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BIOL 1201 exam 2

biology online quizzes, moodle quizzes, mastering biology quiz, and clicker questions
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Which one of the following statements is true about diffusion?
It is a passive process
Which of the following statements is true about passive transport?
Passive transport permits the transported molecule to move in either direction, but the majority of transport occurs down the concentration gradient of the molecule.
Which of the following statements about the role of phospholipids in forming membranes is correct?
Phospholipids form a selectively permeable structure.
Cells A and B are the same size, shape, and temperature, but cell A is metabolically quiet and cell B is actively consuming oxygen. Oxygen will diffuse more quickly into cell _____ because _____.
B ... the diffusion gradient in cell B is steeper
Which statement(s) about the sidedness of the plasma membrane is (are) correct?
The asymmetrical distribution of membrane proteins, lipids, and carbohydrates across the plasma membrane is determined as the membrane is being constructed.
Every integral membrane protein has specific orientation in the plasma membrane.
Parts of proteins that are exposed on the cytoplasmic side of the endoplasmic reticulum are also exposed on the cytoplasmic side of the plasma membrane.
The plasma membrane is referred to as a "fluid mosaic" structure. Which of the following statements is true?
The fluid component of the membrane is phospholipid, and the mosaic is protein.
Which of the following reactions would be endergonic?
glucose + fructose to sucrose
Which of the following states the relevance of the first law of thermodynamics to biology?
Energy can be freely transformed among different forms as long as the total energy is conserved.
Organisms are described as thermodynamically open systems. Which of the following statements is consistent with this description?
Organisms acquire energy from their surroundings.
An exergonic (spontaneous) reaction is a chemical reaction that _____.
releases energy when proceeding in the forward direction
Which of the following is an example of the second law of thermodynamics as it applies to biological reactions?
The aerobic respiration of one molecule of glucose produces six molecules each of carbon dioxide and water.
Which is the most abundant form of energy in a cell?
chemical energy
Which of the following is not an example of the cellular work accomplished with the free energy derived from the hydrolysis of ATP?
the production of heat, which raises the temperature of the cell
Which of the following are examples of the cellular work accomplished with the free energy derived from the hydrolysis of ATP?
transport work, such as the active transport of an ion into a cell
chemical work, such as the synthesis of new protein
mechanical work, such as the beating of cilia
Which of the following statements about feedback regulation of a metabolic pathway is incorrect?
The products of the pathway become the reactants for a different reaction, and thus products are unable to accumulate.
Which of the following statements about feedback regulation of a metabolic pathway are correct?
The compound that regulates the pathway acts as a non-competitive inhibitor or a negative allosteric regulator.
Accumulation of the product of the pathway will tend to slow down further formation of that product.
The final product of a metabolic pathway is the compound that regulates the pathway.
The enzyme that is regulated by feedback inhibition is usually the first enzyme in the metabolic pathway.
Which of the following statements about the combustion of glucose with oxygen to form water and carbon dioxide (C6H12O6 + 6 O2→ 6 CO2 + 6 H2o) is incorrect?
The free energy lost to the system in this combustion is greater than the energy that appears as heat.
Which of the following statements about the combustion of glucose with oxygen to form water and carbon dioxide (C6H12O6 + 6 O2→ 6 CO2 + 6 H2o) are correct?
The reverse reaction, making glucose from water and carbon dioxide, must be an endergonic reaction.
This reaction is spontaneous with the release of free energy.
The entropy of the universe increases as the result of this reaction.
The entropy of the products is greater than the entropy of the reactants.
The binding of a compound to an enzyme is observed to slow down or stop the rate of the reaction catalyzed by the enzyme. Which of the following could account for this observation?
The compound is a negative allosteric regulator.
The compound is a competitive inhibitor.
The compound causes a cofactor to be lost from the enzyme.
The process of cellular respiration, which converts simple sugars such as glucose into CO2 and water, is an example of _____.
an energy-releasing pathway
a pathway in which the entropy of the system increases
a catabolic pathway
Energy is observed in two basic forms: potential and kinetic. Which of the following correctly matches these forms with a source of energy?
the covalent bonds of a sugar molecule—potential energy
Enzymes are described as catalysts, which means that they _____.
increase the rate of a reaction without being consumed by the reaction
Which of the following statements about equilibrium of chemical reactions is correct?
A reaction that is at equilibrium is not capable of doing any work.
A chemical reaction is designated as exergonic rather than endergonic when _____.
the potential energy of the products is less than the potential energy of the reactants
Which of the following statements correctly describe(s) the role(s) of heat and temperature in biological reactions?
Heat from the environment is necessary for substrates to get over the activation energy barrier.
Increasing temperature increases the kinetic energy of the substrates.
The mechanism of enzyme action is _____.
lowering the energy of activation for a reaction
When 1 mole of ATP is hydrolyzed in a test tube without an enzyme, about twice as much heat is given off as when 1 mole of ATP is hydrolyzed in a cell. Which of the following best explains these observations?
In the cell, the hydrolysis of ATP is coupled to other endergonic reactions.
Which of the following statements about enzymes is true?
Enzymes speed up the rate of the reaction without changing the Delta G for the reaction.
