AP BIO TEST UNIT 3

blue, violet

A plant has a unique photosynthetic pigment. The leaves of this plant appear to be reddish yellow. What wavelengths of visible light are being absorbed by this pigment?

Elysia chlorotica grows when exposed to light in the absence of other food sources.

A scientist claims that Elysia chlorotica, a species of sea slug, is capable of photosynthesis. Which of the following observations provides the best evidence to support the claim?

For each glucose molecule consumed, more ATP will be formed.

A tissue culture of vertebrate muscle was provided with a constant excess supply of glucose under anaerobic conditions starting at time zero and the amounts of pyruvic acid and ATP produced were measured. The solid line in the graph above represents the pyruvic acid produced in moles per liter per minute. ATP levels were also found to be highest at points A and C, lowest at B and D. A second culture was set up under the same conditions, except that substance X was added, and the results are indicated by the dotted line. Question Which of the following is most likely to result if oxygen is added to the tissue culture?

- phosphorylation of 2 ADP to 2 ATPS - reduction of NAD+ to NADH which is used in electron transport change to create proton gradient - as protons flow with gradient across membrane, they drive ATP synthase which phosphorylates ADP to ATP

Cellular respiration includes the metabolic pathways of glycolysis, the Krebs cycle, and the electron transport chain, as represented in the figures. In cellular respiration, carbohydrates and other metabolites are oxidized, and the resulting energy-transfer reactions support the synthesis of ATP. Question Using the information above, describe ONE contribution of each of the following in ATP synthesis. -Catabolism of glucose in glycolysis and pyruvate oxidation -Oxidation of intermediates in the Krebs cycle -Formation of a proton gradient by the electron transport chain

2-phosphoglycerate

Certain chemicals, including sodium fluoride (NaF), are capable of inhibiting specific steps of glycolysis. Figure 1 shows the steps of the glycolysis pathway, indicating where various macromolecules enter the pathway as well as the specific reaction inhibited by NaF. If NaF is added to cells undergoing cellular respiration, which of the following will most likely accumulate in the cells? FLIPNEXT

protons down a concentration gradient

During respiration, most ATP is formed as a direct result of the net movement of

Temperature: Raising temperature generally speeds up a reaction, and lowering temperature slows down a reaction. However, extreme high temperatures can cause an enzyme to lose its shape (denature) and stop working Ph: Enzymes are also sensitive to pH . Changing the pH of its surroundings will also change the shape of the active site of an enzyme.

Identify TWO environmental factors the impact enzymatic activity and explain their effect in enzymatic reactions.

inability to grow, repair tissues, plants weakening or dying because every demands cannot be met

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. Question Describe and explain the most likely effects on individual infected plants

The additional pigments allow the species containing them to harvest energy from wavelengths of light that the other photosynthetic species cannot use.

In addition to the pigments commonly associated with photosynthesis, a certain photosynthetic species contains two additional pigment types. Which of the following best supports the claim that this species is better adapted to environmental changes than other photosynthetic species are?

No ATP is synthesized when channel proteins that allow the free passage of protons are inserted into the thylakoid membrane.

In chloroplasts, ATP is synthesized from ADP plus an inorganic phosphate (Pi) in a reaction catalyzed by ATP synthase molecules that are embedded in the thylakoid membrane. Which of the following statements provides evidence to support the claim that no ATP will be synthesized in the absence of a proton gradient across the thylakoid membrane?

Increase in lactate levels are due to fermentation/anaerobic metabolism

Many aquatic animals can hold their breath and dive underwater for long periods of time. During long dives, lactic acid builds up in tissues of the organism. The graph above shows blood lactate levels following dives of different duration for three species. Lactate is produced when lactic acid is dissolved in the blood and becomes ionized. Question Based on the data, propose a hypothesis to explain the change in blood lactate levels in Weddell seals for dives lasting longer than 20 minutes.

