YouConnect Homework #8
Escherichia coli and Psudomonas aeruginosa both have an electron transport chain that uses O2 as a terminal electron acceptor, yet E.coli is oxidase negative. Based on this information, it is logical to assume that E. Coli
Lacks cytochrome C
Ethanol Fermentation
Saccharomyces
Microorganisms can grow on a variety of organic compounds other than glucose, including polysaccharides, proteins, and lipids. How do they accomplish this?
They beak these macromolecules down into appropriate precursor metabolites that are then introduced into central metabolism or used in biosynthesis
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
The electron lost from photosystem II are replaced by electrons derived from a molecule of ______
Water
The electrons lost from photosystem II are replaced by electrons derived from a molecule of _____
Water
Proteins are hydrolyzed by proteases, enzymes that break the peptide bonds between _____________ subunits
Amino acids
Quinones
Lipid-soluble organic molecules that move freely in the membrane; includes one that serves as a source of vitamin K for humans and other mammals
Consider the representation of an electron transport chain, O2 is serving as the terminal electron acceptor. Is it being oxidized or reduced?
Reduced
What microorganisms use a fermentation pathway that results in CO2 and thane production?
Saccharomyces species (yeast) and Zymomonas species (bacteria)
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 ________
Severes as a source of vitamin K, proving much of the host's requirement via absorption in the intestinal tract
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
The ATP generated by fermentation comes from ______
Substrate-level phosphorylation during glycolysis
Starch and cellulose are both polymers made up of the monosaccharide _______, which means that hydrolysis of the polymers releases subunits that can enter directly into the central metabolic pathway of _____ to be oxidized
Glucose Glycolysis
In the case of plants, algae, and cyanobacteria, the two major products of photosynthesis are _______
Glucose and oxygen
Fats, the most common simple lipids, are broken down by lipases into their component _______
Glycerol and fatty acids
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
Which of the following correctly describe cytochromes found in an electron transport chain?
- Cytochromes are proteins that contain heme, a molecule that holds an iron atom in its center - Several different cytochromes exist
In addition to glucose, which of the following organic compounds can serve as energy sources for microbes?
- Disaccharides - Proteins - Lipids - Monosaccharides - Polysacchardies - Fatty acids
In an electron transport chain, electron carriers are found in what two general locations?
- Grouped into large protein complexes that function as proton pumps - Freely moving in the membrane where they can shuttle electrons between protein complexes
In additional to glucose, which of the following organic compounds can serve as energy source of microbes?
- Monosaccharides - Lipids - Fatty acids - Polysaccharides - Disacchardies
the three main types of electron carriers in a typical electron transport chain are _______, _______, and flavoproteins
- Quinones - Cytochromes
A general group of electron carriers found in electron transport chains is quinones that _______
- Are lipid-soluble organic molecules that move freely in the membrane transferring electrons between different protein complexes - Exist as several types, including ubiquinone and menaquinone
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?
- Contributes to tooth decay - Creating flavor and texture of yogurt and certain cheeses - Production of picked and cured sausages - Results in food spoilage
In an electron transport chain, electron carriers are found in what tw general locations?
- Grouped into large protein complexes that function as proton pumps - Freely moving in the membrane where they can shuttle electrons between protein complexes
The electron transport chain is a cluster of membrane- embedded electron carriers that accept electrons from the coenzymes _______ and ______ and then pass these electrons along the chain
- NADH - FADH2
In prokaryotes, how does the energy yield of aerobic respiration compare to anaerobic respiration?
Te energy yield is aerobic respiration is greater than anaerobic respiration
As part of cellular respiration, a membrane-bund enzyme called ATP _______ uses energy from a proton-motive force to add a phosphate group to ADP
Synthase
6 ATP
Transition Step
This picture of a set of stairs best exemplifies the electron _______
Transport chain
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
Cyanobacteria and photosynthetic eukaryotic cells have how many distinct types of photosystems?
Two
Which of the following are reasons an organism might use fermentation?
- A suitable inorganic terminal electron acceptor is not available - They lack an electron transport chain
Spatial Arrangement of Electron Carriers in a Bacterial Electron Transport Chain
- An electron carrier (NADH + H+) donates electrons to a hydrogen carrier, which also picks up protons - The hydrogen carrier passes electrons to a carrier that only accepts electrons - Because the electron carrier only accepts electrons, the protons are released to the outside of the cell - A proton motive force is set up as protons are moved from the inside of the cell to the outside
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 - In photosynthetic organisms, the process is called the light independent reactions - It is called carbon fixation
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 - In photosynthetic organisms, the process is called the light-independent reactions - It is called carbon fixation
Flavoproteins
Proteins that are synthesized from the vitamin riboflavin
Cytochromes
Proteins that contain heme, a molecule that holds an iron atom in its center
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
Protons
_______ - center pigments function as electron donors in the photosynthetic process, emitting high-energy electrons that are then passed to an electron transport chain
Reaction
Butyric Acid Fermentation
Butyric acid, butanol, acetone, isopropanol, CO2, H2
Considering the general equation that describes photosynthesis, the rate of the process would be out influenced by the availability of _______ in the atmosphere
CO2
8 ATP
Glycolysis
The Calvin Cycle
Incorporates carbon dioxide into organic compounds
The Calvin cycle
Incorporates carbon dioxide into organic compounds
How does the oxidase test help in bacterial identification?
It detects the activity of cytochrome c oxidase, a component of the electron transport chain of some but not all bacteria
The mechanism by which cellular respiration uses reducing power generated in glycolysis, the transition step, and the TCA cycle to synthesize ATP is _________ phosphorylation
Oxidative
In no -cyclic potophosphoryation, electrons from _______ are used to replenish the electrons lost from photosystem I
Photosystem II
In non-cyclic photophosphorylation, electrons from ______ are used to replenish the electrons lost from photosystem I
Photosystem II
In prokaryotes, how does the energy yield of aerobic respiration compare to anaerobic respiration?
