ex 3 ch 6
Photosynthetic organisms use the light-dependent reactions to accomplish which two tasks?
Generate ATP via photophosphorylation; generate reducing power
Lactic acid is a common fermentation product of which of the following types of cells
Gram-positive lactic acid bacteria
H2 gas
Hydrogen bacteria
Which is the correct order for the three stages of the Calvin cycle?
incorporation → reduction → regeneration
Electron carriers of the electron transport chain are able to move protons across a membrane. They are able to do so because ______.
some accept only hydrogen atoms (proton-electron pairs), whereas others accept only electrons
Clostridium species are obligate anaerobes. Might they be able to grow using fermentation, or must they use anaerobic respiration
Yes, Clostridium species are able to use fermentation and anaerobic respiration
Microorganisms that can grow on polysaccharides and disaccharides first break these down to glucose or precursor metabolites that can then enter into the pathway of to be oxidized.
glycolysis
Purines and pyrimidines are synthesized
in distinctly different manners
The Calvin cycle ______.
incorporates carbon dioxide into organic compounds
The reactions that capture radiant energy and convert it into chemical energy in the form of ATP are called the blank blank reactions.
light dependent
The generation of ATP via photophosphorylation and the generation of reducing power in the form of either NADPH or NADH are accomplished during the
light-dependent reactions of photosynthesis Reason: Recall, the light-independent reactions use the energy from the light-dependent reactions to fix CO2.
Compared to the ATP gain per glucose molecule in prokaryotes, that of eukaryotes is
lower
Why does anaerobic respiration yield less energy than aerobic resaerobic respiration
lower affinity
Some prokaryotes can extract electrons from inorganic energy sources and pass them to an electron transport chain to generate a proton motive force to make ATP. These types of prokaryotes are called
chemolithotrophs
Considering the general equation that describes photosynthesis, the rate of the process would be most influenced by the availability of _______ in the atmosphere.
co2
In addition to four protein complexes, the mitochondrial electron transport chain has two freely-moving ______, ubiquinone and cytochrome c, that serve to
electron carriers; shuttle electrons between the complexes
Hydrogen sulfide is produced as a result of certain types of anaerobic respiration. Some chemolithotrophs can then use this as a/an
energy source
In the case of plants, algae, and cyanobacteria, the two major products of photosynthesis are
glucose and oxygen
The Calvin cycle involves an enzyme commonly called rubisco. What is the product of the reaction it catalyzes?
3-phosphoglycerate
The electron transport chain of mitochondria has ______ different protein complexes.
4
The first step of aromatic amino acid synthesis is the formation of a 7-carbon compound. This is made from a 4-carbon and a 3-carbon compound that originate, respectively, from what two central metabolic pathways?
4-carbon from the pentose phosphate pathway; 3-carbon from glycolysis
The Voges-Proskauer test detects acetoin, the terminal electron acceptor of 2,3-butanediol fermentation. Similar to how the methyl-red test can test for mixed acids fermentation, the Voges-Proskauer test is important in helping differentiate between _
members of the Enterobacteriaceae family
In non-cyclic photophosphorylation, electrons from _______ are used to replenish the electrons lost from photosystem I.
photosystem II
The pigments of photosynthetic organisms capture blank energy.
radiant
he ability of organisms such as E. coli to ferment via the mixed acids pathway can be tested by the methyl-red test, which detects
the low pH resulting from the acidic end products
In respiring bacteria, how does ATP synthase generate ATP?
It uses the energy released from allowing protons to flow back into the cell to add a phosphate group to ADP.
The electron transport chain (ETC) components used by E. coli vary depending on all of the following conditions EXCEPT
temp
Flavoproteins are synthesized from the vitamin _______ and play a major role in the _______.
riboflavin; electron transport chain
The process that links the electron transport chain to ATP synthesis is called the theory.
chemiosmotic
Examples of electron carriers are proteins that contain heme, a molecule that holds an iron in its center. These are called
cytochromes
After a deamination reaction removes the amino group from amino acids, the remaining carbon skeletons are converted into the appropriate blank metabolites for entry into central metabolic pathways.
precursor
Which of the following correctly describe cytochromes found in an electron transport chain?
