Glycolysis Overview and Cellular Respiration
37 Questions
2 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

How many ATPs are produced per NADH according to modern theory?

2.5 ATPs are produced per NADH according to modern theory.

What is the primary location of glycolysis within the cell?

Glycolysis occurs in the cytoplasm.

What are the two types of shuttle systems mentioned, and what do they do?

The glycerol phosphate and malate phosphate shuttles transfer electrons across the mitochondrial membrane.

Explain the role of glycerol-3-phosphate in the shuttle system of insect flight muscle.

<p>Glycerol-3-phosphate is formed by reducing dihydroxyacetone phosphate (DHAP) and migrates into mitochondria to donate electrons to the ETC.</p> Signup and view all the answers

Why are mammalian mitochondrial membranes significant in the context of NAD+ and NADH?

<p>Mammalian mitochondrial membranes are impermeable to NAD+ and NADH, requiring a shuttle mechanism for transport.</p> Signup and view all the answers

What is the role of glyceraldehyde 3-phosphate dehydrogenase in glycolysis?

<p>It is the only step where NAD+ is reduced to NADH.</p> Signup and view all the answers

How many molecules of ATP are utilized for each glucose molecule entering glycolysis?

<p>Two molecules of ATP are utilized.</p> Signup and view all the answers

What is the net energy release from glycolysis?

<p>The net energy release is four molecules of ATP produced per two molecules of glyceraldehyde-3-phosphate converted to pyruvate.</p> Signup and view all the answers

What limits the progress of glycolysis when NAD+ is inactive?

<p>The second half of glycolysis slows or shuts down.</p> Signup and view all the answers

What type of phosphorylation occurs during the energy-generating phase of glycolysis?

<p>Substrate-level phosphorylation occurs.</p> Signup and view all the answers

How does thermodynamics affect the reaction cycle of glycolysis?

<p>Glycolysis can proceed only if the change in free energy ($ riangle G$) values of all reactions are negative.</p> Signup and view all the answers

In the presence of oxygen, where does NADH go after glycolysis?

<p>NADH is reoxidized in the mitochondria.</p> Signup and view all the answers

What is the fate of the electrons stored in NADH during glycolysis?

<p>They are used for indirect ATP production in the electron transport chain.</p> Signup and view all the answers

What is glycolysis and where does it occur in the cell?

<p>Glycolysis is the anaerobic metabolic pathway that breaks down one molecule of glucose into two molecules of pyruvate, and it occurs in the cytosol of cells.</p> Signup and view all the answers

What is the net yield of ATP in anaerobic glycolysis?

<p>The net yield of ATP in anaerobic glycolysis is 2 ATP.</p> Signup and view all the answers

Name two key enzymes involved in the energy investment phase of glycolysis.

<p>Phosphoglucose isomerase and phosphofructose kinase are two key enzymes in the energy investment phase.</p> Signup and view all the answers

How does glycolysis contribute to energy production during intense exercise?

<p>Glycolysis provides rapid energy for short, intense bouts of exercise through anaerobic breakdown of glucose.</p> Signup and view all the answers

What is the total ATP yield from aerobic glycolysis including NADH contributions?

<p>The total ATP yield from aerobic glycolysis is 7 ATP, comprising 4 ATP and 2 NADH worth 5 ATP.</p> Signup and view all the answers

Outline the main outcome of the energy-generating phase of glycolysis.

<p>The main outcome of the energy-generating phase of glycolysis is the production of 4 ATP and 2 NADH.</p> Signup and view all the answers

Why are enzymes critical to the process of glycolysis?

<p>Enzymes are critical in glycolysis because they act as catalysts, accelerating the chemical reactions involved in breaking down glucose.</p> Signup and view all the answers

What transformation does glucose undergo during the first four reactions of glycolysis?

<p>During the first four reactions, glucose is converted to glucose-6-phosphate and subsequently cleaved into two molecules of glyceraldehyde 3-phosphate.</p> Signup and view all the answers

What is the role of G3PDH in the glycerol phosphate shuttle?

