Unit 2 quizzes

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 This solution is hypertonic to the plant cell. Water will leave the cell, and eventually the plasma membrane will pull away from the cell wall, resulting in plasmolysis.

If glucose is the sole energy source, what fraction of the carbon dioxide exhaled by animals is generated by the reactions of the citric acid cycle?

2/3

Green olives may be preserved in brine, which is a 30% salt solution. How does this method of preservation prevent microorganisms from growing in the olives?

A 30% salt solution is hypertonic to the bacteria, so they lose too much water and undergo plasmolysis. If a cell is placed in a hypertonic solution, it will lose water to its environment, shrivel, and probably die.

Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle?

ATP and NADPH

In the absence of oxygen, yeast cells can obtain energy by fermentation, resulting in the production of _____.

ATP, CO2, and ethanol (ethyl alcohol)

Active and passive transport of solutes across a membrane typically differ in which of the following ways?

Active transport always involves the utilization of cellular energy, whereas passive transport does not require cellular energy.

Which of the following is a correct difference between active transport and facilitated diffusion?

Active transport requires energy from ATP, and facilitated diffusion does not. Active transport can move substances against the concentration gradient, but it requires energy in the form of ATP.

Which of the following statements about enzymes is INCORRECT?

An enzyme is consumed during the reaction it catalyzes.

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 The synthesis of complex molecules in anabolic pathways requires an input of energy from catabolic pathways.

Living organisms increase in complexity as they grow, resulting in a decrease in the entropy of an organism. How does this relate to the second law of thermodynamics?

As a consequence of growing, organisms cause a greater increase in entropy in their environment than the decrease in entropy associated with their growth.

Which statement is correct? A. A solution of distilled water is hypotonic. B. The contents of a red blood cell are hyperosmotic to distilled water. C. A solution of seawater is hypertonic.

B

Cells A and B are the same size, shape, and temperature, but cell A is metabolically less active than cell B. and cell B is actively converting oxygen to water in cellular respiration. Oxygen will diffuse more rapidly into cell __________ because __________.

B ... the diffusion gradient in cell B is steeper As long as a metabolically active cell converts oxygen to water during cellular respiration shortly after it enters, diffusion into the cell will continue because the concentration gradient favors movement in that direction.

Seawater is hypertonic to cytoplasm in vertebrate cells and in plant cells. 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 the following statements is TRUE with regard to this animation?

Both sodium and potassium ions are transported against their concentration gradients

Five dialysis bags constructed of membrane, which is permeable to water and impermeable to sucrose, were filled with various concentrations of sucrose and then placed in separate beakers containing an initial concentration of 0.6 M sucrose solution. At 10-minute intervals, the bags were massed (weighed) and the percent change in mass of each bag was graphed.

C

Which of the listed statements describes the results of the following reaction? C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + Energy

C6H12O6 is oxidized and O2 is reduced.

Which of the following would likely move through the lipid bilayer of a plasma membrane most rapidly?

CO2

Which of the following environments or actions would NOT affect the rate of an enzyme reaction?

Changes in temperature, substrate concentration, and pH are all likely to affect enzyme activity.

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 law of thermodynamics?

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 law of thermodynamics?

Which of the following correctly describes a general property of all electrogenic pumps?

Electrogenic pumps create a voltage difference across the membrane. An electrogenic pump creates a net charge difference across a membrane (a membrane potential).

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. Energy can be freely transformed among different forms as long as the total energy is conserved.

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 to drive the decrease in entropy. If the entropy is decreasing, this would tend to make the free energy change associated with this positive. Thus, an input of energy would be required to make this decrease in entropy occur.

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.

Which of the following statements about enzymes is/are true?

Enzymes speed up the rate of the reaction without changing the DG for the reaction.

Which of the following statements is a logical consequence of the second law of thermodynamics?

Every chemical reaction must increase the total entropy of the universe.

Which of these is NOT a product of glycolysis?

FADH2 FADH2 is a product of the citric acid cycle.

