Untitled
41 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which characteristic defines extremophiles?

  • They favor conditions outside the normal range. (correct)
  • They are easily cultured in standard laboratory settings.
  • They thrive in typical environmental conditions.
  • They only survive in human-engineered environments.

What legal change occurred regarding the use of biological resources from Yellowstone National Park after the Thermus aquaticus discovery?

  • All biological resources were declared public domain.
  • Tom Brock was given exclusive rights to all thermophile research.
  • Yellowstone started signing revenue-sharing agreements. (correct)
  • The ATCC received all future royalties from discoveries.

What is the primary industrial application of Thermus aquaticus that led to substantial financial gain?

  • Development of new biofuels
  • Application in polymerase chain reaction (PCR) (correct)
  • Production of antibiotics
  • Use in bioremediation of polluted sites

What was the approximate financial compensation received by Tom Brock and Yellowstone National Park for the discovery and use of Thermus aquaticus?

<p>Tom Brock and Yellowstone National Park received very little financial compensation initially. (B)</p> Signup and view all the answers

Why is Taq polymerase from Thermus aquaticus so valuable in biotechnology?

<p>It remains stable and active at high temperatures. (D)</p> Signup and view all the answers

Assuming a newly discovered extremophile enzyme doubles the efficiency of a chemical reaction, which also reduces energy consumption by 30%, what is the most likely economic impact?

<p>Greater profitability and competitiveness in related industries (A)</p> Signup and view all the answers

Consider an extremophile found in a highly alkaline environment. If its cellular machinery is adapted to function optimally at a pH of 10, what challenge would it face if transferred to a neutral pH environment?

<p>Enzyme denaturation and disruption of membrane potential (B)</p> Signup and view all the answers

What is the primary challenge microbes face at low temperatures regarding their proteins?

<p>Proteins become too rigid, slowing down reaction rates (B)</p> Signup and view all the answers

How do microbes adapt to maintain membrane fluidity at low temperatures?

<p>By increasing the proportion of unsaturated fatty acids (D)</p> Signup and view all the answers

What genomic adaptation helps microbes thrive in low-temperature environments?

<p>Decreased G+C content in their DNA/RNA (A)</p> Signup and view all the answers

What is the defining characteristic of neutrophiles regarding their growth environment?

<p>They grow optimally at pH levels between 5.5 and 7.9 (D)</p> Signup and view all the answers

Which of the following adaptations would you expect to find in an obligate acidophile?

<p>A cell membrane highly impermeable to protons to maintain a near-neutral cytoplasm (A)</p> Signup and view all the answers

What is a critical function of the cell membrane for microbes living in extreme pH environments?

<p>To maintain a constant internal pH that is close to neutral, regardless of the external pH (A)</p> Signup and view all the answers

How do acidophiles maintain a proper proton motive force (PMF) in their extreme environments?

<p>By using a proton pump to expel protons from the cell (C)</p> Signup and view all the answers

Considering the challenges posed by extreme pH levels, what is the general pH range within which the cytoplasm of most microbes must be maintained?

<p>Near neutral (pH 4.6 - 9.5) (C)</p> Signup and view all the answers

Which of the following is most likely an adaptation of alkaliphiles to maintain a functional proton motive force (PMF)?

<p>Using sodium ion gradients ($Na^+$) rather than proton gradients to drive ATP synthesis and transport (A)</p> Signup and view all the answers

A microbe thrives in a solution of 20% NaCl. Based on the provided information, how would you classify this microbe?

<p>Extreme halophile (C)</p> Signup and view all the answers

If a cell is placed in a hypersaline environment, what is the likely direction of water movement, and what cellular adaptation would best counteract this?

<p>Water moves out of the cell; increase internal solute concentration. (D)</p> Signup and view all the answers

How does a halophile maintain osmotic balance in a high-salt environment?

<p>By accumulating compatible solutes in the cytoplasm. (B)</p> Signup and view all the answers

An organism is found to grow optimally in environments with high sugar concentrations. Which term BEST describes this organism?

