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What function do the spikes on viruses serve?
What function do the spikes on viruses serve?
What is meant by the term 'tropism' in the context of viruses?
What is meant by the term 'tropism' in the context of viruses?
Which of the following viruses exhibits tropism for the respiratory tract?
Which of the following viruses exhibits tropism for the respiratory tract?
Who is credited as the original discoverer of viruses?
Who is credited as the original discoverer of viruses?
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How are viruses classified based on their shape?
How are viruses classified based on their shape?
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What is the overall net gain from the breakdown of a single glucose molecule during glycolysis?
What is the overall net gain from the breakdown of a single glucose molecule during glycolysis?
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What process generates ATP using light energy absorbed by chlorophyll molecules?
What process generates ATP using light energy absorbed by chlorophyll molecules?
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Which method is the primary way for generating ATP in most cells?
Which method is the primary way for generating ATP in most cells?
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In oxidative phosphorylation, what is the ultimate electron acceptor?
In oxidative phosphorylation, what is the ultimate electron acceptor?
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What drives ATP synthesis in photophosphorylation?
What drives ATP synthesis in photophosphorylation?
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What mechanism directly transfers a phosphate group to ADP, producing ATP?
What mechanism directly transfers a phosphate group to ADP, producing ATP?
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Which of the following is not a product of glycolysis?
Which of the following is not a product of glycolysis?
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How do protons contribute to ATP production during oxidative phosphorylation?
How do protons contribute to ATP production during oxidative phosphorylation?
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What characterizes the protein PrPsc in relation to PrPc?
What characterizes the protein PrPsc in relation to PrPc?
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What is the primary cause of brain damage in Transmissible Spongiform Encephalopathy (TSE)?
What is the primary cause of brain damage in Transmissible Spongiform Encephalopathy (TSE)?
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Which of the following is NOT a type of TSE found in humans?
Which of the following is NOT a type of TSE found in humans?
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Why are prions considered extremely resilient pathogens?
Why are prions considered extremely resilient pathogens?
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What are the potential consequences of TSE on affected individuals?
What are the potential consequences of TSE on affected individuals?
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What do plaques in a bacterial lawn correspond to?
What do plaques in a bacterial lawn correspond to?
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Which method is used to detect the presence of RNA viruses?
Which method is used to detect the presence of RNA viruses?
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What are cytopathic effects (CPEs)?
What are cytopathic effects (CPEs)?
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In which environment do animal viruses require for replication?
In which environment do animal viruses require for replication?
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What is a key characteristic of viroids?
What is a key characteristic of viroids?
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What could be a possible outcome of viral infection in a developing embryo?
What could be a possible outcome of viral infection in a developing embryo?
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Which of the following describes the use of serological tests?
Which of the following describes the use of serological tests?
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What type of cells are typically associated with carcinomas and sarcomas due to viral transformation?
What type of cells are typically associated with carcinomas and sarcomas due to viral transformation?
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What is the function of the reaction center in the photosystem?
What is the function of the reaction center in the photosystem?
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What is produced as a byproduct of oxygenic photosynthesis?
What is produced as a byproduct of oxygenic photosynthesis?
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What are thylakoids in prokaryotes?
What are thylakoids in prokaryotes?
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Which of the following is NOT a component of a photosystem?
Which of the following is NOT a component of a photosystem?
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In oxygenic photosynthesis, what is the primary electron source?
In oxygenic photosynthesis, what is the primary electron source?
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Which type of photosynthesis does cyanobacteria perform?
Which type of photosynthesis does cyanobacteria perform?
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What is the main role of the light-harvesting complex within a photosystem?
What is the main role of the light-harvesting complex within a photosystem?
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What is generated as a result of anoxygenic photosynthesis?
What is generated as a result of anoxygenic photosynthesis?
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What is a cytokine storm most likely to cause?
What is a cytokine storm most likely to cause?
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What is the main function of superantigens?
What is the main function of superantigens?
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Which of the following organisms is the prototype superantigen associated with toxic shock syndrome?
Which of the following organisms is the prototype superantigen associated with toxic shock syndrome?
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Which component is identified as an endotoxin?
Which component is identified as an endotoxin?
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Why do superantigens stimulate a larger proportion of T cells compared to normal antigens?
Why do superantigens stimulate a larger proportion of T cells compared to normal antigens?
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Study Notes
Microbial Metabolism
- Substrate Level Phosphorylation is one of two mechanisms for producing ATP.
- In substrate-level phosphorylation, a phosphate group is removed from an organic molecule and directly transferred to ADP, producing ATP.
- During glycolysis, high-energy phosphate groups from intermediate molecules are added to ADP to produce ATP.
- Overall, during glycolysis, the net gain from the breakdown of a single glucose molecule is two ATP molecules, two NADH molecules, and two pyruvate molecules.
Photophosphorylation
- Photophosphorylation is the process plants use to convert ADP into ATP during photosynthesis.
- It involves the movement of electrons through an electron transport chain.
- This generates a proton gradient.
- The energy is absorbed by chlorophyll molecules.
Oxidative Phosphorylation
- Oxidative Phosphorylation is a cellular process that generates ATP.
- It uses an electron transport chain to transfer electrons from NADH and FADH2 to oxygen.
- The energy released is used to pump protons across a membrane.
- This creates a gradient, driving ATP synthesis through ATP synthase.
- Ion pumps are used to pump H+ out of the bacterial cytoplasm into the extracellular space.
- H+ flow back through ATP synthase, providing the energy for ATP production.
Respiration vs. Fermentation
- Cellular respiration is the breakdown of molecules in the presence of oxygen.
