Cellular Respiration

Question 1

What is cellular respiration?

Answer 1

The process by which glucose is broken down to produce ATP

It involves three stages: Glycolysis, Citric acid cycle, and Electron transport chain.

Question 2

What does ATP stand for?

Answer 2

Adenosine triphosphate

ATP is used to transfer energy to synthetic pathways and other cellular processes.

Question 3

What is the role of phosphorylation in cellular respiration?

Answer 3

An enzyme-controlled process that adds a phosphate group to a molecule

For example, phosphorylation occurs when Pi combines with low-energy ADP to form high-energy ATP.

Question 4

List the three stages of cellular respiration.

Answer 4

• Glycolysis
• Citric acid cycle
• Electron transport chain

Glycolysis occurs in the cytoplasm, the citric acid cycle in the mitochondria, and the electron transport chain on the inner membrane of the mitochondria.

Question 5

Where does glycolysis take place?

Answer 5

In the cytoplasm

Glycolysis is the breakdown of glucose to pyruvate.

Question 6

What is the net gain of ATP during glycolysis?

Answer 6

More ATP is generated than used up

This occurs through an energy investment stage followed by an energy pay-off stage.

Question 7

What is the initial substrate broken down in glycolysis?

Answer 7

Glucose

Glucose is converted to pyruvate during this process.

Question 8

What are the products of the citric acid cycle?

Answer 8

Hydrogen ions and electrons

These are removed from substrates by dehydrogenase enzymes, releasing ATP.

Question 9

What is the function of the electron transport chain?

Answer 9

To produce ATP through the transfer of electrons

It takes place on the inner membrane of the mitochondria.

Question 10

What is the process called that involves the breakdown of glucose to produce energy?

Answer 10

cellular respiration

Cellular respiration includes glycolysis, the citric acid cycle, and the electron transport chain.

Question 11

During glycolysis, what are the two phases called?

Answer 11

• energy investment phase
• energy pay-off phase

Glycolysis occurs in the cytoplasm and results in the production of ATP and pyruvate.

Question 12

What is produced when pyruvate undergoes fermentation in the absence of oxygen?

Answer 12

lactate

This process is known as lactate fermentation and occurs in animal cells.

Question 13

What is the first product formed when pyruvate combines with coenzyme A?

Answer 13

acetyl coenzyme A

This reaction occurs in the matrix of the mitochondria during the citric acid cycle.

Question 14

What is the cycle that follows the formation of acetyl coenzyme A called?

Answer 14

citric acid cycle

The citric acid cycle generates ATP, releases carbon dioxide, and regenerates oxaloacetate.

Question 15

What are the two main products generated during the citric acid cycle?

Answer 15

• ATP
• carbon dioxide

The cycle also regenerates oxaloacetate for continued operation.

Question 16

What role do dehydrogenase enzymes play in cellular respiration?

Answer 16

They remove hydrogen ions and electrons

These are passed to the coenzyme NAD, forming NADH.

Question 17

How many ATP are produced during the citric acid cycle?

Answer 17

2 ATP

This production occurs alongside the release of carbon dioxide.

Question 18

What is the function of coenzyme A in cellular respiration?

Answer 18

It acts as a carrier molecule

Coenzyme A can be recycled and used multiple times in the metabolic processes.

Question 19

What is the initial substrate for glycolysis?

Answer 19

glucose

Glycolysis begins with glucose and results in the formation of pyruvate.

Question 20

Where does the electron transport chain take place?

Answer 20

On the folded inner membrane of the mitochondrion

This stage is crucial for ATP synthesis.

Question 21

What is the role of NADH in the electron transport chain?

Answer 21

Source of electrons

NADH donates electrons to the electron transport chain.

Question 22

What is produced as a result of the electron transport chain?

Answer 22

ATP

Most ATP is produced by the electron transport chain.

Question 23

What combines with hydrogen ions and electrons to form water?

Answer 23

Oxygen

Oxygen acts as the final acceptor of hydrogen ions and electrons.

Question 24

What is the function of ATP synthase in the electron transport chain?

Answer 24

Catalyzes the synthesis of ATP

The rotation of ATP synthase is driven by the flow of hydrogen ions.

Question 25

True or false: The **electron transport chain** is a series of carrier proteins attached to the outer mitochondrial membrane.

Answer 25

FALSE ## Footnote The electron transport chain is located on the inner mitochondrial membrane.

Question 26

What is the process of **pumping hydrogen ions** across a membrane associated with?

Answer 26

ATP synthesis ## Footnote This process is essential for generating ATP in the mitochondrion.

Question 27

Fill in the blank: The **electron transport chain** results in the synthesis of _______.

Answer 27

ATP ## Footnote ATP is the main energy currency produced during this process.

Question 28

What is the **final acceptor** of hydrogen ions and electrons in the electron transport chain?

Answer 28

Oxygen ## Footnote Oxygen's role is critical for the formation of water.