Which of these statements describes some aspect of facilitated diffusion?

Facilitated diffusion of solutes may occur through channel or transport proteins in the membrane. The passageways for facilitated diffusion may be either protein pores or carrier proteins.

During photosynthesis in chloroplasts, O2 is produced from __________ via a series of reactions associated with __________.

H2O ... photosystem II

Which of the following statements correctly describe(s) the role or roles of heat in biological reactions?

Heat from the environment is necessary for substrates to get over the activation energy barrier. The kinetic energy of the substrates is increased as the amount of heat in the system is increased.

A young dog has never had much energy. He is brought to a veterinarian for help and she decides to conduct several diagnostic tests. She discovers that the dog's mitochondria can use only fatty acids and amino acids for respiration, and his cells produce more lactate than normal. Of the following, which is the best explanation of the dog's condition?

His mitochondria lack the transport protein that moves pyruvate across the outer mitochondrial membrane.

If, during a process, the system becomes more ordered, then __________.

In an endergonic reaction, in which order is increased, the change in entropy, symbolized by ΔS, is negative.

In the citric acid cycle, ATP molecules are produced by _____.

In the citric acid cycle, ATP molecules are produced by _____.

What is the role of NADP+ in photosynthesis?

It forms NADPH to be used in the Calvin cycle.

Which of the following statements about diffusion is true?

It is a passive process. Diffusion is the tendency of molecules to spread out in the available space. A substance will diffuse from an area of higher concentration to an area of lower concentration without energy input.

What is the role of NADP+ in photosynthesis?

It is reduced and then carries electrons to the Calvin cycle.

When ATP releases some energy, it also releases inorganic phosphate. What happens to the inorganic phosphate in the cell?

It may be used to form a phosphorylated intermediate.

Which of the following describes the process of glycolysis?

It represents the first stage in the chemical oxidation of glucose by a cell.

Which of the following statements concerning carbohydrates associated with the plasma membrane is correct?

Membrane carbohydrates function primarily in cell-cell recognition. Variations in carbohydrate structure distinguish one species from another, one individual from another, and even one cell type from another.

Which of the following functions of membrane proteins is important in tissue formation during embryonic development in animals?

Membrane proteins with short sugar chains form identification tags that are recognized by other cells. Cell-cell recognition is an important function of membrane proteins, and this cell-cell recognition is important in tissue formation during embryogenesis.

The light reactions of photosynthesis generate high-energy electrons, which end up in __________ through linear electron flow. The light reactions also produce __________ and __________.

NADPH ... ATP ... oxygen

What do the sign and magnitude of the ΔG of a reaction tell us about the speed of the reaction?

Neither the sign nor the magnitude of ΔG has anything to do with the speed of a reaction

A selectively permeable membrane separates two solutions. Water is able to pass through this membrane; however, sucrose (a disaccharide) and glucose (a monosaccharide) cannot pass. The membrane separates a 0.2-molar sucrose solution from a 0.2-molar glucose solution. With time, how will the solutions change?

Nothing will happen, because the two solutions are isotonic to one another. Osmotic pressure is produced by the concentration of dissolved substances and is not influenced by the relative sizes of the solutes.

Organisms are described as thermodynamically open systems. Which of the following statements is consistent with this description?

Organisms acquire energy from, and lose energy to, their surroundings.

Which of the following statements about passive transport is correct?

Passive transport permits the solute to move in either direction, but the net movement of solute molecules occurs down the concentration gradient of the molecule. Passive transport can occur in either direction, but the direction of net diffusion is down the concentration gradient of the solute.

Which of the following statements about the role of phospholipids in the structure and function of biological membranes is correct?

Phospholipids form a selectively permeable structure. Their structure allows some substances to penetrate easily and blocks others.

When 10,000 molecules of ATP are hydrolyzed to ADP and i in a test tube, about half as much heat is liberated as when a cell hydrolyzes the same amount of ATP. Which of the following is the best explanation for this observation?

