Microbiology Ch. 6 Connect
pentose phosphate pathway
breaks down glucose, although primary role is production of NADPH and two precursor metabolites for use in biosynthesis
allosteric
cells can quickly alter the activity of certain key enzymes, using other molecules that bind reversible and distort them. The control of enzymes is called ___________ regulation
respiration
cellular _______ is the process that transfers electrons extracted from glucose via the central metabolic pathways to the electron transport chain, where they are used to generate a proton motive force that can be harvested to make ATP via oxidative phosphorylation
energy, terminal
consider how cells obtain energy to make ATP, the chemical that serves as the electron donor is the _________ source, and the one that ultimately accepts those electrons is the ________ electron acceptor
NO3- and oxygen
consider the figure showing chemical energy sources and terminal electron acceptors. If Mn2+ were used as an energy source, the two molecules on the chart that can serve as terminal electron acceptors are ______ and _____
C
consider two different processes for converting glucose to CO2 and water. In the first, the glucose is burned (literally, as in fire); in the second, the glucose is covered in a series of multiple steps in a cell. Which of the following statements correctly describes the free energy of these two approaches? A) the change in free energy is greater in the first reaction, since the glucose is converted directly to CO2 and water B) the change in free energy is greater in the second reaction, since the glucose is carefully converted to CO2 and water C) the change in free energy is the same regardless of the number of steps involved D) there is not enough information to determine how the change in free energy will compare between the two approaches
protons
electron carriers can also be considered hydrogen carriers. This is because, along with electrons, they carry _______________
free energy
energy that is available to do work
glycolysis
the primary pathway used by many organisms to convert glucose to pyruvate is ___________
chemiosmotic
the process that links the electron transport chain to ATP synthesis is called the __________ theory
metabolic
the series of sequential chemical reactions that converts a starting compound to an end product is called a _______________ pathway
transition
the step that links glycolysis to the TCA cycle is called the ________ step
glycolysis, pentose phosphate, TCA
the three central pathways that gradually oxidize glucose to CO2 are __________, the _________ _________ pathway, and the _________ cycle
A, C, D
when a reduced electron carrier (reducing power) transfers its electrons to another molecule, what occurs? A) the energy level of the recipient is raised B) the energy level of the recipient is lowered C) the recipient molecule is reduced D) the electron carrier is oxidized E) the electron carrier is degraded, and the cell must generate a replacement carrier
transforming
when photosynthetic organisms convert the energy of sunlight to the energy of chemical bonds and when chemoorganotrophs convert the energy of one type of chemical bond to that of another, they are (transforming or making) energy
B
which of the following is a true statement regarding forms of energy? A) the total amount of energy in the universe changes continuously as some is created and some is destroyed B) energy can be changed from one form to another C) energy can be created when it is changed from one form to another, for example, a hydroelectric dam generating electricity D) when the form of energy is changed, some is lost forever
ATP
the main energy currency of cells is _________
B, C
Pyruvate and pyruvic acid __________ A) differ from each other in the number of carbon molecules they have B) are terms that refer to the ionized and the undissociated forms of the molecule C) are terms often used interchangeably by biologists
A, B
Consider the 3 central metabolic pathways that gradually oxidize glucose to CO2. Why are these amphibole pathways? A) Although they are catabolic, the precursor metabolites and reducing power they generate can be diverted for biosynthesis (anabolism) B) "Amphi" means "both kinds" which reflects the dual role of these central metabolic pathways C) The term "amphibole" reflects that these are metabolic pathways that take place in an aqueous environment D) "Amphibolic" is another word for "catabolic" which refers to the set of processes that breaks down molecules and releases energy
A to C B to B C to A
Consider the ATP-generating processes of prokaryotic chemoorganoheterotrophs. Match the process with its correct terminal electron acceptor A) aerobic respiration B) anaerobic respiration C) fermentation A) organic molecule (pyruvate or a derivative) B) molecule other than O2, such as nitrate, nitrite, or sulfate C) O2
cofactor
Consider the illustration of an enzyme and a substrate. The remaining item by an arrow and question mark is most likely a __________
A to B B to C C to A
Consider the maximum theoretical ATP yield from oxidative phosphorylation of a single molecule of glucose in prokaryotes. Match the relative contributions of the central metabolic pathways and final yield with their approximate contribution in terms of ATP. Include the following pair, already given: 6 ATP from the transition step A) 6 ATP B) 22 ATP C) 34 ATP A) total maximum yield B) glycolysis C) TCA cycle
D, E