The formation of glucose-6-phosphate from glucose is an endergonic reaction and is coupled to which of the following reactions or pathways?
the hydrolysis of ATP
A chemical reaction is designated as endergonic rather than exergonic when _____.
the potential energy of the reactants is less than the potential energy of the products
Which of the following statements about enzymes are correct?
Most enzymes are proteins.
An enzyme is not consumed by the catalytic process.
An enzyme lowers the activation energy of a chemical reaction.
An enzyme is very specific in terms of which substrate it binds to.
What best characterizes the role of ATP in cellular metabolism?
The free energy released by ATP hydrolysis may be coupled to an endergonic process via the formation of a phosphorylated intermediate.
Most of the energy that enters electron transport enters as
FADH2 and NADH.
Cells do not catabolize carbon dioxide because
CO2 is already completely oxidized.
Which statement about the citric acid cycle are correct?
The citric acid cycle oxidizes the products of glycolysis to carbon dioxide.
The last reaction in the citric acid cycle produces a product that is a substrate for the first reaction of the citric acid cycle.
The citric acid cycle produces most of the NADH that is subsequently used by the electron transport chain.
The citric acid cycle depends on the availability of NAD+, which is a product of the electron transport chain.
Glycolysis is an ________ reaction.
exergonic
A glucose molecule is completely broken down to carbon dioxide and water in glycolysis and the citric acid cycle, but together these two processes yield only a few molecules of ATP. What happened to most of the energy that the cell obtains from the oxidation of glucose?
It is stored in NADH.
In fermentation, ________ is ________.
NADH; oxidized
How many ATP molecules are produced (total) by glycolysis?
4
Pyruvate is formed
in the cytosol
Most CO2 from catabolism is released during
the citric acid cycle.
In the absence of oxygen, what is the net gain of ATP for each glucose molecule that enters glycolysis?
2 ATP
In the combined processes of glycolysis and cellular respiration, what is consumed and what is produced?
Glucose is consumed, and carbon dioxide is produced.
Which 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.
When light strikes chlorophyll molecules, they lose electrons, which are ultimately replaced by _____.
splitting water
Which of the following is not a product of the light reactions of photosynthesis?
sugar
Which of the following are products of the light reactions of photosynthesis?
oxygen, NADPH, high-energy electrons, ATP
Plants are photoautotrophs. What does this mean?
They are in the same category as algae and cyanobacteria.
They use light energy to drive the synthesis of organic molecules.
They make their own food from inorganic materials.
They are among the producers of the biosphere.
The photosynthetic membranes are found in the _____ in plant cells.
chloroplasts
In the electromagnetic spectrum, the type of radiation that we call visible light occurs between _____.
ultraviolet radiation and infrared radiation
Photosynthesis is an _____ process of carbon _____, while respiration is an _____ process of carbon _____.
endergonic ... reduction ... exergonic ... oxidation
The overall function of the Calvin-Benson cycle is _____.
making sugar
C4 plants occur more commonly in desert conditions because _____.
they can fix carbon at the lower CO2 concentrations that develop when the stomata are closed
The ultimate source of energy to support most life on Earth is _____.
sunlight
Which of the following is produced by the light reactions of photosynthesis and consumed by the Calvin-Benson cycle?
NADPH
Which of the following statements about the role of phospholipids in forming membranes is correct?
Phospholipids form a selectively permeable structure.
The plasma membrane is referred to as a "fluid mosaic" structure. Which of the following statements is true?
The fluid component of the membrane is phospholipid, and the mosaic is protein
Which of the following types of information is (are) most likely to be derived from freeze-fracture of biological samples?
proteins imbedded in membrane bilayers
Consider the currently accepted fluid mosaic model of the plasma membrane. Where in the plasma membrane would cholesterol most likely be found?
in the interior of the membrane
Which of the following functional processes result(s) from the presence of proteins in or on the plasma membrane?
enzymatic activity, cell-cell recognition, intercellular joining, cell-cell communication
What are functions of membrane proteins?
Membrane proteins attach the membrane to the cytoskeleton.
Membrane proteins provide receptors for chemical messengers.
Membrane proteins form channels, which move substances across the membrane.
Membrane proteins with short sugar chains form identification tags that are recognized by other cells.
Select the correct statement concerning carbohydrates associated with the plasma membrane.
Membrane carbohydrates function primarily in cell-cell recognition.
Consider the currently accepted fluid mosaic model of the plasma membrane. Where in the membrane would oligosaccharides most likely be found?
on the outside (external) surface of the membrane
Which statement(s) about the sidedness of the plasma membrane is (are) correct?
Parts of proteins that are exposed on the cytoplasmic side of the endoplasmic reticulum are also exposed on the cytoplasmic side of the plasma membrane.
The asymmetrical distribution of membrane proteins, lipids, and carbohydrates across the plasma membrane is determined as the membrane is being constructed.
Every integral membrane protein has specific orientation in the plasma membrane.
Which one of the following molecules is most likely to diffuse freely across the lipid bilayer of the plasma membrane without the involvement of a transport protein?
carbon dioxide
Which of the following would be least likely to diffuse through a plasma membrane without the help of a transport protein?
a large polar molecule
Which of the following structures is most consistent with the selective permeability property of biological membranes?
proteins embedded in two layers of phospholipid
Which of the following statements is true about passive transport?
