AP Biology Unit 3 Hager
FRQ 1: Polyphenel oxidase activity Based on the experimental results, estimate the optimal pH of the enzyme. Explain your estimate by connecting the experimental results to the structure and function of proteins
(1) 7, or between 5 and 9 (2) Highest absorbance amount at that pH value while others were lower (3)denatures/alters shape of the enzyme and reduces its activity; alters the structure of the enzyme's active site and reduces its activity
FRQ 3: Photosynthetic rates of shrubs b) Construct an appropriately labeled graph to represent the data
-use title of table as title of graph -x-axis: Photosynthetic Photon Flux Density -y-axis: Net Leaf Photosynthesis -plot line graph
An experiment to measure the rate of respiration in crickets and mice at 10 C and 25 C was performed using a respirometer, an apparatus that measures changes in gas volume. Respiration was measured in mL of O2 consumed per gram of organism over several five-minute trials, and the following data were obtained. [graph of mouse/ cricket data at 10 & 25 degrees]. According to the data, the mice at 10 C demonstrated greater oxygen consumption per gram of tissue than did the mice at 25 C. This is most likely explained by which of the following statements?
A) The mice at 10 C had a higher rate of ATP production than the mice at 25 C
Which of the following statements best helps explain the reaction specificity of an enzyme?
C) The shape and charge of the substrates are compatible with the active site of the enzyme.
ATP serves as a common energy source for organisms because
C) its energy can be easily transferred to do cellular work
[table with hydrogen peroxide solution % and disk floating time] Which of the following best describes why the disks rose to the surface faster in the more concentrated hydrogen peroxide solutions?
D) The higher substrate concentrations in the more concentrated solutions speeded the reaction.
According to the chemiosmotic theory (chemiosmotic coupling), the energy required to move protons from the mitochondrial matrix to the intermembrane space against a concentration gradient comes most directly from
D) electrons flowing along the electron transport chain
FRQ 3: Photosynthetic rates of shrubs c) Based on the data, identify the shrubs and data point where the greatest flow of electrons through chloroplast electron transport chains most likely occurs.
Greatest flow most likely occurs in full-sun shrubs at photosynthetic photon flux density of 1,500 since photosynthesis is conducted through the passage of ETC
FRQ 3: Photosynthetic rates of shrubs a) Describe how plants absorb photons of light energy
plants contain pigments such as chlorophyll that absorb photons of light (of certain wavelength) during photosynthesis
Which of the following questions is most relevant to understanding the Calvin cycle?
*May be wrong D) How is ATP produced in chemiosmosis? B) How is ATP used in the formation of 3-carbon carbohydrates
Which of the following statements is true about the Krebs (citric acid) cycle and the Calvin (light-independent) cycle?
*may be wrong B) They both require a net input of ATP. E) They both are carried out by enzymes located within an organelle matrix.
FRQ 2: solar-powered food web Discuss the flow of energy from producers through top carnivores in a food web in terms of the laws of thermodynamics
1st law= heat is form of energy, is converted, not created nor destroyed -1st law illustrated as conversion of solar energy to chemical energy or as conversion of chemical energy to chemical energy (e.g., Glucose to ATP) 2nd law=energy is transferred or transformed, more and more of it is wasted. -10 percent rule/Not all energy transferred to next level/Very little energy transferred to next level/energy lost at each level - Explanation of energy loss (e.g., used in metabolism, locomotion, etc.) -Lost energy as heat/entropy/2nd law illustrated as heat loss or inefficiency -Energy pyramid (explained) *More energy at producer level than at consumer levels *Scarcity of energy at higher trophic levels *Limited number of consumer levels • Very few top carnivores
The following questions refer to an experiment that is set up to determine the relative volume of O2 consumed by germinating and nongerminating (dry) pea seeds at two different temperatures. The change in volume is detected by using a respirometer over a given period of time. The data are given below. [graph of germinating and nongerminating peas at 10 and 26 degrees] The rate of oxygen consumption in germinating pea seeds at 26ºC is
A) 0.05 mL / min
The energy required to run the Calvin cycle reactions of photosynthesis comes from which two substances produced during the light-dependent reactions?
A) ATP and NADPH
Butterflies of the genus Colias live in the Rocky Mountains, where they experience a wide range of temperatures. Different variants of a particular glycolytic enzyme in the flight muscles are optimally active at different temperatures. Within the same population, some individual butterflies fly most effectively at 29°C , while others fly most effectively at 40°C. Still others can be equally active at both temperatures. Which of the following claims is most consistent with the observed butterfly behavior?
A) Butterflies that express two variants of the enzyme are active over a greater range of temperature.
The diagram below shows energy changes in a specific chemical reaction with and without the addition of an enzyme to the reaction. [graph of energy and progress of reactions]
A) Does the addition of an enzyme reduce the activation energy required for a reaction?
A respirometer is a container used to measure the amount of oxygen consumed by an organism. A respirometer was used to determine how environmental temperature affects the uptake of oxygen in one 300-gram rat and one 50-gram mouse. The results of this experiment are shown on the graph below. [graph of mouse and rat at 12 and 20 degrees] Which of the following hypotheses is best supported by the results of this experiment?
A) Metabolic rate per gram of tissue is higher in smaller mammals.
A researcher claims that some bacteria contain factors that influence the function of a particular enzyme but other bacteria do not. To test the claim experimentally, the researcher will grow two different bacterial strains in separate liquid cultures and isolate the contents of the cells in each culture. The researcher will add different combinations of cellular contents, substrate, and enzyme to test tubes containing a buffer solution adjusted to the optimal pH of the enzyme and then measure the rate of product formation. The design of the researcher's experiment is presented in Table 1. [table with test tubes, cellular contents, substrate, and enzyme] Which of the following statements best justifies the inclusion of test tubes 3 and 7 in the experiment?
