Biology semester 2 first test

Which of the following statements regarding enzymes is FALSE? An enzyme may be used many times for the same specific reaction. The activity of enzymes can be regulated by factors in their environment. Enzymes are proteins that function as biological catalysts. Enzymes provide energy for the reactions they catalyze. Enzymes are highly specific for the molecules to which they attach.

Enzymes provide energy for the reactions they catalyze.

Imagine that you are conducting an experiment on a yeast enzyme known as sucrase. This enzyme is used by yeast cells to break down the disaccharide sucrose into the monosaccharides glucose and fructose. What type of reaction is this? Spontaneous Exergonic Metergonic Endergonic

Exergonic

AMP stores energy in its chemical bonds and is able to use that energy for work in the cell. True False

False

In cells, endergonic reactions are often coupled with exergonic reactions that store energy. True False

False

Kinetic energy is like sitting at the top of a hill, and potential energy is like coasting down that hill on your bike. True or False?

False

The burning of sugar is an example of an endergonic reaction, and photosynthesis is an example of an exergonic reaction. True or False?

False

The law of conservation of energy states that although the form of energy used remains the same, the total amount of energy changes. True or False?

False

Some people restate the second law of thermodynamics this way: "When energy changes forms, some energy is always permanently lost." Why is this statement incorrect? This statement implies that energy conversion is not 100% efficient. This statement implies that some energy is destroyed. This statement implies that energy changes forms. This statement implies that useful energy is reduced during energy conversions.

This statement implied that NRG is destroyed

Which trait below is a characteristic of energy carriers? ability to break down endergonically ability to create energy where needed ability to capture heat energy ability to release energy easily ability to store energy for a long time

able to release energy easily

The addition of a competitive inhibitor slows down a particular reaction. What could be done to increase the rate of the reaction, even in the presence of the inhibitor? Add more inhibitor. Lower the temperature of the reaction. Add more substrate. Allow the reaction to reach equilibrium. Add a coenzyme.

add more substrate

In an isolated system, all of the following are true of the second law of thermodynamics EXCEPT there is a natural tendency toward greater disorder in the organization of matter (increase in entropy). all chemical reactions release more energy than they consume. reactions cause energy to be converted from more useful to less useful forms. the amount of useful energy decreases.

all chemical reactions release more energy than they consume.

Enzymes are important because they can enable organisms to evade the laws of thermodynamics. are structural proteins that make up bodily tissues. allow reactions to occur at body temperature. bind irreversibly to substrates. increase the body temperature of organisms.

allow reactions to occur at body temperature

Why does feedback inhibition occur at the beginning of a metabolic pathway instead of in the middle?

because all of the initial substrates would still be used up if the pathway were stopped in the middle

Why is the first law of thermodynamics called "the law of conservation of energy"? because the first law states that all energy can be converted from one form to another because the first law states that energy can't be created or destroyed because the first law states that energy stays in its current form because the first law states that all energy is converted from one useable form into another because the first law states that no energy is wasted in converting one form into another

because the first law states that energy can't be created or destroyed

Which of the following will bind to the active site of an enzyme? Substrate only Allosteric inhibitor only Competitive inhibitor only Both substrate and competitive inhibitor Noncompetitive inhibitor only

both substrate and competitive inhibitor

All of the following statements about catalysts are true EXCEPT catalysts can be used repeatedly. biological catalysts are specific enzymes. catalysts increase the reaction rate. catalysts are not permanently altered during reaction. catalysts increase activation energy requirements.

catalysts increase activation energy requirements.

Activation energy is necessary for all ________ reactions. coupled endergonic exergonic chemical

chemical

Which of the following is true about catalysts? Catalysts convert endergonic reactions into exergonic reactions. Catalysts raise the activation energy of an endergonic reaction. Catalysts convert exergonic reactions into endergonic reactions. Catalysts provide energy for an endergonic reaction. Catalysts provide the activation energy for an exergonic reaction. Catalysts lower the activation energy of an exergonic reaction.

