bio chapt 6

Which of the following statements are true regarding endergonic reactions? Require the addition of free energy Products have a higher free energy than reactants Release free energy Are not spontaneous Have a positive change in free energy

-Require the addition of free energy -Products have a higher free energy than reactants -Are not spontaneous -Have a positive change in free energy

Which of the following statements correctly describe metabolic pathways? The same enzyme catalyzes all the steps in the pathway. A different enzyme catalyzes each step. They do not stop once they begin. They can result in the breakdown of large molecules. They can result in the synthesis of larger molecules from smaller molecules. The product of one reaction becomes the substrate for the next reaction.

-They can result in the breakdown of large molecules. -They can result in the synthesis of larger molecules from smaller molecules. -The product of one reaction becomes the substrate for the next reaction. -A different enzyme catalyzes each step.

What are the two general functions of catabolic pathways? To obtain energy for use in endergonic processes To convert matter into energy To synthesize new macromolecules that may be needed in cells To recycle the components of organic molecules for use in the synthesis of new molecules

-To obtain energy for use in endergonic processes -To recycle the components of organic molecules for use in the synthesis of new molecules

The three levels at which metabolic pathways are regulated are

1.) genetic 2.) cellular 3.) biochemical

Where does a substrate bind on an enzyme in order for a chemical reaction to take place? Enzyme-substrate complex Catalytic site Active site Allosteric site

Active site

At what levels are metabolic pathways regulated? Population Individual Biochemical Genetic Atomic Cellular

Biochemical Genetic Cellular

Which of these is a synonym for anabolic reactions? Catabolic reactions Allosteric reactions Biosynthetic reactions Redox synthesis

Biosynthetic reactions

What is the main factor that can affect the rate of a reaction? Thermodynamics Increased activation energy Catalysis Increased entropy

Catalysis

Why do changes in the pH of the fluid in which an enzyme is dissolved affect the enzyme's ability to function? Enzymes have particular pH values at which they function best. The enzyme's bonds become too weak to hold the enzyme together due to increased random movement of atoms in the enzyme. The enzyme becomes inflexible, and induced fit is not possible.

Enzymes have particular pH values at which they function best.

Increasing the temperature outside the optimal range for an enzyme can lead to _____ of the enzyme, altering the enzyme's structure and function.

denaturing

During the breakdown of small organic molecules, oxidation occurs when Blank______. electrons are removed from an atom or molecule protons are removed from an atom or molecule Reason: Oxidation involves the removal of electrons. Protons do not have electrons. Oxidation reactions may involve the removal of hydrogen atoms. electrons are added to an atom or molecule protons are added to an atom or molecule

electrons are removed from an atom or molecule

When the addition of free energy from the environment is required for a reaction to proceed, the reaction is said to be

endergonic

What is the term for the ability to do work?

energy

For living organisms, the total energy (H) is called ,_____ while the free energy (G) is the amount available to do work.

enthalpy

True or false: When two reactions are coupled, the first reaction must always be exergonic for both to proceed exergonically. True false question.

false; A coupled reaction will proceed exergonically when the overall change in free energy of both reactions combined is negative.

The term that describes the energy of a system that is available to do work is ______ energy

free

Altering the pH outside the optimal range for a protein can cause denaturation and can Blank______ the function of an enzyme. impair not affect enhance

impair

What occurs during the process of autophagy in cells? Extracellular materials are brought into the cell by phagocytosis. Extracellular materials are brought into the cell by pinocytosis. Intracellular materials are digested by proteasomes. Intracellular materials are digested by the lysosomes.

intracellular materials are digested by the lysosomes.

The general term for all types of coordinated sequences of chemical reactions that occur in cells is _____ pathways.

metabolic

Cells can recycle ______, such as RNA and protein.

molecules

Enzymes that cleave the bonds between adjacent amino acids in a protein are called

proteases

Vmax is the maximum ____ of a chemical reaction.

rate

Why do most enzymes function maximally in a narrow range of temperature and pH? Enzymes only function at a narrow range of conditions in which their substrates are available. Enzymes evolved to function best at body temperature, with an optimum temperature of 37oC. Exposing enzymes to temperatures and pH outside the optimal range can change the conformation of the active site or denature the protein.

Exposing enzymes to temperatures and pH outside the optimal range can change the conformation of the active site or denature the protein.

is the usable energy of a system.

Free energy

What is the function of a protease? Transport of proteins across the plasma membrane Protein degradation Protein synthesis

Protein degradation

What type of reaction or process occurs without needing an input of energy? Spontaneous Endergonic Activated Instantaneous

Spontaneous

Enzyme-mediated chemical reactions take place when the substrate molecules bind to the ____-____ of an enzyme.

active site

A chemical reaction that will proceed without the input of energy is a(n)

spontaneous or exergonic reaction

Metabolic pathways can be categorized according to whether the sequence of coordinated chemical reactions leads to the _____ or ______ of substances

synthesis or breakdown

Which statement best describes an exergonic reaction? The products have more total energy than the reactants. The reaction proceeds with a net release of free energy. A net input of energy from the surroundings is required for the reaction to proceed. The reaction is nonspontaneous.

the reaction proceeds with a net release of free energy.

What is enthalpy?

the total energy of a system

True or false: Enzymes are sensitive to environmental conditions and, as a result, many enzymes function best only across a narrow range of temperature and pH.

true

When will an endergonic and exergonic reaction that are coupled proceed spontaneously? When the first reaction is endergonic and the second is exergonic When the first reaction is exergonic and the second is endergonic When the net free energy change for both reactions combined is negative (exergonic)

When the net free energy change for both reactions combined is negative (exergonic)

What factors determine the direction and rate of a chemical reaction? Multiple select question. Catalysts influence the rate of a chemical reaction. Catalysts determine the direction and rate of a chemical reaction. The change in free energy will determine the direction of the reaction. Thermodynamics governs the direction of a reaction but not the rate of a reaction.

-Catalysts influence the rate of a chemical reaction. -The change in free energy will determine the direction of the reaction. -Thermodynamics governs the direction of a reaction but not the rate of a reaction.

Identify the statements that are true of exergonic reactions. Exergonic reactions have a positive change in free energy. Reason: Exergonic reactions have a negative change in free energy. Exergonic reactions release energy during product formation. Exergonic reactions are spontaneous. The products of an exergonic reaction have a higher free energy than the reactants.

-Exergonic reactions have a negative change in free energy. -Exergonic reactions release energy during product formation. -Exergonic reactions are spontaneous.

A macromolecule that is not recycled but is instead stably maintained is

DNA

What are the two main factors that determine the outcome of a chemical reaction in a living cell?

Direction and rate

What are the two general forms in which energy exists? Multiple choice question. Kinetic energy and potential energy Chemical energy and potential energy Kinetic energy and chemical energy

Kinetic energy and potential energy

Which statement best describes an exergonic reaction? A net input of energy from the surroundings is required for the reaction to proceed. The products have more total energy than the reactants. The reaction is nonspontaneous. The reaction proceeds with a net release of free energy.

The reaction proceeds with a net release of free energy.

The digestion of intracellular material, such as worn-out organelles, occurs by a process called

autophagy

The two main functions of ______ pathways are to recycle components of macromolecules and to produce energy intermediates, such as ATP, which are directly used to drive ______ reactions in cells. catabolic; endergonic anabolic; endergonic catabolic; exergonic anabolic; exergonic

catabolic; endergonic

A(n) Blank______ is a substance that speeds up the rate of a chemical reaction without being consumed or altered in the process. enhancer inducer coefficient catalyst equilibrium constant primer

catalyst