Reactant and product concentrations in the test tube are different from those in the cell.

A semipermeable membrane is placed between the following solutions. Which solution will decrease in volume? Solution A: 1.4% (m/v) starch Solution B: 7.62% (m/v) starch

Solution A: 1.4% (m/v) starch

A semipermeable membrane is placed between the following solutions. Which solution will increase in volume? Solution C: 9% (m/v) NaCl Solution D: 12.4% (m/v) NaCl

Solution D: 12.4% (m/v) NaCl

The reactions of the Calvin cycle are NOT directly dependent on light, but they usually do NOT occur at night. Why?

The Calvin cycle requires products only produced when the photosystems are illuminated.

Which of these statements about enzyme inhibitors is true?

The action of competitive inhibitors may be reversible or irreversible.

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.

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.

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. The second law of thermodynamics states that every energy transformation makes the universe more disordered—carbon dioxide and water are more disordered than glucose.

Which of the following statements about the chemiosmotic synthesis of ATP is correct?

The chemiosmotic synthesis of ATP requires that the electron transport in the inner mitochondrial membrane be coupled to proton transport across the same membrane.

The binding of a compound to an enzyme is observed to slow down or stop the rate of the reaction catalyzed by the enzyme. Increasing the substrate concentration reduces the inhibitory effects of this compound. Which of the following could account for this observation?

The compound is a competitive inhibitor.

Which of the following statements about ATP (adenosine triphosphate) is correct?

The cycling between ATP and ADP + Pi provides an energy coupling between catabolic and anabolic pathways.

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 increased entropy in the environment in which life exists. The second law of thermodynamics demands that total entropy increase with any reaction.

Which of the following statements correctly describe(s) the driving forces for diffusion of Na+ and K+ ions through their respective channels? Select all that apply.

The diffusion of Na+ ions into the cell is facilitated by the Na+ concentration gradient across the plasma membrane. The diffusion of K+ ions out of the cell is impeded by the electrical gradient across the plasma membrane. The electrochemical gradient is larger for Na+ than for K+.

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 correct?

The entropy of the products is greater than the entropy of the reactants.

What is meant by the "induced fit" of an enzyme?

The enzyme changes its shape slightly as the substrate binds to it.

The plasma membrane is referred to as a "fluid mosaic" structure. Which of the following statements about that model is true?

The fluid aspect of the membrane is due to the lateral and rotational movement of phospholipids, and embedded proteins account for the mosaic aspect.

Which of the following 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.

What is the free energy change (ΔG) of the hydrolysis of ATP to ADP?

The free-energy change (ΔG) of the hydrolysis of ATP to ADP and Pi may vary considerably with variations in pH, temperature, atmospheric pressure, and concentrations of reactants and products.

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, do protons not move back into the cell through the sucrose-proton cotransport protein?

The movement of protons through the cotransport protein cannot occur unless sucrose moves at the same time.

Part complete For living organisms, which of the following is an important consequence of the first law of thermodynamics?

The organism ultimately must obtain all of the necessary energy for life from its environment.

Which of the following statements about osmosis is correct?

The presence of aquaporins (proteins that form water channels in the membrane) should speed up the process of osmosis.

Which of the following is true for all exergonic reactions?

The reaction proceeds with a net release of free energy.

Molecules A and B contain 110 kcal/mol of free energy, and molecules B and C contain 150 kcal/mol of energy. A and B are converted to C and D. What can be concluded?

The reaction that proceeds to convert A and B to C and D is endergonic; the products are more organized than the reactants.

Active transport requires an input of energy and can also generate voltages across membranes. Based on this information, which of the following statements is true?

The sodium-potassium pump hydrolyzes ATP and results in a net positive change outside the cell membrane.

Which statements about the sidedness of the plasma membrane is correct?

The two lipid layers may differ in specific lipid composition. 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 a 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.

Which of the following statements about a typical plasma membrane is correct?

The two sides of the plasma membrane have different lipid and protein composition.

