AP Bio U3: Cellular Energetics
Describe the effect on the free energy of doubling the amount of enzyme.
no effect on free energy
Where did photosynthesis first evolve?
prokaryotic organisms
Where does the Calvin cycle take place?
stroma
Which structure is unaffected by denaturation?
Primary
Which process releases energy in glucose to form ATP, NADH, and pyruvate?
Glycolysis
What are the products of the light-dependent reactions of photosynthesis?
NADPH & ATP
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. 10º C: Mouse: 0.0518 mL O2/g/min Cricket: 0.0013 mL O2/g/min 25º C: Mouse: 0.0321 mL O2/g/min Cricket: 0.0038 mL O2/g/min During aerobic cellular respiration, oxygen gas is consumed at the same rate as carbon dioxide gas is produced. In order to provide accurate volumetric measurements of oxygen gas consumption, the experimental setup should include which of the following? a. A substance that removes carbon dioxide gas b. A plant to produce oxygen c. A glucose reserve d. A valve to release excess water
a. A substance that removes carbon dioxide gas
Which process does NOT require oxygen? a. Glycolysis b. Oxidative Phosphorylation c. Krebs Cycle d. Aerobic respiration
a. Glycolysis
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. 10º C: Mouse: 0.0518 mL O2/g/min Cricket: 0.0013 mL O2/g/min 25º C: Mouse: 0.0321 mL O2/g/min Cricket: 0.0038 mL O2/g/min 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. b. The mice at 10°C had a lower metabolic rate than the mice at 25°C. c. The mice at 25°C weighed less than the mice at 10°C. d. The mice at 25°C were more active than the mice at 10°C.
a. The mice at 10°C had a higher rate of ATP production than the mice at 25°C.
In order to maintain order and power cellular processes, a. energy input must exceed energy loss b. energy input equals energy loss c. energy loss must exceed energy input d. energy loss equals energy input
a. energy input must exceed energy loss
What is the function of the electron transport chain between Photosystem II and Photosystem I? a. establish electrochemical gradient of protons b. to funnel electrons into photosystem I for the Calvin cycle c. transport electrons to oxygen to make water d. to synthesize ATP using ATP synthase
a. establish electrochemical gradient of protons
A student placed 20 tobacco seeds of the same species on moist paper towels in each of two petri dishes. Dish A was wrapped completely in an opaque cover to exclude all light. Dish B was not wrapped. The dishes were placed equidistant from a light source set to a cycle of 14 hours of light and 10 hours of dark. All other conditions were the same for both dishes. The dishes were examined after 7 days and the opaque cover was permanently removed from dish A. Both dishes were returned to the light and examined again at 14 days. The following data were obtained. According to the results of this experiment, germination of tobacco seeds during the first week is a. increased by exposure to light b. unaffected by light intensity c. prevented by paper towels d. accelerated in green-leaved seedlings
a. increased by exposure to light
What is oxidation? a. loss of electrons b. loss of water c. gain of electrons d. gain of water
a. loss of electrons
Where on an enzyme does the substrate bind?
active site
Students in a class measured the mass of various living organisms. They then kept the organisms in the dark for 24 hours before remeasuring them. None of the organisms were provided with nutrients during the 24-hour period. The data are as follows. Elodea (submerged aquatic plant): 15.10g --> 14.01g Goldfish: 10.10g --> 9.84g Sea anemone: 25.60g --> 24.98g Which of the following is the best explanation for the pattern of change in mass of the organisms over time? a. Water loss due to evaporation b. Cellular respiration c. The law of conservation of matter d. Growth and reproduction
b. Cellular respiration
The chemical reaction for photosynthesis is 6 CO2 + 12 H2O + light energy → C6H12O6 + 6 O2 + 6 H2O If the input water is labeled with a radioactive isotope of oxygen, 18O, then the oxygen gas released as the reaction proceeds is also labeled with 18O. Which of the following is the most likely explanation? a. During the light reactions of photosynthesis, water is split, the hydrogen atoms combine with the CO2, and oxygen gas is released b. During the light reactions of photosynthesis, water is split, removing electrons and protons, and oxygen gas is released. c. During the Calvin cycle, water is split, regenerating NADPH from NADP+, and oxygen gas is released. d. During the Calvin cycle, water is split, the hydrogen atoms are added to intermediates of sugar synthesis, and oxygen gas is released.
b. During the light reactions of photosynthesis, water is split, removing electrons and protons, and oxygen gas is released.