<p>Osmophile (A)</p> Signup and view all the answers

Cells use the $F_0F_1$ ATPase. According to the image, what roles does $F_0F_1$ ATPase play in the transport of ions and energy production within the cell?

<p>It uses the proton motive force (pmf) to synthesize ATP and transport $Na^+$ ions out of the cell (D)</p> Signup and view all the answers

In alkaliphilic bacteria, what is the primary mechanism to maintain a neutral cytoplasmic pH?

<p>Active transport of $H^+$ ions out of the cell, often coupled with $Na^+$ import. (A)</p> Signup and view all the answers

What is the direct consequence of disrupting the proton motive force (PMF) in a bacterial cell?

<p>Reduced or absent ATP production by the $F_0F_1$ ATPase. (A)</p> Signup and view all the answers

Under what conditions would the $F_0F_1$ ATPase likely function in reverse, hydrolyzing ATP rather than synthesizing it?

<p>When the PMF is diminished and the cell needs to maintain a stable internal pH. (B)</p> Signup and view all the answers

How does the $Na^+/H^+$ antiporter contribute to pH homeostasis in alkaliphiles?

<p>It exchanges intracellular $Na^+$ for extracellular $H^+$, maintaining a low cytoplasmic $H^+$ concentration. (B)</p> Signup and view all the answers

Which cellular component is directly responsible for utilizing the proton motive force to synthesize ATP?

<p>The $F_0F_1$ ATPase (C)</p> Signup and view all the answers

If a bacterium's proton pumps are inhibited, what immediate effect would this have on the cell's ability to perform essential functions?

<p>Disruption of the proton motive force (B)</p> Signup and view all the answers

In an environment with a pH of 10, what challenge do alkaliphiles face in maintaining their internal pH?

<p>The need to prevent $H^+$ ions from leaking out of the cell (C)</p> Signup and view all the answers

What distinguishes the ATP production strategy of alkaliphiles from bacteria living in neutral pH environments?

<p>Alkaliphiles rely on a $Na^+$ motive force in addition to, or instead of, a proton motive force. (A)</p> Signup and view all the answers

How does a decrease in environmental pH affect the activity of the $Na^+/H^+$ antiporter in alkaliphiles?

<p>It decreases the antiporter's activity. (B)</p> Signup and view all the answers

What would happen if the $F_0F_1$ ATPase in a bacterium were mutated such that it could no longer transport protons?

<p>The bacterium would lose its ability to synthesize ATP using the PMF. (C)</p> Signup and view all the answers

In alkaliphilic bacteria, how is ATP production primarily driven, considering their external environment?

<p>By exporting protons to maintain a less alkaline cytoplasm relative to their extremely alkaline surroundings. (B)</p> Signup and view all the answers

If a cell's F0F1 ATPase is inhibited, what would be the immediate consequence on the proton motive force (PMF)?

<p>The PMF would increase as protons accumulate on one side of the membrane. (A)</p> Signup and view all the answers

What is the primary role of the proton motive force (PMF) in cellular energy production?

<p>To provide the energy for the mechanical rotation of the F0F1 ATPase, which then synthesizes ATP. (D)</p> Signup and view all the answers

In a bacterium with a malfunctioning proton pump, how would its ability to maintain a neutral intracellular pH be affected when placed in an acidic environment?

<p>The bacterium would experience a decrease in intracellular pH as protons flood into the cytoplasm. (D)</p> Signup and view all the answers

How does the activity of the F0F1 ATPase contribute to maintaining cellular pH homeostasis?

<p>It synthesizes ATP, using the proton gradient, thereby regulating the concentration of protons. (D)</p> Signup and view all the answers

In a hypothetical scenario where the proton permeability of a cell membrane suddenly increases, what immediate effect would this have on ATP production?

<p>ATP production would decrease as the proton motive force dissipates. (C)</p> Signup and view all the answers

How could a researcher experimentally determine whether a newly discovered bacterium is an alkaliphile?

