Bio 1610 Reading Quiz 3
Which of the summary statements below best describes the results of the following reaction?C6H12O6 + 6O2 →→ 6CO2 + 6H2O + Energy
C6H12O6 is oxidized and O2 is reduced.
Which of the following statements best describes the accompanying figure?
It represents a C4 photosynthetic system.
Which of the following statements best describes the primary role played by oxygen in cellular respiration?
It serves as the final acceptor for electrons from the electron transport chain.
A flask containing photosynthetic green algae and a control flask containing only water are exposed to a cycle of 12 hours of light and 12 hours of darkness. Which of the following statements best describes how the relative dissolved oxygen concentration in the flask with algae will compare to the control flask?
It will be lower in the control in the light, but higher in the control in the dark.
Depletion of which of the following molecules from the mitochondria will most directly inhibit the citric acid cycle?
NAD+
In the absence of oxygen, yeast cells can obtain energy by fermentation, which results in the net production of which of the following sets of molecules?
ATP, CO2, and ethanol
Which of the following events is most immediately associated with the absorption of energy by chlorophyll molecules of the reaction-center complex?
An electron is excited.
Which of the following processes occurs in the Calvin cycle?
reduction of CO2
The oxygen released by photosynthesis is produced by which of the following processes?
splitting water molecules
Which of these equations best summarizes photosynthesis?
6 CO2 + 6 H2O → C6H12O6 + 6 O2
If photosynthesizing green algae are provided with CO2 containing heavy oxygen (18O), which of the following molecules produced by the algae (refer to the accompanying figure) would be least likely to contain 18O in subsequent analyses?
ADP
Which of the following molecules will accumulate if light reactions occur normally, but the Calvin Cycle is inhibited?
ATP and NADPH
The enzyme phosphofructokinase (PFK) catalyzes a key step in glycolysis and is inhibited by high levels of which of the following molecules?
ATP and citrate
Which of the following statements best summarizes the metabolic results of photorespiration?
ATP is hydrolyzed, carbon dioxide is produced, and oxygen is consumed.
Select the correct statement about cellular respiration.
Cellular respiration and breathing differ in that cellular respiration is at the cellular level, whereas breathing is at the organismal level.
Which of the following molecules is the lowest-energy donor of electrons to the electron transport chain?
FADH2
Select the correct molecule that is the main product of the Calvin cycle.
G3P
Which of the following sequences correctly represents the flow of electrons during photosynthesis?
H2OH2O →→ NADPHNADPH →→ Calvin cycle
How is photosynthesis similar in C4C4 plants and CAM plants?
In both cases, rubisco is not used to fix carbon initially.
Which of the following statements best describes the electron transport chain?
It consists of a series of redox reactions.
Which of the following statements best describes what happens to a molecule of NAD+ (nicotinamide adenine dinucleotide) when it gains a hydrogen atom?
NAD+ becomes reduced.
Which of the following products result from the oxidation of pyruvate to acetyl-CoA?
NADH and CO2
Which of the following molecules is the final electron acceptor for electrons from photosystem I?
NADP+
Which of the following statements correctly describes a distinction between autotrophs and heterotrophs?
Only autotrophs can produce organic molecules from CO2 and other inorganic materials.
The citric acid cycle. If pyruvate oxidation is blocked, what is the most likely effect on the levels of oxaloacetate and citrate in the citric acid cycle shown in the accompanying figure?
Oxaloacetate will accumulate and citrate will decrease.
Which of the following statements best describes the conditions under which the Calvin cycle and cellular respiration occur in plants?
The Calvin cycle and cellular respiration both occur in the dark and the light.
Select the correct statement about the Calvin cycle.
The Calvin cycle has three phases: carbon fixation, reduction, and regeneration of RuBP.
In cellular respiration, a series of molecules forming an electron transport chain alternately accepts and then donates electrons. What is the advantage of such an electron transport chain?
The advantage of an electron transport chain is that a small amount of energy is released with the transfer of an electron between each pair of intermediates.
Identify all correct statements about the basic function of fermentation.
The basic function of fermentation is the regeneration of NAD+, which allows continued ATP production by glycolysis.
What assumptions did Engelmann make in order to conclude that red and violet-blue light were more effective than green light in driving photosynthesis? Select the two that apply.