Catalysts lower the activation energy of an exergonic reaction.

How do competitive inhibitors stop a chemical reaction?

Competitive inhibitors bind in the active site of an enzyme.

Sulfa antibiotics damage bacteria by affecting a certain bacterial enzyme. The sulfa antibiotic looks similar to a substrate normally required by the bacterial cells to live. The sulfa antibiotic occupies the active site of the required enzyme and blocks entry of its normal substrate. This prevents the bacteria from making nucleotides that are required for their reproduction and survival. Based on this information, the action of sulfa antibiotics is an example of denaturing of proteins. electron carriers. competitive inhibition. activation energy.

competitive inhibition

FADH2 is an example of a(n) active site. enzyme. electron carrier molecule. enzyme-substrate complex. protein.

electron carrier

Which of the following functions as a biological catalyst? Amino acid Steroid Enzyme Substrate Energy-carrier molecule

enzyme

In the liver, the polysaccharide glycogen is broken down into glucose monomers. The glucose molecules are then released into the blood when blood sugar levels need to be raised. This process is an example of a(n) ________ reaction. kinetic endergonic exergonic potential

exergonic

When solid sodium hydroxide is added to water, the solution gets hot. This is an example of a(n) release of activation energy. enzyme-catalyzed process. endergonic process. conversion of kinetic energy to potential energy. exergonic process.

exergonic process

A(n) ________ chemical reaction releases energy, whereas a(n) ________ reaction requires an input of energy. exergonic; endergonic equilibrium; exergonic endergonic; exergonic enzymatic; endergonic endergonic; enzymatic

exergonic; endergonic

The end product of a biosynthetic pathway often acts to block the initial step in that pathway. This phenomenon is called substrate activation. irreversible inhibition. feedback inhibition. denaturation. allosteric activation.

feedback inhibition

Imagine a candy bar sitting on a table in front of you. Which specific types of energy are present in the candy bar? electrical, potential, heat, and chemical energy potential and heat energy potential and chemical energy chemical and heat energy chemical, kinetic, and heat energy heat, chemical, and potential energy

heat, chemical, and positional energy

The reactant in an enzyme-catalyzed reaction is the substrate. active site. allosteric inhibitor. product. activation energy.

substrate

All of the following statements are true of the first law of thermodynamics EXCEPT the total amount of energy within a closed system remains the same. one form of energy may be converted to a different form of energy. the amount of useful energy decreases when energy is converted from one form to another. the first law of thermodynamics is often called the law of the conservation of energy.

the amount of useful energy decreases

ATP is an energy carrier. Where is the energy actually located? Inside the phosphate Between the sugar and the phosphate In the bonds between phosphate groups Attached to the nucleotide Attached to the phosphate group

the bonds between the phosphate groups

Which of the following reactions could be coupled with the synthesis of ATP from ADP and Pi? the breakdown of ATP into ADP and phosphate the assembly of sugar from water and carbon dioxide the assembly of amino acids into a protein the breakdown of sugar into water and carbon dioxide

the breakdown of sugar into water and carbon dioxide

Competitive and noncompetitive enzyme inhibitors differ with respect to their pH. their energies of activation. the precise location on the enzyme to which they bind. the temperature at which they work best.

the precise location on the enzyme to which they bind

A "high-energy" bond in an ATP molecule is located between adenine and the first phosphate group. ribose and the first phosphate group. two phosphate groups. adenine and ribose.

two phosphate groups

Which of the following is the best description of a coupled reaction? Two reactions that occur simultaneously A reaction that occurs right after another reaction Two reactions that occur in the same organelle Two reactions, where the product of the first reaction is the reactant of the second reaction Reactions that occur during sexual reproduction

two reactions that involve one providing energy for the other

Which molecule stores energy for just a short period of time? Glycogen Phospholipids Steroids Protein ATP