Glucose can be moved into cells via an active transport mechanism when the concentration of glucose inside the cell is higher than the concentration of glucose outside of the cell. This active transport mechanism moves glucose and sodium into the cell at the same time. The glucose moves up its gradient and the sodium moves down its gradient. Which of the following statements about this mechanism is accurate?

To pump glucose up its concentration gradient, sodium moves down its concentration gradient, and the distribution of sodium ions across the membrane forms an electrochemical gradient that drives this mechanism. The movement of sodium down its gradient drives glucose up its gradient, and because sodium is at different concentrations on either side of the membrane and as sodium has a +1 charge, an electrochemical gradient also exists.

In facilitated diffusion, what is the role of the transport protein?

Transport proteins provide a hydrophilic route for the solute to cross the membrane.

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. The added salt makes the solution hypertonic compared to the cell. Water will leave the cell by osmosis.

oxygen

What molecule is indicated by the letter D?

Glycolysis Glycolysis occurs in the cytosol.

What process occurs in Box A?

the citric acid cycle The citric acid cycle transfers electrons to NADH and FADH2.

What process occurs within Box B?

Which of the following is FALSE in regard to facilitated diffusion?

Which of the following is FALSE in regard to facilitated diffusion? This statement is false. Facilitated diffusion, like simple diffusion, needs only a concentration gradient—no energy input is required.

The process of cellular respiration, which converts simple sugars such as glucose into CO2 and water, is an example of _____.

a catabolic pathway

From the equation ΔG = ΔH - TΔS 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, and increasing the temperature of a system will increase the probability of spontaneous change

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 When a cell is placed in a hypertonic environment, water will leave the cell, causing it to shrink.

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 The combination of being polar and large means that this molecule will be the slowest one from the choices to move across the membrane.

Which of the following is an example of potential rather than kinetic energy?

a molecule of glucose

Which of these is exhibiting kinetic energy?

a space station orbiting Earth

The oxygen consumed during cellular respiration is involved directly in which process or event?

accepting electrons at the end of the electron transport chain

Which one of the following is formed by the removal of a carbon (as CO2) from a molecule of pyruvate?

acetyl CoA

Reactants capable of interacting to form products in a chemical reaction must first overcome a thermodynamic barrier known as the reaction's _____.

activation energy

The process of stabilizing the structure of an enzyme in its active form by the binding of a molecule outside the active site is an example of __________.

allosteric activation

Based on the work of Engelmann, a plot of photosynthetic activity versus wavelength of light is referred to as __________.

an action spectrum

Which of the following statements correctly describes the normal tonicity conditions for typical plant and animal cells? The animal cell is in _____.

an isotonic solution, and the plant cell is in a hypotonic solution

Which of the following types of reactions would decrease the entropy within a cell?

anabolic reactions

Every ecosystem must have _____.

autotrophs

A photon of which of these colors would carry the most energy?

blue

What is the range of wavelengths of light that are absorbed by the pigments in the thylakoid membranes?

blue-violet and red-orange

How do enzymes lower activation energy?

by locally concentrating the reactants

A system at chemical equilibrium _____.

can do no work

The most important role of pigments in photosynthesis is to _

capture light energy

In photosynthesis, plants use carbon from __________ to make sugar and other organic molecules.

carbon dioxide

Which of the following molecules is most likely to passively diffuse across the plasma membrane?

carbon dioxide Hydrophobic molecules, such as hydrocarbons, carbon dioxide, and oxygen, can dissolve in the membrane and cross it with ease.

An animal cell lacking oligosaccharides on the external surface of its plasma membrane would likely be impaired in which function?

cell-cell recognition

In your body, what process converts the chemical energy found in glucose into the chemical energy found in ATP?

cellular respiration

The photosynthetic membranes are found in the _____ in plant cells.

chloroplasts An elaborate system of interconnected thylakoid membranes segregates the stroma from the thylakoid space in the chloroplast.

