MCB2010 - Exam 2 Questions and Complete Solutions
What is metabolism? - ✔✔The collection of all controlled biochemical reactions that occur
within a microbe Anabolic - ✔✔Reactions that build larger molecules from smaller
molecules; these are endergonic reactions because they require the input of energy
Catabolic - ✔✔Reactions that break down larger molecules into smaller molecules; these
reactions release energy so they are exergonic reactions; this energy is either stored for
later use (usually as ATP) or lost as heat What are redox reactions? - ✔✔Transfer of
electrons from an electron donor to an electron acceptor What occurs during oxidation? -
✔✔The loss of an electron What occurs during reduction? - ✔✔The gain of an electron
How is energy stored and released? - ✔✔Energy is stored in chemical bonds, and released
through the breaking of bonds What molecule is the main source of energy in an organism?
- ✔✔ATP What is an enzyme's function and how do they carry out this function? -
✔✔Organic catalysts that increase the speed at which a reaction occurs What are the
structural components of a Holoenzyme? - ✔✔Contain a protein called an apoenzyme and
a nonprotein What is a substrate and where does it bind to an enzyme? - ✔✔A substrate is
the molecule which the enzyme acts upon. A substrate binds to an enzyme on the
enzyme's active site, where it should be complementary in shape to the substrate What is
the difference between the active site and an allosteric site? - ✔✔An active site is an
enzyme's function site and also where competitive inhibitors bind to. An allosteric site is a
site other than the active site, where noncompetitive inhibitors bind What factors affect
the rate of a chemical reaction? - ✔✔Temperature, pH, concentration of enzyme or
substrate, inhibition What is inhibition? - ✔✔Substances which stop an enzyme from
carrying out a chemical reaction Competitive inhibition - ✔✔Bind to enzyme's active site
and prevent a substrate Noncompetitive inhibition - ✔✔Do not bind to enzyme's active
sites but to an allosteric site which includes a change in shape of the active site, so that
the substrate cannot be bound. Can be inhibitory or excitatory Feedback inhibition - ✔✔An
end product of a series of reactions (called a pathway) which acts as an allosteric inhibitor
to an earlier step in the pathway Aerotolerant - ✔✔Do not use aerobic respiration; tolerate
O2 through enzymes which detoxify it Facultative anaerobe - ✔✔They utilize oxygen if
present; in the absence of oxygen, they use fermentation pathway to synthesize ATP
Microaerophile - ✔✔They need lower concentrations of oxygen than are present in the air
Obligate aerobe - ✔✔Require oxygen to grow; to generate ATP, these organisms need
oxygen as the hydrogen acceptor Obligate anaerobe - ✔✔They cannot grow in the
presence of oxygen What is cellular respiration and why does it occur? - ✔✔The process by
which biological fuels are oxidized in the presence of an inorganic electron acceptor to
, drive the bulk production of ATP Aerobic respiration - ✔✔A series of multiple reactions in
which various enzymes break down glucose to release energy; creates the greatest
number of ATP molecules; oxygen is the final electron acceptor; 36 ATP produced Stages
of aerobic respiration - ✔✔Kreb's cycle, glycolysis, ETC Anaerobic respiration - ✔✔When
oxygen is not available, some organisms will use inorganic compounds as the final
electron acceptor; follows the same main steps of aerobic respiration but produces less
ATP and an inorganic ion is the final electron acceptor; 32 ATP produced Glycolysis -
✔✔Integral pathway for all the metabolic pathways; occurs within the cytoplasm
Glycolysis stage one - ✔✔Energy investment stage: energy contained in 2 molecules of ATP
invested to phosphorylate glucose and rearrange its C atoms Glycolysis stage two -
✔✔Lysis stage: converts from 6 C molecules to convertible 3 C molecules Glycolysis stage
three - ✔✔Energy conserving stage: 3 C molecules oxidized to form pyruvic acid (the end
product of glycolysis); yields to 4 ATP molecules Glycolysis net production - ✔✔2 ATP, 2
NADH, 2 pyruvic acid molecules Kreb's cycle - ✔✔Occurs within the cytoplasm in
prokaryotes. Occurs within the mitochondria in eukaryotes. Major function if the reduction
of coenzymes Kreb's cycle starting point - ✔✔Acetyl-CoA Kreb's cycle net production -
✔✔2 ATP, 6 NADH, 2 FADH2, 4 CO2 Electron transport chain (ETC) - ✔✔Occurs within the
cell membrane for prokaryotes. Occurs within the mitochondrial membrane in eukaryotes.