Passive transport permits the transported molecule to move in either direction, but the majority of transport occurs down the concentration gradient of the molecule.
Cells A and B are the same size, shape, and temperature, but cell A is metabolically quiet and cell B is actively consuming oxygen. Oxygen will diffuse more quickly into cell _____ because _____.
B ... the diffusion gradient in cell B is steeper
Which one of the following statements is true about diffusion?
It is a passive process.
The internal solute concentration of a plant cell is about 0.8 M. To demonstrate plasmolysis, it would be necessary to suspend the cell in what solution?
1.0 M
A single plant cell is placed in an isotonic solution. Salt is then added to the solution. Which of the following would occur as a result of the salt addition?
Water would leave the cell by osmosis, causing the volume of the cytoplasm to decrease.
If a red blood cell and a plant cell were placed in seawater, what would happen to the two types of cells?
Both cells would lose water; the red blood cell would shrivel, and the plant plasma membrane would pull away from the cell wall.
Which of these statements describes some aspect of facilitated diffusion?
Facilitated diffusion of solutes may occur through protein pores in the membrane.
Which one of the following is not in some way involved in facilitated diffusion?
an outside energy source
Movement of phospholipids from one side of a membrane to the other does occur under appropriate circumstances. Based on your understanding of membrane structure and transport, which of the following is likely to describe this movement of phospholipids between the two sides of a membrane?
None of the above could facilitate movement of phospholipids from one side of the membrane to the other
Imagine two solutions separated by a selectively permeable membrane that allows water to pass, but not sucrose or glucose. The membrane separates a 0.2-molar sucrose solution from a 0.2-molar glucose solution. With time, how will the solutions change?
Nothing happens because the two solutions are isotonic to one another.
The concentration of solutes in a red blood cell is about 2%, but red blood cells contain almost no sucrose or urea. Sucrose cannot pass through the membrane, but water and urea can. Osmosis would cause red blood cells to shrink the most when immersed in which of the following solutions?
a hypertonic sucrose solution
Green olives may be preserved in brine, which is a 30% salt solution. How does this method of preservation prevent contamination by microorganisms?
A 30% salt solution is hypertonic to the bacteria, so they lose too much water and cannot survive.
Active transport requires a cell to expend energy. Which of the following statements is not true?
Active transport usually moves solutes down the concentration gradient.
Glucose is a six-carbon sugar that diffuses slowly through artificial membranes. The cells lining the small intestine, however, rapidly move glucose from the gut into their cytoplasm. This occurs whether the gut concentrations of glucose are higher or lower than the glucose concentrations in intestinal cell cytoplasm. Using this information, which transport mechanism is most likely responsible for the glucose transport in intestinal cells?
active transport
Which of the following is a difference between active transport and facilitated diffusion?
Active transport requires energy from ATP, and facilitated diffusion does not.
Which of the following statements about the sodium-potassium pump are correct?
The sodium-potassium pump transports Na+ and K+ ions across the plasma membrane in opposite directions at the expense of ATP hydrolysis.
The sodium-potassium pump creates an electrochemical gradient.
The sodium-potassium pump is electrogenic.
The sodium-potassium pump creates concentration gradients of both Na+ and K+ across the plasma membrane
A cell has a membrane potential of -100 mV (more negative inside than outside) and has 1,000 times more calcium ions outside the cell than inside. Which of the following best describes a mechanism by which Ca2+ enters the cell?
facilitated diffusion of Ca2+ into the cell down its electrochemical gradient
Which of the following correctly describes a general property of all electrogenic pumps?
creates a voltage difference across the membrane
Which of the following statements about cotransport of solutes across a membrane is correct?
Cotransport proteins allow a single ATP-powered pump to drive the active transport of many different solutes.
Consider the transport of protons and sucrose into a plant cell by the sucrose-proton cotransport protein. Plant cells continuously produce a proton gradient by using the energy of ATP hydrolysis to pump protons out of the cell. Why, in the absence of sucrose, don't protons move back into the cell through the sucrose-proton cotransport protein?
The movement of protons through the cotransport protein cannot occur unless sucrose also moves at the same time.
Which of the following enables a cell to pick up and concentrate a specific kind of molecule?
receptor-mediated endocytosis
Which of the following processes, normally associated with membrane transport, must occur in order to account for the increase in the surface area of a cell?
exocytosis
A nursing infant is able to obtain disease-fighting antibodies, which are large protein molecules, from its mother's milk. These molecules probably enter the cells lining the baby's digestive tract via which process?
endocytosis
The transmission of nerve impulses between adjacent nerve cells requires the release of a neurotransmitter (a molecule or small peptide) by exocytosis. Which of the following processes would most likely follow the release of neurotransmitter to bring the cell back to its original state?
receptor-mediated endocytosis
Which one of the following pairs matches the name of a membrane transport process with the primary function of that process?
pinocytosis—the uptake of water and small solutes into the cell by formation of vesicles at the plasma membrane.
Which of the following correctly states the relationship between anabolic and catabolic pathways?
Anabolic pathways synthesize more complex organic molecules using the energy derived from catabolic pathways.