Several different cytochromes exist. Cytochromes are proteins that contain heme, a molecule that holds an iron atom in its center.
Propionibacterium species use a multistep fermentation pathway that first adds CO2 to pyruvate to generate a compound that serves as a terminal electron acceptor. After reduction by NADH, it is further modified to form propionate. Humans take advantage of this process to make what product?
Swiss cheese
In prokaryotes, the electron transport chain is located in the blank membrane, whereas in eukaryotic cells it is in the blank membrane of mitochondria.
cytoplasmic internal
A general group of electron carriers found in electron transport chains is quinones, that
exist as several types, including ubiquinone and menaquinone are lipid-soluble organic molecules that move freely in the membrane, transferring electrons between different protein complexes
The chemiosmotic theory, proposed by Peter Mitchell in 1961, explain
how the electron transport chain is linked to ATP synthesis
The synthesis of aromatic amino acids such as tyrosine, phenylalanine, and tryptophan requires what type of metabolic pathway?
A multi-step, branching pathway
The electron transport chain is a cluster of membrane-embedded electron carriers that accept electrons from the coenzymes blank and blank and then pass these electrons along the chain.
nadh fadh2
The electron transport chain consists of large protein-complexes embedded in a membrane. These pass electrons from one to the next, while simultaneously pumping across the membrane,
proton(h+)
Menaquinone is a quinone used in the electron transport chain of some prokaryotes. It plays an important role for humans and other mammals because it
serves as a source of vitamin K, providing much of the host's requirement via absorption in the intestinal tract
The ATP generated by fermentation comes from
substrate-level phosphorylation during glycolysis
2 nadh to 6 atp theoretical atp yeild in oxidative phosphorlation
glycolysis
Cyanobacteria and photosynthetic eukaryotic cells have how many distinct types of photosystems?
2
Detecting different fermentation products can be an important tool in identifying bacteria. What two fermentation pathways are particularly useful in differentiating members of the family Enterobacteriaceae?
2,3-butanediol fermentation; mixed acids fermentation
Proteins are composed of various combinations of usually how many different amino acids?
20
Multiple Choice Question With respect to their synthesis, how are amino acids typically grouped?
By structurally related families that share common biosynthesis pathways
Non-cyclic photophosphorylation
Choice Generates ATP and NADPH
Testing for the ability of organisms to produce mixed acids via fermentation can be clinically important because it can differentiate members of the ______ family.
Enterobacteriaceae
in order to form lipids, how are fatty acids and glycerol synthesized?
Fatty acid chains are assembled from 2-carbon acetyl groups from the transition step; the precursor to glycerol comes from glycolysis
Fe2+
Iron bacteria
What happens to an organism if it lacks one or more enzymes in a given biosynthetic pathway?
It must have the end product provided from an external source.
Autotrophs use carbon dioxide (CO2) to synthesize organic compounds. Which of the following descriptions of this process are true?
It often involves the Calvin cycle. It is called carbon fixation. In photosynthetic organisms, the process is called the light-independent reactions.
Why is glutamate synthesis especially important for bacteria?
It provides a mechanism for incorporating nitrogen into organic material.
Which of the following combinations of molecules is produced during the light-dependent reactions of photosynthesis and used in the light-independent reactions?
NADPH and ATP Reason: While oxygen is generated during the light-dependent reactions, it is not utilized during the light-independent reactions.
NH3, HNO2
Nitrifying bacteria
Glutamate synthesis is especially important for bacteria, because it provides a mechanism for the incorporation of blank into organic material.
Nitrogen
In photosynthesis, the protein complexes located within photosynthetic membranes that contain pigments and are responsible for capturing radiant energy are called
Photosystems
Some members of which of the following groups can use inorganic chemicals such as hydrogen sulfide and ammonia for energy?
Prokaryotes only
A genus of bacteria that uses fermentation to produce propionic acid and is used as a part of Swiss cheese production is
Propionibacterium
Fats are hydrolyzed by lipases. The glycerol component is then converted to a precursor metabolite, and the fatty acids are degraded using a series of reactions called β-oxidation that remove successive 2-carbon units. Where do these components enter the central metabolic pathways for further oxidation?