NADH and FADH2 electrons are accepted and are moved by electron carriers. As they are
moved down the membrane, hydrogen ions are pumped across the membrane which
creates a H+ gradient which serves as potential energy ETC net production - ✔✔32 ATP
Proton gradient and ATP synthase role in creating ATP - ✔✔The proton gradient is used to
synthesize ATP. Protons flow down their concentration gradient and into the matrix through
the membrane protein, ATP synthase, causing it to spin and catalyze conversion of ADP to
ATP What is the role of fermentation? - ✔✔Fermentation is an alternative system that
allows glycolysis to continue without the other steps of respiration Net products of
fermentation - ✔✔Alcoholic fermentation: Ethanol, CO2, 2 ATP What is the Essential
Function of Fermentation and why is it important? - ✔✔Regeneration of NAD+ for return to
glycolysis; this allows ATP production to continue in absence of cellular respiration
Genetics - ✔✔The study of inheritance and inheritable traits as expressed in an organism's
genetic material Gene - ✔✔Specific sequences of nucleotides that code for polypeptide
molecules Genome - ✔✔The entire genetic complement of both genes and noncoding
nucleotides in an organism; genomes of all cells and DNA viruses composed of DNA;
genome of RNA viruses composed of RNA Genotype - ✔✔The actual set of genes in a
genome; the portion of DNA which carries the instructions for an organism's life Phenotype
What is metabolism? - ✔✔The collection of all controlled biochemical reactions that occur
within a microbe Anabolic - ✔✔Reactions that build larger molecules from smaller
molecules; these are endergonic reactions because they require the input of energy
Catabolic - ✔✔Reactions that break down larger molecules into smaller molecules; these
reactions release energy so they are exergonic reactions; this energy is either stored for
later use (usually as ATP) or lost as heat What are redox reactions? - ✔✔Transfer of
electrons from an electron donor to an electron acceptor What occurs during oxidation? -
✔✔The loss of an electron What occurs during reduction? - ✔✔The gain of an electron
How is energy stored and released? - ✔✔Energy is stored in chemical bonds, and released
through the breaking of bonds What molecule is the main source of energy in an organism?