<p>By measuring its growth rate at different pH levels and observing optimal growth at high pH. (A)</p> Signup and view all the answers

How does the environmental pH impact the proton motive force (PMF) in bacteria, and subsequently, ATP production?

<p>Environmental pH influences the PMF, affecting the proton gradient available to drive ATP synthesis. (C)</p> Signup and view all the answers

What is the consequence of disrupting the proton gradient across the cell membrane on ATP production, and how does this affect cellular function?

<p>ATP production decreases, impairing energy-dependent cellular functions. (D)</p> Signup and view all the answers

If a bacterium were engineered to express a channel that allows free flow of protons across the cell membrane, what would be the likely consequence on its internal pH and ATP production?

<p>Internal pH would become harder to regulate, and ATP production would decrease due to a compromised proton motive force. (D)</p> Signup and view all the answers

Flashcards

Extremophiles

Organisms thriving in conditions outside the 'normal' range.

Thermophile

An extremophile that thrives in high temperatures.

Taq polymerase

A DNA polymerase enzyme isolated from Thermus aquaticus, used in PCR.

Thermus aquaticus

Bacterium from which Taq polymerase is derived.

Signup and view all the flashcards

Cetus Corporation (Roche)

Company that made billions in royalties (and a Nobel Prize for Kary Mullis) from Taq polymerase.

Signup and view all the flashcards

Tom Brock

Scientist who discovered Thermus aquaticus.

Signup and view all the flashcards

Yellowstone National Park

Park where Thermus aquaticus was originally found.

Signup and view all the flashcards

Public Domain

Freely available for public use without copyright restrictions.

Signup and view all the flashcards

Low Temperature Protein Problem

Proteins become too rigid at low temperatures, slowing down reaction rates.

Signup and view all the flashcards

Low Temperature Membrane Problem

At low temperatures membranes become too viscous

Signup and view all the flashcards

Low Temperature DNA/RNA Problem

DNA/RNA becomes too rigid at low temperatures.

Signup and view all the flashcards

Alkaliphiles

Microbes adapted to high pH levels (≥ 8).

Signup and view all the flashcards

Acidophiles

Microbes adapted to low pH levels (< 5.5).

Signup and view all the flashcards

Neutrophiles

Microbes that grow best within a pH range of 5.5 to 7.9.

Signup and view all the flashcards

Cytoplasmic pH Challenge

The need to maintain a near-neutral pH inside the cell despite external pH.

Signup and view all the flashcards

Proton Impermeability

The cell membrane acts as a barrier to proton flow.

Signup and view all the flashcards

Halophiles

Organisms adapted to high salt concentrations.

Signup and view all the flashcards

Xerophiles

Organisms adapted to dry conditions.

Signup and view all the flashcards

Osmophiles

Organisms adapted to environments with high sugar concentrations.

Signup and view all the flashcards

Hypersaline

Having more salt than typical seawater (3.5% w/w NaCl).

Signup and view all the flashcards

Water activity (aw)

The measure of the free energy of water in a system.

Signup and view all the flashcards

Cellular pH Maintenance

The process of cells keeping a stable pH level.

Signup and view all the flashcards

Proton Motive Force (PMF)

A gradient generated by pumping protons (H+) across a membrane. Acid and charge are out.

Signup and view all the flashcards

F0F1 ATPase

An enzyme that uses the proton gradient to produce ATP.

Signup and view all the flashcards

Proton Pump

A mechanism used to move protons (H+) across a membrane against their concentration gradient.

Signup and view all the flashcards

Electron Transport Chain

Process that uses electron transfer to pump H+ and create PMF

Signup and view all the flashcards

ATP

A molecule composed of ribose, adenine, and a triphosphate unit that is used to temporarily store energy within the cell.

Signup and view all the flashcards

ADP

Adenosine diphosphate; a molecule composed of ribose, adenine, and a diphosphate unit that acts as a precursor to ATP.

