Plant Biology - AP Biology

Carbon fixation, catalyzed by Rubisco, occurs during the first step of the light independent reaction.

Chloroplasts are the organelles that contains chlorophyll. Mitochondria produce ATP and are not directly involved in capturing light and photosynthesis. The Golgi apparatus is involved in packaging substances, and Smooth endoplasmic reticulum are involved in lipid production.

A stack of thylakoids is known as granum. Stroma is the region outside the thylakoid membranes, but still inside the chloroplast. Mitochondria is the organelle that produces ATP, and there is no such organelle called thylakoidum.

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.

Chlorophyll is what gives plants their green color. The chlorophyll located in the chloroplasts captures the light energy that drives the synthesis of food molecules in the chloroplasts—photosynthesis.

Chloroplasts are found mainly in the cells of the mesophyll, which is the tissue in the interior of the leaf. Stomata are the pores that allow carbon dioxide to enter and oxygen to exit the leaf. The stroma is the dense fluid content of the chloroplast.

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.

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.