- Fermentation is the breakdown of molecules in the absence of oxygen.
Glycolysis Pathways
- The Embden-Meyerhof-Parnas (EMP) pathway is a type of glycolysis found in animals and is the most common in microbes.
- Glycolysis in EMP pathway consists of two distinct phases: energy investment and energy payoff—using 2 ATP and producing 4 ATP—resulting in a net gain of 2 ATP with 2 NADH from one glucose molecule.
- The Entner-Doudoroff (ED) pathway is another pathway.
- The pentose phosphate pathway (PPP) pathway is also called phosphogluconate pathway or the hexose monophosphate shunt.
Pentose Phosphate Pathway (PPP)
- PPP yields NADPH and five-carbon sugars as well as ribose 5-phosphate.
- One glucose produces two molecules of pyruvate.
- Glycolysis, Breakdown of pyruvate, Citric acid cycle, and Oxidative phosphorylation occur in bacteria and eukaryotic cells in different locations.
Transition Reaction, Coenzyme A, and the Krebs Cycle
- Pyruvate first needs to be decarboxylated.
- A two-carbon acetyl group is attached to coenzyme A.
- The two-carbon acetyl group is attached to coenzyme A (CoA).
- Electrons are transferred to NAD+ to form NADH.
- Occurs in the mitochondrial matrix of eukaryotes and in the cytoplasm of prokaryotes.
- Also called the citric acid cycle, or the tricarboxylic acid cycle (TCA).
Transition Reaction, Coenzyme A, and the Krebs Cycle (continued)
- Electrons are transferred during oxidation.
- Acetyl CoA enters the TCA cycle.
Comparison of Respiration vs. Fermentation
- Summarized data concerning respiration versus fermentation are provided.
Photosynthesis (General)
- Photosynthesis is when phototrophic organisms convert solar energy to chemical energy.
- Two sequential stages: light-dependent and light-independent.
Light-Dependent Reactions
- Energy from sunlight is converted into stored chemical energy.
- Produces ATP, O2, and either NADPH or NADH to store energy temporarily.
Light-Independent Reactions (Calvin Cycle)
- Chemical energy from light-dependent is used to build sugar energy molecules.
Photosynthetic Structures (Prokaryotes and Eukaryotes)
- In prokaryotes: Photosynthetic membranes aren't organized into distinct, membrane-enclosed organelles, but are infolded regions of the plasma membrane.
- In eukaryotes: Photosynthesis occurs within chloroplasts, which have three membranes (inner, outer, thylakoids).
- Thylakoids are disc-shaped photosynthetic structures arranged in stacks called granum.
Oxygenic Photosynthesis
- In oxygenic photosynthesis, water is split and provides the electron needed in the reaction center.
- Oxygen is a byproduct.
- The process occurs in eukaryotes and cyanobacteria.
Anoxygenic Photosynthesis
- Uses a different electron donor instead of water.
- Does not produce oxygen.
Acellular Pathogens (Viruses)
- Viruses are infectious, acellular pathogens.
- They need a host cell to reproduce
- They have a protein capsid surrounding their nucleic acid (DNA or RNA).
- Virion is the complete, infective form of a virus outside the host cell.
- Viral structures include: capsid, viral genome, sheath, and tail fibers.
- Viruses can be helical, polyhedral or complex in shape.
- Viruses can be enveloped or naked.
- Viral replication cycles vary.
- Some viruses replicate in the cytoplasm, whereas others replicate in the nucleus.
- Enzymes such as reverse transcriptase are used at different stages of the replication cycles.
- Viruses use different methods (e.g., attachment, penetration, uncoating, replication, assembly, and release) of replication cycles.
- Know basic viral diseases.
- The process of horizontal gene transfer where DNA or RNA is moved to a different cell (transduction, transformation, and conjugation)
Cytopathic Effects (CPEs)
- Observable cell abnormalities; distinct changes in shape, or shrinkage of nucleus or cytoplasm.
- Normal cells are transformed, and inclusion bodies might be observed.
Characteristics of Viruses
- Infectious, acellular pathogens.
- Have a unique genome made up of DNA or RNA.
- Intracellular obligate parasites.
- Host/cell type specificity may vary.
Viroids
- Consist of a short strand of circular RNA.
- They don't have a protein coat.
- They can self-replicate.
- They can cause diseases in plants.
Prions
- Misfolded rogue proteins.
- Can be infectious.
- Stimulate other proteins to misfold, forming plaques.
- Cause Transmissible spongiform encephalopathy (TSE).
Bacterial Pathogenic Mechanisms
- Acute: hours, days, or weeks
- Chronic: month, years or lifetime
- Latent: dormant for extended periods with no active replication.
- Asymptomatic: no noticeable signs.
Endotoxins vs Exotoxins
- Endotoxins are part of the gram negative outer membrane, liberated when the bacteria die.
- Exotoxins are protein produced inside pathogenic bacteria. Most commonly gram-positive, secreted or released during lysis.
- The roles of exotoxin are: intracellular targeting, membrane disruption, or superantigens.
- Heat stability and LD50 (median lethal dose) characteristics of exotoxins and endotoxins provided.
Viral Growth Curve
- In a one-step multiplication curve, host cells lyse, releasing a large number of viral particles.
- During eclipse, the viral particles penetrate and fuse with the host cells.
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Description
Explore the concepts of microbial metabolism, focusing on the processes of substrate-level phosphorylation, photophosphorylation, and oxidative phosphorylation. This quiz will test your understanding of how ATP is produced through different biochemical pathways in living organisms.
