Chapter 4 - Energy
NADH: a. has three 5-carbon ribose sugars. b. is the reduced form of NAD+. c. becomes NADPH when reduced. d. is a form of nucleotide used to store energy. e. catalyzes the dark reactions of photosynthesis.
Is the reduced form of NAD+
In the Krebs cycle, the pieces of the starting glucose molecule (now pyruvate) are completely broken apart to produce carbon dioxide. What happened to all the energy that was contained in the bonds of the original glucose molecule? a. It was transferred into NADH and FADH2 and some ATP. b. It was used to turn oxygen gas into water. c. It was lost as heat. d. It was all used in the Krebs cycle to make ATP. e. It is still in the bonds of pyruvate.
It was transferred into NADH and FADH2 and some ATP.
According to the video clip, what is the main function of photosynthesis? a. make sugars for food b. harvest energy from carbon dioxide c. harvest energy from glucose d. make green plant material e. release oxygen into the atmosphere
Makes sugars for food
At the end of the Krebs cycle, carbon atoms from sugar are: a. converted back into glucose. b. taken into NADH. c. converted into FADH2. d. exhaled back into the air as CO2. e. recycled back to glycolysis.
Exhaled back into the air as CO2.
Which of the following metabolic processes results in the production of ATP in the absence of oxygen? A. the mannose-6-phosphate cycle B. oxidative phosphorylation C. photosynthesis D. the Krebs cycle E. glycolysis
Glycolysis
About how many mitochondria might you expect to find in a single human skin cell? A. one B. two C. ten D. none E. hundreds or thousands
Hundreds or thousands
As energy is released, cells capture and store it in the bonds of: a. water molecules. b. carbon dioxide molecules. c. chlorophyll molecules. d. ATP molecules. e. sugar molecules.
ATP molecules
By weight, the bulk of a plant's organic material is derived from: a. oxygen. b. atmospheric nitrogen. c. soil minerals. d. carbon dioxide. e. water.
Carbon dioxide
Photosynthesis is the process by which plants, some bacteria, and some protistans, use the energy from sunlight to produce sugar, which _______________ converts to ATP, the "fuel" used by all living things. a. cellular respiration b. phosphorylation c. glycolysis d. photorespiration e. eutrophication
Cellular respiration
During photosynthesis, which of the following is the most important molecule in the conversion of light energy from the sun into chemical energy? a. carotenoid b. chlorophyll c. glucose d. oxygen e. water
Chlorophyll
What happens if oxygen is not present to capture electrons? a. hydrogen ions get released as hydrogen gas b. NADH is formed c. the concentration gradient disappears d. ATP production is halted e. Both c and d are correct.
NADH is formed The concentration gradient disappears Both c and d are correct.
Energized electrons from the water-splitting photosystem pass down an electron-transport chain to the ___________-producing photosystem. a. NADP+ b. ADP c. NADPH d. ATP e. carbohydrate
NADPH
Which of the following products of the light reactions of photosynthesis are later employed in the Calvin cycle? a. ADP and RuBP b. electrons and H+ c. free oxygen and water d. glucose and carbon dioxide e. NADPH and ATP
NADPH and ATP
Mitochondria have a "bag within a bag" structure. This is necessary to: a. allow light-reactive accessory pigments to be embedded within the membranes. b. create two distinct regions with a concentration differential, a form of potential energy. c. segregate the most toxic digestive enzymes from molecules of ATP and NADP. d. keep molecules of ADP close in proximity to molecules of ATP-synthase. e. None of the above.
Create two distinct regions with a concentration differential, a form of potential energy.
Glycolysis takes place in the: a. centriole. b. nucleus. c. cytoplasm. d. Golgi apparatus. e. thylakoid membrane.
Cytoplasm
A plant whose leaves are reddish yellow is NOT absorbing light from which wavelengths of the visible light spectrum? A. blue and violet B. blue, green, and red C. red and yellow D. green, blue, and violet E. green and yellow
Red and yellow
Life gains most of its energy from a. sugar molecules. b. oxygen. c. sunlight. d. carbohydrate molecules. e. water.