Which of the following situations does represent a transformation of one type of energy to another?
the burning of gasoline in a car engine to move a car
the production of sugar by photosynthesis
the production of electrical power by damming a river
playing music by putting new batteries in your CD player
Organisms are described as thermodynamically open systems. Which of the following statements is consistent with this description?
Organisms acquire energy from their surroundings.
Consider the growth of a farmer's crop over a season. Which of the following correctly states a limitation imposed by the first or second laws of thermodynamics?
In order to obey the first law, the crop must represent an open system.
Which of the following states the relevance of the first law of thermodynamics to biology?
Energy can be freely transformed among different forms as long as the total energy is conserved.
Which is the most abundant form of energy in a cell?
chemical energy
Which of the following is an example of the second law of thermodynamics as it applies to biological reactions?
The aerobic respiration of one molecule of glucose produces six molecules each of carbon dioxide and water.
According to the second law of thermodynamics, which of the following is true?
The decrease in entropy associated with life must be compensated for by an increase in entropy in the environment that life occurs in.
If the entropy of a living organism is decreasing, which of the following is most likely to be occurring simultaneously?
Energy input into the organism must be occurring in order to drive the decrease in entropy.
Which one of the following has the most free energy per molecule?
a starch molecule
Which part of the equation DG = DH - TDS tells you if a process is spontaneous?
DG
If, during a process, the system becomes more ordered, then _____.
DG is negative
When one molecule is broken down into six component molecules, which one of the following will always be true?
DS is positive
From the equation DG = DH - TDS it is clear that _____.
a decrease in the system's total energy will increase the probability of spontaneous change
increasing the entropy of a system will increase the probability of spontaneous change
increasing the temperature of a system will increase the probability of spontaneous change
What must be true if the reaction AB + CD ® AC + BD occurs spontaneously?
The difference between DH and TDS must be negative.
An exergonic (spontaneous) reaction is a chemical reaction that _____.
releases energy when proceeding in the forward direction
Which of the following reactions would be endergonic?
glucose+fructose=surcrose
Metabolic pathways in cells are typically far from equilibrium. Which of the following processes tend to keep these pathways away from equilibrium?
the continuous removal of the products of a pathway to be used in other reactions
an input of free energy from outside the pathway
Which of the following is are examples of the cellular work accomplished with the free energy derived from the hydrolysis of ATP?
mechanical work, such as the beating of cilia
transport work, such as the active transport of an ion into a cell
chemical work, such as the synthesis of new protein
20 . In general, the hydrolysis of ATP drives cellular work by _____.
releasing free energy that can be coupled to other reactions
Which of the following statements correctly describes some aspect of ATP hydrolysis being used to drive the active transport of an ion into the cell against the ion's concentration gradient?
This is an example of energy coupling.
Which compound could be most easily modified to form ATP?
the RNA nucleotide adenosine
the RNA nucleotide adenosine
Much of the suitability of ATP as an energy intermediary is related to the instability of the bonds between the phosphate groups. These bonds are unstable because _____.
the negatively charged phosphate groups vigorously repel one another and the terminal phosphate group is more stable in water than it is in ATP
When 1 mole of ATP is hydrolyzed in a test tube without an enzyme, about twice as much heat is given off as when 1 mole of ATP is hydrolyzed in a cell. Which of the following best explains these observations?
In the cell, the hydrolysis of ATP is coupled to other endergonic reactions.
What best characterizes the role of ATP in cellular metabolism?
The free energy released by ATP hydrolysis may be coupled to an endergonic process via the formation of a phosphorylated intermediate.
The formation of glucose-6-phosphate from glucose is an endergonic reaction and is coupled to which of the following reactions or pathways?
the hydrolysis of ATP
A chemical reaction is designated as exergonic rather than endergonic when _____.
the potential energy of the products is less than the potential energy of the reactants
What do the sign and magnitude of the DG of a reaction tell us about the speed of the reaction?
Neither the sign nor the magnitude of DG have anything to do with the speed of a reaction.
The mechanism of enzyme action is _____.
lowering the energy of activation for a reaction
Which of the following statements about enzymes is true?
Enzymes speed up the rate of the reaction without changing the DG for the reaction.
Which of the following statements about enzyme function is correct?
Enzymes can lower the activation energy of reactions, but they cannot change the equilibrium point because they cannot change the net energy output.
32 . A plot of reaction rate (velocity) against temperature for an enzyme indicates little activity at 10°C and 45°C, with peak activity at 35°C. The most reasonable explanation for the low velocity at 10°C is that _____.
there is too little activation energy available
Which of the following statements about enzymes are correct?
Most enzymes are proteins.
An enzyme is not consumed by the catalytic process.
An enzyme is very specific in terms of which substrate it binds to.
An enzyme lowers the activation energy of a chemical reaction.
Which of the following statements about the active site of an enzyme is correct?
The active site may resemble a groove or pocket in the surface of a protein into which the substrate fits.
What is meant by the "induced fit" of an enzyme?
The enzyme changes its shape slightly as the substrate binds to it.
Which of the following statements correctly describe(s) the role(s) of heat and temperature in biological reactions?
Heat from the environment is necessary for substrates to get over the activation energy barrier.
Increasing temperature increases the kinetic energy of the substrates.
