Chapter 1

Gibbs ____________ energy is defined by enthalpy minus temperature times entropy.

free

What 6 characteristics distinguish living organisms from inanimate objects?

1) chemically complex and highly organized 2) extract, transform and use energy from environment 3) can precisely self-replicate and self-assemble 4) exploit a chemical interplay w/ their environment 5) posses programmatically defined functions 6) evolve to new forms over generations

A spontaneous process always happens very quickly. A. False. Thermodynamics does not specify the rate of reaction. B. True. Spontaneous reactions are always very fast. C. False. A spontaneous reaction usually happens very quickly. D. True. Thermodynamics tells us that spontaneous reactions are kinetically favored reactions.

A. False. Thermodynamics does not specify the rate of reaction.

The major carrier of chemical energy in all cells is what?

ATP, adenosine triphosphate

A process in which large molecules are built from small molecules

Anabolic

Which group of single-celled micro-organisms has many members found growing in extreme environments?

Archaea

Which feature of eukaryotes is most common to prokaryotes? A. Multicellular organisms B. An organized cytoplasm C. Mitochondria D. A membrane-enclosed nucleus

B. An organized cytoplasm

Which is NOT thought to have been an important step during the evolution of cells? A. Development of energy metabolism B. Development of sensitivity to oxidative damage C. Compartmentation of self-replicating molecules D. Development of chemical synthetic mechanisms

B. Development of sensitivity to oxidative damage

A reaction is said to be spontaneous when it can proceed in either the forward or reverse direction. A. False. A reaction that can proceed in either forward or reverse directions is in equilibrium. B. False. A reaction can only have a negative Gibbs Free Energy in one direction. C. True. A reaction can have a negative Gibbs Free Energy in both directions. D. True. This is the definition of spontaneity.

B. False. A reaction can only have a negative Gibbs Free Energy in one direction.

A spontaneous process can occur with a large decrease in entropy. A. False. A large decrease in entropy means a reaction is nonspontaneous. B. True. As long as the Gibbs Free Energy is negative the reaction is spontaneous. C. False. A large decrease in entropy will mean that the enthalpy will be too large for the reaction to be spontaneous. D. True. As long as the Gibbs Free Energy is positive the reaction is spontaneous.

B. True. As long as the Gibbs Free Energy is negative the reaction is spontaneous.

A chemist working in a pharmaceutical lab synthesized a new drug as a racemic mixture. Why is it important that she separate the 2 enantiomers and test each for its biological activity?

Biomolecules such as receptors for drugs are stereospecific, so each of the 2 enantiomers of the drug may have different effects on an organism, one may be beneficial the other toxic

Which statement about Gibbs free energy is true? A. The free energy of a molecule depends upon the method used to synthesize the molecule. B. If temperature and pressure are constant, ∆G must be greater than zero for a spontaneous reaction. C. Endergonic reactions have ∆G > 0. D. ∆G=∆H+T∆S

C. Endergonic reactions have ∆G > 0.

A nonspontaneous reaction will proceed spontaneously in the reverse direction. A. False. A nonspontaneous reaction is nonspontaneous in both directions. B. False. A nonspontaneous reaction cannot proceed in the reverse direction. C. False. Reversing the reaction changes the sign of the Gibbs Free Energy. D. True. Reversing the reaction changes the sign of the Gibbs Free Energy.

C. False. Reversing the reaction changes the sign of the Gibbs Free Energy.

Which is thought NOT to have been an important step during the period of chemical evolution? A. Self-replication of molecules from smaller, complementary molecules. B. Different functional groups combined into single, larger molecules. C. The development of oxidative metabolism. D. Simple molecules condensed to form more complex molecules.

C. The development of oxidative metabolism.

obtain energy directly from inorganic molecules

Chemoautotrophs

acquire energy and carbon from organic molecules

Chemoheterotrophs

Hereditary information (with the exception of some viruses) is preserved in:

DNA

What is the equation for Delta G prime?

Delta G prime= -RT ln( C x D/ A x B) ; R=8.314, temp 25 Celsius

Chemical reactions that absorb energy, positive delta G

Endogonic

The heat content of a system at constant pressure; negative is exothermic and positive is endothermic

Enthalpy (delta H)

A measure of disorder or randomness; energy of system will be more spread out; to be spontaneous it has to be positive, the products have to be higher than reactants

Entropy (delta S)

Random mutation in a genome that gives it a higher expectancy to be passed down to the next generation

Evolution

Chemical reactions that release energy, negative delta G

Exergonic

The energy in a system that can be used to drive chemical reactions. If the change in free energy of a reaction (Delta G, the free energy of the products minus the free energy of the energy of the reactants) is negative, the reaction will occur spontaneously, if positive than will go to the left and if 0 then its at equilibrium

Gibbs Free Energy

What are the 4 types of noncovalent interactions and why is it important that they aren't covalent bonds?

Hydrogen bonds, ionic interactions between charged groups, van der waals and hydrophobic interactions; noncovalent interactions are weak and can form/break/re-form rapidly w/ less energy than covalent bonds

Why is an asymmetric carbon atom called a chiral center?

It has 4 different substituents and cannot be superimposed on its mirror image and will have 2 stereoisomers

Explain why living organisms are able to produce particular chiral forms of different biomolecules while lab chemical synthesis produces a racemic mixture?