The energy yield oa aerobic respiration is greater than anaerobic respiration
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, involves what two steps?
- The electron transport chain generates a proton motive force - ATP synthase uses the energy of the proton motive force to drive the synthesis of ATP
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?
- Wine and beer making -Bread making - Making biofuels
The light independent reaction of photosynthesis occur _______ the light-dependent reactions, and function to
After; synthesize organic compounds from CO2
The light-independent reactions of photosynthesis occur _____ the light-dependent reactions and function to ______
After; synthesize organic compounds from CO2
This diagram depicts the production of ethanol from pyruvate via fermentation. What best explains the mechanism?
CO2 removal converts pyruvate to the terminal electron acceptor acetaldehyde, which receives 2 electrons and proton from NADH + H+ taking ethanol
The process by which chemolithoautotrophs and photoautotrophs incorporate CO2 into organic compounds Is called ______
Carbon fixation
Butyric Acid Fermentation
Clostridium
Hydrogen sulfide is produced as a result of certain types of anaerobic respiration. Some chemolithotrophs can then use this an an
Energy source
2,3 Butanediol Fermentation
Enterbacter
Ethanol Fermentation
Ethanol, CO2
The Calvin cycle is a two-step linear pathway that photosynthetic organisms use to dix carbon dioxide
False
With respect to prokaryotic species such as E. coli, each individual cell will have an electron transport chain made up of the same components
False
The general group of electron carriers synthesized from the vitamin riboflavin is called ________
Flavoproteins
2,3 Butanediol Fermentation
Formic acid, ethanol, lactic acid, 2,3-butanediol, CO2, H2
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
Lactic acid is a common fermentation product of which of the following types of cells?
Gram-positive lactic acid bacteria
In photosynthesis by cyanobacteria and chloroplasts, why is O2 generated?
The process strips electrons from H2O generating O2
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
The lactic acid fermentation pathway is shown here. What statement best explains what is happening in the diagram?
NADH+ H+ are donating 2 electrons and 2 protons to pyruvate, an organic terminal electron acceptor, reducing it to lactate
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
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
In the representation of an electron transport chain, the terminal electron acceptor is ______
O2
Flavoproteins are synthesized from the vitamin ______ and plays a major role in the ______
Riboflavin, electron transport chain
24 ATP
TCA Cycle
Why does anaerobic respiration yield less energy than aerobic respiration?
The terminal electron acceptors used in anaerobic respiration have lower electron affinities than O2
Why does anaerobic respiration yield less energy than aerobic respiration?
The terminal electron accepts used in anaerobic respiration have lower electron affinities than O2
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
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
Other than generating some ATP via the substrate-level phosphorylation steps of glycolysis, what critical role do the additional steps of fermentation accomplish?
They consume excess reducing power in order to regenerate NAD+ so that t can accept electrons to keep glycolysis going
38 ATP
Total yield of aerobic respiration
Mixed Acids Fermentation
E.coli
Lacic Acid Fermentation
Streptococcus, Lactobacillus
Lactic Acid Fermentation
Lactic Acid
If there theoretical maximum ATP yield in prokaryotes from oxidative phosphorylation is 34 ATP for a single glucose molecule, what is the total ATP gain when substrate-level phosphorylation is included?
38 ATP
All of the following are essential for an electron transport chain to function EXCEPT _____
ATP
Complex II
Accepts electrons from FADH2
Complex I
Accepts electrons from NADH
Complex IV
Accepts electrons from cytochrome C
Complex III
Accepts electrons from ubiquinone
Mixed Acids Fermentation
Acetic acid, lactic acid, succinct acid, ethanol, CO2, H2
E. coli wil preferentially use _______ respiration in the presence of O2 but when O2 is not available, it can switch to _____ respiration if a suitable electron acceptor such as nitrate is present
Aerobic Anaerobic
4 Different Protein Complexes of ETC of Mitochondria
Complex I Complex II Complex III Complex IV
There are four electron transport carriers in the ETC of eukaryotes. Which pair is correctly matched?
Complex IV- Cytochrome c oxidase complex
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 reactions that capture radiant energy and convert it into chemical energy in the form of ATP are called the __________ reactions
Light-dependent
Quinones
Lipid- soluble organic molecules that move freely in the membrane: includes one that serves as a source of vitamin K for humans and other mammals
After a deamination reaction removes the amino group from amino acids, the remaining carbon skeletons are converted into the appropriate ______ metabolites for entry into central metabolic pathways
Precursor
Some members of which of the following groups can use inorganic chemicals such as hydrogen sulfide and ammonia for energy?
Prokaryotes only
Propionic Acid Fermentation
Propionbacterium
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 Saccaromyces 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
Propionic Acid Fermentation
Propionic avid, acetic acid, CO2
In prokaryotes, the electron transport chain is located in the _______ membrane, whereas in eukaryotic cells it is in the _______ membrane of mitochondria
- Plasma -Inner
Examples of electron carriers are proteins that contain heme, a molecule that holds an iron in its center. These are called ______
Cytochromes
In oxidative phosphorylation quinones, cytochromes, and flavoproteins are all ______ carriers
Electron
In addition to four proteins complexes, the mitochondrial electron transport chain has two freely-moving _______, ubiquinone and cytochrome c, that serve to ________
Electron carriers; shuttle electrons between the complexes
Photosynthetic organisms use the light-dependent reactions to accomplish which two tasks?
Generate ATP via photophosphoylation, generate reducing power
The electron transport chain of mitochondria has ______ different protein complexes
Four
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 B- oxidation that remove successive 2-carbon units. Where o 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
