Podcast
Questions and Answers
What primarily limits ATP yield during fermentation of pyruvate?
What primarily limits ATP yield during fermentation of pyruvate?
- Excess oxygen reduction
- Inability to convert pyruvate to Acetyl-CoA (correct)
- NADH2 & FADH not further oxidized in ETC (correct)
- High levels of substrate-level phosphorylation
Which type of fermentation only produces acid as the product?
Which type of fermentation only produces acid as the product?
- Mixed-Acid fermenters
- Acetogenic fermenters
- Heterofermenters
- Homofermenters (correct)
In anaerobic catabolism, what role does the organic compound serve?
In anaerobic catabolism, what role does the organic compound serve?
- Both electron donor and acceptor (correct)
- Only as an electron acceptor
- Neither an electron donor nor acceptor
- Only as an electron donor
What is the main process responsible for energy generation in fermentation?
What is the main process responsible for energy generation in fermentation?
Which group of microorganisms is an example of heterofermenters?
Which group of microorganisms is an example of heterofermenters?
What is produced from the decarboxylation of pyruvate in ethanol fermentation?
What is produced from the decarboxylation of pyruvate in ethanol fermentation?
Which fermentative process yields acetic acid as a product?
Which fermentative process yields acetic acid as a product?
What is the primary substrate for acetogenic fermentation?
What is the primary substrate for acetogenic fermentation?
Which enzyme is responsible for converting pyruvate into acetyl-CoA?
Which enzyme is responsible for converting pyruvate into acetyl-CoA?
In which type of fermentation do you primarily find enteric bacteria?
In which type of fermentation do you primarily find enteric bacteria?
During ethanolic fermentation, how many ATP molecules are produced?
During ethanolic fermentation, how many ATP molecules are produced?
Which of the following is a characteristic of chemolithotrophic acetogens?
Which of the following is a characteristic of chemolithotrophic acetogens?
What are the products of mixed-acid fermentation?
What are the products of mixed-acid fermentation?
What is the first product generated from glucose during glycolysis?
What is the first product generated from glucose during glycolysis?
Which enzyme is involved in the conversion of lactate to pyruvate?
Which enzyme is involved in the conversion of lactate to pyruvate?
What is produced from alanine during the Stickland reaction?
What is produced from alanine during the Stickland reaction?
What is the result of the reduction of glycine in the Stickland reaction?
What is the result of the reduction of glycine in the Stickland reaction?
Which reaction involves substrate-level phosphorylation and yields ATP?
Which reaction involves substrate-level phosphorylation and yields ATP?
What are the main products of the amino acid fermentation via the Stickland reaction?
What are the main products of the amino acid fermentation via the Stickland reaction?
In the succinate-propionate pathway, what is formed from lactate first?
In the succinate-propionate pathway, what is formed from lactate first?
Which metabolic pathway yields Butyrate as a final product?
Which metabolic pathway yields Butyrate as a final product?
At which wavelength does bacteriochlorophyll a primarily absorb light?
At which wavelength does bacteriochlorophyll a primarily absorb light?
What role do phycobiliproteins play in cyanobacteria?
What role do phycobiliproteins play in cyanobacteria?
How do phycobilisomes benefit cyanobacteria's growth in low light conditions?
How do phycobilisomes benefit cyanobacteria's growth in low light conditions?
Which of the following light absorption features is characteristic of allophycocyanin?
Which of the following light absorption features is characteristic of allophycocyanin?
In what organisms are chlorosomes primarily found?
In what organisms are chlorosomes primarily found?
What is the efficiency of ATP production from glucose under standard conditions?
What is the efficiency of ATP production from glucose under standard conditions?
Which process uses light energy to reduce CO2 to organic compounds?
Which process uses light energy to reduce CO2 to organic compounds?
What is the role of carotenoids in photosynthesis?
What is the role of carotenoids in photosynthesis?
Which of the following explains the significance of chlorophyll and bacteriochlorophyll in photosynthesis?
Which of the following explains the significance of chlorophyll and bacteriochlorophyll in photosynthesis?
In the context of energy efficiency, what does Ereact represent?
In the context of energy efficiency, what does Ereact represent?
What products are generated from the conversion of succinate through the pathway ending in propionate?
What products are generated from the conversion of succinate through the pathway ending in propionate?
What does the chlorophyll a structure contain that distinguishes it from cytochromes?
What does the chlorophyll a structure contain that distinguishes it from cytochromes?
Which reaction center is involved primarily in ATP synthesis?
Which reaction center is involved primarily in ATP synthesis?
Which organism utilizes H2S as an electron donor in photosynthesis?
Which organism utilizes H2S as an electron donor in photosynthesis?
What is the formula for calculating the efficiency of energy capture in ATP production?
What is the formula for calculating the efficiency of energy capture in ATP production?
What are phycobiliproteins primarily associated with?
What are phycobiliproteins primarily associated with?
What is the main light absorption property of blue phycobilin?
What is the main light absorption property of blue phycobilin?
Which process is more energy-efficient: ethanolic-CO2 fermentation or lactate fermentation?
Which process is more energy-efficient: ethanolic-CO2 fermentation or lactate fermentation?
What type of phototroph does not utilize chlorophylls or bacteriochlorophylls freely?
What type of phototroph does not utilize chlorophylls or bacteriochlorophylls freely?