Signup and view all the flashcards

Cellular pH Balance

The concentration of protons (H+) is crucial for maintaining a neutral pH inside cells.

Signup and view all the flashcards

PMF and ATP Production

ATP is not produced if there is no PMF

Signup and view all the flashcards

F0F1 ATPase Function

The F0F1 ATPase uses the proton gradient (PMF) to synthesize ATP.

Signup and view all the flashcards

Na+/H+ Antiporter

The Na+/H+ antiporter exchanges sodium ions (Na+) for protons (H+), helping to maintain pH balance.

Signup and view all the flashcards

Sodium Dependence in Alkaliphiles

Alkaliphiles use sodium-dependent transport systems to maintain internal pH.

Signup and view all the flashcards

Proton Pump Function

Proton pumps actively transport H+ ions across the membrane to maintain cellular pH.

Signup and view all the flashcards

Internal pH of Alkaliphiles

Alkaliphiles maintain an internal pH that is closer to neutral despite living in extremely alkaline environments.

Signup and view all the flashcards

Ion Transport Significance

The movement of ions, such as Na+ and H+, across the membrane, is crucial for energy conservation and pH regulation.

Signup and view all the flashcards

Study Notes

  • Extremophiles are organisms thriving in conditions outside of what is considered "normal".
  • Examined extremophiles are covered in Section 4.11-4.16 pp 126-137 of the textbook.

Thermophiles & Biotechnology

  • The Cetus corporation (Roche) made an estimated $2 billion in royalties thanks to thermophiles.
  • Roche also won a Nobel Prize for Kary Mullis.
  • Tom Brock and Yellowstone National Park did not get any royalties.
  • The ATCC got $100 in royalties.
  • Yellowstone now enters into long-time revenue-sharing agreements for discoveries made in the park.
  • Taq polymerase is derived from Thermus aquaticus.

Microbial Life at Low Temperatures

  • Problems with microbial life at low temperatures:
    • Proteins become too rigid slowing reaction rates
    • Membranes become too viscous
    • DNA/RNA becomes too rigid
  • Solutions to these problems:
    • Reduced amino acid interactions to stabilize the tertiary structure
    • Increased membrane fluidity
    • Decreased G+C content

Effects of pH on Microbial Growth

  • Each microbe grows within a pH range of ~2-3 pH units.
  • Neutrophiles grow optimally within a pH range of 5.5-7.9.
  • Alkaliphiles grow best at high pH (≥ 8).
    • Natronobacterium gregoryi (an archaeon) grows at an optimum of pH 10 but can grow up to pH 12.
  • Acidophiles grow best at low pH (< 5.5).
    • Picrophilus torridus grows at pH 0, it lives in sulfur fumaroles.

The Problem

  • The cytoplasm must remain near a neutral pH.
  • Minimum 4.6 and maximum 9.5 pH values have been recorded.
  • The cell membrane must be very impermeable to protons.
  • It is difficult to maintain a proper proton motive force in both extremes.

pH and the pmf: Acidophiles

  • Acidophiles use a proton pump to maintain a cellular neutral pH.
  • Proton motive force has acid and charge (+) outside, which leads to ATP production.

pH and the pmf: Alkaliphiles

  • Alkaliphiles use a proton pump to maintain a cellular neutral pH.
  • An alkaline environment outside leads to no proton motive force and therefore no ATP produced.

pH and the pmf: Alkaliphiles - Sodium Version

  • Alkaliphiles move sodium outside to generate a sodium motive force
  • An antiporter is used for Na+/H+ exchange
  • High [Na+] outside = smf (sodium motive force)

Osmotic Stress, Salt Stress

  • Halophiles are organisms that like salt and include Bacteria, Archaea and Eukarya
  • Xerophiles are organisms that like dry conditions, especially fungi
  • Osmophiles are organisms that live with osmotic stress, especially high sugar concentrations of yeasts

Halophiles

  • Seawater has 3.5% w/w of mostly NaCl.
  • Hypersaline environments have greater salt content than seawater.
  • NaCl saturation is 35.8%.
  • Non-halophiles grow best in 0% salt
  • Halophiles grow best in 1-15% salt
  • Extreme halophiles grow best in >15% salt
  • Halotolerant organisms can tolerate salt

Osmolarity and Microbial Growth

  • Water activity measures vapor pressure/free energy of water, being aw = 1 for pure water at atmospheric pressure, reduced by solutes/dryness
  • Cytoplasm usually has a higher solute concentration, leading to water moving into the cell.