Sunlight
During photosynthesis, which step is most responsible for a plant's acquisition of new organic material: A. the loss of water through evaporation. B. the "plucking" of carbon molecules from the air and affixing of them to organic molecules within the chloroplast. C. the production of ATP during the "light reactions." D. the excitation of chlorophyll molecules by photons of light. E. the "building" of NADPH during the Calvin cycle.
The "plucking" of carbon molecules from the air and affixing of them to organic molecules within the chloroplast.
Although the reactions of the Calvin cycle do not depend directly on light, they do not usually occur at night. Why? a. At night, plants have a negative water balance with the soil, due to reduced evaporation. b. It is usually too cold at night for these reactions to take place. c. The Calvin cycle depends on products of the light reactions that cannot occur at night. d. Plants must open their stomata to restore their water balance each night. e. Carbon dioxide concentrations decrease at night.
The Calvin cycle depends on products of the light reactions that cannot occur at night.
If a thylakoid were punctured so that its interior was no longer separated from the stroma, which of the following processes would be most directly affected? a. the synthesis of ATP b. the splitting of water c. the oxidation of NADPH d. the absorption of energy by chlorophyll e. the flow of electrons from photosystem I to photosystem II
The synthesis of ATP
Which of the following is FALSE? a. The thylakoid membrane lies outside of the stroma. b. Chloroplasts, and leaves in turn, are green because chloroplasts have chlorophyll in them. c. The thylakoid is the location of the "photo" reactions in which sunlight is converted to chemical energy. d. Sugar is synthesized from carbon dioxide in the stroma. e. Chlorophyll is found embedded in the thylakoid membranes.
The thylakoid membrane lies outside of the stroma.
The net result of glycolysis is that each glucose molecule is broken down into: a. one molecule of ATP. b. three molecules of phosphate. c. two molecules of pyruvate. d. three molecules of NAD+. e. four molecules of water.
Two molecules of pyruvate
A green plant can carry out photosynthesis if given nothing more than: a. water, light, and oxygen. b. water and light. c. carbon dioxide. d. oxygen and carbon dioxide. e. water, light, and carbon dioxide.
Water, light, and carbon dioxide
Where are the molecules of the mitochondrial electron transport chain located? A. within the thylakoid B. within in the inner membrane C. in the stroma D. in the matrix E. in the intermembrane space
Within in the inner membrane
The actual production of sugars during photosynthesis takes place: a. within the stroma, inside the thylakoids of the chloroplast. b. within the stroma, outside of the thylakoid, but still inside the chloroplast. c. within the outer membrane of the chloroplast. d. just outside the chloroplast, within the mitochondria. e. within the thylakoid membrane of the chloroplast.
Within the stroma, outside of the thylakoid, but still inside the chloroplast.
How many turns of the Krebs cycle (also called the citric acid cycle) are needed to fully breakdown the energy in one glucose molecule? a. 2 turns b. 4 turns c. 1 turn d. 3 turns e. 1.5 turns
2 turns
When a muscle cell metabolizes glucose in the complete absence of molecular oxygen, all of the following substances are produced EXCEPT: a. acetyl-CoA. b. lactate. c. ATP. d. glucose 6-phosphate. e. pyruvate.
Acetyl-CoA
Which organism listed below does NOT extract energy through cellular respiration? a. horse b. bison c. sequoia tree d. human e. All living organisms extract energy from food through cellular respiration.
All living organisms extract energy from food through cellular respiration.
Which of the following statements about fermentation is NOT correct? a. Fermentation is an anaerobic process. b. In fermentation, the molecules that are used as electron acceptors differ from those used when glycolysis occurs in the presence of oxygen. c. Fermentation is a less efficient energy producer than aerobic respiration. d. Fermentation utilizes the electrons generated in the glycolytic breakdown of glucose. e. All of the above are correct.