Flashcards are hidden until you start studying
Study Notes
Fermentation
- Anaerobic catabolism
- Organic compound serves as electron donor and acceptor
- Substrate-level phosphorylation is the main energy production mechanism
- No oxygen is involved - end products act as electron acceptors
- Can occur in the presence or absence of oxygen
Kinds of Fermentation
- Lactate fermentation
- Ethanol fermentation
- Acetogenic fermentation
- Mixed-acid and butanediol fermentation
- Butyrate fermentation
Ethanolic Fermentation
- Substrate: hexose (glucose) or pyruvate
- Glucose undergoes glycolysis to produce 2 pyruvate
- 2 pyruvate decarboxylated to 2 acetaldehyde by pyruvate decarboxylase
- 2 acetaldehyde reduced to 2 ethanol by alcohol dehydrogenase
- Products: 2 ethanol, 2 CO2, 2 ATP
Acetogenic Fermentation
- Substrate: hexose (glucose) or pyruvate
- Glucose undergoes glycolysis to produce 2 pyruvate
- 2 pyruvate is converted to 2acetate, 2CO2 and 4H+
- 2CO2 can be converted to 1 acetate
- Products: 3 acetate, 3H+, 4 ATP
Butanediol & Mixed-Acid Fermentation
- Common to enteric bacteria and anaerobic Fungi
Mixed-Acid Fermentation
- Substrate: hexose (glucose) or pyruvate
- Glucose undergoes glycolysis to produce 2 pyruvate
- Pyruvate decarboxylated to Acetyl-CoA
Butanediol Fermentation
- Substrate: glucose or pyruvate
- Glucose undergoes glycolysis to produce 2 pyruvate
- Pyruvate decarboxylated to Acetyl-CoA
- Acetyl-CoA converts to Acetoacetyl-CoA
- Acetoacetyl-CoA reduced to B-Hydroxybutyryl-CoA
- B-Hydroxybutyryl-CoA reduced to Butyryl-CoA
- Butyryl-CoA converted to Butyrate
- Products: Butyrate
Butyrate Fermentation
- Similar to mixed-acid fermentation
- Starts with glucose undergoing glycolysis to produce 2 pyruvate
- Products: Butyrate
Amino Acid Fermentation
- Also known as the Stickland reaction
- Oxidation of one amino acid and reduction of another amino acid
- Example: Alanine is oxidized (electron donor) and glycine is reduced (electron acceptor)
- Starting material: Alanine and Glycine
- Alanine oxidized to pyruvate
- Glycine reduced to Acetyl-P
- Pyruvate converts to Acetyl-P
- Acetyl-P converted to Acetate
- Products: 3 acetate, CO2, 3 NH4+, 3 ATP
Propionate Fermentation
- Also known as the succinate-propionate pathway
- Lactate undergoes oxidation reactions
- Starting material: 3 Lactate
- 3 Lactate converted to 3 Pyruvate
- 3 Pyruvate converted to acetate and succinate
- Succinate converted to Propionate
- Products: 2 propionate, acetate, CO2, H2O, 3 ATP
Energy Efficiency
- N=# of ATP formed
- EATP= E in 1 high energy phosphoanhydride bond
- Ereact= E released as heat in the chemical reaction (total free energy yield)
- Efficiency = (EATP/Ereact)*100
Photosynthesis
- Autotrophs grow with CO2 as a carbon source
- Photoautotrophy - light energy used to reduce CO2 to organic compounds
- Photoheterotrophy - light energy used to reduce organic carbon to organic compounds
- Generally, carbon reduction to cell material requires energy from ATP and electrons from NADH or NADPH
- Anaerobic phototrophs are purple and green bacteria
- Oxygenic phototrophs are algae and cyanobacteria
Photosynthetic System Components
- Light-harvesting molecules
- Carotenoids
- Phycobilins
- Bacteriochlorophylls
- Chlorophylls
- Reaction centers
Photosystems
- Reaction centers are directly involved in ATP synthesis
- Light harvesters - antenna pigments that funnel light energy to reaction centers
Chromatophores or Lamellae
- Membrane vesicle/membrane sac
- House photosynthetic pigments
- Found in purple bacteria
Thylakoids
- Resemble thylakoids in algae chloroplast
- Found in cyanobacteria
- House photosynthetic pigments
Chlorophyll & Bacteriochlorophyll
- Contain specific constituents on a tetrapyrrole ring and a hydrophobic alcohol
- Chlorophyll a - absorbs red and blue light (green transmission)
- Bacteriochlorophyll a - absorption depends on arrangement in membrane
Accessory Pigments
- Not required for photosynthesis
- Carotenoids
- Most widespread accessory pigment
- Embedded in the membrane
- Hydrophobic long chain of hydrocarbons
- Photoprotective agents
- Phycobilins
- Main light harvesting systems in cyanobacteria
- Responsible for red or blue-green linear tetrapyrroles - Assemble into "phycobilisomes" that attach to thylakoids
Chlorosomes
- Found in anoxygenic green S and non-sulfur bacteria
- Houses bacteriochlorophylls
Non-cyclic Photophosphorylation
- Also known as the "Z" scheme
- Electrons are excited by light energy and move through a series of carriers. This generates a proton gradient across the membrane, which is used to produce ATP.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