A) They will show whether the isolated cellular contents have enzymatic activity.
The reactions of glycolysis occur in the
A) cytosol
Which metabolic process is common to both aerobic cellular respiration and alcoholic fermentation?
B) Glycolysis
The O2 released during photosynthesis comes from
B) H2O
[image of ATP synthase] Which of the following questions will best direct an investigation of the mechanism of ATP synthase?
B) Is the phosphorylation of ADP by ATP synthase dependent on the formation of a proton gradient?
A researcher claims that increasing the environmental temperature by 10°C will double the rate of an enzyme-catalyzed reaction. To test the claim, the researcher designs an experiment that uses a particular enzyme isolated from plants. The design of the experiment is presented in Table 1. For each test tube in the experiment, the researcher will measure the rate of product formation. [graph of test tubes, temperature, substrate, enzyme, and boiling] Which of the following statements best helps justify the inclusion of test tube 5 as a control in the experiment?
B) It will provide a measurement of product formation in the presence of a denatured enzyme.
In most freshwater fish, nitrogenous waste is primarily excreted as ammonia, which is highly soluble in water and is toxic at low concentrations. In terrestrial mammals, ammonia is converted to urea before it is excreted. Urea is also highly soluble in water but is less toxic than ammonia at low concentrations. Which of the following best explains why freshwater fish do not convert ammonia to urea for excretion?
B) The dilution of ammonia by direct excretion into freshwater conserves energy
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. [table with hydrogen peroxide solution % and disk floating time] Which of the following best describes why ice was used during this experiment?
B) To retard the breakdown of the catalase
The carbon 'that makes up organic molecules in plants is derived directly from
B) carbon fixed in photosynthesis
Carbohydrate-synthesizing reactions of photosynthesis directly require
B) products of the light reactions
During respiration, most ATP is formed as a direct result of the net movement of
B) protons down a concentration gradient
FRQ 3: Photosynthetic rates of shrubs d) Predict the effect on shrubs growing in one area if they are treated with a compound that blocks electron flow through the electron transport chains of chloroplasts. Provide reasoning to justify your prediction.
Blocking electron flow prevents formation of the proton gradient required to produce ATP used for sugar production; shrub would subsequently wither and die.
In an experiment, a scientist isolates mitochondria from living cells and suspends them in two different buffered solutions. One solution is maintained at pH 4, while the other solution is maintained at pH 9. The scientist finds that mitochondria in the solution at pH 4 continue to produce ATP but those in the pH 9 solution do not. The results of the experiment can be used as evidence in support of which of the following scientific claims about mitochondrial activity?
C) ATP production in mitochondria requires a hydrogen ion gradient that favors movement of protons into the mitochondrial matrix.
If an individual with diabetes consumes food that is high in simple carbohydrates, blood-sugar levels can rise above normal levels. Which of the following questions would provide the best direction for a researcher who wanted to study the impact of abnormally high blood-sugar levels on cellular homeostasis in diabetics?
C) Does water move from cells into blood vessels more rapidly in diabetics than in nondiabetics when blood-sugar levels are higher than normal?
Amylase is a protein that catalyzes the conversion of starch to simple sugars. Amylase activity in an aqueous solution can be measured by using iodine as a starch indicator. A solution containing iodine and starch will have a dark-blue color, whereas a solution containing iodine but no starch will have a light-brown color. The color change of an iodine solution from dark blue to light brown can be used to measure the rate at which starch is converted to simple sugars. A student designs an experiment to investigate the effect of environmental pHpH on amylase function. The design of the experiment is presented in Table 1. [table of test tubes, pH, enzymes, and boiling] Which of the following statements best justifies the inclusion of test tube V as a control in the experiment?
C) It will show the color change that occurs in the absence of enzyme activity.
A researcher claims that different enzymes exhibit maximal function over different pH ranges. To test the claim, the researcher carries out an experiment that includes three different enzymes: pepsin, salivary amylase, and arginase. The results of the experiment are represented in Figure 1. [graph of 3 enzymes compared to each other] Which of the following actions will provide the most appropriate negative control for the experiment?
C) Repeating the experiment with denatured enzymes
A researcher claims that increased atmospheric carbon dioxide levels cause increased growth rates in plants. Which of the following statements best supports the researcher's claim?
D) Atmospheric carbon dioxide is the raw material for photosynthesis, which plants rely on for producing sugars and other organic compounds.
The enzyme hexokinase catalyzes the conversion of glucose to glucose-6-phosphate, which is an important step in glycolysis. The reaction involves the transfer of a phosphate group from ATP to glucose. Either a glucose molecule or a water molecule can fit in the active site of hexokinase. The presence of a water molecule in hexokinase's active site would result in the hydrolysis of ATP to ADP instead of the conversion of glucose to glucose-6-phosphate. Which of the following statements best helps explain the reaction specificity of hexokinase?
D) Glucose has the right shape and charge to cause hexokinase to undergo a structural change needed for catalysis, whereas water does not.
[graph of germinating and nongerminating peas at 10 and 26 degrees] Which of the following conclusions is best supported by the data?
E) In pea seeds an increase in temperature results in an increase in oxygen consumption.
Which of the following is an important difference between light-dependent and light-independent reactions of photosynthesis?
E) The light-dependent reactions produce ATP and NADPH; the light-independent reactions use energy stored in ATP and NADPH.
