Biology Chapter 8
Which of the following statements is consistent with the second law of thermodynamics?
A constant input of energy is required to maintain the high level of cellular organization.
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.
Which of the following statements describes the first law of thermodynamics?
Energy cannot be created or destroyed.
When the noncompetitive inhibitor is bonded to the enzyme, the shape of the ________ is distorted.
Enzyme
________ is a regulatory mechanism in which the end product of a metabolic pathway inhibits an enzyme that catalyzes an early step in the pathway.
Feedback inhibition
What type of reaction breaks the bonds that join the phosphate groups in an ATP molecule?
Hydrolysis involves breaking bonds with the addition of water.
2. An enzyme is considered _________ a because it speeds up chemical reactions without being used up.
catalyst
In your body, what process converts the chemical energy found in glucose into the chemical energy found in ATP?
cellular respiration
Which of the following conditions may be overcome by increasing the substrate concentration in an enzymatic reaction with a fixed amount of enzyme?
competitive inhibition
A decrease in entropy is associated with which type of reaction?
dehydration
An enzyme is _________ when it loses its native conformation and its biological activity
denatured
A chemical reaction that has a positive ΔG is best described as _____.
endergonic
Which of these reactions requires a net input of energy from its surroundings?
endergonic
"Conservation of energy" refers to the fact that _____.
energy cannot be created or destroyed but can be converted from one form to another Submit
The relationship between catabolism and anabolism is most similar to the relationship between which of the following pairs of terms?
exergonic; endergonic
Which of these are by-products of cellular respiration?
heat, carbon dioxide, and water
Enzymes are described as catalysts, which means that they _____.
increase the rate of a reaction without being consumed by the reaction
2. A _________ inhibitor binds to a site on the enzyme that is not the active site.
noncompetitive
What is energy coupling?
the use of energy released from an exergonic reaction to drive an endergonic reaction
Which part of the adenosine triphosphate molecule is released when it is hydrolyzed to provide energy for biological reactions?
γ-phosphate (the terminal phosphate)
5. When properly aligned, the enzyme and substrate form an enzyme-substrate (ES) ________
Complex
In cells, what is usually the immediate source of energy for an endergonic reaction?
ATP
Which of the following statements describes a central role that ATP plays in cellular metabolism?
ATP provides energy coupling between exergonic and endergonic reactions.
4. The competitive inhibitor competes with the substrate for the __________ on the enzyme.
Active Site
A substrate binds to an enzyme at the _______, where the reaction occurs.
Active site
Which of the following statements is an important consequence of the first law of thermodynamics for a living organism?
An organism ultimately must obtain all of the necessary energy for life from its environment.
A _________ such as a vitamin, binds to an enzyme and plays a role in catalysis.
Cofactor
1. A ________ (n) inhibitor has a structure that is so similar to the substrate that it can bond to the enzyme just like the substrate.
Competitive
How do cells use the ATP cycle illustrated in the figure?
Cells use the cycle to recycle ADP and phosphate.
The reaction ADP + P --> ATP is a(n) _____ reaction.
Endergonic
3. Usually, a(n) ___________ inhibitor forms a covalent bond with an amino acid side group within the active site, which prevents the substrate from entering the active site or prevents catalytic activity.
Irreversible
Which of the following is a primary function of the active site of an enzyme?
It catalyzes the reaction associated with the enzyme.
What is the fate of the phosphate group that is removed when ATP is converted to ADP?
It is acquired by a reactant in an endergonic reaction.
When chemical, transport, or mechanical work is done by an organism, what happens to the heat generated?
It is lost to the environment.
Chemical energy is a form of _____ energy.
Potential
6. Enzyme inhibitors disrupt normal interactions between an enzyme and its ________
Substrate
In a catalyzed reaction a reactant is often called a ______
Substrate
Which of the following is NOT a way in which an enzyme can speed up the reaction that it catalyzes?
The active site can provide heat from the environment that raises the energy content of the substrate.
Which of the following is true when comparing an uncatalyzed reaction to the same reaction with a catalyst?
The catalyzed reaction will have the same Δ_G_.
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?
The decrease in entropy is associated with growth of an organism. As a consequence of growth, organisms cause a greater increase in entropy in their environment than the decrease in entropy associated with their increased complexity.
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
Which of the following statements describes a common characteristic of catabolic pathways?
They are exergonic and provide energy that can be used to produce ATP from ADP and i.
Which of the following statements about anabolic pathways is true?
They consume energy to build up polymers from monomers.
Which of the following statements is true regarding potential energy and kinetic energy?
Water at the top of a dam has potential energy; water falling through a dam has kinetic energy. The moving water performs work by moving the blades of turbines in the dam to generate electricity.
The process of cellular respiration, which converts simple sugars such as glucose into CO2 and water, is an example of _____.
a catabolic pathway
Zinc, an essential trace element for most organisms, is present in the active site of the enzyme carboxypeptidase. The zinc most likely functions as _____.
a cofactor necessary for enzyme activity
Which of these is exhibiting kinetic energy?
a space station orbiting Earth
3. An enzyme is considered ____________ because of its ability to recognize the shape of a particular molecule.
specific
Most cells cannot harness heat to perform work because _____.
temperature is usually uniform throughout a cell S
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
Chemical equilibrium is reached when
the forward and reverse reactions occur at the same rate.
