2_Aerobic Cellular Respiration

Question 1

What is the overall equation for aerobic metabolism?

Answer 1

See diagram in 2_2 notes
The energy production from one glucose molecule can be summarized in the following two equations:

glucose + O2 + ADP yields CO2 + H2O + ATP

30-32 ADP + P [yields 30-32 ATP]
C6H12O6 + 6 O2 yields 6 CO2 + 6 H2)

Question 2

Describe the difference between the energy released during the combustion (burning) of glucose versus glucose breakdown in a cell.

Answer 2

Burning or combustion is a high temperature, exothermic, redox reaction, occurring between a fuel and an oxidant.

Respiration or cellular respiration is the set of chemical reactions that take place in a cell, converting biochemical energy into ATP. Although it is technically a type of combustion reaction, it occurs inside the cell, slowly releasing energy through a series of reactions. Furthermore, nutrients used in respiration include sugar, amino acids, and fatty acids. Meanwhile, the main form of respiration is aerobic respiration, which uses oxygen as the final electron acceptor. Basically, during aerobic respiration, glycolysis breaks down nutrients into pyruvate, which enters into mitochondria in order to undergo complete oxidization into carbon dioxide and water. Moreover, the energy released by the chemical reactions is stored in ATP through the substrate-level phosphorylation of NADH and FADH2.

Question 3

Define Glycolysis

Answer 3

A

Question 4

Where does glycolysis occur in a cell?

Answer 4

cytosol

Question 5

How many net ATP are produced per glucose during glycolysis?

Answer 5

30-32 ATP

Question 6

What does the “energy investment phase” of glycolysis refer to?

Answer 6

The cell spends ATP

Question 7

What are the ATP used for during this “energy investment phase” of glycolysis?

Answer 7

To split glucose into 2 ADP + 2 molecules of pyruvate (NADH)

Question 8

Per glucose, how many NADH are produced?

Answer 8

2 NADH

Question 9

​What two entities are “harvested” by NAD+?

Answer 9

2 NADH and 2 H2O

Question 10

What three-carbon molecule is produced by glycolysis? Hint: there are two of them.

Answer 10

Two 3-carbon pyruvate

Question 11

Define substrate-level phosphorylation

Answer 11

Substrate-level phosphorylation is a process in which ATP is synthesized as a result of the oxidation of an organic compound, the substrate, without the participation of any external electron donor (e.g., NADH) or external electron acceptor (e.g., O2).ATP synthesis via substrate-level phosphorylation takes place at various steps during complete oxidation of glucose molecule in aerobic respiration (glycolysis and TCA cycle) Out of all 32 ATP molecules, 26 are produced by way of oxidative phosphorylation with the involvement of NADH and FADH2, whereas the remaining 6 are the result of substrate-level phosphorylation.

Question 12

Does glycolysis require oxygen?

Answer 12

No, glycolysis does NOT require oxygen. Glycolysis is the common pathway for both aerobic and anaerobic catabolism of glucose.

Question 13

Where in a cell does the TCA cycle (Kreb’s cycle) occur?

Answer 13

mitochondria

Question 14

Sketch a mitochondrion and label its structural features:

Answer 14

see diagram 2_2

• outer membrane
• inner membrane
• inter membrane space

Question 15

What molecule produced by glycolysis is transported into mitochondrion to begin the TCA cycle?

Answer 15

Pyruvate is produced by glycolysisn transported into the mitochondria via active transport with the help of a transport protein and combines with coenzyme A to produce acetyl CoA, NADH, and one CO2 molecule.

Question 16

What key molecules are produced during the TCA cycle?

Answer 16

8 NADH, 2 FADH2, 2 ATP (per 1 glucose)

Question 17

What two entities are “harvested” by NAD+ and FADH+ during the TCA cycle?

Answer 17

A

Question 18

What metabolic process uses the NADH and FADH2 produced during the TCA cycle?

Answer 18

A

Question 19

How many ATP molecules are produced during the TCA cycle?

Answer 19

2

Question 20

How many ATP molecules are synthesized via the electron transport (aka “transfer”) chain coupled to ATP synthase?

Answer 20

26-28 ATP

Question 21

What molecules transport electrons and hydrogens to be used by the electron transport (aka “transfer”) chain?

Answer 21

A

Question 22

The exchange of electrons between protein complexes provides energy for the transport of what ion?

Answer 22

A

Question 23

Where is ATP synthase located?

Answer 23

A

Question 24

What process drives the activity of ATP synthase?

Answer 24

A

Question 25

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

Answer 25

A

Question 26

Why does ATP synthase depend upon the electron transport chain to synthesize ATP?

Answer 26

A