<p>G3PDH catalyzes the reduction of dihydroxyacetone phosphate (DHAP) to glycerol 3-phosphate (G3P).</p> Signup and view all the answers

How is FAD involved in the glycerol phosphate shuttle?

<p>FAD binds to mitoG3PDH and accepts 2 electrons and 2 protons to produce FADH.</p> Signup and view all the answers

Describe the outcome of the malate-aspartate shuttle in terms of ATP production.

<p>The malate-aspartate shuttle produces 2.5 molecules of ATP per NADH oxidized.</p> Signup and view all the answers

What happens to pyruvate under aerobic conditions?

<p>Under aerobic conditions, pyruvate is converted to 3CO2 and 3H2O.</p> Signup and view all the answers

What is the fate of pyruvate in anaerobic conditions in yeast?

<p>In anaerobic conditions, pyruvate is converted to ethanol.</p> Signup and view all the answers

What must happen to OAA to maintain the malate-aspartate shuttle?

<p>OAA must be transaminated to aspartate to maintain the cycle.</p> Signup and view all the answers

Which complexes in the electron transport chain (ETC) utilize NADH from the malate-aspartate shuttle?

<p>NADH from the malate-aspartate shuttle is used by complex I in the ETC.</p> Signup and view all the answers

How does the glycerol phosphate shuttle compare to the malate-aspartate shuttle in terms of ATP yield?

<p>The glycerol phosphate shuttle yields 1.5 molecules of ATP, while the malate-aspartate shuttle yields 2.5 molecules.</p> Signup and view all the answers

What is the main product of anaerobic glycolysis in muscles?

<p>Lactate</p> Signup and view all the answers

How many molecules of ATP are generated in anaerobic glycolysis?

<p>2 ATP</p> Signup and view all the answers

What role does lactate dehydrogenase play in anaerobic glycolysis?

<p>It catalyzes the conversion of pyruvate to lactate.</p> Signup and view all the answers

What is the total ATP yield from aerobic glycolysis per molecule of glucose?

<p>7 ATP</p> Signup and view all the answers

In aerobic glycolysis, how are the 5 additional ATPs generated aside from direct ATP production?

<p>Through the oxidation of 2 NADH.</p> Signup and view all the answers

What is the final step of glycolysis involving phosphoenolpyruvate?

<p>Transfer of the phosphoryl group to ADP.</p> Signup and view all the answers

What are the two important types of shuttle systems mentioned and their ATP yield?

<p>Glycerol-3-phosphate shuttle (1.5 ATP) and malate-aspartate shuttle (2.5 ATP).</p> Signup and view all the answers

Why is there a difference in ATP yield from one glucose molecule depending on the metabolic pathway?

<p>The difference arises from whether glycolysis occurs under aerobic or anaerobic conditions.</p> Signup and view all the answers

Study Notes

Glycolysis Overview

  • Glycolysis is a metabolic pathway that breaks down glucose into pyruvate
  • It's a crucial process for energy production, particularly in short bursts of intense exercise.
  • It occurs in the cytosol of cells.
  • The process involves a sequence of 10 reactions.
  • Glucose (6 carbons) is broken down to two pyruvate molecules (3 carbons each).

Learning Objectives

  • Understand the role of glycolysis
  • Describe the detailed steps of glycolysis
  • Explain how glycolysis contributes to energy production

Cellular Respiration

  • Glycolysis is the first stage of cellular respiration.
  • Pyruvate from glycolysis goes on to the Krebs cycle which occurs in the mitochondria.
  • The electron transport chain and oxidative phosphorylation occur in the mitochondria, which generate ATP.

Enzymes

  • Enzymes are proteins that accelerate chemical reactions in biological systems.
  • They are crucial for breaking down food, converting nutrients into energy, and building/repairing tissues.
  • Without enzymes, biological processes would be much slower or less efficient.

Glycolysis Pathway Details

  • Glycolysis is a sequence of 10 reactions
  • Breaks down one glucose molecule (6 carbons) to two pyruvate molecules (3 carbons each)
  • Includes energy investment and energy generating stages

Energy Production: With or Without Oxygen?