The precursor metabolites from glycerol enter glycolysis; the 2-carbon units from fatty acids are added to coenzyme A and enter the TCA cycle.
In photosynthesis by cyanobacteria and chloroplasts, why is O2 generated?
The process strips electrons from H2O, generating O2.
Prokaryotes as a group are unique in their ability to use reduced inorganic chemicals such as hydrogen sulfide (H2S) and ammonia (NH3) as sources of energy. Why is this an important example of how waste products of one organism serve as an energy source for another?
These compounds are produced by anaerobic respiration from inorganic molecules (sulfate, nitrate) serving as terminal electron acceptors.
Instead of fulfilling both their energy and carbon needs from organic compounds the way chemoheterotrophs do, why do chemolithotrophs incorporate CO2 into an organic form to fulfill their carbon needs?
They fulfill their energy needs from inorganic compounds such as H2S and NH3 that lack carbon, so they need to obtain their carbon elsewhere.
Which of the following are reasons an organism might use fermentation?
They lack an electron transport chain. A suitable inorganic terminal electron acceptor is not available.
Although the actual procedure is much more involved, the basic metabolism of wine-making involves inoculating grape juice with a special strain of the yeast Saccharomyces cerevisiae. S. cerevisiae will preferentially perform aerobic respiration on sugars in the juice but can also ferment those sugars to yield CO2 and alcohol, an important component of wine. Assume you inoculate a completely full container of juice and then close the lid. What will the yeast do?
They will grow aerobically, consume the O2 dissolved in the juice, and then switch to fermenting sugars to yield alcohol.
Accessory pigments increase the efficiency of light capture by
absorbing wavelengths of light not absorbed by the other pigments
Pigments that increase the efficiency of light capture by absorbing wavelengths not absorbed by other pigments are called blank pigments.
accessory
If E. coli is cultured in a medium that includes both nitrate and O2, it would be expected to grow using ______ respiration.
aerobic respiration Reason: E. coli will respire aerobically if O2 is available.
The light-independent reactions of photosynthesis occur _______ the light-dependent reactions, and function to _______.
after; synthesize organic compounds from CO2
Ethanol can be produced during fermentation by removing CO2 from pyruvate to generate acetaldehyde, which then serves as the terminal electron acceptor, yielding ethanol. Humans have taken advantage of microorganisms capable of this process in a number of ways. Which of the following are examples of this?
bread making wine and beer making making biofuels
The process by which chemolithoautotrophs and photoautotrophs incorporate CO2 into organic compounds is called
carbon fixation
The pigment that gives plants their green color is called
chlorophyll
Escherichia coli's electron transport chain (ETC) is
modular, meaning that different components are used depending on the conditions
In addition to glucose, which of the following organic compounds can serve as energy sources for microbes?
monosaccharides fatty acids proteins lipids polysaccharides disaccharides
Which of the following produces ATP and reducing power?
noncyclic photophosphorylation only
When photosynthetic cells need to produce both ATP and NADPH, they use photosystem I and photosystem II together in a process called _______ photophosphorylation, but when they need to produce ATP but not NADPH, they use only photosystem I in a process called _______ photophosphorylation.
noncyclic; cyclic
Cyclic photophosphorylation uses ______, whereas non-cyclic photophosporylation uses ______.
photosystem I only; photosystem I and II
34atp theoretical atp yeild in oxidative phosphorlation
total max yield
Anoxygenic photosynthetic bacteria like the purple bacteria and green bacteria may use any of the following as electron donors for reducing power EXCEPT
water
Oxygenic photosynthesis produces O2 from the splitting of blank molecules.
water
the electrons lost from photosystem II are replaced by electrons derived from a molecule of
water
What microorganisms use a fermentation pathway that results in CO2 and ethanol production?
yeast and bacteria
What is the role of reaction-center pigments?
Function as electron donors, emitting high-energy electrons that are then passed to an electron transport chain.
