1. Membrane-bound organelles have been an important component in the evolution of complex, multicellular organisms. Which of the following best summarizes an advantage of eukaryotic cells having internal membranes?
(A) Eukaryotic cells are able to reproduce faster because of the presence of organelles.
(B) Some organelles, such as mitochondria and chloroplasts, are similar to prokaryotic cells in structure.
(C) Organelles isolate specific reactions,increasing metabolic efficiency.
(D) Compartmentalization leads to a higher mutation rate in DNA, which leads to more new species.
2. By discharging electric sparks into a laboratory chamber atmosphere that consisted of water vapor, hydrogen gas, methane, and ammonia,Stanley Miller obtained data that showed that a number of organic molecules, including many amino acids, could be synthesized. Miller was attempting to model early Earth conditions as understood in the 1950s. The results of Miller’s experiments best support which of the following hypotheses?
(A) The molecules essential to life today did not exist at the time Earth was first formed.
(B) The molecules essential to life today could not have been carried to the primordial Earth by a comet or meteorite.
(C) The molecules essential to life today could have formed under early Earth conditions.
(D) The molecules essential to life today were initially self-replicating proteins that were synthesized approximately four billion years ago.
3. Simple cuboidal epithelial cells line the ducts of certain human exocrine glands. Various materials are transported into or out of the cells by diffusion. (The formula for the surface area of a cube is 6*S2, and the formula for the volume of a cube is S3, where S = the length of a side of the cube.)Which of the following cube-shaped cells would be most efficient in removing waste by diffusion?
4. The area covered by tropical rain forest is reduced by millions of hectares per year due to agriculture and logging. Which of the following best describes a likely result of tropical rain forest deforestation?
(A) Populations of plants and animals will decrease as more rain forest disappears,leading to a decrease in biodiversity.
(B) An increase of soil moisture will lead to a rapid increase in new vegetation coverage.
(C) An increase in atmospheric carbon dioxide will lead to higher levels of ultraviolet radiation reaching the surface of Earth.
(D) More oxygen will be available to other organisms as plant numbers decrease.
5. Which of the following statements best supports the claim that organisms share fundamental processes as a result of evolution?
(A) All organisms that are introduced into new environments have the capacity to fill vacant ecological roles.
(B) All organisms have the ability to utilize oxygen to harness energy from the chemical breakdown of organic compounds.
(C) All organisms share a genetic code organized into triplet codons, making it possible for one organism to express a gene from another organism.
(D) All organisms possess structures such as chloroplasts and mitochondria within their cells that reflect past symbiotic relationships between prokaryotic precursors.
6. When DNA replicates, each strand of the original DNA molecule is used as a template for the synthesis of a second, complementary strand.Which of the following figures most accurately illustrates enzyme-mediated synthesis of new DNA at a replication fork?
1. In a certain prairie community, a dominant prairie grass species has recently been infected with a virus that disrupts one of the electron transport proteins in the chloroplasts of infected cells.
(a) Describe the most likely effects on cellular processes (be specific as to which processes and molecules are most likely to be directly affected).
(b) Describe and explain the most likely effects on individual infected plants.
(c) Predict the short-term effects (within a year of infection) on the infected plant populations and their communities. Justify your prediction.
(d) Predict the long-term effects (years to decades after infection) on the infected plant populations and their communities. Justify your prediction.
2. Plants lose water from their aboveground surfaces in the process of transpiration. Most of this water is lost from stomata, microscopic openings in the leaves. Excess water loss can have a negative effect on the growth,development, and reproduction of a plant. Severe water loss can be fatal. Environmental factors have a major impact on the rate of plant transpiration.
(a) Using the data above and the axes provided, draw a graph showing the effect of temperature change on the rate of transpiration. Explain the shape of the curve from 23 degrees to 28 degrees.
(b) Humidity is another environmental factor that affects transpiration rate. Using the axes provided, draw a curve that illustrates what you predict would be the rate of transpiration with increasing humidity and constant temperature. Justify the shape of the curve based on your prediction.
(c) The curve below illustrates the rate of transpiration related to the percent of open stomata on the leaf of a particular plant. Explain why the curve levels off with increasing percentage of open stomata per area of the leaf.
(d) The data below show the density of stomata on the leaf surfaces of three different species of plants.Describe the environments in which each plant most likely evolved. Justify your descriptions.
Graph for part (a) showing the effect of temperature on the rate of transpiration.
Graph for part (b) showing the predicted effect of humidity on the rate of transpiration.