Term
| What is stored energy in a system that can be transferred as heat? |
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Definition
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Term
| The second law of thermodynamics states that every energy transfer or transformation makes the universe more __________. |
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Definition
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Term
| What is the total of all chemical processes in an organism? |
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Definition
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Term
| What is a reaction that proceeds with a net loss of energy? |
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Definition
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Term
| The nucleotide that provides the majority of a cells energy. |
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Definition
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Term
| The metabolic pathway that releases energy by breaking down molecules. |
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Definition
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Term
| What is a reaction that proceeds with a net input of energy? |
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Definition
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Term
| The portion of a system's energy available to do work. |
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Definition
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Term
| Biological catalysts that accelerate reactions in cells. |
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Definition
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Term
| Enzymes _________ the activation energy of reactions. |
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Definition
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Term
| What is a molecule that reacts with an enzyme called? |
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Definition
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Term
| Metabolic pathway that forms energy by building molecules. |
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Definition
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Term
| What is the measure of the tendency towards disorder (random distribution) in a system? |
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Definition
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Term
| The type of reaction that will proceed on its own with no external input. |
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Definition
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Term
| Site of an enzyme other than the active site that can induce structural changes in the enzyme. |
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Definition
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Term
| What are small nonprotein molecules (succh as magnesium) that help speed up enzymatic reactions? |
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Definition
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Term
| What is the capacity to do work? |
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Definition
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Term
| What is the energy of motion? |
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Definition
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Term
| What is potential energy? |
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Definition
| Energy that is stroed beccause of where an object is or the shape of that object. |
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Term
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Definition
| Energy in the process of doing work (motion) |
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Term
| What type of energy is chemical energy? |
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Definition
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Term
| What type of energy is light energy? |
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Definition
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Term
| What type of energy is heat energy? |
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Definition
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Term
| What type of energy is a moving car? |
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Definition
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Term
| What type of energy is a car parked on a hill? |
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Definition
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Term
| What is the first law of thermodynamics? |
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Definition
| Energy can be transferred and transformed, but it can never be created nor destroyed. |
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Term
| Give an example of entropy. |
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Definition
| Frozen water molecules is less random than liquid water molecules. |
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Term
| Which chemical reactions occur by itself without external help? |
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Definition
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Term
| Which chemical reactions cannot occur unless external energy is continuously added? |
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Definition
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Term
| What two factors determine if a reaction is spontaneous or not? |
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Definition
| Enthalpy (H) and Entropy (S) |
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Term
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Definition
| Total energy stored in a substance (reactants) that can be transferred as heat by a process (reaction) |
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Term
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Definition
| The tendency of things to go from a state of order to randomness. |
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Term
| What is the equation for free energy? |
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Definition
G = H - TS
G:Free energy
H:Enthalpy in bonds
T:Temperature
S:Entropy |
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Term
| What does the equation for free energy mean? |
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Definition
Free energy (G) is the portion of a systems energy available to do work.
The difference between the total energy of the system (enthalpy - H) and the energy not available to do work (T*S - Entropy) |
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Term
| If free energy is negative, what can you say about the reaction? |
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Definition
| It is a favorable (spontaneous) reaction |
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Term
| If free energy is positive, what can you say about the reaction? |
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Definition
| It is an unfavorable (nonspontaneous) reaction |
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Term
| What happens to free energy if we increase temperature? |
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Definition
| Make change in free energy more negative |
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Term
| What happens to free energy if we increase entropy? |
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Definition
| Make change in free energy more negative |
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Term
| What happens to free energy if we increase enthalpy? |
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Definition
| Make change in free energy more positive |
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Term
| What happens to free energy if we decrease temperature? |
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Definition
| Make change in free energy more positive |
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Term
| What happens to free energy if we decrease entropy? |
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Definition
| Make the change in free energy more positive |
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Term
| What happens to free energy if we decrease enthalpy? |
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Definition
| Make the change in free energy more negative |
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Term
| Do the products or reactants have the most energy? |
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Definition
In exergonic reactions, the reactants have the most energy.
