AP Bio Mock

Researchers investigating the regulation of neurotransmitter release from presynaptic neurons proposed a model (Fig. 1) in which CDK5, a protein expressed in axon terminals, inhibits the movement of synaptic vesicles to the presynaptic membrane.

To test their model, the researchers used a modified version of green flourescent protein (GFP*). In slightly alkaline conditions, GFP* exhibits a bright green flourescence. In acidic conditions GFP* exhibits no flourescence. Using standard techniques, the gene encoding GFP* is easily introduced into living cells. By engineering the expression of GFP* in laboratory-cultured nerve cells, the researchers found that a bright green flourescence was exhibited only when a pre-synaptic neuron was given a certain stimulus.

Many human cells can be stimulated to divide by hormonelike growth factors that bind to receptor proteins (R) on the plasma membrane and trigger an internal signal-transduction cascade. In many cases, however, the process of contact inhibition prevents mitosis when cells are in direct contact with one another. Contact inhibition occurs when proteins called cell adhesion molecules (CAMs) interact, causing them to change shape so that the growth-factor signaling proteins that normally associate with CAMs are replaced by another protein, called M. Both pathways are depicted in the figures below.

Which of the following statements accurately uses the information presented to support the hypothesis that interruption of M function in a single body cell can result in cancer?

The following questions refer to the data in Figures 1 through 4 below, which were collected during a study of the growth of plant seedlings.

When the concentration of GA₁ is highest, the average height of the control seedlings is approximately

The endocrine system incorporates feedback mechanisms that maintain homeostasis. Which of the following demonstrates negative feedback by the endocrine system?

Which of the following diagrams best represents hormone-activated gene expression?

Which of the following representations best shows a portion of an axon at rest (before or after an action potential)?

Human papillomavirus can cause cervical cancer. The virus itself produces a protein called E6. E6 is a protein that binds p53, which is a protein produced by a common tumor supressor gene.

Based on this fact and what you know about tumor suppressor genes, what effect do you think E6 binding has?

In the diagram above, notice that cyclin levels CYCLE (get the name now?), and MPF (maturation promoting factor, a specific name of a cyclin/CDK complex) follows the same pattern. When cyclin levels are high, MPF activity is high, and vice versa. The height of activity peaks at M phase. This tells us that the role of this active complex is to move through M phase, and then cyclin levels, and MPF activity levels, drop off quickly after that.

Given all this information, what do you know about associated CDK levels during the time shown on this graph?

The figure shows the absorption spectrum for chlorophyll a and the action spectrum for photosynthesis. Halobacterium has a photosynthetic membrane that appears purple. Its photosynthetic action spectrum is the inverse of the action spectrum for green plants. (That is, the Halobacterium action spectrum has a peak where the green plant action spectrum has a trough.) What wavelengths of light do the Halobacterium photosynthetic pigments absorb?

The water molecules in the diagram are attracted to the cell walls of water-conducting cells by adhesion due to hydrogen bonds. What conclusion is supported by this information?

Which molecule has both hydrophilic and hydrophobic properties and is found in plasma membranes?

Enzymes that break down DNA catalyze the hydrolysis of the covalent bonds that join nucleotides together, as opposed to separating hydrogen bonds. What would happen to DNA molecules treated with these enzymes?

Use the following fisgure to answer the question.

Based on your knowledge of the polarity of water molecules, the solute molecule 'A' depicted is most likely ________.

Hydrophobic substances such as vegetable oil are _____.

Use the following figure to answer the question.

The molecule illustrated in the figure ________.

Which statement is supported by the diagram?

A potted plant is placed inside a clear, sealed vacuum container where no gases can get inside. The container has water pumped into it on a regular basis. The container is placed in the sun and the plant's growth is monitored. Which statement best describes what will most likely happen to the plant over time?

Which of the following is the most common pathway taken by a newly synthesized protein that will be secreted by a cell?

Gaucher disease is the most common of lipid storage diseases in humans. It is caused by a deficiency of an enzyme necessary for lipid metabolism. This leads to a collection of fatty material in organs of the body including the spleen, liver, kidneys, lungs, brain, and bone marrow. Using your knowledge of the structure of eukaryotic cells, identify the statement below that best explains how internal membranes and the organelles of cells would be involved in Gaucher disease.

The Rough Endoplasmic Reticulum (RER) is characterized by ribosomes bound to its surface, while the Smooth Endoplasmic Reticulum (SER) lacks them. This structural difference accounts for which primary functional distinction between the two?

You have a cube of modeling clay in your hands. Which of the following changes to the shape of this cube of clay will decrease its surface area relative to its volume?

Two test tubes were filled with a solution of bromothymol blue. A student exhaled through a straw into each tube, and the bromothymol blue turned yellow. An aquatic green plant was placed into each tube, and the tubes were corked. One tube was placed in the dark, and one was placed in direct sunlight. The yellow solution in the tube in sunlight turned blue, while the one in the dark remained yellow.

Which statement best explains why the solution in the test tube placed in sunlight returned to a blue color?

A weightlifter is using heavy weights in short bursts for a competition. Because his muscle cells are not able to take enough oxygen to make very much ATP the weightlifter begins to get fatigue in his muscles.

Which of the following processes is most likely going on in the muscles of the weightlifter as he competes in his event?

Under which conditions is enzyme A most productive?

Which of the following is true?

A group of AP Biology students is testing the effect of the amount of peroxidase enzyme on oxygen production. In cells, peroxidase breaks down hydrogen peroxide into water and oxygen gas. Identify an appropriate control group for this experiment.