ATP

Each of the following requires 12 carbon atoms. Which of the arrangements of carbon atoms has the greatest entropy? Each of the following requires 12 carbon atoms. Which of the arrangements of carbon atoms has the greatest entropy? 2 molecules of the monosaccharide glucose, C6H12O6 1 molecule of the disaccharide maltose, C12H22O11 4 molecules of the monosaccharide pyruvate, C3H4O3 12 molecules of carbon dioxide, CO2

12 molecules of CO2

Place these steps of enzyme catalysis in the correct order: 1. The substrate and enzyme change shape. 2. The substrate enters the active site. 3. The enzyme reverts to its original configuration. 4. The product is expelled. 2, 1, 4, 3 2, 3, 1, 4 1, 2, 3, 4 1, 3, 4, 2 2, 1, 3, 4

2, 1, 4, 3

Similar to a car, a human body is about ________ efficient in converting chemical energy to movement. Similar to a car, a human body is about ________ efficient in converting chemical energy to movement. 95% 25% 75% 1%

25%

The most common energy carrier molecule in living organisms is DNA. ATP. ADP. glucose. NADPH.

ATP

Which of the following has the greatest amount of kinetic energy? Which of the following has the greatest amount of kinetic energy? The cool air surrounding the car engine An unlit firecracker A hot car engine A moving car A tank of gasoline

A moving car

Preservatives such as citric acid are added to foods to interfere with bacterial growth. This creates an acidic pH in the food. Why does this affect the bacteria that are present?

An acidic environment causes bacterial enzymes to fail or work less efficiently.

Why is photosynthesis a coupled reaction? Photosynthesis requires two reactants: carbon dioxide and water. The exergonic reaction occurs in the plant, and the endergonic reaction occurs in the soil. Sunlight energy enters a plant and is ultimately lost as heat. The exergonic reaction occurs in the plant, and the endergonic reaction occurs in the sunlight. An exergonic reaction occurs in the sunlight, and an endergonic reaction occurs in the plant.

An exergonic reaction occurs in the sun, and an endergonic reaction occurs in the plant.

How is an intermediate best defined?

An intermediate is a product of one reaction that will serve as a reactant in another reaction

When, if ever, do molecules stop moving? At the freezing point (0°C) At the boiling point (100°C) At absolute zero (-273.15°C) Never

At absolute zero

For many enzymes, the rate of product formation increases as the concentration of the substrate increases. Eventually the rate of the reaction reaches a maximum at which further increases in the concentration of the substrate have no effect. Why? At high concentrations of substrate, the reaction is endergonic. At high concentrations of substrate, all of the enzyme active sites are being occupied by substrate molecules. The enzyme is no longer specific for the substrate. At high concentrations of substrate, the activation energy of the reaction decreases. At high concentrations of substrate, the activation energy of the reaction increases. Submit

At high concentrations of substrate, all of the enzyme molecules are bound to substrate molecules.

Which of the scenarios below is most likely irreversible and an example of allosteric inhibition? husband is watching a football game on the television. His wife turns off the television and begins a discussion about finances. Girl A is fighting with girl B over a doll. During the fight, they rip the doll in half Boy A is playing a video game system. Boy B trips over the cords, pulling the game system off the shelf and breaking it. Company B makes more cars than company A, so customers buy cars from company B more often. A cat is chasing a bird. A dog begins barking and scares the cat off.

Boy A is playing a video game system. Boy B trips over the cords, pulling the game system off the shelf and breaking it.

In the last step of extracting energy from sugar, an enzyme called cytochrome c oxidase attaches electrons to oxygen and hydrogen ions, forming water. The electrons are temporarily bound to an iron atom in the enzyme before they are attached to oxygen. Cyanide is a poison that acts by permanently binding to the enzyme near this iron atom, preventing oxygen from getting near enough to accept the electrons. How would you describe the action of cyanide? Cyanide is regulating cytochrome oxidase c by feedback inhibition. Cyanide is a competitive inhibitor of cytochrome c oxidase. Cyanide is a noncompetitive inhibitor of cytochrome c oxidase. Cyanide is a noncompetitive inhibitor of oxygen. Cyanide is a competitive inhibitor of oxygen. Cyanide is an allosteric regulator of cytochrome c oxidase.

