Biology: ATP and Coupled Reactions

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Questions and Answers

What are the by-products produced by the Krebs cycle?

2 ATP, 4 NADH, 1 FADH2

2 ATP, 6 NADH, 2 FADH2 (correct)

6 ATP, 2 NADH, 4 FADH2

4 ATP, 2 NADH, 2 FADH2

Which complex in the electron transport chain is responsible for proton pumping from the mitochondrial matrix to the intermembrane space after the oxidation of NADH?

Complex I (correct)

Coenzyme Q

Complex III

Complex II

What occurs when FADH2 is oxidized in the electron transport chain?

It produces ATP directly.

It donates protons to Complex I.

It pumps electrons into the mitochondrial matrix.

It is converted to FAD+ without proton pumping. (correct)

Which component receives electrons from Complex III and passes them on to Complex IV?

Cytochrome C Signup and view all the answers

What is the final electron acceptor in the electron transport chain?

Oxygen Signup and view all the answers

What is the main outcome of chemiosmosis during oxidative phosphorylation?

Synthesis of ATP Signup and view all the answers

How does the electron transport chain contribute to the proton gradient across the mitochondrial membrane?

It pumps protons into the intermembrane space during electron transport. Signup and view all the answers

What happens immediately after oxygen receives electrons in the electron transport chain?

It combines with protons to form water. Signup and view all the answers

What is the primary function of ATP in biological systems?

It acts as the main energy currency of cells. Signup and view all the answers

Which of the following best describes the significance of coupled reaction processes?

They allow energetically unfavorable reactions to occur by using energy. Signup and view all the answers

What occurs during the hydrolysis of ATP?

ATP is broken down to ADP and releases energy. Signup and view all the answers

Why are the phosphoanhydride bonds in ATP considered high-energy bonds?

Breaking them releases a significant amount of energy. Signup and view all the answers

Which statement about ATP regeneration is true?

ATP regeneration is important because cells quickly use up ATP. Signup and view all the answers

How does ATP function similar to a rechargeable battery?

ATP can store energy and can be reused after regeneration. Signup and view all the answers

In the context of cellular functions, what happens when the energy from ATP is depleted?

The cell processes will halt and may lead to cell death. Signup and view all the answers

What role do carrier and motor proteins play in the context of ATP?

They rely on energy from ATP to transport substances. Signup and view all the answers

What is the immediate product of fructose-1,6-bisphosphate during glycolysis?

Pyruvate Signup and view all the answers

How many ATP molecules are used in the initial steps of glycolysis?

Two Signup and view all the answers

What happens to the three-carbon molecule pyruvate in the mitochondrial matrix?

It becomes acetyl CoA Signup and view all the answers

Why is the citric acid cycle crucial for cellular respiration?

It acts as a pathway for all metabolic fuels Signup and view all the answers

What is produced alongside acetyl CoA during pyruvate oxidation?

NADH and carbon dioxide Signup and view all the answers

Which substances enter the citric acid cycle primarily?

Acetyl CoA Signup and view all the answers

What type of reactions are predominantly involved in the citric acid cycle?

Oxidation-reduction reactions Signup and view all the answers

What role does acetyl CoA play in the citric acid cycle?

It acts as a fuel source Signup and view all the answers

What is the immediate product of the oxidation of succinate?

Fumarate Signup and view all the answers

Which enzyme is responsible for the reversible hydration of fumarate to L-malate?

Fumarase Signup and view all the answers

What is the final product of the oxidation of malate in the citric acid cycle?

Oxaloacetate Signup and view all the answers

What role does oxygen play in oxidative phosphorylation?

Serves as the final electron acceptor Signup and view all the answers

What happens in the absence of oxygen during cellular respiration?

Electron transport chain and chemiosmosis halt Signup and view all the answers

What are the components of the electron transport chain?

Ubiquinone and cytochrome c Signup and view all the answers

Which statement best describes chemiosmosis?

It uses the proton gradient to power ATP synthesis. Signup and view all the answers

What will occur if a person holds their breath for too long?

Decreased production of ATP and eventual cell death Signup and view all the answers

What is the primary role of oxaloacetate in the citric acid cycle?

It catalyzes the oxidation of acetyl groups. Signup and view all the answers

Which statement correctly describes the role of NADH and FADH2 during oxidative phosphorylation?