Use the following passage and data tables to answer the following question

Students investigated the effect of light on the carbon cycle in aquatic ecosystems by performing the controlled experiment summarized below.

The students placed equal amounts of water (pH 7) from a large aquarium in glass beakers. The students transferred aquatic plants from the aquarium to several of the beakers, and then they placed equal numbers of the beakers in the light or the dark (Figure 1: groups I and II). Similarly, the students transferred goldfish from the same aquarium to other beakers, and then they placed equal numbers of those beakers in the light or dark (*Figure 1: groups III and IV). Finally, the students placed an equal number of beakers containing water only in the light or dark (Figure 1: Groups V and VI).

After exposing the samples to light or dark for one hour, the students recorded the pH of the water in each beaker. Carbon dioxide dissolved in water will lower the pH of an aqueous solution. In the experiment, the students used changes in pH to monitor changes in the amount of Carbon dioxide in the water. For each treatment group, the students calculated the mean pH and standard error, as documented in the table below.

To investigate whether an organism in the study is capable of both photosynthesis and respiration, a comparison of which treatment groups is the most appropriate?

During aerobic cellular respiration, a proton gradient in mitochondria is generated by ____ and used primarily for ____.

Glycolysis is considered ancient, one of the first metabolic pathways to evolve because

In anaerobic respiration glycolysis is followed by fermentation – the conversion of pyruvate to alcohol or lactic acid. The purpose of this step is to allow the cell to

Tortoises on one island had short legs to better move on rocky land. Tortoises on another island had longer legs to move through grass. Which statement best summarizes this information?

A student conducts an experiment to test how reptiles’ skin color affects survival rate. She places 100 green lizards and 100 brown lizards in a marked area in a forest. After 10 days she returns to count how many lizards of each color survived. As a follow-up, she places 100 green lizards and 100 brown lizards in a desert. After 10 days she counts how many lizards of each color are alive. The # of surviving lizards is below. Which of the following statements could the student use as a conclusion to her experiment?

Male frigate birds are black with red skin at the throat. During courtship, the male forces air into the red sac, causing it to inflate. If the display is attractive enough, then the female will land beside the male to mate. Male frigate birds that don’t have an attractive red throat will be less likely to reproduce. What term best describes the male frigate bird’s red throat color?

Natural Selection is usually simplified to the phrase "Survival of the Fittest." A better term might be "Differential Reproductive Success." With that in mind, which of the following examples would be considered the most fit individual?

A cymothoid isopod lives inside the mouth of a snapper fish. The isopod severs blood vessels in the fish’s tongue, causing the tongue to atrophy and degenerate. The isopod then hooks its pereopods, or legs, to the base of the fish’s tongue, essentially replacing the tongue. The isopod stays there for the rest of its life, feeding on blood, mucus, and stray pieces of food from the fish.

What type of symbiotic relationship is this?

In a species of plant, flower color is controlled by a single gene exhibiting incomplete dominance. Homozygous dominant plants produce red flowers, homozygous recessive plants produce white flowers, and heterozygotes produce pink flowers. In a population of 500 plants in Hardy-Weinberg equilibrium, there are 45 white-flowered plants. Approximately how many pink-flowered plants are expected in this population?

A student investigates the effects of varying sucrose concentrations on potato cores. The student determines that the initial water potential (Ψ) of the potato cells is -0.4 MPa. The cores are then placed in an open beaker containing a 0.3 M sucrose solution at 27°C (300 K). The solute potential equation is Ψs = -iCRT, where the pressure constant R is 0.00831 L MPa / mol K. Based on this data, which of the following correctly predicts the movement of water and the resulting effect on the potato cores?

Dinitrophenol (DNP) is a chemical that acts as an uncoupling agent, making the inner mitochondrial membrane highly permeable to protons (H+). DNP was once prescribed as a weight-loss drug in the 1930s until it was found to be fatally toxic. If a patient ingests a dangerous dose of DNP, which of the following would most likely occur at the cellular level?

In a certain mutant strain of E. coli, a nonsense mutation occurs in the regulatory gene (lacI) of the lac operon, resulting in a truncated, nonfunctional repressor protein that cannot bind to the operator region. How will this mutation directly affect the expression of the lac operon structural genes (lacZ, lacY, lacA)?

A researcher creates an isolated suspension of chloroplasts in a buffer solution and exposes them to a light source of 680 nm. After 30 minutes, the researcher observes that oxygen gas is actively being produced, but no G3P (sugars) are being synthesized. Which of the following is the most likely explanation for this observation?

In a marine ecosystem along the Pacific coast, giant kelp is the primary producer, sea urchins are the primary consumers, and sea otters are the secondary consumers that keep the urchin population in check. Recently, transient orcas (apex predators) have begun preying heavily on the sea otters due to a decline in their usual prey. Which of the following best describes the likely cascading ecological effect of the orcas' new dietary preference?

A diploid eukaryotic organism has a normal somatic chromosome number of 2n = 12. During spermatogenesis, a non-disjunction event occurs during Meiosis I involving exactly one pair of homologous chromosomes. Meiosis II proceeds normally. What will be the chromosome numbers in the four resulting sperm cells?

A microbiologist discovers a new bacterial toxin that specifically binds to and blocks the A site (aminoacyl site) of the bacterial ribosome. Which of the following steps of translation would be directly inhibited by the introduction of this toxin?

Which statement could explain the data shown in the graph?