Describe the pathway of electrons in the light reactions. a. H2O → PSI → ETC → PSII → NADPH b. H2O → PSII → ETC → PSI → NADPH c. H2O → PSII → ETC → PSI → NADH d. H2O → PSI → ETC → PSII → NADH
b. H2O → PSII → ETC → PSI → NADPH
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?
b. How is ATP used in the formation of 3-carbon carbohydrates?
It is estimated that oxygen production first evolved in photosynthetic prokaryotes approximately 2.7 billion years ago. The first photosynthetic prokaryotes are presumed to be similar to today's cyanobacteria. Which of the following best supports the claim that photosynthetic prokaryotes were responsible for the oxygen in Earth's atmosphere? a. The light reactions of photosynthesis split carbon dioxide into carbon and oxygen. b. The light reactions of photosynthesis split water into hydrogen ions and oxygen. c. The Calvin cycle splits glucose into carbon, hydrogen, and oxygen. d. The Calvin cycle splits water into hydrogen ions and oxygen.
b. The light reactions of photosynthesis split water into hydrogen ions and oxygen.
Describe the difference between competitive and noncompetitive inhibitors. a. noncompetitive binds to active site and competitive binds to other site b. competitive is irreversible and noncompetitive is reversible binding c. competitive is irreversible and noncompetitive is reversible binding d. noncompetitive is irreversible and competitive is reversible binding
c. competitive is irreversible and noncompetitive is reversible binding
A student placed 20 tobacco seeds of the same species on moist paper towels in each of two petri dishes. Dish A was wrapped completely in an opaque cover to exclude all light. Dish B was not wrapped. The dishes were placed equidistant from a light source set to a cycle of 14 hours of light and 10 hours of dark. All other conditions were the same for both dishes. The dishes were examined after 7 days and the opaque cover was permanently removed from dish A. Both dishes were returned to the light and examined again at 14 days. The following data were obtained. Additional observations were made on day 21, and no yellow-leaved seedlings were found alive in either dish. This is most likely because a. yellow-leaved seedlings were unable to absorb water from the paper towels b. taller green-leaved seedlings blocked the light and prevented photosynthesis c. yellow-leaved seedlings were unable to convert light energy to chemical energy d. a higher rate of respiration in yellow-leaved seedlings depleted their stored nutrients
c. yellow-leaved seedlings were unable to convert light energy to chemical energy
The enzyme trypsin aids in protein digestion in the small intestine. The relative activity of trypsin at different pH values is shown in Figure 1. Figure 1: trypsin activity vs pH Which of the following statements best explains the activity levels of trypsin shown in Figure 1? a. The small intestine releases inhibitor molecules that block the activity of trypsin unless it is at its optimum pH. b. The number of effective collisions between trypsin and its substrate increase at higher pH values. c. As pH values increase, the substrate concentration decreases, leading to an eventual decline in the rate of the trypsin-catalyzed reaction. d. At extremely low pH values, trypsin is denatured and cannot function efficiently
d. At extremely low pH values, trypsin is denatured and cannot function efficiently
Which of the following are electron carriers for the electron transport chain in cellular respiration? a. NADPH b. FADH2 c. NADH d. NADH & FADH2
d. NADH & FADH2
Where does the electron transport chain take place? a. chloroplasts b. prokaryotic plasma membrane c. mitochondria d. all of the choices
d. all of the choices
Which of the following will increase the rate of the reaction? a. increase product b. increase substrate c. increase inhibitor d. increase enzyme
d. increase enzyme
In the electron transport chain of cellular respiration, where is the electrochemical gradient of protons generated? a. cytosol b. cristae c. matrix d. inter-membrane space
d. inter-membrane space
What is the process of an endergonic reaction being fueled by an exergonic reaction called?
energy coupling
Which environmental conditions can cause denaturation of the enzyme?
extreme increase in temperature and pH changes
Describe why an increase in temperature increases the rate of the reaction.
increase in temperature increases the speed/kinetic energy of particles