Above a certain substrate concentration, the rate of an enzyme-catalyzed reaction drops as the enzymes become saturated. Which of the following would lead to a faster conversion of substrate into product under these saturated conditions?
an increase in concentration of enzyme
increasing the temperature by a few degrees
Which of the following environments or actions does not affect the rate of an enzyme reaction?
heating the enzyme
cooling the enzyme
substrate concentration
pH
all of the above
all of the above
Enzyme activity is affected by pH because _____.
high or low pH may disrupt hydrogen bonding or ionic interactions and thus change the shape of the active site
Which of these statements about enzyme inhibitors is true?
The action of competitive inhibitors may be reversible or irreversible.
Succinylcholine is structurally almost identical to acetylcholine. If succinylcholine is added to a mixture that contains acetylcholine and the enzyme that hydrolyzes acetylcholine (but not succinylcholine), the rate of acetylcholine hydrolysis is decreased. Subsequent addition of more acetylcholine restores the original rate of acetylcholine hydrolysis. Which of the following correctly explains this observation?
Succinylcholine must be a competitive inhibitor with acetylcholine.
The process of stabilizing the structure of an enzyme in its active form by the binding of a molecule is an example of _____.
allosteric regulation
Which, if any, of the following statements is not true about allosteric proteins?
They can bind to a range of substrates.
The binding of an allosteric inhibitor to an enzyme causes the rate of product formation by the enzyme to decrease. Which of the following best explains why this decrease occurs?
The allosteric inhibitor causes a structural change in the enzyme that prevents the substrate from binding at the active site.
Under most conditions, the supply of energy by catabolic pathways is regulated by the demand for energy by anabolic pathways. Considering the role of ATP formation and hydrolysis in energy coupling of anabolic and catabolic pathways, which of the following statements is most likely to be true?
High levels of ADP act as an allosteric activator of catabolic pathways
A molecule becomes more oxidized when it _____.
loses an electron
In the overall process of glycolysis and cellular respiration, _____ is oxidized and _____ is reduced.
glucose ... oxygen
Most of the ATP produced in cellular respiration comes from which of the following processes?
oxidative phosphorylation
Oxygen gas (O2) is one of the strongest oxidizing agents known. The explanation for this is that _____.
the oxygen atom is very electronegative
The function of cellular respiration is to _____.
extract usable energy from glucose
During the reaction C6H12O6 + 6 O2 ® 6 CO2 + 6 H2O, which compound is reduced as a result of the reaction?
oxygen
Which of the following statements provides the best explanation for why the oxidation of organic compounds by molecular oxygen (O2) yields so much energy?
The oxygen atom has a higher affinity for electrons than the carbon atom.
Each ATP molecule contains about 1% of the amount of chemical energy available from the complete oxidation of a single glucose molecule. Cellular respiration produces about 38 ATP from one glucose molecule. What happens to the rest of the energy in glucose?
it is converted to heat
A small amount of ATP is made in glycolysis by which of the following processes?
transfer of a phosphate group from a fragment of glucose to ADP by substrate-level phosphorylation
A chemist has discovered a drug that blocks phosphoglucoisomerase, an enzyme that catalyzes the second reaction in glycolysis. He wants to use the drug to kill bacteria in people with infections. But he can't do this because _____.
human cells must also perform glycolysis; the drug might also poison them
In glycolysis, there is no production of carbon dioxide as a product of the pathway. Which of the following is the best explanation for this?
The two pyruvate molecules produced from each glucose molecule each contain three carbon atoms.
Of the following molecules in the glycolytic pathway (the process of glycolysis), the one with the most chemical energy is _____.
fructose-1,6-bisphosphate
During respiration in a eukaryotic cell, reactions of glycolysis occur _____.
in the cytosol
What is the name of the process in which glucose is converted to pyruvate with the production of ATP and NADH?
glycolysis
Most of the NADH that delivers electrons to the electron transport chain comes from which of the following?
the citric acid cycle
In an experiment, mice were fed glucose (C6H12O6) containing a small amount of radioactive oxygen. The mice were closely monitored, and in a few minutes radioactive oxygen atoms showed up in which compound?
carbon dioxide
In preparing pyruvate to enter the citric acid cycle, which steps occur?
It is oxidized, and the resulting electrons reduce an NAD+ to an NADH.
A carbon atom is released in carbon dioxide.
A compound called coenzyme A binds to a two-carbon fragment.
The product of this reaction is transferred from the cytoplasm to the matrix of the mitochondria.
Why is the citric acid cycle called a cycle?
The four-carbon acid that accepts the acetyl CoA in the first step of the cycle is regenerated by the last step of the cycle.
In the citric acid cycle, for each pyruvate that enters the cycle, 1 ATP, 3 NADH, and 1 FADH2 are produced. For each glucose molecule that enters glycolysis, how many ATP, NADH, and FADH2 are produced in the citric acid cycle?
2 ATP, 6 NADH, 2 FADH2
During respiration in a eukaryotic cell, reactions of the citric acid cycle occur _____.
in the matrix of the mitochondrion
How many molecules of ATP are gained by substrate-level phosphorylation from the complete breakdown of a single molecule of glucose in the presence of oxygen?