Cyanide is a competitive inhibitor of cytochrome c oxidase.

Hydrogen gas (H2), methane gas (CH4), and a liquid called hexane (C6H14) all burn when lit with a match. They all combine with oxygen to produce carbon dioxide gas (CO2) and water (H2O) when they burn. Looking at these molecules, what conclusion can you draw about exergonic reactions? During exergonic reactions, more energy is released than is put in as activation energy. During exergonic reactions, organic compounds are converted into inorganic compounds. During exergonic reactions, nonpolar molecules are broken down, and polar bonds are created in the product. During exergonic reactions, larger molecules are broken down into smaller ones. During exergonic reactions, useful energy is lost in the form of heat.

During exergonic reactions, nonpolar molecules are broken down, and polar bonds are created in the product.

Which of the following is part of the first law of thermodynamics? Potential energy equals kinetic energy in a reaction. Energy cannot be created or destroyed. Energy cannot be transferred or transformed. Exergonic reactions are coupled with endergonic reactions. Kinetic energy is stored energy.

Energy cannot be created or destroyed

How do energy carriers participate in coupled reactions? Energy carriers can be broken apart to power an endergonic reaction or assembled using energy from an exergonic reaction. Energy carriers can be broken apart to power an exergonic reaction. Energy carriers can be assembled using the power from an exergonic reaction. Energy carriers can be assembled to power an endergonic reaction. Energy carriers can be broken apart to power an exergonic reaction or assembled using energy from an endergonic reaction. Energy carriers can be broken apart to power an endergonic reaction.

Energy carriers can be broken apart to power an endergonic reaction or assembled using energy from an exergonic reaction.

Animals have enzymes that break apart starch molecules but not cellulose, despite the fact that both are made up of glucose subunits. Which enzyme characteristic best explains this? Enzyme activity is regulated. Enzymes are highly specific. Enzymes usually speed up chemical reactions. All enzymes are proteins. Enzymes are not permanently changed by the reactions they promote.

Enzymes are highly specific

Most enzymes do not work if the temperature is raised too much. Why is this? Reactions require more activation energy at higher temperatures. Enzymes denature at higher temperatures. Substrates change shape at higher temperatures. Enzymes cannot make temporary bonds with substrates at higher temperatures. The substrate molecules are moving too quickly at high temperature for the reaction to occur.

Enzymes denature at higher temperatures.

This figure shows the metabolism of glucose and oxygen to CO2 and H2O. From what molecule do the carbon in CO2 and the hydrogen in H2O come from? Glucose The catalyst The product O2

Glucose

Which of the following is NOT a commonly used energy carrier in the cell? FAD H2O ATP NAD

H2O

Energy that is not converted to useful energy is usually given off as Energy that is not converted to useful energy is usually given off as heat. entropy. light. radioactivity. electricity.

Heat

You fill two balloons with gas, one with hydrogen and one with carbon dioxide. You hold a match to each balloon. The hydrogen balloon explodes in a small fireball. The carbon dioxide balloon pops where the match burns it, but nothing else happens. How can you explain this? The match did not have enough activation energy to light the carbon dioxide. Hydrogen was able to participate in an exergonic reaction and carbon dioxide wasn't. Hydrogen is a reactant and carbon dioxide is a product. Hydrogen contains chemical energy and carbon dioxide does not. The carbon dioxide smothered the match before it could start a fire.

Hydrogen was able to participate in an exergonic reaction and carbon dioxide wasn't

Which of these is a correct description of a coupled reaction? In a coupled reaction, one exergonic reaction provides activation energy to power another exergonic reaction. In a coupled reaction, two exergonic reactions are performed simultaneously to lower their activation energy. In a coupled reaction, an exergonic reaction provides energy to run an endergonic reaction. In a coupled reaction, one endergonic reaction provides energy to power another endergonic reaction. In a coupled reaction, an endergonic reaction provides energy to run an exergonic reaction.

