Chapter 6: Cellular Respiration Flashcards
Question: What event is hypothesized to have caused the Great Oxygenation Event over 2 billion years ago?
Cyanobacteria like blue-green algae dominating the oceans and producing enough oxygen through photosynthesis.
What are the three main stages of aerobic cellular respiration?
Glycolysis, the Krebs cycle, and the electron transport chain.
Where does glycolysis occur?
In the cytosol of the cell.
What are the main outputs of glycolysis?
Two pyruvate molecules, two ATP molecules, and two NADH molecules.
What is the role of the Krebs cycle in aerobic cellular respiration?
he Krebs cycle generates high-energy electron and proton carriers (NADH and FADH2) and releases carbon dioxide.
Where does the Krebs cycle occur?
In the mitochondrial matrix.
What is the primary function of the electron transport chain?
To produce the majority of ATP in aerobic cellular respiration and convert NADH and FADH2 back to NAD+ and FAD.
How does the electron transport chain produce ATP?
By utilizing the energy from the electrons unloaded by NADH and FADH2 to generate a proton gradient that drives ATP production.
What are some examples of key enzymes in cellular respiration?
Pyruvate kinase, citrate synthase, and cytochrome c oxidase.
What is the function of coenzymes in cellular respiration?
Coenzymes assist enzymes in catalyzing reactions by cycling between unloaded and loaded states, providing or receiving energy as needed.
What is the overall equation for aerobic cellular respiration?
Glucose + oxygen → carbon dioxide + water + ATP
How many ATP molecules are produced per glucose molecule in aerobic cellular respiration?
30 (eukaryotes) or 32 (prokaryotes) ATP molecules as the ATP molecules produced in prokaryotes dont need to be transported anywhere else so no energy is lost
What is the difference between aerobic cellular respiration and anaerobic fermentation?
Aerobic cellular respiration requires oxygen and produces more ATP, while anaerobic fermentation does not require oxygen and produces only 2 ATP.
What are the two main types of anaerobic fermentation and their byproducts?
Animals: lactic acid fermentation (produces lactic acid); Plants and yeast: alcohol fermentation (produces ethanol and carbon dioxide).
What is the function of NADH and FADH2 in aerobic cellular respiration?
They are high-energy electron carriers that deliver electrons to the electron transport chain to generate ATP.
What is the role of mitochondria in aerobic cellular respiration?
Mitochondria are the organelles where the Krebs cycle and the electron transport chain occur.
How is ATP produced in the electron transport chain?
ATP is produced as protons move through ATP synthase, powered by the proton gradient created by electron transport.
What happens if the electron transport chain is inhibited by cyanide?
Answer: Cyanide inhibits ATP production, potentially leading to cell death or organism death.
What is end-product inhibition?
It is a regulatory mechanism where the final product of a metabolic pathway inhibits an earlier step in the pathway to control the rate of reaction.
How do coenzymes assist enzymes in cellular respiration?
Coenzymes help enzymes by cycling between unloaded (ADP, NAD+, FAD) and loaded (ATP, NADH, FADH2) states, providing or receiving energy as needed.
What is the role of enzymes in cellular respiration?
Enzymes catalyze the biochemical reactions of cellular respiration, allowing them to proceed at biologically relevant rates.
Where does the link reaction occur, and what does it produce?
The link reaction occurs in the mitochondrial matrix and produces acetyl-CoA and carbon dioxide.
How many CO2 molecules are produced in the Krebs cycle for every acetyl-CoA molecule?
Four CO2 molecules are produced for every acetyl-CoA molecule.
What is the primary function of the mitochondrial matrix?
The mitochondrial matrix is the site of the Krebs cycle, where multiple reactions occur to generate ATP, NADH, FADH2, and CO2.
What happens to the electrons and protons unloaded by NADH and FADH2 in the electron transport chain?
They generate a proton gradient that drives ATP production as they are transferred through protein complexes embedded in the inner mitochondrial membrane.
What is anaerobic fermentation?
Anaerobic fermentation is a metabolic pathway that occurs in the absence of oxygen, involving glycolysis followed by further reactions to recycle NADH and produce ATP.
Where does anaerobic fermentation occur?
Anaerobic fermentation occurs in the cell cytosol in the absence of oxygen.
Question: What are the inputs and outputs of anaerobic fermentation in animals and yeasts?
What are the inputs and outputs of anaerobic fermentation in animals and yeasts?
Inputs: glucose; Outputs: In animals, lactic acid and 2 ATP; In yeasts, ethanol, carbon dioxide, and 2 ATP.
What is the primary purpose of anaerobic fermentation?
The primary purpose of anaerobic fermentation is to regenerate NAD+ for continued use in glycolysis when oxygen is not available.
How does anaerobic fermentation differ from aerobic cellular respiration?
Anaerobic fermentation occurs in the absence of oxygen and produces only 2 ATP per glucose molecule, while aerobic cellular respiration requires oxygen and produces 30 or 32 ATP per glucose molecule.
Describe lactic acid fermentation in animals.
Lactic acid fermentation in animals involves the conversion of pyruvate to lactic acid, regenerating NAD+ for glycolysis to continue.
Describe ethanol fermentation in yeasts.