In endergonic reactions, the products have the most energy. |
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Term
| What is the free energy value for exergonic and endergonic reactions? |
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Definition
Exergonic - Negative
Endergonic - Positive |
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Term
| Give a biological example for exergonic and endergonic reactions. |
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Definition
Exergonic - Cellular Respiration
Endergonic - Photosynthesis |
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Term
| Why doesn't the existence of life go against the second law of thermodynamics? |
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Definition
| Life is an open system that uses external inputs of energy to build things up. |
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Term
| What happens if a cells overall free energy is zero? |
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Definition
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Term
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Definition
| Nucleotide with unstable phosphate bonds that the cell hydrolyzes (breaks) for free energy to drive endergonic reactions |
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Term
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Definition
| Nitrogenous base adenine, sugar ribose, and a chain of three phsopate groups |
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Term
| What molecule from chapter 5 does ATP most resemble? |
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Definition
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Term
| Why is ATP important to cells? |
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Definition
| It is an immediate source of energy |
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Term
| Name the three types of work ATP can do in cells and give an example of each. |
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Definition
Mechanical:contraction of muscle cells
Transport:actively pumping substances across membranes
Chemical:synthesis of polymers |
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Term
| What type of reaction provides energy by converting ATP to ADP? |
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Definition
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Term
| Is the reaction to form ATP from ADP exergonic or endergonic? |
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Definition
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Term
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Definition
| Transferring the phosphate group to another molecule |
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Term
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Definition
| Chemical agent that accelerates a reaction without being consumed in the process |
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Term
| Why are enzymes/catalysts important in biology? |
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Definition
A reaction may occur spontaneously if it releases free energy but it may occur too slowly to be of use to the cell.
So enzymes are very important to help speed things up.
I.e. DNA polymerase |
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Term
| How do enzymes speed up the reaction? |
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Definition
| Enzymes speed up reactions by loowering EA (activation energy) |
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Term
| What is activation energy? |
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Definition
| The amount of free energy that reactant molecules must gain to start a reaction (EA) |
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Term
| Why is activation energy important? |
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Definition
| This is the energy required to reach the transition state (to transition from reactants to products) |
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Term
| What is the transition state? |
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Definition
| The point at which reactants have gained enough free energy to react (unstable state) |
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Term
| Define change in free energy. |
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Definition
| Difference between free energes of the products and reactants |
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Term
| How is a substrate related to enzymes? |
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Definition
| Enzymes are specific for a particular substrate. |
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Term
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Definition
| Region of an enzyme that binds to a substrate. |
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Term
| How much of a protein forms the active site? |
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Definition
| Formed by only a few amino acids in the protein. |
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Term
| What does induced fit mean? |
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Definition
| Changes shape in response to the substrate to induce the reaction. |
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Term
| Give the three ways an active site can help a reaction. |
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Definition
1. Hold substrates in proper position so they can react.
2. Distort the substrates chemical bonds so less thermal energy is needed.
3. Provide a micro-environment which progresses the reaction. |
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Term
| What is enzyme saturation? |
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Definition
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Term
| How do you overcome saturation of the reaction? |
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Definition
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Term
| Does the reaction rate depend on the concentration of substrate? |
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Definition
| Yes, more substrate = faster reaction |
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Term
| Name four things that can affect enzyme activity. |
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Definition
Temperature
pH
Co-Factors
Enzyme inhibitors |
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Term
| What does optimal temperature mean? |
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Definition
| It means the highest (and best) temperature an enzyme can work until it gets denatured. |
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Term
| What does optimal pH mean? |
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Definition
| Level that the enzyme work most effectively |
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Term
| What is the difference between a co-factor and a coenzyme? |
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Definition
Co-factors aree small inorganic non-protein molecules
Coenzymes are organic (e.g. vitamins) |
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Term
| What is an enzyme inhibitor and how does it work? |
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Definition
Molecules that interact in some way with the enzyme to prevent it from working in the normal manner.
-Competitive Inhibitors work by binding to the active site of an enzyme.
