Question 1

According to the first and second laws of thermodynamics

Accepted Answer

A)  energy flows spontaneously from systems with high free energy to systems with low free energy in a series of step-by-step transformations. 
B)  the quantity of energy in the universe is constant but its quality is not. 
C)  transformation of potential energy in a biological system results in the loss of a small amount of energy. 
D)  energy can be transformed from one form to another, but can be neither created nor destroyed. 
E)  energy is lost from systems during energy transformations resulting in increasing entropy in the universe. 
A)  energy flows spontaneously from systems with high free energy to systems with low free energy in a series of step-by-step transformations. 
B)  the quantity of energy in the universe is constant but its quality is not. 
C)  transformation of potential energy in a biological system results in the loss of a small amount of energy. 
D)  energy can be transformed from one form to another, but can be neither created nor destroyed. 
E)  energy is lost from systems during energy transformations resulting in increasing entropy in the universe.

Question 2

The role of an enzyme in an enzyme-catalysed reaction is to

Accepted Answer

A)  increase the rate at which the substrate is converted to product. 
B)  increase the activation energy of the reaction. 
C)  form an enzyme-substrate complex which cannot be converted back to free substrate. 
D)  convert all the substrate to product. 
E)  All of these are true about enzyme-catalysed reactions. 
A)  increase the rate at which the substrate is converted to product. 
B)  increase the activation energy of the reaction. 
C)  form an enzyme-substrate complex which cannot be converted back to free substrate. 
D)  convert all the substrate to product. 
E)  All of these are true about enzyme-catalysed reactions.

Question 3

The binding of a substrate to the active site of an enzyme

Accepted Answer

A)  is irreversible. 
B)  may produce changes in the shape of the enzyme. 
C)  is coupled to the hydrolysis of ATP. 
D)  requires activation energy. 
E)  is by the formation of covalent bonds. 
A)  is irreversible. 
B)  may produce changes in the shape of the enzyme. 
C)  is coupled to the hydrolysis of ATP. 
D)  requires activation energy. 
E)  is by the formation of covalent bonds.

Question 4

The rate of an enzyme-catalysed reaction can be influenced by

Accepted Answer

A)  temperature. 
B)  pH. 
C)  concentration of the reactants. 
D)  concentration of the products. 
E)  All of the answers are correct. 
A)  temperature. 
B)  pH. 
C)  concentration of the reactants. 
D)  concentration of the products. 
E)  All of the answers are correct.

Question 5

Allosteric enzymes are enzymes that

Accepted Answer

A)  exist in at least two different shapes. 
B)  require cofactors for activity. 
C)  are easily phosphorylated and inactivated. 
D)  use coenzymes for activity. 
E)  contain metal ions. 
A)  exist in at least two different shapes. 
B)  require cofactors for activity. 
C)  are easily phosphorylated and inactivated. 
D)  use coenzymes for activity. 
E)  contain metal ions.

Question 6

An example of catabolism would be

Accepted Answer

A)  assembling cellulose from glucose. 
B)  the light-independent reactions of photosynthesis. 
C)  anaerobic respiration. 
D)  transport across membranes. 
E)  synthesis of glycogen from glucose. 
A)  assembling cellulose from glucose. 
B)  the light-independent reactions of photosynthesis. 
C)  anaerobic respiration. 
D)  transport across membranes. 
E)  synthesis of glycogen from glucose.

Question 7

Each step in the biochemical reaction A > B > C > D is catalysed by a specific enzyme. Product D binds to the enzyme that converts B to C at a specific site that is not part of its active site. The binding of D to the enzyme decreases the activity of the enzyme. In this biochemical reaction, substance D is

Accepted Answer

A)  an enzyme-substrate complex. 
B)  an allosteric inhibitor. 
C)  a substrate. 
D)  an enzyme. 
E)  a cofactor. 
A)  an enzyme-substrate complex. 
B)  an allosteric inhibitor. 
C)  a substrate. 
D)  an enzyme. 
E)  a cofactor.

Question 8

Spontaneous biochemical reactions

Accepted Answer

A)  reach equilibrium rapidly. 
B)  proceed without enzymes. 
C)  produce products with less free energy than the reactants. 
D)  occur when an enzyme lowers the activation energy required for the reaction. 
E)  are initiated without the absorption of activation energy by the reactants. 
A)  reach equilibrium rapidly. 
B)  proceed without enzymes. 
C)  produce products with less free energy than the reactants. 
D)  occur when an enzyme lowers the activation energy required for the reaction. 
E)  are initiated without the absorption of activation energy by the reactants.

