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