They donate electrons to the electron transport chain. Signup and view all the answers

What process occurs first in cellular respiration?

Glycolysis breaking down glucose. Signup and view all the answers

How is ATP synthesized during oxidative phosphorylation?

Through the flow of protons via ATP synthase. Signup and view all the answers

Which of the following best describes glycolysis?

It is a metabolic pathway present in nearly all organisms. Signup and view all the answers

What happens to oxygen at the end of the electron transport chain?

It accepts electrons and forms water. Signup and view all the answers

What other molecules are produced as a result of the citric acid cycle alongside energy carriers?

CO2 and water. Signup and view all the answers

How does glucose enter the glycolysis pathway?

Through phosphorylation by hexokinase. Signup and view all the answers

What role does the ATP synthase play in the electron transport chain?

It converts ADP into ATP using the proton gradient. Signup and view all the answers

What is the main reason for the movement of protons from the intermembrane space to the mitochondrial matrix?

To achieve chemical equilibrium in proton concentrations. Signup and view all the answers

Which process results in the production of 26 to 28 ATP molecules?

Chemiosmosis Signup and view all the answers

What is the primary function of ATP in cells?

It acts as a cellular energy currency. Signup and view all the answers

What would most likely occur if mitochondria failed to produce sufficient ATP?

Development of mitochondrial diseases. Signup and view all the answers

How much ATP is produced from one molecule of glucose during cellular respiration, including glycolysis and citric acid cycle?

30 – 32 ATP Signup and view all the answers

What is the significance of inorganic phosphate in the ATP production process?

It is required for the conversion of ADP to ATP. Signup and view all the answers

What are some symptoms of mitochondrial disease?

Muscle weakness and lack of coordination. Signup and view all the answers

Study Notes

Coupled Reaction Processes

A cell functions like a bustling town, with carrier proteins moving substances, motor proteins carrying cargo, and metabolic enzymes building and breaking down macromolecules
These processes occur even if they are not energetically favourable because energy is available to power them, much like a town's economy
Adenosine triphosphate (ATP) is the main energy currency of cells, like money in human societies
ATP is a small molecule that can be thought of as the main energy currency of cells
The energy released by hydrolyzing ATP is used to power energy-requiring cellular reactions

ATP Structure and Hydrolysis

ATP is an RNA nucleotide with a chain of three phosphates
The molecule has a ribose sugar and an adenine base
The high-energy phosphoanhydride bonds in ATP are broken in a hydrolysis reaction, releasing a substantial amount of energy
The hydrolysis of ATP to ADP releases energy from the bonds of phosphates
The reaction is ATP + H₂O → ADP + Pi + energy. (Pi represents inorganic phosphate)
ATP regeneration is important to cells due to the continual use of ATP in cellular functions

Reaction Coupling

Reaction coupling is a strategy cells use to link an energetically favorable reaction (like ATP hydrolysis) with an unfavorable (endergonic) reaction
A favourable reaction (e.g. ATP hydrolysis) is linked to an unfavourable reaction to make the unfavourable one possible.
This often happens through a shared intermediate, where the product of one reaction becomes a reactant in the other reaction

Cellular Respiration: Stages

Cellular respiration is a metabolic pathway that breaks down glucose to produce ATP
The stages include glycolysis, pyruvate oxidation, the citric acid cycle (Krebs cycle), and oxidative phosphorylation
Glycolysis occurs in the cytoplasm and splits glucose into two pyruvate molecules, producing ATP and NADH
Pyruvate oxidation converts pyruvate into acetyl CoA, releasing carbon dioxide and producing NADH
The citric acid cycle further oxidizes acetyl CoA, producing ATP, NADH, and FADH₂
Oxidative phosphorylation occurs in the mitochondria and uses NADH and FADH₂ to generate a large amount of ATP

Importance of ATP Production

ATP is crucial for all cellular functions, as it provides the energy needed for various cellular processes. Without ATP, cells cannot function properly, ultimately leading to the death of the organism.

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Description

Explore the essential role of ATP as the energy currency in cellular processes. This quiz covers the structure of ATP, its hydrolysis, and how coupled reactions function to drive biological activities. Test your understanding of the intricate mechanisms that keep cells functioning like a bustling town.