Singer and Nicolson's fluid mosaic model of the membrane proposed that membranes_____.

consist of protein molecules embedded in a fluid bilayer of phospholipids

Anabolic pathways _____.

consume energy to build up polymers from monomers

The movement of glucose into a cell against a concentration gradient is most likely to be accomplished by which of the following?

cotransport of the glucose with a proton or sodium ion that was pumped across the membrane using the energy of ATP hydrolysis

A red blood cell is placed into each of the following solutions. Indicate whether crenation, hemolysis, or neither will occur. Solution A: 3.21% (m/v) NaCl Solution B: 1.65% (m/v) glucose Solution C: distilled H2O Solution D: 6.97% (m/v) glucose Solution E: 5.0% (m/v) glucose and 0.9%(m/v) NaCl

crenation-A,D,E hemolysis-B,C

Which of the following is cycled in the cyclic variation of the light reactions?

electrons

According to the fluid mosaic model of membrane structure, proteins of the membrane are mostly

embedded in a lipid bilayer.

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 . Endocytosis is the procedure that cells use to import large molecules across their plasma membrane.

"Conservation of energy" refers to the fact that _____.

energy cannot be created or destroyed but can be converted from one form to another

Which of the following is NOT a function of membrane proteins?

energy, carbon, and nitrogen storage Proteins are not present in biological membranes to act as stores of energy, carbon, and nitrogen.

Which of the following processes and organelles account for the replacement of lipids and proteins lost from the plasma membrane?

exocytosis and smooth ER and rough ER . In exocytosis, vesicles derived from the endomembrane system fuse with the plasma membrane, thus increasing the number of phospholipids in the plasma membrane and increasing its surface area. The smooth ER is largely responsible for production of lipids destined for the membrane, and the rough ER produces proteins destined for 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 Both the electrical and chemical (concentration) gradients contribute the energy to move Ca2+ into the cells by facilitated diffusion as long as there is a channel or carrier that is specific for Ca2+.

Which of the following reactions would be endergonic?

glucose + fructose → sucrose In this case, the product is more complex (lower entropy) than the reactants, and like many anabolic reactions, this one requires an input of energy.

During aerobic respiration, electrons travel downhill in which sequence?

glucose → NADH → electron transport chain oxygen

Which of the following normally occurs regardless of whether or not oxygen (O2) is present?

glycolysis

Carbohydrates and fats are considered high-energy foods because they _____.

have a lot of electrons associated with hydrogen.

You could distinguish a thylakoid membrane from an inner mitochondrial membrane because the thylakoid membrane would __________.

have photosynthetic pigments

Which of these are by-products of cellular respiration?

heat, carbon dioxide, and water

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

What type of reaction breaks the bonds that join the phosphate groups in an ATP molecule?

hydrolysis

In photosynthesis, what is the fate of the oxygen atoms present in CO2? They end up

in sugar molecules and in water

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 The steroid cholesterol, wedged between phospholipid molecules in the plasma membranes of animals, helps stabilize the membrane.

Enzymes are described as catalysts, which means that they _____.

increase the rate of a reaction without being consumed by the reaction

The membranes of winter wheat are able to remain fluid when it is extremely cold by _____.

increasing the percentage of unsaturated phospholipids in the membrane

Molecular oxygen is produced during __________.

linear electron flow during the light reactions

The molecule that functions as the reducing agent (electron donor) in a redox or oxidation-reduction reaction _____.

loses electrons and loses potential energy

The energy used to produce ATP in the light reactions of photosynthesis comes from __________.

movement of H+ through a membrane

Consider the currently accepted fluid mosaic model of the plasma membrane. Where in the membrane would carbohydrates most likely be found?

on the outside (external) surface of the membrane

Carbon dioxide (CO2) is released during which of the following stages of cellular respiration?

oxidation of pyruvate to acetyl CoA and the citric acid cycle

White blood cells engulf bacteria using _____.

phagocytosis

Which of the following pairs correctly matches a membrane transport process to its primary function?

pinocytosis: the uptake of water and small solutes into the cell by formation of vesicles at the plasma membrane

Chemical energy is a form of _____ energy.

potential

The free energy derived from the hydrolysis of ATP can be used to perform many kinds of cellular work. Which of the following is an example of the cellular work involved in the production of electrochemical gradients?

proton movement against a gradient of protons Protein pumps that hydrolyze ATP can generate electrochemical gradients.

