Stages of Cellular Respiration Flashcards

Questions and Answers

What is the first stage of cellular respiration?

Glycolysis

Where does glycolysis occur in the cell?

Cytoplasmic fluid

How does glycolysis begin cellular respiration?

By breaking glucose into two molecules of pyruvate

What is the second stage of cellular respiration?

Citric acid cycle (Krebs cycle) Signup and view all the answers

Where does the citric acid cycle take place?

Mitochondria Signup and view all the answers

What occurs in the citric acid cycle?

Pyruvate is oxidized to a two-carbon compound and glucose is broken down to carbon dioxide. Signup and view all the answers

What is the main function of the first two stages of cellular respiration?

To supply the third stage with electrons Signup and view all the answers

What does oxidative phosphorylation require?

An electron transport chain and chemiosmosis Signup and view all the answers

What stage produces the majority of ATP in cellular respiration?

Oxidative phosphorylation Signup and view all the answers

What is the energy released by the downhill fall of electrons from NADH and FADH2 to O2 used for?

To phosphorylate ADP Signup and view all the answers

What occurs in chemiosmosis?

The potential energy of the concentration gradient is used to make ATP Signup and view all the answers

Of the three main stages of cellular respiration, which one uses oxygen to extract chemical energy from organic compounds?

Oxidative phosphorylation Signup and view all the answers

How is ATP formed in glycolysis?

Substrate-level phosphorylation Signup and view all the answers

How does substrate-level phosphorylation work?

An enzyme transfers a phosphate group from a substrate molecule directly to ADP. Signup and view all the answers

Where is energy extracted from glucose during glycolysis banked?

In a combination of ATP and NADH Signup and view all the answers

Can the energy in ATP and NADH be used immediately?

True Signup and view all the answers

What are intermediates?

Compounds that form between glucose and pyruvate Signup and view all the answers

What occurs in steps 1-4 in glycolysis?

The energy investment phase consumes energy and splits glucose. Signup and view all the answers

What occurs in steps 5-9 in glycolysis?

The energy payoff phase yields energy for the cell, producing NADH and ATP. Signup and view all the answers

For each glucose molecule processed, what are the net molecular products of glycolysis?

Two molecules of pyruvate, two molecules of ATP, and two molecules of NADH. Signup and view all the answers

Study Notes

Stages of Cellular Respiration

Glycolysis is the first stage of cellular respiration.
Occurs in the cytoplasmic fluid of the cell.
Breaks down glucose into two molecules of pyruvate, a three-carbon compound.

Citric Acid Cycle

The second stage is known as the citric acid cycle or Krebs cycle.
Takes place within the mitochondria.
Pyruvate is oxidized into a two-carbon compound, completing glucose breakdown into carbon dioxide.
Small amounts of ATP are produced during this stage.

Function of Initial Stages

The first two stages primarily supply electrons for the third stage of respiration.

Oxidative Phosphorylation

Requires an electron transport chain and chemiosmosis.
This stage produces the majority of ATP during cellular respiration.
The energy released from electrons moving downhill from NADH and FADH2 to O2 is used to phosphorylate ADP.

Chemiosmosis

In chemiosmosis, potential energy from a concentration gradient is harnessed to produce ATP.

Oxygen Utilization

Oxidative phosphorylation utilizes oxygen to extract chemical energy from organic compounds via the electron transport chain.

ATP Formation

Glycolysis uses substrate-level phosphorylation to form ATP.
In this process, phosphate groups are transferred directly from substrate molecules to ADP.

Energy Storage and Usage

Energy extracted from glucose during glycolysis is stored in ATP and NADH.
The energy in ATP is immediately usable, while NADH electrons require passage through the electron transport chain before energy can be harnessed.

Intermediates and Glycolysis Phases

Intermediates are compounds formed between glucose and pyruvate.
Steps 1-4 of glycolysis are the energy investment phase, using ATP to energize glucose before splitting it into two smaller sugars.
Steps 5-9 are the energy payoff phase, generating energy through the production of two NADH and four ATP molecules, resulting in a net gain of two ATP per glucose molecule.

Glycolysis Products

For each glucose molecule processed, the net products of glycolysis are two molecules of pyruvate, two molecules of ATP, and two molecules of NADH.

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Description

Test your knowledge on the stages of cellular respiration with these flashcards. Learn about glycolysis, where it occurs, and its role in breaking down glucose. Perfect for students studying biology and cellular processes.