Question 9

Where are cytochromes located?

Accepted Answer

A)  membranes of prokaryotes, mitochondria of eukaryotes. 
B)  membranes of eukaryotes, mitochondria of prokaryotes. 
C)  membranes of both prokaryotes and eukaryotes. 
D)  mitochondria of both prokaryotes and eukaryotes. 
E)  chloroplasts. 
A)  membranes of prokaryotes, mitochondria of eukaryotes. 
B)  membranes of eukaryotes, mitochondria of prokaryotes. 
C)  membranes of both prokaryotes and eukaryotes. 
D)  mitochondria of both prokaryotes and eukaryotes. 
E)  chloroplasts.

Question 10

Oxidative phosphorylation occurs in the

Accepted Answer

A)  nucleus. 
B)  chloroplasts. 
C)  cell membrane. 
D)  cytosol. 
E)  mitochondria. 
A)  nucleus. 
B)  chloroplasts. 
C)  cell membrane. 
D)  cytosol. 
E)  mitochondria.

Question 11

In biological systems, whenever energy is transformed there is always a (an)

Accepted Answer

A)  increase in the entropy in the system. 
B)  decrease in the free energy in the system. 
C)  increase in the potential energy in the system. 
D)  increase in the entropy in the universe. 
E)  increase in the free energy in the universe. 
A)  increase in the entropy in the system. 
B)  decrease in the free energy in the system. 
C)  increase in the potential energy in the system. 
D)  increase in the entropy in the universe. 
E)  increase in the free energy in the universe.

Question 12

Which of the following does NOT occur as a result of transferring electrons across the electron transport chain?

Accepted Answer

A)  Creation of an electrochemical gradient 
B)  Formation of glucose 
C)  Regeneration of ATP from ADP and Pi 
D)  Pumping of protons across a proton impermeable membrane 
E)  Release of free energy 
A)  Creation of an electrochemical gradient 
B)  Formation of glucose 
C)  Regeneration of ATP from ADP and Pi 
D)  Pumping of protons across a proton impermeable membrane 
E)  Release of free energy

Question 13

An exergonic reaction

Accepted Answer

A)  requires energy. 
B)  has a negative $\Delta$G. 
C)  is not spontaneous. 
D)  can be driven by an endergonic reaction. 
E)  requires heat to proceed. 
A)  requires energy. 
B)  has a negative $\Delta$G. 
C)  is not spontaneous. 
D)  can be driven by an endergonic reaction. 
E)  requires heat to proceed.

Question 14

The rate of an enzyme-catalysed reaction

Accepted Answer

A)  increases with an increase in enzyme concentration. 
B)  decreases with an increase in the substrate concentration. 
C)  increases in the presence of allosteric inhibitors. 
D)  decreases in the presence of cofactors. 
E)  increases with a decrease in the amount of product. 
A)  increases with an increase in enzyme concentration. 
B)  decreases with an increase in the substrate concentration. 
C)  increases in the presence of allosteric inhibitors. 
D)  decreases in the presence of cofactors. 
E)  increases with a decrease in the amount of product.

Question 15

Which statement about activation energy is CORRECT?

Accepted Answer

A)  Lowering the activation energy of a reaction increases the proportion of molecules that have enough energy to react. 
B)  A catalyst increases the activation energy of the reactant molecules and allows the reaction to proceed more easily. 
C)  Activation energy is not needed if the reaction is exergonic. 
D)  Increasing the activation energy of a reaction decreases the amount of the product at equilibrium. 
E)  Activation energy is the average kinetic energy of the reactant molecules. 
A)  Lowering the activation energy of a reaction increases the proportion of molecules that have enough energy to react. 
B)  A catalyst increases the activation energy of the reactant molecules and allows the reaction to proceed more easily. 
C)  Activation energy is not needed if the reaction is exergonic. 
D)  Increasing the activation energy of a reaction decreases the amount of the product at equilibrium. 
E)  Activation energy is the average kinetic energy of the reactant molecules.

Question 16

The proton motive force produces

Accepted Answer

A)  ATP. 
B)  NADH. 
C)  RNA. 
D)  free electrons. 
E)  protons. 
A)  ATP. 
B)  NADH. 
C)  RNA. 
D)  free electrons. 
E)  protons.