All of the above are correct.
The inputs of cellular respiration are oxygen and sugar. The outputs are: a. carbon dioxide, water, and energy. b. nitrogen, water, and energy. c. water and carbon. d. carbon dioxide and energy. e. carbon dioxide and water.
Carbon dioxide, water, and energy
The three steps, in order, of the Calvin cycle are: a. sugar creation, regeneration, ATP production. b. the splitting of water, the electron transport chain, the passing of electrons to NADP+. c. ATP production, the electron transport chain, and fixation of NADPH. d. regeneration, fixation of NADP+, sugar creation. e. fixation of CO2, sugar creation, regeneration.
Fixation of CO2, sugar creation, regeneration.
Which of the following does NOT occur during the Calvin cycle? a. consumption of ATP b. generation of oxygen c. oxidation of NADPH d. carbon fixation e. regeneration of the CO2 acceptor
Generation of oxygen
Why do hydrogen ions (protons) flow back across the mitochondrial membrane? a. because of their attraction to electron-greedy oxygen atoms in the matrix b. because of the difference in concentration of hydrogen ions between the inter membrane space and the matrix c. because of their attraction to water molecules in the matrix d. because ATP can be generated as hydrogen ions flow from the intermembrane space into the matrix e. None of the above.
Because of the difference in concentration of hydrogen ions between the inter membrane space and the matrix
Cellular respiration is the process by which a. ATP molecules are converted into water and sugar. b. oxygen is produced during metabolic activity. c. energy from the chemical bonds of food molecules is captured by an organism. d. oxygen is used to transport chemical energy throughout the body. e. light energy is converted into kinetic energy.
Energy from the chemical bonds of food molecules is captured by an organism.
Potential energy a. is stored energy unavailable to do work. b. contains less energy than kinetic energy. c. transfers motion to matter. d. is kinetic energy that has not yet been turned to heat. e. is contained in matter placed in certain positions or arrangements.
Is contained in matter placed in certain positions or arrangements.
The byproduct of photosynthesis that makes all animal life possible is: a. nitrogen. b. carbon. c. carbon dioxide. d. oxygen. e. water.
Oxygen
The conversion of radiant energy to chemical energy occurs in photosynthesis and many other common phenomena, such as brewing tea, fading of dyes in the sun, and photography. In what way is photosynthesis different from these other processes? a. Photosynthesis relies on both radiant energy and air molecules. b. Photosynthesis needs no other chemical compounds besides light and water. c. Photosynthesis fixes light energy in the form of low potential chemical energy in compounds that do not break down spontaneously and that can be stored until required later for the carrying out of life processes. d. Photosynthesis fixes chemical energy in the form of potential light energy in compounds that do not break down spontaneously and that can be stored until required later for the carrying out of life processes. e. Photosynthesis fixes light energy in the form of high potential chemical energy in compounds that do not break down spontaneously and that can be stored until required later for the carrying out of life processes.
Photosynthesis fixes light energy in the form of high potential chemical energy in compounds that do not break down spontaneously and that can be stored until required later for the carrying out of life processes.
What is the main purpose of the electron transport chain in cellular respiration? a. to generate additional molecules of NADH and FADH2 b. to harvest the energy held in NADH and FADH2 to make ATP c. to generate carbon dioxide and water d. to use available oxygen e. to generate molecules of water
To harvest the energy held in NADH and FADH2 to make ATP
What is the source of the electrons that replace those lost by chlorophyll a in the photosystems? A. oxygen gas B. carbon dioxide C. water D. chlorophyll b E. carotenoids
Water
The Calvin cycle produces G3P, with the formula C3H7O6P. This is combined inside the chloroplast to make the six-carbon glucose sugar, C6H12O6. How many turns of the Calvin cycle would be required to build and produce a completed glucose molecule? a. 1 b. 6 c. 3 d. 2 e. 12
6
You eat a chocolate bar to get you through a late-night studying session. Your body quickly begins to break down the macromolecules in the candy, using the sugars, lipids, and protein to make ATP. Which of the following is NOT a step in the process of breaking down the candy bar's macromolecules? a. First Step: The sugars are broken down to simple glucose molecules and the proteins and lipids are broken down to acetyl-CoA molecules. No energy is produced in this first step. b. Second Step: Glycolysis converts the glucose to two molecules of pyruvate. Six ATP molecules are produced in this step. c. Third Step: Oxidation of each pyruvate produces two molecules of acetyl-CoA. Six ATP molecules are produced in this step. d. Fourth Step: Two acetyl-CoA molecules go through the Krebs (citric acid) cycle. Twenty-four ATP molecules are produced through this process. e. All of the above steps are part of the break down of the candy bar's macromolecules.