In a coupled reaction, an exergonic reaction provides energy to run an endergonic reaction.

When a high-energy bond in ATP is broken, what primarily happens to the released energy? It provides the energy needed to drive endergonic reactions in the cell. It converts inorganic phosphates to energy-carrier molecules. It functions as a second messenger. It is lost as light energy. It polarizes the cell.

It provides the energy needed to drive endergonic reactions in the cell.

A man wants to build a windmill to generate electricity. What type of energy is the man trying to take from the wind? heat energy electrical energy kinetic energy potential energy positional energy

Kinetic NRG

You place a pot of water on the stove and turn the stove on. In a short period of time, the water begins to boil. What kind of energy are you giving to the pot of water? chemical energy potential energy kinetic energy positional energy electrical energy

Kinetic NRG

Why is photosynthesis considered an endergonic reaction? Sugar has less energy than does the sun. Protein catalysts are not needed. Activation energy is not required. Photosynthesis does not comply with the physical laws of the universe. Low-energy reactants are converted to high-energy products. Submit

Low-energy reactants are converted to high-energy products.

All of the following are examples of noncompetitive inhibitors EXCEPT mercury. nerve gas. lead. arsenic.

Nerve gas

Imagine that you are conducting an experiment on an enzyme known as sucrase. This enzyme is synthesized and used by yeast cells to break down the disaccharide sucrose (table sugar) into the monosaccharides glucose and fructose. You decide to conduct an experiment to test whether the sucrase enzyme can break down the artificial sweetener sucralose. Sucralose (a "chlorinated" carbohydrate) has some chemical similarity to sucrose, but is different in that three of its hydroxyl groups are missing and replaced with chlorine atoms instead. Based on the details provided in this scenario, do you think the sucrase enzyme will be able to interact with sucralose? Yes; the enzymes in human cells can interact with artificial sweeteners as if they were sugars. No; all enzymes are highly specific and can react with only a specific substrate. Yes; enzymes such as sucrase are not specific for their substrate. No; sucralose is an ion and not a true carbohydrate.

No; all enzymes are highly specific and can react with only a specific substrate.

When certain molecules are pumped across biological membranes against a concentration gradient via active transport, ATP is used. In the cells of our bodies, for example, sugars are actively transported and metabolized within the membrane-enclosed mitochondria. Prokaryotes, in contrast, lack mitochondria but are nonetheless able to metabolize the same sugars. Based on the details provided in this scenario, which of the following statements is expected to be true? Overall, prokaryotes will gain more ATP per sugar molecule metabolized than will eukaryotes. The sugar-digesting enzymes in eukaryotic cells, such as sucrase, are not the same sugar-digesting enzymes found in prokaryotic cells. Prokaryotes and eukaryotes should have the same metabolic efficiency when digesting the same sugars, assuming their enzymes are the same. Sugar metabolism in prokaryotes is exergonic, whereas in eukaryotes it is endergonic.

Overall, prokaryotes will gain more ATP per sugar molecule metabolized than will eukaryotes.

At which pH does pepsin have maximum activity? At which pH does trypsin have maximum activity? pepsin: 2 trypsin: 6 pepsin: 2 trypsin: 8 pepsin: 7 trypsin: 8 pepsin: 8 trypsin: 7 pepsin: 8 trypsin: 2

Pepsin:2 trypsin:8

A ball is sitting on top of a shelf. What kind of energy is represented by the ball resting on the edge of the shelf potential energy chemical energy gravitational energy kinetic energy heat energy

Potential NRG

Which of the following lowers the activation energy of a biochemical reaction? Low concentration of reactants High temperature Presence of a catalyst High concentration of products Altering pH to 7

Presence of a catalyst

When grilling using charcoal, people often wet the charcoal with lighter fluid first. The lighter fluid catches fire first and eventually sets the coals burning. Why does the lighter fluid light faster than the charcoal? Burning lighter fluid is a more exergonic reaction than burning charcoal. Burning lighter fluid is exergonic and burning charcoal is endergonic. The lighter fluid is warmer than the charcoal, which makes it easier to burn. Setting the lighter fluid on fire is a spontaneous reaction and lighting the charcoal is a stable reaction. Setting lighter fluid on fire takes less activation energy than setting charcoal on fire.