Question 17

If oxidation can involve the adding of oxygen, removal of hydrogen or removal of electrons, reduction must therefore involve

Accepted Answer

A)  removing oxygen, electrons or hydrogen. 
B)  adding oxygen, removing electrons or hydrogen. 
C)  removing oxygen, adding electrons, removing hydrogen. 
D)  adding oxygen, electrons or hydrogen. 
E)  removing oxygen, adding electrons or hydrogen. 
A)  removing oxygen, electrons or hydrogen. 
B)  adding oxygen, removing electrons or hydrogen. 
C)  removing oxygen, adding electrons, removing hydrogen. 
D)  adding oxygen, electrons or hydrogen. 
E)  removing oxygen, adding electrons or hydrogen.

Question 18

When a reversible metabolic reaction is in a state of maximum disorder, the system contains its maximum

Accepted Answer

A)  potential energy. 
B)  entropy. 
C)  free energy. 
D)  value for Keq. 
E)  kinetic energy. 
A)  potential energy. 
B)  entropy. 
C)  free energy. 
D)  value for Keq. 
E)  kinetic energy.

Question 19

In cells, non-spontaneous endergonic processes can proceed by

Accepted Answer

A)  lowering the equilibrium constant (Keq). 
B)  reducing the amount of entropy required. 
C)  changing the concentration of the reactants. 
D)  linking them to spontaneous energy-yielding processes. 
E)  linking them to another endergonic reaction. 
A)  lowering the equilibrium constant (Keq). 
B)  reducing the amount of entropy required. 
C)  changing the concentration of the reactants. 
D)  linking them to spontaneous energy-yielding processes. 
E)  linking them to another endergonic reaction.

Question 20

Photosynthesis is summarised in the equation CO2 + H2O + radiant energy ===> sugars (CH2O) + O2 + heat. This is an example of

Accepted Answer

A)  an open system where energy and materials are exchanged with the environment. 
B)  a closed system with an equilibrium between the environment and the materials. 
C)  an open system where energy is exchanged with the environment but materials are recycled. 
D)  an open system where energy is conserved but materials are exchanged with the environment. 
E)  a closed system where energy and materials are conserved. 
A)  an open system where energy and materials are exchanged with the environment. 
B)  a closed system with an equilibrium between the environment and the materials. 
C)  an open system where energy is exchanged with the environment but materials are recycled. 
D)  an open system where energy is conserved but materials are exchanged with the environment. 
E)  a closed system where energy and materials are conserved.

Exam 3: The Chemistry of Life

According to the first and second laws of thermodynamics

The role of an enzyme in an enzyme-catalysed reaction is to

The binding of a substrate to the active site of an enzyme

The rate of an enzyme-catalysed reaction can be influenced by

Allosteric enzymes are enzymes that

An example of catabolism would be

Spontaneous biochemical reactions

Where are cytochromes located?

Oxidative phosphorylation occurs in the

In biological systems, whenever energy is transformed there is always a (an)

Which of the following does NOT occur as a result of transferring electrons across the electron transport chain?

An exergonic reaction

The rate of an enzyme-catalysed reaction

Which statement about activation energy is CORRECT?

The proton motive force produces

If oxidation can involve the adding of oxygen, removal of hydrogen or removal of electrons, reduction must therefore involve

When a reversible metabolic reaction is in a state of maximum disorder, the system contains its maximum

In cells, non-spontaneous endergonic processes can proceed by

Photosynthesis is summarised in the equation CO2 + H2O + radiant energy ===> sugars (CH2O) + O2 + heat. This is an example of

Nature of Molecules

Biomolecules

Functioning Cells

Movement Across Membranes

Harvesting Energy

Cells, Tissues and Signals

Cell Division

Inheritance

Genes, Chromosomes and Dna

The Genetic Code

Gene Expression

Genomes, Mutation and Cancer

Viruses

Genetic Engineering and Biotechnology

Reproduction, Growth and Development of Flowering Plants

Structure of Plants

Plant Nutrition, Transport and Adaptation to Stress

Plant Hormones and Growth Responses

Animal Reproduction

Animal Development

Homeostasis: Water, Solutes and Excretion

Gas Exchange in Animals

Circulation

Metabolism, Temperature Regulation and Environmental Stress

Animal and Human Nutrition

Innate Defences and the Immune System

Hormonal Control in Animals

Nervous Systems

Animal Movement

Animal Behaviour

Evolving Life

Evolving Earth

Mechanisms of Evolution

Bacteria

The Protists

Plants

Fungi

Simple Animals: Sponges to Flatworms

Annelids, Molluscs, Nematodes and Arthropods

Echinoderms and Chordates

Australian Biota

Population Ecology

Living in Communities

Ecosystems

Human Impacts

Filters

Photosynthesis is summarised in the equation CO₂ + H₂O + radiant energy ===> sugars (CH₂O) + O₂ + heat. This is an example of