Purpose of Cellular Respiration
What is the primary purpose of cellular respiration in cells?
To convert glucose and other organic molecules into ATP to meet the cell's energy needs.
What 3 carbon molecule is produced at the end of glycolysis?
Pyruvate
In glycolysis, what molecule is primarily broken down?
Glucose
How many ATP molecules are produced per glucose molecule under aerobic conditions?
Approximately 30-34
What role does oxygen play in the electron transport chain?
It acts as the final electron acceptor.
How does cellular respiration support cellular growth and maintenance?
By providing ATP, which powers essential processes needed for cell division, repair, and various cellular functions.
Under aerobic conditions, pyruvate is converted into what molecule before entering the citric acid cycle?
Acetyl-CoA.
During the citric acid cycle, which two electron carriers are generated that play key roles in the electron transport chain?
NADH and FADH₂.
How many ATP molecules are produced per glucose molecule during fermentation?
2 ATP
What molecule is produced when oxygen accepts electrons at the end of the electron transport chain?
Water.
In which organelle does most of cellular respiration occur in eukaryotic cells?
The mitochondria.
What enzyme complex is responsible for converting pyruvate to acetyl-CoA?
The pyruvate dehydrogenase complex.
What is the role of the electron transport chain in cellular respiration?
To create a proton gradient across the inner mitochondrial membrane that drives ATP production.
Why is fermentation less efficient than cellular respiration?
Fermentation only produces 2 ATP per glucose, while cellular respiration produces up to 38 ATP by fully breaking down glucose.
How does the absence of oxygen affect the electron transport chain?
It causes a backup of electrons in the chain, halting ATP production through oxidative phosphorylation.
What type of organisms rely on cellular respiration for energy?
Nearly all aerobic organisms, including plants, animals, and many types of bacteria.
What happens to pyruvate in the absence of oxygen?
It undergoes fermentation to produce either lactate or ethanol, depending on the organism.
What is the process called when ATP is generated as protons move back across the mitochondrial membrane?
Chemiosmosis.
What advantage does fermentation provide when oxygen is unavailable?
It allows cells to regenerate NAD⁺ so glycolysis can continue, even without oxygen.
Why is oxygen essential for the completion of cellular respiration?
Without oxygen, the electron transport chain cannot function, stopping ATP production by oxidative phosphorylation.
Why is cellular respiration considered fundamental to metabolism?
It’s essential for converting energy stored in food molecules into a usable form (ATP) to power cellular functions across various tissues and organs.
How does the conversion of pyruvate to acetyl-CoA regulate aerobic respiration?
This conversion acts as a regulatory step, with acetyl-CoA levels influencing the continuation of the citric acid cycle.
In the citric acid cycle, which molecule is regenerated at the end of each cycle, allowing the process to continue with the addition of a new acetyl-CoA?
Oxaloacetate.
During anaerobic respiration in muscle cells, which byproduct builds up and causes muscle fatigue?
lactic acid
How does oxygen availability impact the efficiency of ATP production?
Higher oxygen availability maximizes ATP production efficiency, while low oxygen leads to less efficient anaerobic processes.