Setting lighter fluid on fire takes less activation energy than setting charcoal on fire.

Which of the following represents an increase in entropy? smashing a drinking glass rearranging the books on a shelf flattening a lump of dough putting trash in a trashcan turning off an oven sorting coins into like groups

Smashing a drinking glass

How is it possible for living organisms to comply with the second law of thermodynamics? Living organisms are unique in that they do not require energy for survival. Living organisms are totally isolated systems that are not subject to the laws of physics. Organisms are able to function efficiently on heat energy alone. Chemical reactions inside cells mostly cause an increase in high-level energy. Sunlight functions as an ultimate source of energy for most forms of life on Earth.

Sunlight functions as an ultimate source of energy for most forms of life on Earth.

During photosynthesis, plants convert light energy to chemical energy. This is an example of increasing entropy. the second law of thermodynamics. the first law of thermodynamics. a spontaneous reaction. chemical equilibrium

The First law of thermodynamics

Where does the energy that life uses to combat entropy ultimately come from? from the sun from the earth from the circle of life from food from plants

The Sun

The enzyme amylase in human saliva breaks down starch polymers into smaller sugar units. However, it cannot break down cellulose polymers. Both are made of glucose monomers, but in cellulose the monomers are linked together in a different shape than in starch. Why can't amylase digest cellulose? Cellulose cannot activate the enzyme. Cellulose cannot bind properly to the allosteric site. The bonds of cellulose require more activation energy to break. Enzymes only combine substrates into a single product; they do not break substrates apart. The alternating bonds of cellulose change the overall shape of the molecule and result in it not fitting properly in the active site.

The alternating bonds of cellulose change the overall shape of the molecule and result in it not fitting properly in the active site.

E. coli bacteria can use the enzyme lactase to digest lactose and use it as an energy source. However, it is more efficient for bacteria to use glucose as an energy source if it is present. Which of the methods of regulating enzyme activity would be most energy efficient for a bacterium that has plenty of glucose? The bacterium should produce a reversible, competitive inhibitor of lactase. The bacterium should produce an irreversible, allosteric inhibitor of lactase. The bacterium should use feedback inhibition to stop the metabolic pathway that lactase starts. The bacterium should stop production of lactase. The bacterium should produce a reversible, allosteric inhibitor of lactase. The bacterium should produce an irreversible, competitive inhibitor of lactase.

The bacterium should stop production of lactase.

Which of the following is true about the reaction of ADP + Pi to form ATP? The reaction requires activation energy. The reaction combines two unstable reactants into a stable product. The reaction releases energy. The reaction combines two products to form a reactant. The reaction is endergonic.

The reaction is endergonic

The hydrolysis of sucrose to glucose and fructose is a spontaneous reaction inside our bodies. However, if you dissolve sucrose in water and keep the solution overnight at room temperature, there is no detectable conversion to glucose and fructose. Why not? The activation energy of the reaction decreases. The reaction is at equilibrium. The energy of the products is higher than that of the energy of the reactants. The reaction is endergonic. The reaction requires a catalyst.

The reaction requires a catalyst

Which statement best describes the relationship between an enzyme and a reactant?

The relationship is temporary

Suppose a scientist wants to alter the speed of enzymatic reactions. Use the graphs to determine which of these statements are true. Most human cellular enzymes will likely have the fastest rate of reaction at a pH of 5 and a temperature of 98°F. To slow down trypsin's rate of reaction, alter the pH of the surrounding environment from pH 8 to pH 9. To speed up a human enzyme, increase the temperature of the environment from 70°F to 100ºF. To stop most human enzymes from catalyzing reactions, increase the temperature of the environment to 105°F. Pepsin will likely have the fastest rate of reaction at a pH of 2 and a temperature of 98°F. Submit

To slow down trypsin's rate of reaction, alter the pH of the surrounding environment from pH 8 to pH 9. To speed up a human enzyme, increase the temperature of the environment from 70°F to 100ºF. Pepsin will likely have the fastest rate of reaction at a pH of 2 and a temperature of 98°F.

