1. A dog is following the scent of a jackrabbit.Which of the following accurately describes how the dog’s brain integrates information for smell?
(A) Chemoreceptors in the brain send impulses for smell in the nasal cavity.
(B) Chemoreceptor cells in the nasal cavity send impulses to the appropriate area of the brain.
(C) Chemoreceptors on epithelial cells of the tongue send hormones to the appropriate area of the brain.
(D) Receptors originating in the nose send action potentials to the motor regions of the brain.
2. Thrips are insects that feed on rose pollen. Scientists noted that the thrips population increased in the spring and decreased dramatically during the summer. The researchers hypothesized that food abundance was the limiting factor for the population. Which of the following types of data would be most useful for the scientists to collect at regular intervals on a designated test plot of rose plants?
(A) Amount of sunlight (hours/day)
(B) Mean temperature (°C)
(C) Density of rose pollen produced (g/m2)
(D) Amount of pollen produced by each flower (g/flower)
3. If ATP breakdown (hydrolysis) is inhibited,which of the following types of movement across cell membranes is also inhibited?
(A) Movement of oxygen into a cell
(B) Movement of water through aquaporins
(C) Passage of a solute against its concentration gradient
(D) Facilitated diffusion of a permeable substance
4. Undersea landslides can disrupt marine habitats by burying organisms that live on the ocean floor.The graph above shows the size of a population of a certain organism that lives on the ocean floor.The population was affected by a recent landslide at the time indicated on the graph. Which of the following best predicts how the population will be affected by the landslide?
(A) The surviving organisms will evolve into a new species.
(B) The reduced population will likely have allelic frequencies that are different from the initial population.
(C) The population will adapt to deeper waters to avoid future landslides.
(D) The reduced population will have a greater number of different genes than the initial population.
5. Which of the following questions is most relevant to understanding the Calvin cycle?
(A) How does chlorophyll capture light?
(B) How is ATP used in the formation of 3-carbon carbohydrates?
(C) How is NADP+ reduced to NADPH?
(D) How is ATP produced in chemiosmosis?
6. Rosalind Franklin’s x-ray diffraction images taken in the 1950s most directly support which of the following claims about DNA?
(A) The ratios of base pairs are constant.
(B) The nucleotide sequence determines genetic information.
(C) The two strands of DNA are antiparallel.
(D) The basic molecular structure is a helix.
1. In an investigation of fruit-fly behavior, a covered choice chamber is used to test whether the spatial distribution of flies is affected by the presence of a substance placed at one end of the chamber. To test the flies’ preference for glucose, 60 flies are introduced into the middle of the choice chamber at the insertion point indicated by the arrow in the figure above. A cotton ball soaked with a 10% glucose solution is placed at one end of the chamber, and a dry cotton ball with no solution is placed at the other end. The positions of flies are observed and recorded every minute for 10 minutes.
(a) Predict the distribution of flies in the chamber after 10 minutes and justify your prediction.
(b) Propose ONE specific improvement to each of the following parts of the experimental design and explain how the modification will affect the experiment.
(c) The experiment described above is repeated with ripe bananas at one end and unripe bananas at the other end. Once again the positions of the flies are observed and recorded every minute for 10 minutes. The positions of flies after 1 minute and after 10 minutes are shown in the table below.
Perform a chi-square test on the data for the 10-minute time point in the banana experiment. Specify the null hypothesis that you are testing and enter the values from your calculations in the table below.
(d) Explain whether your hypothesis is supported by the chi-square test and justify your explanation.
(e) Briefly propose a model that describes how environmental cues affect the behavior of the flies in the choice chamber.
2. An absorption spectrum indicates the relative amount of light absorbed across a range of wavelengths. The graphs above represent the absorption spectra of individual pigments isolated from two different organisms. One of the pigments is chlorophyll a, commonly found in green plants. The other pigment is bacteriorhodopsin, commonly found in purple photosynthetic bacteria. The table above shows the approximate ranges of wavelengths of different colors in the visible light spectrum.
(a) Identify the pigment (chlorophyll a or bacteriorhodopsin) used to generate the absorption spectrum in each of the graphs above. Explain and justify your answer.
(b) In an experiment, identical organisms containing the pigment from Graph II as the predominant lightcapturing pigment are separated into three groups. The organisms in each group are illuminated with light of a single wavelength (650 nm for the first group, 550 nm for the second group, and 430 nm for the third group). The three light sources are of equal intensity, and all organisms are illuminated for equal lengths of time. Predict the relative rate of photosynthesis in each of the three groups. Justify your predictions.
(c) Bacteriorhodopsin has been found in aquatic organisms whose ancestors existed before the ancestors of plants evolved in the same environment. Propose a possible evolutionary history of plants that could have resulted in a predominant photosynthetic system that uses only some of the colors of the visible light spectrum.