Fewer protons are pumped across the inner mitochondrial membrane when FADH2 is the electron donor than when NADH is the electron donor

On average, more ATP can be produced from an NADH molecule than can be produced from a molecule of FADH2. Based on the figure, which of the following best explains the difference in ATP production between these two molecules?

necessary for ATP synthesis by oxidative phosphorylation (ETC and chemiosmosis)

Oxygen consumption can be used as a measure of metabolic rate because oxygen is...

The mitochondrial matrix

Pyruvate dehydrogenase is an enzyme that converts pyruvate to acetyl-CoA. Acetyl-CoA is further metabolized in the Krebs cycle. A researcher measured the accumulation of acetyl- CoA in a reaction containing pyruvate and pyruvate dehydrogenase under several different conditions (Figure 1). Which of the following best describes the cellular location where pyruvate dehydrogenase is most likely active?

Alanine binds to an allosteric site of the enzyme, changing the shape of the enzyme's activity site.

Pyruvate kinase, a key enzyme in the glycolysis pathway, is inhibited by the amino acid alanine. The ability of alanine to inhibit the enzyme is not affected by increasing the concentration of substrate. Which of the following best explains the mechanism by which alanine inhibits pyruvate kinase activity?

Treated cells are not able to break down NADH because certain enzymes of the electron transport chain are inhibited.

Scientists were interested in testing the effects of rotenone, a broad-spectrum pesticide, on a cell culture. Cell culture A was used as a control, while culture B was treated with rotenone. After a period of time, the scientists measured the concentration of several metabolites. Based on the data in the table, which of the following best explains the effects of rotenone on cellular respiration in the mitochondria of cells in both cultures. Their results are shown in the table below.

(a) It excites the electron that will flow downhill. (b) A positive control will be used as standard. This is the plant of same species having normal growth. This help to compare the effect of mutant plant with normal plant. (c) A plant having different pigment molecules have a wider excess of spectrum. This help the plant to take more energy to grow.

The chloroplasts of flowering land plants typically contain at least two photosynthetic pigments, chlorophyll a and chlorophyll b, that differ in the wavelengths of light they absorb. The synthesis of chlorophyll pigments from precursor molecules is a process that involves many sequential enzyme-catalyzed steps. Researchers studied the growth and photosynthetic ability of a plant that contained a mutant form of one of the enzymes required for chlorophyll biosynthesis. (a) Describe the effect on chlorophyll-containing photosystems when the chlorophyll molecules absorb photons of light. (B)Identify an appropriate control that the researchers should use when they study the growth and photosynthetic ability of the plant with the mutant enzyme. (c) Scientists claim that a plant that has more than one type of photosynthetic pigment has greater fitness than a plant that has only one type of photosynthetic pigment. Provide reasoning to justify this claim

ATP and NADPH

The energy required to run the Calvin cycle reactions of photosynthesis comes from which two substances produced during the light-dependent reactions?

The inner membrane has specialized proteins that create a hydrogen ion concentration gradient between the intermembrane space and the matrix.

The figure shows an organelle typically found in eukaryotic cells. Which of the following best describes the function of the double membrane system of this organelle?

Do electron transport chains create a gradient so that ATP synthase can generate ATP molecules?

The figures below illustrate the similarities between ATP synthesis in mitochondria and chloroplasts. The figures can best assist in answering which of the following questions?

65 micromoles/sec

The maximum production rate of acetyl-CoA under condition 1 is closest to which of the following?

pH affects the shape of the active site of the enzyme

The most likely explanation for the results shown in Graph I is that

Light-Dependent reactions

The process in which O2 is released as a by-product of oxidation-reduction reactions is

The higher substrate concentrations in the more concentrated solutions sped up the reaction.

To study the actions of the enzyme catalase on hydrogen peroxide, students performed the following experiment. Catalase was extracted from potatoes by blending raw potatoes in a blender with cold distilled water. The filtrate was stored on ice. The following hydrogen peroxide solutions were made: 1 percent, 5 percent, 10 percent, and 15 percent. Filter paper disks were soaked in the catalase filtrate and dropped into beakers containing the various solutions. The activity of the enzyme was measured by the amount of time it took for the disks to float to the surface of the solution on the bubbles produced by the reaction. The following data were obtained. Which of the following best describes why the disks rose to the surface faster in the more concentrated hydrogen peroxide solutions?