Osmolarity and Microbial Growth

  • As water moves in, the pressure in the cell increases the water activity inside, balancing the solute effect.
  • A normal freshwater bacterium in high salt would not have this effect.

Strategies of Halophiles

  • "Salt in" strategy: accumulate KCl, requiring salt-adapted enzymes, mostly Archaea (few Bacteria).
  • "Compatible solutes" strategy: accumulate organic solutes, Bacteria, and Eukarya.
  • Compatible solutes do not damage enzymes, unlike salts.

Compatible Solutes of Microorganisms

  • Most nonphototrophic Bacteria (Escherichia) and freshwater cyanobacteria (Anabaena) use amino acids and/or sucrose, trehalose.
  • Marine cyanobacteria (Synechococcus) use a-Glucosylglycerol.
  • Marine algae (Phaeocystis) use Mannitol, glycosides, dimethylsulfoniopropionate.
  • Halotolerant Bacteria (Staphylococcus) uses amino acids.
  • Salt lake cyanobacteria (Aphanothece) use glycine betaine.
  • Halophilic phototrophic purple Bacteria (Halorhodospira) use glycine betaine, ectoine, trehalose.

Light-Driven ATP Synthesis

  • Halobacterium can use light to make ATP via a simple system.
  • This is done using Bacteriorhodopsin

Oxygen and Microbial Growth

  • Aerobes need O₂ for respiration.
  • Microaerophiles need for O₂ but at low concentrations.
  • Facultative anaerobes will respire using O₂ if it is available, but they can survive without it.
  • Aerotolerant anaerobes do not use O₂ but can still tolerate it.
  • Obligate anaerobes do not use O₂ and cannot tolerate it.

Thioglycolate Broth

  • Thioglycolate broth can be used, it is a complex medium to distinguish microbes based on oxygen requirements.
  • Resazurin reacts with oxygen, which can only penetrate a few mm from the top of the tube.

Oxygen Toxicity

  • Molecular oxygen (O₂) has low toxicity.
  • Reactive oxygen species (ROS) include:
    • Superoxide anion (O₂⁻)
    • Hydrogen peroxide (H₂O₂)
    • Hydroxyl radical (OH•)

Enzymes That Remove Reactive Oxygen Species

  • Catalase formula: 2 H₂O₂ → 2 H₂O + O₂
  • Peroxidase formula: H₂O₂ + NADH + H+ → 2 H₂O + NAD+
  • Superoxide Dismutase formula: O₂⁻ + O₂⁻ + 2 H+ → H₂O₂ + O₂
  • Superoxide Dismutase/Catalase in combination: 4 O₂⁻ + 4 H+ → 2 H₂O + 3 O₂
  • Superoxide Reductase formula: O₂⁻ + 2 H+ + rubredoxin reduced → H₂O₂ + rubredoxin oxidized

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

Ecosystems - Extremophiles - Pearson PDF

More Like This

Untitled
110 questions

Untitled

ComfortingAquamarine avatar
ComfortingAquamarine
Untitled Quiz
6 questions

Untitled Quiz

AdoredHealing avatar
AdoredHealing
Untitled Quiz
18 questions

Untitled Quiz

RighteousIguana avatar
RighteousIguana
Untitled Quiz
50 questions

Untitled Quiz

JoyousSulfur avatar
JoyousSulfur
Use Quizgecko on...
Browser
Open
Browser
Browser