A genus that includes obligate anaerobes that can produce butyric acid and a number of other end products via fermentation is
Clostridium
Cyclic photophosphorylation
Generates ATP only
Microorganisms can grow on a variety of organic compounds other than glucose, including polysaccharides, proteins, and lipids. How do they accomplish this?
They break these macromolecules down into appropriate precursor metabolites that are then introduced into central metabolism or used in biosynthesis.
In photosynthesis, what do the light reactions, or light-dependent reactions, accomplish?
They capture radiant energy and convert it to chemical energy in the form of ATP.
t or f The Calvin cycle is a two-step linear pathway that photosynthetic organisms use to fix carbon dioxide
false
Unlike organisms that use organic molecules to fill both their energy and carbon needs, chemolithotrophs must use a process called carbon blank to produce organic carbon compounds to fulfill their carbon needs.
fixation
Fill in the Blank Question Fill in the blank question. Starch and cellulose are both polymers made up of the monosaccharide blank , which means that hydrolysis of the polymers releases subunits that can enter directly into the central metabolic pathway of blank to be oxidized.
glucose glycolysis
Lipid synthesis generally requires the components blank and blank acids.
glycerol and fatty
How many turns of the Calvin cycle does it take to generate one molecule of the 6-carbon sugar fructose?
6
Consider the theoretical maximum ATP yield from the complete oxidation of glucose via aerobic respiration in prokaryotes. Match the relative contribution in terms of ATP (substrate-level phosphorylation plus oxidative phosphorylation) with the correct metabolic component.
8 ATP-Glycolysis 6 ATP-Transition step 24 ATP-TCA cycle 38 ATP-Total yield of aerobic respiration
Fill in the Blank Question Fill in the blank question. Proteins are hydrolyzed by proteases, enzymes that break the peptide bonds between blank blank subunits.
amino acid
6 nadh & 2 fadh 2 to 22atp theoretical atp yeild in oxidative phosphorlation
tca cycle
Fats, the most common simple lipids, are broken down by lipases into their component
glycerol and fatty acids
H2S
Sulfur bacteria
Photosynthesis in groups of bacteria called purple and green bacteria involves the use of H2S instead of water. This process is called photosynthesis.
anoxygenic
Nucleotide subunits of DNA and RNA are composed of three units: a 5-carbon sugar, a phosphate group, and a nucleobase. They are initially synthesized ______.
as ribonucleotides that can be converted to deoxyribonucleotides by replacing the 2' hydroxyl group with a hydrogen atom
As part of cellular respiration, a membrane-bound enzyme called Blank uses energy from a proton-motive force to add a phosphate group to ADP.
atp synthase
Lactic acid production by fermenting microorganisms has many benefits for humans, but also can cause some problems. Which of the following are examples of these advantages and disadvantages?
Results in food spoilage. Creating flavor and texture of yogurt and certain cheeses. Production of pickles and cured sausages. Contributes to tooth decay.
Purple bacteria and green bacteria have only a single photosystem and cannot use water as an electron donor, with production of O2 as a byproduct. This makes them photosynthetic bacteria.
anoxygenic
Chemolithotrophs fall into four general groups
h2s,h2 gas, fe2+, nh3, nho2
In terms of their metabolism, prokaryotes are _______ with respect to compounds they use for energy and _______ in their biosynthetic processes.
highly diverse; remarkably similar
blank-center pigments function as electron donors in the photosynthetic process, emitting high-energy electrons that are then passed to an electron transport chain.
reaction
true or false: With respect to the location of the electron transport chain, the inner membrane of mitochondria is analogous to the cytoplasmic membrane of bacterial cells.
true
All of the following are essential for an electron transport chain to function EXCEPT
atp bc it is generating atp
You wish to isolate some chemolithotrophs. Where might be a good place to start looking for them?
Specific environments where reduced inorganic compounds are found, such as hydrothermal vents. Reason: Remember, chemolithotrophs obtain their energy from reduced inorganic compounds.
Cellular respiration involves the mechanism of oxidative phosphorylation, which uses the energy of a proton motive force to produce ______.
atp