Activation energy can be provided by the kinetic energy of moving molecules. True or False?

True

Energy is defined as the capacity to do work True False

True

The metabolism of a cell is the sum of all of its chemical reactions. True False

True

The photosynthetic reaction is considered an endergonic reaction. True False

True

Outside the body, sugar can catch fire and burn in an exergonic reaction. Inside the body, we also talk about burning sugar in an exergonic reaction, but it never catches fire. Why not? When sugar is lit on fire, there is nothing nearby to capture the energy, so it all becomes heat. When the body burns sugar, it captures all of the energy in ATP. When sugar is lit on fire, it releases more energy than when the body breaks down sugar. When sugar is lit on fire, it is dry, so it can continue burning. When the body burns sugar, it does so in the presence of water, which prevents a fire. When sugar is lit on fire, it converts all of the chemical energy into heat energy. When the body burns sugar, it converts all of the chemical energy into chemical energy in ATP. When sugar is lit on fire, all of the bonds are broken at once. When the body breaks down sugar,

When sugar is lit on fire, all of the bonds are broken at once. When the body breaks down sugar, enzymes break down one bond at a time.

Which of the following does NOT have much potential energy? A water droplet at the top of a waterfall A ball that has rolled downhill and stopped A glucose molecule A diver on a springboard A 9-volt battery Submit

a ball that has rolled downhill and stopped

Which of the following is most like an intermediate in a metabolic pathway?

a carrot that has been peeled and is waiting to be cut

Entropy is a tendency toward __________. a decrease in energy a decrease in life a decrease in order an increase in energy an increase in complexity

a decrease in order

All of the following are ways in which enzymes are regulated by the cell EXCEPT by feedback inhibition. a gene coding for the enzyme may be turned off. a heavy metal (such as lead) may block the enzymes non-active site. by first synthesizing the enzyme in an inactive form.

a heavy metal may block the enzymes active site.

What is the definition of an endergonic reaction? a reaction in which products are combined to form reactants a reaction in which reactants are combined to make products a reaction in which the products give off energy a reaction in which the reactants have more energy than the products a reaction in which the products have more energy than the reactants

a reaction where the products have more energy than the reactants

Triclosan is a broad-spectrum antibacterial agent used in many household products. It is structurally similar to polychlorobiphenylol, a substrate that binds to the active site of the enzyme sulfotransferase. Based on these facts, you can conclude that triclosan most likely:

is a competitive inhibitor

When a muscle cell demands energy to perform its work of contraction, ATP is phosphorylated. catalyzes the reaction. manufactures more ATP. enters a metabolic pathway. is broken down and liberates energy.

is broken down

To say that an enzyme has been denatured means that the enzyme is working at its maximal rate. the enzyme is working at an optimal temperature. its three-dimensional structure has changed and the enzyme can no longer function properly. an inhibitor has bound the enzyme at the active site.

its three-dimensional structure has changed and the enzyme can no longer function properly.

Plants use sunlight to convert carbon dioxide and water into sugar and oxygen. The energy in the sunlight is what type of energy? potential energy kinetic energy heat activation energy reactant energy

kinetic energy

How is your body able to work against the effects of entropy? Regular exercise Regular work Eating a balanced diet and proper nourishment Sunbathing

proper nourishment

Entropy is a measure of an increase in randomness. organization. high-level energy. potential energy. kinetic energy. Submit

randomness

In exergonic chemical reactions, the reactants and products have equal amounts of energy. the reactants have more energy than do the products. the reactants have less energy than do the products. energy is stored by the reactions.

reactants have more energy than products

What is the ultimate source of energy for almost all forms of life on Earth Heat energy Thermal energy Chemical energy Solar energy Nuclear energy Submit

solar energy