All of the above steps are part of the break down of the candy bar's macromolecules.
Which of the following statements is FALSE? a. Life depends on energy gained from sunlight. b. Fats and oils share a chemical structure similar to gasoline. c. Biofuels are produced from plant and animal products. d. Burning fossil fuels releases energy, oxygen, and water. e. Fossil fuels are the decayed remains of animals and plants.
Burning fossil fuels releases energy, oxygen, and water.
All alcoholic beverages are produced as the result of cellular respiration a. by bacteria occurring in the absence of oxygen. b. by bacteria occurring in the absence of free electrons. c. by yeast occurring in the absence of free electrons. d. occurring in the absence of sugar. e. by yeast occurring in the absence of oxygen.
By yeast occurring in the absence of oxygen.
The function of NADH is to: a. produce acetyl-CoA. b. fuel the process of glycolysis. c. carry electrons from a glucose molecule to ATP. d. provide energy for the breakdown of glucose. e. carry electrons from a glucose molecule to the electron transport chain.
Carry electrons from a glucose molecule to the electron transport chain.
Why are leaves green? a. Chlorophyll molecules mainly absorb light in the ultraviolet and red-orange part of the electromagnetic spectrum. Chlorophyll does not absorb much green light, which is reflected to our eyes. b. Chlorophyll molecules mainly absorb light in the blue-violet and red-orange part of the electromagnetic spectrum. Chlorophyll does not absorb much green light, which is reflected to our eyes. c. Chlorophyll molecules mainly absorb light in the ultraviolet and infrared part of the electromagnetic spectrum. Chlorophyll does not absorb much green light, which is reflected to our eyes. d. Chlorophyll molecules mainly absorb light in the blue-violet and infrared part of the electromagnetic spectrum. Chlorophyll does not absorb much green light, which is reflected to our eyes. e. Chlorophyll molecules mainly absorb light in the green part of the electromagnetic spectrum.
Chlorophyll molecules mainly absorb light in the blue-violet and red-orange part of the electromagnetic spectrum. Chlorophyll does not absorb much green light, which is reflected to our eyes.
Recently, the world followed the story of baby Gard who suffers from a rare inherited disease resulting from abnormal mitochondria passed from mother to child. Using your knowledge of mitochondria's function within human cells, which of the following is the most likely description of the symptoms of this disease? a. extreme sensitivity to UV light, resulting in skin cancer at a very young age b. extreme muscle weakness c. inability to absorb iron, resulting in extreme anemia d. color blindness c. fragile bones and arthritis
Extreme muscle weakness
If ATP is being generated in the cytosol, which of the following processes is responsible? A. alcohol fermentation B. oxidative phosphorylation C. glycolysis D. lactate fermentation E. the Krebs cycle
Glycolysis
A lot of energy is contained in each mole of glucose (686 kcal), and if a cell were to release all that energy at once, the amount of heat produced would kill the cell. Which of the following statements is the most likely explanation for how a cell keeps itself from bursting into flames? a. Glycolysis occurs in steps. Although each step does release heat, it is not enough at one time to damage the cell. b. The cell has several protective organelles that absorb the excess energy released from glucose. The organelles store this energy in the form of fat cells, explaining why lots of sugar will make you gain weight. c. The cell extracts the energy from one mole of glucose, all at once; however, the cell couples the reaction with an equally powerful endergonic reaction that uses up the excess energy. d. The cell extracts energy from one mole of glucose, all at once; however, the heat is used to maintain the cell's internal temperature. Why else would humans have such a warm body temperature? e. Both b and d are correct.