  • Aerobic glycolysis yields a net 7 ATPs
  • Anaerobic glycolysis yields a net 2 ATPs
  • Aerobic glycolysis occurs when oxygen is present.
  • Energy from the oxidation of NADH leads to more ATP generation in aerobic glycolysis.
  • Anaerobic glycolysis occurs in the absence of oxygen.

Glycolysis Stages

  • Energy Investment Phase: Requires 2 ATP molecules per glucose molecule
  • Energy Payoff Phase: Produces 4 ATP molecules and 2 NADH molecules per glucose molecule

Energy Yielding Reaction

  • The reaction involving Glyceraldehyde-3-phosphate dehydrogenase (GAPDH), is the first energy yielding step
  • It's the key reaction where NAD+ is reduced to NADH.

Substrate-level Phosphorylation

  • A phosphate group is directly transferred from an intermediate substrate in glycolysis to ADP, forming ATP.
  • This process occurs in two steps of the energy generating phase.

Thermodynamics

  • Glycolysis involves energy changes in intermediate compounds
  • Some steps are endothermic, others are exothermic. It is essentially a sequence of reactions proceeding from one intermediate compound to the next.

Fate of NADH

  • In aerobic conditions (with oxygen), NADH, along with Hydrogen ions and oxygen are converted back to NAD+ and Water within the mitochondria.
  • This process releases a large amount of energy, used to create 3 ATPs

Location of Glycolysis and NADH Reoxidation

  • Glycolysis occurs in the cytoplasm
  • NADH is reoxidized in the mitochondria at the electron transport chain
  • Mitochondrial membranes (especially in yeast) are permeable to NAD+ and NADH.

Shuttle Systems

  • The glycerol phosphate and malate-aspartate shuttles are how NADH transfers electrons from cytoplasm to mitochondria without passing through mitochondrial membranes
  • Different organisms use different shuttle systems

Fate of Pyruvate

  • Pyruvate's fate depends on oxygen availability
    • Aerobic conditions: Pyruvate is converted to Acetyl CoA, enters the Krebs cycle, and further energy is generated
    • Anaerobic conditions: Pyruvate is converted to lactate in animals, or to ethanol in yeast
    • In both cases, NAD+ is regenerated.

Ethanol Production

  • In yeast under anaerobic conditions, pyruvate is converted to ethanol and carbon dioxide.
  • Alcohol dehydrogenase is the enzyme involved.

Lactic Acid Production

  • In animals, especially muscle cells under anaerobic conditions, pyruvate is converted to lactate
  • Lactate dehydrogenase catalyzes this reaction, regenerating NAD+

Summary of Glycolysis

  • Glycolysis is an initial investment of 2 ATP molecules per glucose molecule
  • The process is repaid with 4 ATP molecules
  • Aerobic conditions lead to a net yield of 7 ATPs
  • Anaerobic conditions lead to a net yield of 2 ATPs

Functions of Glycolysis:

  • Energy liberation and conservation
  • Precursors for biosynthesis
  • Metabolism of other nutrients
  • The final step transfers the phosphoryl group from phosphoenolpyruvate to ADP for ATP production
  • Overall, Glycolysis efficiently yields energy that the cell can utilize.

Studying That Suits You

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

Quiz Team

Related Documents

Description

This quiz covers the essential aspects of glycolysis, including its role in cellular respiration and energy production. You'll learn about the detailed steps of this metabolic pathway and the significance of enzymes in these processes. Test your knowledge and deepen your understanding of how glucose is transformed into energy.

More Like This

Cellular Respiration Process Quiz
12 questions

Cellular Respiration Process Quiz

PleasantWillow avatar
PleasantWillow
Cellular Respiration and Glycolysis
48 questions

Cellular Respiration and Glycolysis

DelicateMountRushmore avatar
DelicateMountRushmore
Cellular Respiration and Energy Metabolism
50 questions

Cellular Respiration and Energy Metabolism

WarmheartedTrombone avatar
WarmheartedTrombone
Cellular Respiration Overview
16 questions

Cellular Respiration Overview

EnrapturedConnemara4643 avatar
EnrapturedConnemara4643
Use Quizgecko on...
Browser
Open
Browser
Browser