The distribution of chloroplasts within each algal cell was approximately the same. The number of bacteria clustered at each wavelength (color) was approximately proportional to the amount of oxygen being produced by that portion of the alga.
Which of the following statements accurately describes the function of a metabolic pathway involved in cellular respiration?
The function of glycolysis is to begin catabolism by breaking glucose into two molecules of pyruvate, with a net yield of two ATP.
Which of the following statements about the citric acid cycle is correct?
The last reaction in the citric acid cycle produces a product that is a substrate for the first reaction of the citric acid cycle.
When electrons flow along the electron transport chains of mitochondria, which of the following changes occurs?
The pH of the matrix increases.
Which of the following events are associated with chemiosmosis in chloroplasts?
The pH of the thylakoid space increases and ATP is synthesized.
Which statement correctly describes how O2 production would be affected? (Assume that the light intensity does not change.)
The rate of O2 production would decrease because the rate of ADP and NADP+production by the Calvin cycle would decrease.
Which one of the following statements about the redox reactions of the electron transport chain is correct?
The redox reactions of the electron transport chain are directly coupled to the movement of protons across a membrane.
Photorespiration can decrease soybeans' photosynthetic output by about 50%%. Would this figure be higher or lower in wild relatives of soybeans? Why?
The wild relatives of modern soybeans would be expected to have levels of photorespiration higher than 50%%. Crop scientists would have selected strains with reduced levels of photorespiration to maximize the size of the harvested soybeans.
A mutation that eliminates a plant's ability to perform photorespiration will most likely have which of the following effects on the plant?
There would be more cellular damage from harmful products of the light reactions of photosynthesis.
Which of the following statements best explains why carbohydrates and fats may be considered high-energy foods?
They contain many electrons associated with hydrogen atoms.
Which of the following statements best explains the ability of CAM plants to synthesize sugars in the daytime while keeping their stomata closed to reduce water loss?
They fix CO2 into organic acids during the night.
Carotenoids are often found in foods that are considered to have antioxidant properties in human nutrition. Which of the following statements best describes a related function they serve in plants?
They protect against oxidative damage from excessive light energy.
Which of the following best predicts the effect of removal of oxygen from a facultative anaerobic organism's environment?
glucose consumption increases, while the growth rate decreases
Exposing inner mitochondrial membranes to ultrasonic vibrations will fragment the membranes and pieces will reseal "inside out" to form small vesicles. The fact that these vesicles can transfer electrons from NADH to oxygen and synthesize ATP suggests that which of the following components must be present?
all of the electron transport system and ATP synthase
What types of cells carry out ATP synthesis by chemiosmosis?
all respiring cells, both prokaryotic and eukaryotic, using either oxygen or other electron acceptors
Which of the following types of metabolic poison would most directly interfere with glycolysis?
an agent that closely mimics the structure of glucose but is not metabolized
Which of the following occurs during the Calvin cycle?
carbon fixation
In which cell of the accompanying figure would elevated oxygen concentrations have the greatest inhibitory effect on carbon fixation reactions?
cell II only
In C4 and CAM plants carbon dioxide is fixed in the _____ of mesophyll cells.
cytoplasm
What is the oxidizing agent in the following reaction? Pyruvate+NADH+H+→Lactate+NAD+Pyruvate+NADH+H+→Lactate+NAD+
pyruvate
Under which conditions will plant cell mitochondria actively oxidize pyruvate and carry out oxidative phosphorylation?
in all cells, with or without light
Energy released from the electron transport chain is used to pump H+ ions into which location in eukaryotic cells?
mitochondrial intermembrane space
Which of the following processes is most directly driven by light energy?
oxidation of chlorophyll molecules
In C3 plants the conservation of water promotes _____.
photorespiration
Which of the following reactions produces the majority of the CO2 released by the complete oxidation of glucose?
the citric acid cycle
When a cell is deprived of oxygen, which of the following processes will be inhibited first?
the electron transport chain
Which of the following events takes place in the electron transport chain?
the harnessing of energy from redox reactions to generate a proton gradient
C4 plants differ from C3 and CAM plants in that C4 plants _____.
transfer fixed carbon dioxide to cells in which the Calvin cycle occurs
The light reactions of photosynthesis use _____ and produce _____.
water ... NADPH
