Energy Flow and Cellular Respiration

Podcast Beta

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What role does ATP play in cellular processes?

It serves as an energy carrier molecule (correct)

It stores genetic information

It acts as a structural component of cells

It functions as a receptor for nutrients

Which of the following pathways is NOT typically involved in cellular respiration?

Electron transport chain

Krebs cycle

Glycolysis

Calvin cycle (correct)

What characterizes catabolic reactions in metabolism?

They synthesize larger molecules from smaller ones

They mainly occur in the cytoplasm

They break down molecules to release energy (correct)

They involve the consumption of energy

How can metabolic pathways be regulated?

Through feedback inhibition and allosteric regulation Signup and view all the answers

Which statement best describes the nature of biochemical pathways?

They can involve multiple substrates and products Signup and view all the answers

What is the correct order of the pathways involved in cellular respiration?

Glycolysis, Citric Acid Cycle, Pyruvate Oxidation, Oxidative Phosphorylation Signup and view all the answers

Where does glycolysis occur within the cell?

Cytosol Signup and view all the answers

What is the primary output of the Citric Acid Cycle?

CO2 Signup and view all the answers

What molecule is formed when acetyl-CoA combines with oxaloacetate?

Citrate Signup and view all the answers

Which type of phosphorylation occurs during glycolysis and the Citric Acid Cycle?

Substrate-level phosphorylation Signup and view all the answers

What role does Acetyl CoA play in cellular respiration?

It enters the Citric Acid Cycle Signup and view all the answers

Which of the following is NOT a product generated by the citric acid cycle?

GTP Signup and view all the answers

Where does the citric acid cycle take place within the cell?

Mitochondrial matrix Signup and view all the answers

Which step follows the oxidation of the remaining 2C fragment in the process leading to acetyl-CoA formation?

Attachment of coenzyme A (CoA) Signup and view all the answers

What are the two main processes involved in oxidative phosphorylation?

Electron Transport Chain and Chemiosmosis Signup and view all the answers

What is a key way to regulate a metabolic pathway?

End product inhibition of earlier enzymes Signup and view all the answers

How do allosteric enzymes regulate metabolic pathways?

By responding to both inhibitors and activators Signup and view all the answers

Which of the following substances can inhibit the enzyme phosphofructokinase (PFK)?

Citrate Signup and view all the answers

What role does G6P play in the regulation of the enzyme hexokinase?

It inhibits hexokinase as a competitive inhibitor Signup and view all the answers

What is the primary purpose of feedback regulation in cellular respiration?

To maximize energy production without waste Signup and view all the answers

Which metabolic process is primarily regulated through feedback inhibition?

Glycolysis Signup and view all the answers

Why is it important for opposing pathways not to run simultaneously in a cell?

It results in waste of energy in the form of ATP Signup and view all the answers

Which factor enhances the activity of phosphofructokinase (PFK)?

ADP Signup and view all the answers

What term best describes the process of breaking down large molecules into smaller ones?

catabolism Signup and view all the answers

Which statement is true regarding anabolic pathways?

They consume energy to synthesize polymers from monomers. Signup and view all the answers

Which of the following statements about ATP is incorrect?

It stands for adenosine diphosphate. Signup and view all the answers

What is the primary metabolic fuel that carbohydrates break down into?

Glucose Signup and view all the answers

What is the role of NAD+ in fermentation?

It allows glycolysis to continue by being regenerated. Signup and view all the answers

What are the end products of the complete oxidation of one glucose molecule?

6CO2 and 6H2O with energy Signup and view all the answers

In which condition does pyruvate undergo fermentation?

When oxygen is absent Signup and view all the answers

What is the primary function of glycolysis in cellular respiration?

To break down glucose into pyruvate Signup and view all the answers

What type of reaction occurs when ATP is synthesized from ADP?

Endergonic reaction Signup and view all the answers

Which process is primarily responsible for generating bioethanol from starch?

Fermentation Signup and view all the answers

Study Notes

Energy Flow in Living Systems

Energy enters ecosystems as sunlight, captured by photosynthesis to create organic molecules like starch and sugar.
Cellular respiration breaks down these molecules, releasing energy to generate ATP, the cell's main energy currency.
Some energy is lost as heat.
Glucose is the primary metabolic fuel, completely oxidized to yield a large amount of ATP.
In the absence of oxygen, pyruvate enters fermentation, regenerating NAD+ for continued glycolysis and producing 2 ATPs.

Cellular Respiration Pathways

Four pathways are involved: Glycolysis, Pyruvate Oxidation, Citric Acid Cycle, and Oxidative Phosphorylation.
Glycolysis occurs in the cytosol, converting glucose to pyruvate. It yields a small amount of ATP.
Pyruvate oxidation, occurring in the mitochondrial matrix, converts pyruvate to Acetyl-CoA, releasing CO2 and generating NADH.
The Citric Acid Cycle (Krebs cycle or TCA cycle), also in the mitochondrial matrix, further oxidizes Acetyl-CoA, producing CO2, ATP, NADH, and FADH2.
Oxidative phosphorylation, in the inner mitochondrial membrane, uses the electron transport chain and chemiosmosis to generate a large amount of ATP from NADH and FADH2. Oxygen is the final electron acceptor.

Regulation of Metabolic Pathways

Metabolic pathways are regulated to ensure efficient energy production and avoid waste.
Two main mechanisms: end-product inhibition (negative feedback) and enzyme synthesis regulation.
End-product inhibition involves the end-product slowing down or blocking the pathway by inhibiting an earlier enzyme.
Enzyme synthesis regulation controls the amount of enzymes produced.
Allosteric enzymes respond to inhibitors and activators, adjusting the pathway's pace (e.g., phosphofructokinase in glycolysis).
Feedback regulation in cellular respiration adjusts the rate based on the cell's needs.

Other Metabolic Pathways

Glycolysis's first step (hexokinase) is regulated by its end-product G6P, which acts as a competitive inhibitor.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Explore the essential processes of energy flow in living systems, focusing on photosynthesis and cellular respiration. This quiz covers glycolysis, citric acid cycle, and oxidative phosphorylation, highlighting how energy is captured, transformed, and utilized within cells.