14C-labeled CO2, because atmospheric carbon is fixed to carbohydrates by photosynthesis

To test the hypothesis that a particular plant synthesizes storage lipids by using glyceraldehyde 3-phosphate (G3P) from photosynthesis, a researcher plans to use radiolabeled precursors to track the molecules through the biosynthetic pathway. Which of the following radiolabeled precursors is most appropriate for the researcher to use?

Pepsin works in the stomach because the optimal pH for pepsin is acidic.

Trypsin and pepsin are enzymes that function in different areas of the digestive tract. One functions in the stomach, where the pH is between 1.5 and 3.5 (acidic), while the other functions in the small intestines, where the pH is between 6 and 8. Based on the figure, which of the following best describes where each enzyme functions?

The rate of proton pumping across the inner mitochondrial membrane is lower in the sample without oxygen.

Two nutrient solutions are maintained at the same pH. Actively respiring mitochondria are isolated and placed into each of the two solutions. Oxygen gas is bubbled into one solution. The other solution is depleted of available oxygen. Which of the following best explains why ATP production is greater in the tube with oxygen than in the tube without oxygen?

Photosynthesis produces more oxygen than is consumed by respiration during the day.

What most likely causes the trends in oxygen concentration shown in the graph above?

Glycolysis

Which metabolic process is common to both aerobic cellular respiration and alcoholic fermentation?

ATP and NADPH

Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin Cycle?

A buildup of lactic acid in the muscle tissue due to fermentation

Which of the following describes a metabolic consequence of a shortage of oxygen in muscle cells?

The light-dependent reactions produce ATP and NADPH; the light-independent reactions use energy stored in ATP and NADPH.

Which of the following is an important difference between light-dependent and light-independent reactions of photosynthesis?

CO2 + H20 + light --> C6H12O6 + O2

Which of the following is the correct equation for photosynthesis?

Is the phosphorylation of ADP by ATP synthase dependent on the formation of a proton gradient?

Which of the following questions will best direct an investigation of the mechanism of ATP synthase?

FADH2

Which of the following transfers electrons from the Krebs cycle to the mitochondrial electron-transport chain at a lower energy level than that of electrons entering at the beginning of the chain

(b) Enzymes speed up chemical reactions but can only do so efficiently in specific environments. One of these environmental factors is temperature. In this experiment, cellular respiration was most effective at 30 degrees Celsius, indicating that it is the enzyme's ideal temperature. As the temperature of the experiment falls from 30 degrees, the efficiency of the enzyme decreases due to slowed enzyme and substrate molecules, which collide less. As the temperature of the experiment increases past 30 degrees, the efficiency of the enzymes decreases due to the denaturing of the enzyme at hot temperatures. (c) Yeast cells are placed in an apparatus with a solution of sugar (a major nutrient for yeast metabolism). The apparatus detects bubbles of gas released by the yeast cells. Repeat this set up five times. Use one apparatus as a control and do not apply any treatment. Vary the pH of the other sugar solutions by adding vinegar for a more acidic solution and by adding baking soda for a more basic solution. After every minute for 12 minutes, count how many bubbles are produced in order to approximate the ideal pH level for respiration. I predict that the ideal pH level is 7 because the cells in the human body have a pH around 7 and enzymes have adapted to fit work efficiently at this pH level in order for cellular respiration to take place.

Yeast cells are placed in an apparatus with a solution of sugar (a major nutrient for yeast metabolism). The apparatus detects bubbles of gas released by the yeast cells. The rate of respiration varies with the surrounding temperatures as indicated by the data below. A) Graph the results on the axes provided. Determine the optimum temperature for respiration in the yeast B) Respiration is a series of enzyme-catalyzed reactions. Using your knowledge of enzymes and the data above, analyze and explain the results of this experiment. C)Design an experiment to test the effect of varying the pH of the sugar solution on the rate of respiration. Include a prediction of the expected results.