Glucose catabolism encompasses two key processes: 1) oxidizing glucose molecules to generate ATP, reducing power, and precursor metabolites; and 2) transferring the electrons carried by NADH and FADH2 to the terminal electron acceptor. The second process, transfer of electrons, is accomplished by which of the following? A) the pentose phosphate pathway B) glycolysis C) the TCA cycle D) fermentation E) cellular respiration
B
How does the oxidase test help in bacterial identification? A) it reacts with NADH and FADH2 to detect the generation of reducing power via central metabolic pathways B) it detects the activity of cytochrome c oxidase, a component of the electron transport chain of some but not all bacteria C) if distinguishes between different types of ATP synthase found in different bacteria D) if tests for the presence of an electron transport chain
oxidized, reduced
In oxidation-reduction reactions, or redox reactions, the substance that loses electrons is _______, and the substance that gains those electrons is __________
A
In prokaryotes, how does the energy yield of aerobic respiration compare to anaerobic respiration A) the energy yield of aerobic respiration is greater than anaerobic respiration B) the energy yield of aerobic respiration is less than anaerobic respiration C) the energy yield from both are equal
cytoplasm
In prokaryotic cells, all the central metabolic pathways occur in the _________
A to A B to C C to B
Match the following three phosphorylation process for ATP production A) substrate-level phosphorylation B) oxidative phosphorylation C) photophosphorylation A) Energy released in an exergonic reaction is used to power the addition of P to ADP B) The suns radiant energy and an electron transport chain creat a proton motive force that drives the addition of P to ADP C) Energy from exergonic reaction is used to create a proton motive force that drives the addition of P to ADP
A to D B to C C to A D to B
Match the numbers with the correct term A) 1 B) 2 C) 3 D) 4 A) ADP B) energy used comes from catabolic reactions C) energy released drives anabolic reactions D) ATP
A to C B to A C to B
Match up the type of enzyme inhibition with its characteristics A) competitive inhibition B) non-competitive inhibition by regulatory molecules C) non-competitive inhibition by enzyme poisons A) inhibitor reversibly changes the shape of the enzyme so that the substrate can no longer bind to the active site B) inhibitor permanently changes the shape of the enzyme, making the enzyme non-functional C) inhibitor binds to the active site of the enzyme, blocking access of the substrate
C, E
Oxidative phosphorylation, the mechanism by which cellular respiration uses the NADH and FADH2 generated in glycolysis, the transition step, and the TCA cycle to synthesize ATP, involving which two steps? A) the electron transport chain uses the energy in protons to transfer electrons across the membrane B) a phosphate group is removed from each NADH and FADH2 C) ATP synthase uses the energy of a proton motive force to drive the synthesis of ATP D) electrons flow through ATP synthase to drive the synthesis of ATP E) the electron transport chain is oxidized by the donation of electrons from NADH and FADH2
3, 2, 1, 4
Place the following steps in the correct order of how the spatial arrangement of electron carriers in a bacterial electron transport chain helps explain how protons are shuttled from one side of the membrane to the other 1) Because the electron carrier only accepts electrons, the protons are released to the outside of the cell 2) The hydrogen carrier passes electrons to carrier that only accepts electrons 3) An electron carrier (e.g. NADH + H+) donates electrons to a hydrogen carrier, which also picks up protons 4) A proton motive force is set up as protons are moved from the inside of the cell to the outside
C
The ATP generated by fermentation comes from _______ A) the TCA cycle B) the reducing power obtained from the oxidation of glucose C) substrate-level phosphorylation during glycolysis D) oxidative phosphorylation driven by NAPH
C
Unlike chemoorganotrophs, photosynthetic organisms generate ATP by _____ A) oxidative phosphorylation B) substrate-level phosphorylation C) photophosphorylation
A, B, D
When a single molecule of glucose is processed of glucose is processed by glycolysis in an E. coli cell, which of the following make up the net gain of this process A) 2 molecules of ATP B) 6 precursor metabolites C) 4 molecules of NADH D) 2 molecules of NADH E) 4 molecules of ATP F) zero precursor metabolites
A, B, C
Which of the following are important electron carriers for a cell? A) NADP+/NADPH B) FAD/FADH2 C) NAD+/NADH D) ATP/ADP
A, B, C
Which of the following are true statements about what happens to glucose inside a cell? A) some glucose might enter glycolysis, only to be siphoned off as a precursor for metabolite for biosynthesis B) some glucose might be oxidized to CO2 generating the maximum amount of ATP C) glucose can be used in catabolism to yield energy, or the precursor metabolites generated from its breakdown can be used in anabolism D) all glucose molecules are oxidized to CO2 generating ATP and reducing power in the process
A, C, D
Which of the following correctly describes some of the forms of energy represented in this photograph? A) kinetic energy of the photons that make up the sunlight B) potential energy of the water flowing through the dam C) potential energy of the water behind the dam D) electricity generated by the hydroelectric dam as it captures the energy from moving water E) kinetic energy of the chemical bonds made by the photosynthetic organisms utilizing the energy of sunlight
B, C, E