Lab syntheses usually use achiral reagents that produce racemic mixtures; All enzymes are made of chiral precursors and are inherently chiral catalysts, showing strong stereoselectivity in reactants and mechanisms creating chiral products

if a stress is applied to a system at equilibrium, the system will shift to reduce the stress; with high heat the system will shift to the left

Lechat's Principle

What is optical activity?

Optical activity is the capacity of a substance to rotate plane polarized light

an organism's complete set of proteins

Proteome

A molecule has a structure that can interact with another molecule because of structural similarity

Structural Complementarity

The 4 covalent bonds in methane (CH4) are arranged around a carbon to give which one of the following geometries?

Tetrahedral

When a region of DNA must be repaired by removing and replacing some of the nucleotides, what ensures that the new nucleotides are in the correct sequence?

The new nucleotide base pair accurately with those on the complementary strand

If delta H is negative and delta S is positive will the reaction be spontaneous?

always

What is the name of the proceeding functional group or linkage: -CO-NH-?

amide

Energy requiring metabolic pathways that yield complex molecules from simpler precursors are:

anabolic

Use the terms a) chemoautotrophs, b) chemoheterotrophs, c) photoautotrophs, and d) photoheterotrophs and identify the answer that correctly finishes the statement: Carnivores are and herbivores are what?

both chemoheterotrophs

The three-dimensional structure of macromolecules is formed and maintained primarily through noncovalent interactions. What is not considered a noncovalent interaction?

carbon-carbon bonds

The bacterium E. Coli requires simple organic molecules for growth and energy- it is therefore a what?

chemoheterotroph

A ___________________ reaction is a chemical reaction in which two molecules or moieties combine to form one single molecule, together with the loss of a small molecule, generally water.

condensation

The cytosol of the cell is the _________________ minus the membrane-enclosed organelles.

cytoplasm

Enzymes are biological catalysts that enhance the rate of a reaction by:

decreasing the activation energy

Humans maintain a nearly constant level of hemoglobin by continually synthesizing and degrading it. This is an example of a(n):

dynamic steady state

Stereoisomers that are nonsuperimposable mirror images of each other are known as what?

enantiomers

If heat energy is absorbed by the system during a chemical reaction, the reaction is said to be:

endothermic

The degree of randomness of a system is indicated by its _____________

entropy

_______________ are organisms whose cells contain a membrane-enclosed nucleus enclosing their DNA.

eukaryotes

If the free energy change G for a reaction is -46.11 kJ/mol, the reaction is:

exergonic

In a hydrolysis reaction, a molecule of water is generated, T/F?

false

The equilibrium constant of a reaction varies with pH but not temperature, T/F?

false

A system is at thermodynamic equilibrium when its entropy has decreased to a minimum, T/F?

false, Thermodynamic equilibrium occurs when the actual free energy change of a reaction is zero

A process with a large negative ∆G will proceed rapidly, T/F?

false, delta G doesn't tell how fast a rx will proceed

delta G and delta G' mean the same thing, T/F?

false, delta G' is the actual free energy of a reaction at pH 7, whereas delta G is the actual free energy of a reaction not at pH 7

According to the second law of thermodynamics, in a spontaneous process, entropy tends to decrease (i.e. ∆S = negative), T/F?

false, entropy tends to increase (i.e. ∆S = positive), although it also depends on the temperature and the value of ∆H

Living systems can be described as being in a steady state and at equilibrium, T/F?

false, never at equilibrium

When 2 genes in an organism share detectable sequence similarity, those genes or their gene products, are said to be:

homologues and paralogues

_____________ is the opposite of a condensation reaction

hydrolysis

If delta H is positive and delta S is negative will the reaction be spontaneous?

never

In eukaryotes, the nucleus is enclosed by a double membrane called the?

nuclear envelope

The macromolecules that serve in the storage and transmission of genetic information are what?

nucleic acids

Where is DNA located in a bacterial cell?

nucleoid

What is the name of the proceeding functional group or linkage: -P(O)OH-O-P(O)OH-O-?

phosphate ester

What is the name of the proceeding functional group or linkage: R-O-P(O)OH-O-R?

phosphodiester

Simple molecules condense to form more complex molecules called ___________

polymers

_____________________ are organisms whose cells lack a nucleus.

prokaryotes

The catalog of all proteins functioning in a cell is the what?

proteome

The enzyme fumarase catalyzes the reversible hydration of fumaric acid to l-malate, but it will not catalyze the hydration of maleic acid, the cis isomer of fumaric acid. This is an example of what?

stereospecificity

A major change occurring in the evolution of eukaryotes from prokaryotes was the development of what....?

the nucleus

The 3-D structure of a protein is determined primarily by:

the sequence of amino acids in the protein

A delta G value of zero indicates that the reactions or processes are at equilibrium, T/F?

true

Carbon, nitrogen, oxygen, hydrogen and calcium are the five most prevalent elements found in the human body, T/F?

true

Many biosynthetic reactions require energy to proceed, T/F?

true

Modern organisms are based on a unit of life called the cell, T/F?

true

The cytoskeleton is an extensive array of filaments inside cells that gives them shape and the ability to move, T/F?

true

The energy change of a system is defined as the difference between the heat absorbed by the system from the surroundings, and the work done by the system on the surroundings, T/F?

true

Viruses are considered neither living organisms nor organelles, T/F?

true

The value of delta Go' for a given reaction is unaffected by other reactions in situ, even if these other reactions generate reactants or products of the given reaction, T/F?

true, it is constant