Ethanol fermentation in yeasts involves the conversion of pyruvate to ethanol and carbon dioxide, regenerating NAD+ for glycolysis to continue.
What happens to the lactic acid produced in animals during anaerobic fermentation?
Lactic acid can be metabolized back into pyruvate once oxygen is available again, and used for aerobic cellular respiration.
How is ethanol fermentation utilized in industry?
Ethanol fermentation by yeasts is used in industries such as brewing and baking to produce ethanol and carbon dioxide, respectively.
Why is anaerobic fermentation important for cells in the absence of oxygen?
Anaerobic fermentation allows cells to continue producing ATP in the absence of oxygen by recycling NADH and producing ATP through glycolysis.
What factors affect the rate of cellular respiration?
Temperature, pH, glucose availability, oxygen concentration, and enzyme inhibitors.
How does temperature affect the rate of cellular respiration?
Enzymes operate optimally at certain temperatures. Below the optimal temperature, respiration slows due to fewer collisions between enzymes and substrates. Above the optimal temperature, enzymes denature, leading to a rapid drop in respiration rate.
What is the optimal temperature for enzyme-catalyzed reactions?
The optimal temperature is the temperature at which enzyme-catalyzed reactions occur at the greatest rate.
How does pH affect the rate of cellular respiration?
Enzymes function optimally at specific pH levels. Deviations from this optimal pH can lead to enzyme denaturation and a decrease in respiration rate.
What is the effect of increasing glucose availability on cellular respiration?
Increasing glucose availability increases the rate of cellular respiration until the enzymes reach saturation. Beyond this point, further increases in glucose concentration do not increase respiration rate.
How does oxygen concentration affect the rate of aerobic respiration?
Increasing oxygen concentration increases the rate of aerobic respiration until the enzymes reach saturation. After reaching saturation, further increases in oxygen do not increase respiration rate.
What is the role of enzyme inhibitors in cellular respiration?
Enzyme inhibitors decrease the rate of cellular respiration by reducing the activity of enzymes involved in the process. They can be competitive or non-competitive and reversible or irreversible.
How does competitive reversible inhibition affect enzyme activity?
Competitive reversible inhibitors bind to the active sites of enzymes, preventing substrate binding. Increasing substrate concentration can overcome the effect of competitive inhibitors.
What is end-product inhibition?
End-product inhibition is a form of inhibition where the final product in a series of reactions inhibits an enzyme in an earlier reaction in the sequence, helping to regulate cellular respiration.
What is biofuel?
Biofuel is fuel created from organic material known as biomass.
What are fossil fuels and why are they non-renewable?
Fossil fuels are formed from decomposing organic material over millions of years, and they are considered non-renewable because their production rate is much lower than their consumption rate.
How are biofuels different from fossil fuels?
Biofuels are made from renewable biomass, while fossil fuels are formed from fossilized organic material and are non-renewable.
What is anaerobic fermentation?
Anaerobic fermentation is a process that produces ethanol and CO2 in yeasts in the absence of oxygen.
How does anaerobic fermentation contribute to biofuel production?
Anaerobic fermentation breaks down plant sugars into ethanol, which can be used for biofuels.
What is bioethanol?
Bioethanol is a type of biofuel produced via the anaerobic fermentation of plant sugars.
What is the role of enzymes in biofuel production?
Enzymes facilitate the breakdown of biomass during anaerobic fermentation for biofuel production.
How is bioethanol produced from biomass?
Bioethanol is produced through steps including deconstruction of biomass, enzymatic hydrolysis, anaerobic fermentation, and dehydration.
What are the uses of biofuels?
Biofuels can be used in transportation, heating, energy generation, and cleaning.
What are some potential implications of biofuel usage?
Some implications include climate impact, energy security, and the food vs. fuel debate.
What are the differences between first-generation and second-generation biofuels?
First-generation biofuels are made from edible food crops and compete directly with agricultural lands, while second-generation biofuels are made from non-edible crop waste and are more sustainable.
How is biofuel production related to enzyme activity?
Factors influencing enzyme activity, such as temperature and substrate concentration, impact the efficiency of biofuel production.
What are some strengths of the biofuel industry?
Strengths include climate impact reduction, energy security, and localised energy production.
What are some weaknesses of the biofuel industry?
Weaknesses include cost, difficulty of uptake, and second-order environmental impacts.
What is the food vs. fuel debate?
The food vs. fuel debate questions the use of arable land for biofuel production instead of food production.
How does the process of biofuel production contribute to carbon neutrality?
Biofuel production involves a carbon-neutral cycle where CO2 released during combustion is reabsorbed by plants during photosynthesis.
What is the general process for turning biomass into bioethanol?
The process includes sourcing and deconstruction of biomass, enzymatic hydrolysis, anaerobic fermentation, and dehydration.
How do first-generation and second-generation biofuels differ in their competition with food crops?
First-generation biofuels compete directly with food crops, while second-generation biofuels are made from non-edible crop waste.
What are some potential applications of biofuels?
Biofuels can be used in transportation, energy generation, heating, and cleaning
What are some potential environmental implications of biofuel production?
Environmental implications include second-order impacts, such as increased nitrous oxide emissions and deforestation.