-Noncompetitive enzyme inhibitors work by binding to an allosteric site of an enzyme. |
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Term
| How is the allosteric site regulated? |
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Definition
Activator molecules turn on active site.
Inhibitor molecules turn off the active site. |
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Term
| What are the two conformations of allosteric enzymes? |
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Definition
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Term
| What is the difference between the two conformations of allosteric enzymes? |
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Definition
The active conformation has an activator molecule that opens the active site.
The inactive conformation has an inhibitor molecule that closes the active site. |
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Term
| What is enzyme cooperatively? |
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Definition
| Substrate binding of the active site of one subunit of the protein inducces a shape change that enhances substrate binding in all other subunits |
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Term
| Describe feedback inhibition. |
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Definition
Regulation of the metabolic pathway by its end-products.
End-products inhibit an enzyme in the pathway to prevent the cell from wasting chemical resources by making unneccessary products. |
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Term
| Distinguish between ATP and ADP. |
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Definition
ADP = Adenosine di-phosphate
ATP = Adenosine tri-phosphate
basically ATP has one more phosphate group than ADP, and because ATP has one more phosphate group than ADP, it contains more potential energy because more bonds could be broken
ATP forms ADP when it breaks a phosphate group to utilize its bond energy to do work |
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Term
| Does ATP or ADP have more energy? |
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Definition
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Term
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Definition
ΔG = change in free energy
ΔH = change in total energy
ΔS = change in entropy (energy required for organization of the system, not available for work) |
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Term
| Which term most precisely describes the general process of breaking down large molecules into smaller ones? |
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Definition
anabolism
catalysis
catabolism.
metabolism
dehydration |
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Term
| Of the following, the structure of ATP is most closely related to |
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Definition
a double helix
a phospholipid
an anabolic steroid
an amino acid with three phosphate groups attached
RNA nucleotides. |
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Term
| ATP generally energizes a cellular process by |
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Definition
acting as a catalyst
releasing ribose electrons to drive reactions
emitting light flashes
releasing heat upon hydrolysis
direct chemical transfer of a phosphate group. |
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Term
| All of the following statements are representative of the second law of thermodynamics except |
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Definition
every time energy changes form, there is a decrease in entropy.
heat energy represents lost energy in most systems
energy transfers are always accompanied by some loss
highly organized systems require energy for their maintenance
systems tend to rearrange themselves toward greater entropy |
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Term
| In an organism, the energy available to do work is called free energy because |
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Definition
it is equivalent to the system's total energy
the organism can live free of it if necessary
it can be obtained with no cost to the system
it can be spent with no cost to the universe
it is available to do work.
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Term
| Why is ATP an important molecule in metabolism? |
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Definition
It energizes other molecules by transferring phosphate groups
Hydrolysis of its phosphate groups is endergonic
Its phosphate bonds are easily formed and broken
Two of the above.
All of the above |
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Term
| Increasing the substrate concentration in an enzymatic reaction could overcome which of the following? |
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Definition
denaturization of the enzyme
competitive inhibition.
noncompetitive inhibition
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Term
| Which of the following statements is true concerning catabolic pathways? |
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Definition
They build up complex molecules such as protein from simpler compounds
They combine molecules into more complex and energy-rich molecules
They involve endergonic reactions that break complex molecules into simpler ones
They are usually coupled with anabolic pathways to which they supply energy in the form of ATP.
They are spontaneous and do not need enzyme catalysis
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Term
| Which of the following is part of the first law of thermodynamics? |
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Definition
The entropy of the universe is constant
Kinetic energy is stored energy that results from the specific arrangement of matter
Energy cannot be transferred or transformed
The entropy of the universe is decreasing
Energy cannot be created or destroyed.
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Term
| Which of the following statements regarding enzymes is true? |
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Definition
Enzymes change the direction of chemical reactions
Enzymes decrease the rate of a reaction
Enzymes increase the rate of reaction.
Enzymes prevent changes in substrate concentrations
Enzymes are permanently altered by the reactions they catalyze |
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