4
Which of the following represents the major (but not the only) energy accomplishment of the citric acid cycle?
formation of NADH and FADH2
After completion of the citric acid cycle, most of the usable energy from the original glucose molecule is in the form of _____.
NADH
Which of the following accompanies the conversion of pyruvate to acetyl CoA before the citric acid cycle?
formation of CO2 and NADH
The energy given up by electrons as they move through the electron transport chain is used in which of the following processes?
the production of CO2
pumping H+ across a membrane
The ATP synthase in a human cell obtains energy for making ATP directly from which of the following processes?
the flow of H+ across a membrane through the ATP synthase enzyme
When a poison such as cyanide blocks the electron transport chain, glycolysis and the citric acid cycle soon grind to a halt as well. Which of the following is the best explanation for this?
NAD+ and FAD are not available for glycolysis and the citric acid cycle to continue.
Which of the following sequences correctly describes the synthesis of ATP associated with electron transport in mitochondria?
NADH, electron transport, proton gradient, chemiosmosis
Most of the electrons removed from glucose by cellular respiration are used for which of the following processes?
reducing NAD+ to NADH in glycolysis and the citric acid cycle
producing a proton gradient for ATP synthesis in the mitochondria
Which part of the cellular catabolism of glucose both requires molecular oxygen (O2) and produces CO2?
the combination of the citric acid cycle and electron transport
During aerobic respiration, molecular oxygen (O2) is used for which of the following purposes?
at the end of the electron transport chain to accept electrons and form H2O
Which of the following substances, if any, is not directly involved in oxidative phosphorylation?
glucose
Which one of the following best describes the electron transport chain?
Electrons are passed from one carrier to another, releasing a little energy at each step.
If a compound that allows protons to freely diffuse across membranes is added to cells that are actively metabolizing glucose via cellular respiration, which of the following processes would stop?
glycolysis
electron transport
ATP synthesis
none of the above
all of the above
none of the above
Which one of the following is the source of the energy that produces the chemiosmotic gradient in mitochondria?
electrons moving down the electron transport chain
During respiration in a eukaryotic cell, the electron transport chain is located in or on the _____.
inner membrane of the mitochondrion
The overall efficiency of respiration (the percentage of the energy released that is saved in ATP) is approximately _____.
40%
Fermentation is essentially glycolysis plus an extra step in which pyruvate is reduced to form lactate or alcohol and carbon dioxide. This last step _____.
enables the cell to recycle NAD+
Sports physiologists at an Olympic training center wanted to monitor athletes to determine at what point their muscles were functioning anaerobically. They could do this by checking for a buildup of which of the following compounds?
lactate
In glycolysis in the absence of oxygen, cells need a way to regenerate which compound?
NAD+
Muscle tissues make lactate from pyruvate in order to do which of the following?
regenerate NAD+
42 . In brewing beer, maltose (a disaccharide of glucose) is _____.
the substrate for alcoholic fermentation
If muscle cells in the human body consume O2 faster than it can be supplied, which of the following is likely to result?
The muscle cells will have more trouble making enough ATP to meet their energy requirements.
The cells will not be able to carry out oxidative phosphorylation.
The cells will consume glucose at an increased rate.
Of the metabolic pathways listed below, which is the only pathway found in all organisms?
glycolysis
When protein molecules are used as fuel for cellular respiration, _____ are produced as waste.
amino groups
A gram of fat oxidized by respiration produces approximately twice as much ATP as a gram of carbohydrate. Which of the following best explains this observation?
Fats are better electron donors to oxygen than are sugars.
If significant amounts of materials are removed from the citric acid cycle to produce amino acids for protein synthesis, which of the following will result?
Less ATP will be produced by the cell.
Less CO2 will be produced by the cell.
The four-carbon compound that combines with acetyl CoA will have to be made by some other process.
In photosynthesis, plants use carbon from _____ to make sugar and other organic molecules.
carbon dioxide
Which of the following would be capable of performing photosynthesis?
a bacterium
a pine tree
seaweed
algae
How does carbon dioxide enter the leaf?
through the stomata
In a rosebush, chlorophyll is located in _____.
thylakoids, which are in chloroplasts in the mesophyll cells of a leaf
Chlorophyll molecules are in which part of the chloroplast?
grana stacks
The source of the oxygen produced by photosynthesis has been identified through experiments using radioactive tracers. The oxygen comes from _____.
water
In photosynthesis, what is the fate of the oxygen atoms present in CO2? They end up ______.
in sugar molecules and in water
Molecular oxygen is produced during _____.
light reactions of photosynthesis
The reactions of the Calvin cycle are not directly dependent on light, but they usually do not occur at night. Why?
The Calvin cycle depends on products of the light reactions.
The photosynthetic event known as the Calvin cycle occurs in the _____.
stroma
A photon of which of these colors would carry the most energy?
blue
The most important role of pigments in photosynthesis is to _____.
capture light energy
The wavelengths of light absorbed by pigments in the granum are mainly in which range?
blue-violet and red-orange
Engelmann's experiment determined which wavelengths of light are most effective at causing photosynthesis. In other words, Engelmann measured _____.
an action spectrum
When chloroplast pigments absorb light, _____.
their electrons become excited
The reaction center, light-harvesting complexes, and primary electron acceptors that cluster in the thylakoid membrane form which structure?
photosystem
Where do the electrons needed by photosystem II originate?
water
During photosynthesis in chloroplasts, O2 is produced from ______ via a series of reactions associated with ______.