Glycolysis occurs in steps. Although each step does release heat, it is not enough at one time to damage the cell.
The three basic steps of cellular respiration are: a. the Calvin cycle, glycolysis, and fermentation. b. the Krebs cycle, the electron transport chain, and photosynthesis. c. glycolysis, the Krebs cycle, and the electron transport chain. d. the Calvin cycle, the Krebs cycle, and the electron transport chain. e. the Krebs cycle, the Calvin cycle, and glycolysis.
Glycolysis, the Krebs cycle, and the electron transport chain.
ATP is produced in the mitochondria by a series of biochemical reactions. In what order do these reactions occur? a. the electron transport chain; glycolysis; the Krebs (citric acid) cycle b. the Krebs (citric acid) cycle; the electron transport chain; glycolysis c. glycolysis; the Krebs (citric acid) cycle; the electron transport chain d. glycolysis; the electron transport chain; the Krebs (citric acid) cycle e. the Krebs (citric acid) cycle; glycolysis; the electron transport chain
Glycolysis; the Krebs (citric acid) cycle; the electron transport chain
Stroma is to the thylakoid interior in chloroplasts as the ______ is to the ________ in mitochondria. a. inner membrane, outer membrane b. matrix, Krebs cycle c. glycolysis, Krebs cycle d. intermembrane space, matrix e. electron transport chain, Krebs cycle
Intermembrane space, matrix
The inputs of photosynthesis are sunlight, water, and carbon dioxide. The outputs are: a. oxygen and sugar. b. oxygen and water. c. carbon and nitrogen. d. water and carbon dioxide. e. ATP and water.
Oxygen and sugar
The energy transformation pathways of cellular respiration and photosynthesis are related in which of the following ways? a. Photosynthesis is the energy-releasing stage, and cellular respiration is the energy-acquiring stage. b. Photosynthesis is the energy-acquiring stage, and cellular respiration is the energy-releasing stage. c. Photosynthesis produces glucose and oxygen, whereas cellular respiration produces carbon dioxide and water. d. Photosynthesis requires carbon dioxide and water, whereas cellular respiration requires oxygen and glucose. e. Choices b, c, and d are correct.
Photosynthesis is the energy-acquiring stage, and cellular respiration is the energy-releasing stage. Photosynthesis produces glucose and oxygen, whereas cellular respiration produces carbon dioxide and water. Photosynthesis requires carbon dioxide and water, whereas cellular respiration requires oxygen and glucose. Choices b, c, and d are correct.
Which one of the following statements best represents the relationship between respiration and photosynthesis? a. Photosynthesis occurs only in the day and respiration occurs only at night. b. Photosynthesis stores energy in complex organic molecules, while respiration releases it. c. Respiration stores energy in complex organic molecules, while photosynthesis releases it. d. Photosynthesis reverses the biochemical pathways of respiration. e. Respiration occurs only in animals and photosynthesis occurs only in plants.
Photosynthesis stores energy in complex organic molecules, while respiration releases it.
During cellular respiration, most of the energy contained within the bonds of food molecules is captured in: a. digestion. b. the Krebs cycle and electron transport chain. c. the conversion of the kinetic energy of food into the potential energy of ATP. d. glycolysis. e. None of the above; energy is lost, not gained, during cellular respiration.