Which of the following enables a cell to pick up and concentrate a specific kind of molecule?

receptor-mediated endocytosis . In receptor-mediated endocytosis, only a specific molecule, called a ligand, can bind to the receptor. Without receptor binding occurring first, endocytosis does not proceed.

An exergonic (spontaneous) reaction is a chemical reaction that __________.

releases energy when proceeding in the forward direction Exergonic reactions proceed with a net release of free energy, and they occur spontaneously.

In general, the hydrolysis of ATP drives cellular work by __________.

releasing free energy that can be coupled to other reactions

What kinds of molecules pass through a cell membrane most easily?

small and hydrophobic

The Calvin cycle occurs in the __________.

stroma

In glycolysis, ATP molecules are produced by _____.

substrate-level phosphorylation A phosphate group is transferred from glyceraldehyde phosphate to ADP.

The ultimate source of energy to support most life on Earth is _____.

sunlight

Which of the following is changed by the presence of an enzyme in a reaction?

the activation energy

Metabolic pathways in cells are typically far from equilibrium. Which of the following processes tend(s) 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

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

Which of the following determines the sign of ΔG for a reaction?

the free energy of the reactants and the free energy of the products

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

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

What structure is formed by the reaction center, light-harvesting complexes, and primary electron acceptors that cluster, and is located in the thylakoid membrane?

the photosystem

When chloroplast pigments absorb light, __________.

the pigments' electrons become excited

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

The permeability of a biological membrane to a specific polar solute may depend on which of the following?

the types of transport proteins in the membrane

How does carbon dioxide enter the leaf?

through the stomata

During photosynthesis in a eukaryotic cell, an electrochemical gradient is formed across the

thylakoid membrane

Chlorophyll molecules are in which part of the chloroplast?

thylakoid membranes

In a rosebush, chlorophyll is located in __________.

thylakoids, which are in chloroplasts in the mesophyll cells of a leaf

Which of the following best describes the main purpose of the combined processes of glycolysis and cellular respiration?

transforming the energy in glucose and related molecules in a chemical form that cells can use for work

In the absence of oxygen, what is the net gain of ATP for each glucose molecule that enters glycolysis?

two ATP

Which of the following best describes the structure of a biological membrane?

two layers of phospholipids with proteins either crossing the layers or on the surface of the layers

In glycolysis, for each molecule of glucose oxidized to pyruvate _____.

two molecules of ATP are used and four molecules of ATP are produced.

In the electromagnetic spectrum, the type of radiation that we call visible light occurs between _____.

ultraviolet radiation and infrared radiation Visible light is a narrow band of the electromagnetic spectrum that lies between ultraviolet radiation and infrared radiation.

Both mitochondria and chloroplasts __________.

use chemiosmosis to produce ATP

The electrons stripped from glucose in cellular respiration end up in which compound?

water

The source of the oxygen produced by photosynthesis has been identified through experiments using radioactive tracers. The oxygen comes from __________.

water

Where do the electrons entering photosystem II come from?

water

Which part of the equation ΔG = ΔH - TΔS tells you if a process is spontaneous?

ΔG In any spontaneous process, the free energy of a system decreases. The change in free energy equals the change in total energy minus the change in entropy times the temperature.

When one molecule is broken down into six component molecules, which of the following will always be true?

ΔS is positive. The large increase in disorder associated with this reaction means that entropy (ΔS) increases.

Which part of the adenosine triphosphate molecule is released when it is hydrolyzed to provide energy for biological reactions?

γ-phosphate (the terminal phosphate)