Plant Biology - AP Biology

Phloem is a type of tissue in vascular plants that transports organic nutrients. Among other components, phloem contains sieve elements, parenchyma cells, and supportive cells.

The cork cambium is a type of secondary meristem tissue found in the periderm. Cork cambium controls lateral growth; specifically, it is the source of secondary epidermis growth.

All plants can be classified as either bryophytes or tracheophytes. Plants that contain transport vessels (xylem and phloem) are tracheophytes, while those without transport vessels are bryophytes. All plants contain cell walls and chloroplasts, but only a tracheophyte would contain xylem. Plasmids are structures that are almost exclusively found in bacteria or protozoans.

Stomata are the pores on the leaves that allow for carbon dioxide to enter and oxygen to leave the leaf. Stroma, thylakoids, and chlorophyll are all components of the chloroplasts.

Carbon fixation converts inorganic carbon dioxide into organic carbon compounds, such as glucose and cellulose. This is a characteristic function of both C3 and C4, and is a primary purpose of light independent reactions.

Closed stomata during the day is a characteristic of CAM plants, which allows for the conservation of water that is usually lost during photorespiration.

Bundle-sheath cells are a characteristic of C4 plants. The presence of bundle-sheath cells isolates rubisco, preventing rubisco from binding to oxygen during photorespiration.

Plants have a multicellular haploid stage called the gametophyte. Gametophytes () produce gametes () through mitosis, which combine to produce a zygote (). The zygote grows into a multicellular, diploid sporophyte (), which produces spores () through meiosis. Those spores give rise to multicellular gametophytes.

The chloroplast is believed to have evolved from photosynthetic bacteria that formed a mutualistic symbiotic relationship with an ancestor of plants through endosymbiosis. There is lots of evidence supporting the endosymbiotic theory, which is based on the principle of one organism phagocytosing another, resulting in mutualism.

Biotic pollinators, such as bees and hummingbirds, share a mutualistic relationship with angiosperms. This leads to co-evolution, in which the selective pressure of one species impacts the genetic composition of another. In this case, the preferences of the pollinators impact the reproductive success of specific angiosperms.

Cell walls were present in plant cells before the transition to land. Seeds, stomata, waxy cuticles, and vascular transport all evolved to reduce water loss and circulate water to all areas of the plant. Water loss and circulation were not an issue before the transition to land; plants were forced to adapt these traits in order to survive in a terrestrial environment.

Thylakoid membranes are found within chloroplasts, which are used for photosynthesis. Plants found in both aquatic and terrestrial environments photosynthesize, so these membranes cannot be considered adaptations uniquely benefiting terrestrial plants.

Comparatively, cutin is a waxy coating found on various parts of plants that helps prevent water loss when exposed to air. Stomata are tiny openings in the epidermis of plants that allow for the exchange of carbon dioxide and oxygen while minimizing water loss. Roots and root hairs allow plants to absorb nutrients and water from the soil. Water loss was the primary challenge plants faced when moving from aquatic to terrestrial environments; cutin, stomata, roots, and root hairs all help terrestrial plants absorb and conserve water.

Plants developed more rigid structures to help maintain their growth on land as opposed to water.

Waxy cuticles developed to help reduce water loss/desiccation. Roots allowed plants greater access to water, as well as provided anchoring to the ground; this allowed plants to grow taller. Vascular tissue facilitated transport of water and nutrients to all parts of the plant. Stomata helped with gas exchange.

The production of a true flower is one of the defining characteristics of an angiosperm. In fact, angiosperms are also called "flowering plants." Groups of plants that are not angiosperms (think ferns, ginkgos, or pine trees) can have roots and spores and are able to survive in aquatic environments and reproduce vegetative.

Both monocots and dicots are angiosperms which means that they both have true flowers. All of the other answer choices are true differences between monocots and dicots.

Angiosperms are flowering plants. They have both male and female reproductive organs.

The pistil is the female reproductive structure, and consists of three parts. The stigma is the sticky knob used to catch pollen. It is situated at the top of the style, while the ovary contains egg cells and is located below the style.

The stamen is the male reproductive structure, and consists of two parts. The anther produces pollen, and the filament helps in holding up the anther.

Angiosperms are a class of land plant that produces seeds. Angiosperms can be distinguished from gymnosperms by characteristics that include flowers, the presence of endosperm, and fruit production.

Angiosperm seeds are enclosed within ovaries, which prevent self-fertilization and allow for selective pollination.

Angiosperms have certain characteristics that distinguish them from gymnosperms including flowering organs, endosperm, and a reduced gametophyte stage. Additionally, angiosperms possess closed seeds that are surrounded by the ovary.

Bryophytes are nonvascular plants, such as mosses. Gametophytes are species that have haploid cells during their mature lives, while sporophytes are predominantly diploid during their adult phases.

Bryophytes have the gametophyte generation as dominant, with the sporophytes relying on the parental gametophyte. Starting with the evolution of seedless vascular plants, the gametophytes become reduced and are no longer the dominant life cycle. By the formation of angiosperms (seed plants), the gametophytes have become dependent on the parental sporophyte.

Swimming sperm is a feature of avascular and early vascular plants, who needed to remain in moist environments in order to retain water.

After gaining vascular systems, plants were able to circulate water and nutrients more efficiently, thus being able to grow larger, have more leaves, develop branched systems of roots and shoots to collect water and nutrients, and better dispersal of spores due to gains in size.

Pith is a type of tissue located in the stems of vascular plants. It stores and transports nutrients throughout the plant. The pith is composed of parenchyma cells.