All AP Biology Resources
Example Questions
Example Question #1 : Plant Evolution
What is a distinct feature of a C4 plant?
Closed stomata during the day
Carbon fixation
Light independent reactions
Bundle-sheath cells
Bundle-sheath cells
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.
Example Question #1 : Understanding Alternation Of Generations
Which of the following refers to the principle of alternation of generations in plants?
The need for external pollinators
A life cycle that includes a multicellular haploid stage
A life cycle which includes a unicellular haploid stage
Gamete-producing sporophytes
The differences between a tree and a seed
A life cycle that includes a multicellular haploid stage
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.
Example Question #802 : Ap Biology
How is it believed that plants first became photosynthetic?
A vacuole became specialized for photosynthesis
The origin of the chloroplast is still largely unknown
The chloroplast was a cluster of synthesized proteins, which evolved over time
An ancestor of modern plants internalized a photosynthetic prokaryote through phagocytosis
An ancestor of modern plants internalized a photosynthetic prokaryote through phagocytosis
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.
Example Question #1 : Plant Biology
Mutualistic relationships between angiosperms and biotic pollinators foster which of the following types of evolution?
Convergent evolution
Co-evolution
Speciation
Divergent evolution
Co-evolution
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.