Which of the following correctly describes the transition step and the tricarboxylic acid (TCA) cycle? A) the TCA reduces a 2-carbon acetyl group to release two molecules of CO2 B) the transition step converts the pyruvate from glycolysis into acetyl-CoA C) together they generate the most reducing power of all the central metabolic pathways D) the TCA cycle generates most of the ATP for the cell E) the TCA oxidizes a 2-carbon acetyl group to release two molecules of CO2
A, D, E
Which of the following describe enzyme specificity? A) with few exceptions, a unique enzyme is required to catalyze each reaction in a cell B) a particular enzyme will only interact with a single class of molecule. For example, enzyme A might only interact with alcohols C) enzymes are made up of the same type of macromolecule with which they interact, e.g., lipids for fats, etc. D) the substrate must align spatially with the active site E) hydrogen and ionic bonding occur to induce the correct fit between substrate and active site
A, B
Which of the following help explain why it is difficult, especially in prokaryotes, to calculate an exact ATP yield from oxidative phosphorylation A) Prokaryotes use proton motive force to drive processes other than ATP synthesis B) Depending on the cell, different carriers are used in the electron transport chain that eject a variable number of protons per pair of electrons C) No experimental studies have been conducted to determine the yield of ATP from oxidative phosphorylation
fermentation
a cell only has a limited number of electron carrier molecules. During glycolysis, if electrons are not removed from NADH, the cell soon runs out of available NAD+, and the breakdown of glucose ends. This presents a problem for cells that lack a suitable terminal electron accepter for the electron transport chain or that cannot respire. The solution to this problem is called _____________
more than a thousandq
a cell will usually contain about how many different enzymes?
B
a good analogy for how energy is gradually released as electrons are passed from one carrier to another in the electron transport chain is ________ A) water flowing through a dam B) a ball falling down a flight of stairs C) a piece of wood burning
oxidative
although a modest amount of ATP is generated via substrate level phosphorylation by the central metabolic pathways, these pathways produce a large amount of reducing power that can be used to generate a much larger quantity of ATP via _____________ phosphorylation
less
an atom that has a lower affinity (attraction) for electrons than another is described as ________ (more or less) electronegative than the other
C
how does a non-competitive inhibitor work on an enzyme? A) it actively reduces the concentration of substrate, thereby slowing the rate of the reaction B) it enzymatically degrades the enzyme, thereby preventing the enzyme from catalyzing the reaction C) it binds to a site other than the active site, altering the shape of the enzyme so the substrate can no longer bind D) it binds to the active site in a concentration-dependent manner
oxygen
in aerobic respiration, _________ serves as the terminal electron acceptor
B, D
in contrast to an endergonic reaction, which of the following accurately describes and exergonic reaction? A) the reaction consumes the energy as it proceeds B) the starting compounds have more free energy than the products C) the products have more free energy than the starting compounds D) the reaction releases energy as it proceeds
A
oxidative phosphorylation and photophosphorylation are similar in that both processes _____ A) use an electron transport chain to set up a proton motive force used to generate ATP B) are used by all living cells C) use the energy released in an exergonic reaction to drive the addition of a phosphate group to ADP
reducing
oxidative phosphorylation uses the __________ power of NADH and FADH2 generated in glycolysis, the transition step, and the TCA cycle to synthesize ATP
TCA cycel
oxidizes and acetyl group to release two molecules of CO2; generates some ATP and precursor molecules and the most reducing power of all the central metabolic pathways
enzymes
proteins that function as biological catalysts are called ___________
B, C, A
rank the following energy-generating processes from greatest energy yield to least energy yield A) fermentation B) aerobic respiration C) anaerobic respiration
glycolysis
splits glucose and gradually oxidizes it to two molecules of pyruvate; generates some ATP and reducing power plus six precursor metabolites
CO2, ATP
the TCA cycle incorporates an acetyl group from the transition step and releases two precursor metabolites, two molecules of _________, and two molecules of ________
active site
the critical site of an enzyme to which a substrate binds by weak forces is called the __________ __________
catabolism, anabolism
the energy released by ________ is captured by cells to make ATP; this ATP can then be used for biosynthesis or ____________
B
the figure shows three examples of chemoorganotrophic metabolism, with glucose serving as the energy source, and either pyruvate, NO3-, and O2 as the terminal electron acceptor. Which of these three possibilities will yield the most energy for the organism? A) glucose as the energy source and NO3- as the terminal electron acceptor B) glucose as the energy source and O2 as the terminal electron acceptor C) glucose as the energy source and pyruvate as the terminal electron acceptor
D
the form of energy that results from the electrochemical gradient established by the electron transport chain is the ______ A) oxidative phosphorylation B) substrate-level phosphorylation C) photophosphorylation D) proton motive force E) chemiosmosis
