemsRhizomes: While typically competition results in vertical stems, there are environments where horizontal stemsare adaptive. These are termed rhizomes.Tubers: Like bulbs these are adaptations for interrupted life. Irish potatoes are tubers. It is clear that they are stems when you realize that the eyes are axillary buds.Corms: Like tubers and bulbs these are adaptations for interrupted life. Often mistakenly called, bulbs, a corm is a solid underground stem, vertically oriented where typically only one bud germinates at the end of dormancy.Stolons: These are like rhizomes in that they are oriented horizontally. However, they are adapted to generate new plants that are clones of the original.Succulent/photosynthetic Stems: In extremely dry environments, often the leaf becomes reduced and non-photosynthetic, and the stem becomes the primary photosynthetic organ of the plant. A barrel shape provides a low surface to volume ratio which reduces water loss.Cladophyll: If a plant becomes genetically boxed in, like the plants in the preceding link, and the environment becomes more mesic, the same set of factors that caused the generic leaf to become thin and flat will work to make barrel-shaped, succulent stems, thin and flat too.Modified LeavesSucculence : In a dry environment, leaves may either become reduced, like in cacti, or, else, become succulent. Succulent leaves not only retain lots of moisture but also have a lower surface to volume ratio.Stipular Spines: Stipules can become modified into spines for defense.Stipular Spines Modified for Mutualistic Ants: In bullhorn acacia, evolution has preceded one more step. In thisplant the stipular spines are hollow and house mutualistic ants. The leaves are further modified to provide yellow structures on the margins of the leaves which only function to feed the ants. The perioles bear glands that excrete nectar for the ants too.Spines for Defense: The non-photosynthetic leaves of cacti have become modified for defense.Tendrils: In peas the terminal leaflet of the leaf has become modified into a tendril for climbing.Leaves modified for Reproduction: Typically, leaves are determinately growth. The grow, function and then die without sustaining new growth. But Kalanchoe has leaves that have become modified to generate new plants. Modified RootsStorage : Like bulbs and tubers, this is an adaptation for interrupted life. Further, unlike stems and shoots, the primitive habit of roots is subterranean, where it is best to secure energy and propagative resources.Climbing: Some vines will form adventitious roots that assist the plant in clinging to a substrate. Poison ivy has this habit.Lecture 132-8. What is meristem? Where could meristem be found in this figure? Where are apical meristem & lateral meristem (vascular cambium) in trees?This is a tissue formed by a group of cells (mitosis). Meristem cells aren't specialized, but when they divide, some of the new cells specialize into tissues. Areas of growth that lengthen the tips of roots and stems are called apical meristems. Lateral meristems, found all along woody roots and stems, increase the thickness of these plant parts.3