H2O ... photosystem II
During photosynthesis, an electron transport chain is used to _____.
transport electrons from photosystem II to photosystem I
Which one of the following is cycled in the cyclic part of light reactions?
electrons
Both mitochondria and chloroplasts _____.
use a hydrogen ion (proton) gradient to produce ATP
You could distinguish a granum from a crista because the granum, but not the crista, would _____.
have photosynthetic pigments
During photosynthesis in a eukaryotic cell, a high proton concentration accumulates or is formed in the ______.
(inner) thylakoid space
The light reactions of photosynthesis generate high-energy electrons, which end up in ____. The light reactions also produce ____ and ____.
NADPH ... ATP ... oxygen
The energy used to produce ATP in the light reactions of photosynthesis comes from _____.
movement of H+ through a membrane
What is the role of NADP+ in photosynthesis?
It is reduced and then carries electrons to the Calvin cycle.
Light reactions do all of the following except _____.
reduce CO2
Rubisco is _____.
the enzyme in plants that first captures CO2 to begin the Calvin cycle
In the Calvin cycle, CO2 is combined _____.
with a 5-carbon compound to form an unstable 6-carbon compound, which decomposes into two 3-carbon compounds
Glyceraldehyde-3-phosphate is produced in the stroma of chloroplasts. Which of the following statements is true about this compound?
It is produced from glucose during glycolysis.
Which of the following correctly matches each of the inputs of the Calvin cycle with its role in the cycle?
carbon dioxide: carbon ... ATP: energy ... NADPH: high-energy electrons
What is the role of NADP+ in photosynthesis?
It forms NADPH to be used in the Calvin cycle
The use of non-C3 and non-CAM plants as crops may be limited in some regions because on hot, dry days, they close their stomata. What happens as a result of closing their stomata?
It reduces water loss.
It prevents carbon dioxide from entering the leaf.
In a process called photorespiration, rubisco binds oxygen instead of carbon dioxide.
It builds up oxygen from the light reactions in the leaf.
Why are C4 plants more suited to hot climates than C3 plants?
Unlike C3 plants, they keep fixing carbon dioxide even when the concentration of carbon dioxide in the leaf is low.
You have a large, healthy philodendron that you carelessly leave in total darkness while you are away on vacation. You are surprised to find that it is still alive when you return. What has the plant been using for an energy source while in the dark?
While it did have access to light, the plant stored energy in the form of sugars or starch, and it was able to derive energy from the stored molecules during your vacation.
Would it be good idea to give a severely dehydrated person an IV solution of sterile water?
NO b/c if you add a lot of fresh water, the water will move in to the red blood cell and it will BURST
When solute concentrations are equal both sides of the diffusion barrier the molecules no longer move.
FALSE (when equal, there is still movement)
Isotonic marine invertebrates tend to:
Neither gain nor lose water (equal concentration)
true or false. Metabolism is a biological chemical reaction.
true.
t or f. energy is the capacity to do work.
true
what is released by spontaneous chemical reactions?
energy (exergonic)
What law of thermodynamics does this apply to? Your roommate's side of the rom keeps getting messier.
2nd law
an exergonic reaction
delta G
true or false. Enzymes accelerate a reaction by making the overall energy more favorable.
False (∆ G) enzymes don't affect that
true or false. Chemical reactions only proceed spontaneously in the "downhill" reaction.
true
Which determines the reaction rate, ∆G or ∆G double dagger?
∆G double dagger
Determines whether a reaction occurs spontaneously.
delta G
true or false. Enzymes work by lowering the activation energy barrier
true.
what has an exergonic reaction
negative delta G
true or false. To make a better catalyst, have a higher ∆G double-dagger.
False (lower ∆G double-dagger)
At a common measurement temperature, ____ will have the faster catalytic rate.
enzyme homologs from cold species
For a biological chemical reaction a 10*C temperate increaser will ___.
double the reaction rate
_____ determines the reaction rate.
delta G double dagger
delta G represents ____.
G products-G reactants
true or false. Enzymes accelerate a reaction by making the overall energetic more favorable.
false.
spontaneous chemical reactions always ____.
release energy
∆G = ∆H
-T ∆S
true or false. Chemical reactions only proceed spontaneously in the "downhill" direction.
true.
uphill reactions can never occur ____.
spontaneously
synthesis of complex biological molecules is ____.
endergonic (input of energy)
hydrolysis=
water added
which are broken when a protein denatures?
hydrogen bonds (not peptide or covalent bonds)
what sets the upper temperature limit for life?
the stability of biological molecules
• At high temperatures, biological molecules, such as proteins and DNA, break down very rapidly
• It is energetically too costly to make biological molecules that breakdown that quickly
Circe Effect: Siren Song =
a positively charged arginine
An enzyme-catalyzed reaction generally doubles its rate for a 10*V temperature increase. However, at some point the enzyme's
high temperature will denature proteins
Circe Effect: Odysseus' men
negatively charged substrate
temperature is
a measure of kinetic energy
heat is
a measure of total energy
an enzyme-catalyzed reaction generally ___ its rate for a 10*C temperature increase.