- ✔✔ATP What is an enzyme's function and how do they carry out this function? -
✔✔Organic catalysts that increase the speed at which a reaction occurs What are the
structural components of a Holoenzyme? - ✔✔Contain a protein called an apoenzyme and
a nonprotein What is a substrate and where does it bind to an enzyme? - ✔✔A substrate is
the molecule which the enzyme acts upon. A substrate binds to an enzyme on the
enzyme's active site, where it should be complementary in shape to the substrate What is
the difference between the active site and an allosteric site? - ✔✔An active site is an
enzyme's function site and also where competitive inhibitors bind to. An allosteric site is a
site other than the active site, where noncompetitive inhibitors bind What factors affect
the rate of a chemical reaction? - ✔✔Temperature, pH, concentration of enzyme or
substrate, inhibition What is inhibition? - ✔✔Substances which stop an enzyme from
carrying out a chemical reaction Competitive inhibition - ✔✔Bind to enzyme's active site
and prevent a substrate Noncompetitive inhibition - ✔✔Do not bind to enzyme's active
sites but to an allosteric site which includes a change in shape of the active site, so that
the substrate cannot be bound. Can be inhibitory or excitatory Feedback inhibition - ✔✔An
end product of a series of reactions (called a pathway) which acts as an allosteric inhibitor
to an earlier step in the pathway Aerotolerant - ✔✔Do not use aerobic respiration; tolerate
O2 through enzymes which detoxify it Facultative anaerobe - ✔✔They utilize oxygen if
present; in the absence of oxygen, they use fermentation pathway to synthesize ATP
Microaerophile - ✔✔They need lower concentrations of oxygen than are present in the air
Obligate aerobe - ✔✔Require oxygen to grow; to generate ATP, these organisms need
oxygen as the hydrogen acceptor Obligate anaerobe - ✔✔They cannot grow in the
presence of oxygen What is cellular respiration and why does it occur? - ✔✔The process by
which biological fuels are oxidized in the presence of an inorganic electron acceptor to
, drive the bulk production of ATP Aerobic respiration - ✔✔A series of multiple reactions in
which various enzymes break down glucose to release energy; creates the greatest
number of ATP molecules; oxygen is the final electron acceptor; 36 ATP produced Stages
of aerobic respiration - ✔✔Kreb's cycle, glycolysis, ETC Anaerobic respiration - ✔✔When
oxygen is not available, some organisms will use inorganic compounds as the final
electron acceptor; follows the same main steps of aerobic respiration but produces less
ATP and an inorganic ion is the final electron acceptor; 32 ATP produced Glycolysis -
✔✔Integral pathway for all the metabolic pathways; occurs within the cytoplasm
Glycolysis stage one - ✔✔Energy investment stage: energy contained in 2 molecules of ATP
invested to phosphorylate glucose and rearrange its C atoms Glycolysis stage two -
✔✔Lysis stage: converts from 6 C molecules to convertible 3 C molecules Glycolysis stage
three - ✔✔Energy conserving stage: 3 C molecules oxidized to form pyruvic acid (the end
product of glycolysis); yields to 4 ATP molecules Glycolysis net production - ✔✔2 ATP, 2
NADH, 2 pyruvic acid molecules Kreb's cycle - ✔✔Occurs within the cytoplasm in
prokaryotes. Occurs within the mitochondria in eukaryotes. Major function if the reduction
of coenzymes Kreb's cycle starting point - ✔✔Acetyl-CoA Kreb's cycle net production -
✔✔2 ATP, 6 NADH, 2 FADH2, 4 CO2 Electron transport chain (ETC) - ✔✔Occurs within the
cell membrane for prokaryotes. Occurs within the mitochondrial membrane in eukaryotes.
NADH and FADH2 electrons are accepted and are moved by electron carriers. As they are
moved down the membrane, hydrogen ions are pumped across the membrane which
creates a H+ gradient which serves as potential energy ETC net production - ✔✔32 ATP
Proton gradient and ATP synthase role in creating ATP - ✔✔The proton gradient is used to
synthesize ATP. Protons flow down their concentration gradient and into the matrix through
the membrane protein, ATP synthase, causing it to spin and catalyze conversion of ADP to
ATP What is the role of fermentation? - ✔✔Fermentation is an alternative system that
allows glycolysis to continue without the other steps of respiration Net products of
fermentation - ✔✔Alcoholic fermentation: Ethanol, CO2, 2 ATP What is the Essential
Function of Fermentation and why is it important? - ✔✔Regeneration of NAD+ for return to
glycolysis; this allows ATP production to continue in absence of cellular respiration
Genetics - ✔✔The study of inheritance and inheritable traits as expressed in an organism's
genetic material Gene - ✔✔Specific sequences of nucleotides that code for polypeptide
molecules Genome - ✔✔The entire genetic complement of both genes and noncoding
nucleotides in an organism; genomes of all cells and DNA viruses composed of DNA;
genome of RNA viruses composed of RNA Genotype - ✔✔The actual set of genes in a
genome; the portion of DNA which carries the instructions for an organism's life Phenotype