The Krebs cycle and electron transport chain
Which of the following statements most accurately depicts the relationship between the light reactions and the Calvin cycle in photosynthesis? A. The light reactions provide ATP and NADPH to the carbon fixation step of the Calvin cycle, and the Calvin cycle provides water and electrons to the light reactions. B. There is no relationship between the light reactions and the Calvin cycle. C. The light reactions supply the Calvin cycle with CO2 to produce sugars, and the Calvin cycle supplies the light reactions with sugars to produce ATP. D. The light reactions provide ATP and NADPH to the Calvin cycle and the Calvin cycle returns ADP, NADP+, and a phosphate group to the light reactions. E. The light reactions provide the Calvin cycle with oxygen for electron flow, and the Calvin cycle provides the light reactions with water to split.
The light reactions provide ATP and NADPH to the Calvin cycle and the Calvin cycle returns ADP, NADP+, and a phosphate group to the light reactions.
Photons excite electrons in chlorophyll. These electrons are then trapped by the primary electron acceptor. How does the photosystem replace the trapped electrons? a. The photosystem replaces its light-excited electrons by extracting electrons from carbon dioxide. b. The photosystem replaces its light-excited electrons by extracting electrons from water. c. The photosystem replaces its light-excited electrons by extracting electrons from oxygen. d. These electrons are not replaced. There are hundreds of millions of free electrons available in the photosystem at any particular time. e. These electrons are not replaced. A molecule of chlorophyll in a photosystem is used up with each electron transferred.
The photosystem replaces its light-excited electrons by extracting electrons from water.
What happens to electrons as they are passed down the photosynthetic electron transport chain from the primary electron acceptor? A. they increase in energetic state and become excited B. they diffuse out of the thylakoid C. they are used to excite pigment molecules D. they fall to a lower energy state and some energy is released E. they are transferred to a chlorophyll a molecule
They fall to a lower energy state and some energy is released
What is the function of the pigment molecules in photosynthesis that are not at the center of a photosystem? a. They gather photons and transfer energy to the reaction-center chlorophyll. b. They concentrate the photons within the stroma. c. They move the electrons down the electron- transport chain. d. They synthesize ADP from ATP and a phosphate group. e. They split water and release oxygen to the reaction- center chlorophyll.
They gather photons and transfer energy to the reaction-center chlorophyll.
The graphs above show data relating to seasonal differences in the amount of pigment molecules present in leaves and how this is related to leaves changing colors. What is the independent variable presented in these graphs? a. The amount of photosynthetic pigment in each leaf. b. The difference in pigment between fall and spring. c. Time at which the amount of pigment in the leaves was measured. d. Time taken to gather the pigment samples. e. The type of photosynthetic pigment that is most abundant.
Time at which the amount of pigment in the leaves was measured.
Which of the following is NOT one of the major molecular changes that occurs in glycolysis? a. Two molecules of ADP are converted to ATP. b. Glucose is converted to two molecules of pyruvate. c. Two molecules of pyruvate are converted into two molecules of Acetyl-CoA. d. Two molecules of NAD+ are converted to NADH. e. All of the above molecular changes occur in glycolysis.
Two molecules of pyruvate are converted into two molecules of Acetyl-CoA.
In photosynthesis, gaseous molecular oxygen (O2) is released. This comes from a compound that goes into photosynthesis. Which compound is it? a. gaseous molecular oxygen (O2) b. ATP c. water (H2O) d. glucose (C6H12O6) e. carbon dioxide (CO2)
Water (H2O)
Potential energy is to kinetic energy as ______________ is to _____________. a. water held behind a dam; water power being used to turn electric turbines b. the amount of energy in a French fry; the amount of energy in a hamburger c. a stick of dynamite; a can of gasoline d. wool; sheep e. a flying bird; a bird laying eggs
Water held behind a dam; water power being used to turn electric turbines
A molecule of chlorophyll increases in potential energy: A. when one of its electrons is boosted to a higher- energy excited state upon being struck by a photon of light. B. when it loses an electron. C. when it binds to a photon. D. only in the presence of oxygen. E. None of the above; the potential energy of a molecule cannot change.
When one of its electrons is boosted to a higher-energy excited state upon being struck by a photon of light.