doubles
how is a pathway turned off?
turn off the first enzyme
The first enzyme of the pathway is allosteric regulated. Why is it not a competitive inhibitor?
the product is dissimilar to the pathway and cannot inhibit the site
• By shutting down the first pathway, you don't have to modify the activity of the other
specialized cellular compartment for digestion of food particles
Lysosomes ("lysis" means to break down)
Allosteric inhibition
binding of a modulator other than active site
true or false. the binding of oxygen to hemoglobin is an example of cooperatively.
true
what are the 2 hallmarks of metabolism?
each step is catalyzed by a specific enzyme and occurs in small steps
Anabolic reactions use what two things?
Use reducing power and Use ATP
When ATP is hydrolyzed to ADP and inorganic phosphate, how much energy is released?
-7.3 kcal/mol
ATP production results from
Catabolic processes
the oxidation of glucose releases 686 kcal/mol
-∆G
Phosphorylation reactions are catalyzed by enzymes called ___.
kinases
Why is the citric acid/ Kreb Cycle called a cycle?
the starting compounds are regenerated
where does the reducing power come from
NADH - glycolysis, Nadh, fadh4
which has more energy, glucose or CO2?
glucose
which has more energy, ATP or glucose?
glucose
which has more energy, ATP or NADH?
NADH
which has more energy, NADH or FADH2?
NADH
In animals, ATP syntheses is located where?
inner membrane mitochondria
if the number of hydrogen ion pumps in the ETS is increased what impact will this have on ATP production?
increase
if the number of hydrogen ion pumps in the ETS is increased what impact will this have on substrate level ATP production?
no impact
A 70 kg man produces 150kg of H per day. This is not a problem because:
the protons are used on oxidative phosphorylation
With inadequate oxygen, why does NAD need to be regenerated?
There is a constant pool of coenzyme and it would all be in the form of NADH & NAD is needed to glycolysis to proceed
With adequate oxygen, why isn't the build up NADH a problem
NAD is regenerated in oxidative
Using glucose as the starting material, how many ATP (total) are generated producing pyruvate?
4
In the oxidation of glucose, which process produces the most ATP?
oxidative phosphorylation
at what stage is CO2 produced?
citric acid cycle
***With inadequate oxygen, why does NAD need to be regenerated?
A: NAD is needed to glycolysis to proceed & there's is a constant pool of coenzyme and it would...
with adequate oxygen, why isn't the build up of NADH a problem?
NAD is regenerated in oxidative phosphorylation
the molecular oxygen in respiration is
used to produce H2O
oxidation of fats occurs in the ___.
mitochondria
how many additional ATPs result from lactate production?
zero
t or f. the purpose of lactase/ethanol os to regenerate NAD
true
t or f. most forging dives by marine mammals are anaerobic dives.
false
how many ATPs are produced using glycogen as a starting material?
4
how many ATPs (net) are produced in glycolysis using glucose as the starting material?
2
How many ATPs (net) are produced in glycogenolysis (using glycogen as the starting material)?
3
in the complete oxidation of glucose which process produces the most ATP?
Oxidative phosphorylation
at which stage is CO2 produced?
krebs
the molecular oxygen in respiration is used to
produce water
which is worth the most energy?
pyruvate (ATP 1, NADH 3, FADH 2)
how many additional ATP are gained by producing lactate from pyruvate?
zero
the purpose of producing lactate/ethanol is to regenerate NAD
true
oxidation of fats occur in
the mitochondria
are there photosynthetic animals?
maybe; Corals grow algae on its tissue and benefits from it. some species from sea slugs. These animals are photosynthesizing from the help of plants.
when a plant grows, the increase in biomass (carbon) comes from ___.
the air (carbon comes from CO2 in the air)
of these three, which has the longest wavelength? (inferred, visible, ultraviolet)
inferred light
high energy light which may damage biological molecules
ultraviolet (the shorter the wavelength, the higher the energy) has sufficient energy that can damage biological molecules and can cause mutations
the tail of chlorophyll which is embedded in the thylakoid membrane is __.
hydrophobic
the purpose of the light reactions is to produce __.
ATP and NADPH
probably should have received the Nobel prize with Calvin for photosynthesis ___.
Benson
the dark reactions of photosynthesis occur in the
stroma of chloroplast
the photosystems/photosynthesis of the light reactions are found in the
thylakoid membrane of chloroplasts
in animals, ATP synthase is located where?
in the inner mitochondria of the membrane
in plants ATP synthase is located where?
inner mitochondria membrane and thylakoid membrane
ATP, NADH, and FADH2 are produced by ___.
krebs cycle
ATP and NADPH are produced
in the light reactions
ATP and NADPH are used by
the Calvin Benson cycle
O2 is produced by the
light reactions
water is split in
the light reactions
water is formed in
oxidative phosphorylation
O2 is used by
oxidative phosphorylation
pores on the lower surface of a leaf
stoma
C4 plants separate C fixation from the Calvin Benson cycle
in space
CAM plants separate C fixation from the Calvin Benson cycle
in time