Chapter 8 - Aerobic & Anaerobic Forms of Metabolism

Question 1

Glycolysis occurs in the _______ and generates _______ NADH molecules.

Answer 1

cytosol; 2

Question 2

The enzyme _______ is needed to convert phosphoenolpyruvic acid to pyruvic acid.

Answer 2

pyruvate kinase

Question 3

The substrate _______ is required for glycolysis to begin.

Answer 3

glucose

Question 4

The enzyme _______ is required to convert glucose to glucose-6-phosphate.

Answer 4

hexokinase

Question 5

The substrate needed to initiate the Krebs cycle is _______.

Answer 5

acetyl coenzyme A

Question 6

Which molecule(s) is(are) generated during aerobic metabolism?

Answer 6

CO2 & H2O

Question 7

Which chemical reaction of the Krebs cycle produces NADH?

Answer 7

Isocitrate → α-ketoglutarate

Question 8

The specific role of oxygen in the cell is to _______________.

Answer 8

act as the final electron acceptor

Question 9

If a cell loses its mitochondria, the net number of ATP molecules that can be produced from one glucose molecule is ___.

Answer 9

2

Question 10

What two molecules make up adenosine?

Answer 10

adenine & ribose

Question 11

What are the two major catabolic pathways that generate energy?

Answer 11

aerobic (with air)

anaerobic (without air)

Question 12

What are the FOUR set of reactions of aerobic catabolism?

Answer 12

1. Glycolysis
2. Kreb’s Cycle
3. Electron Transport Chain
4. Oxidative Phsophorlyation

Question 13

What are the inputs/outputs of glycolysis and where does it occur in the cell?

Answer 13

Inputs: Glucose, 2 ATP

Outputs: 2 pyruvic acid, 2 NADH2, 2ATP

Location: Cytosol

Question 14

What are the 10 steps of glycolysis?

Answer 14

glucose (6C)
glucose-6-phsophate 
fructose-1,6-diphosphate
glyceraldehyde-3-phosphate
2 1,3 diphsphoglyeric acid
2 3-phosphoglyceric acid
2 2-phosphoglyceric acid
2 phosphoenolpyruvic acid
2 pyruvic acid (3C)

Question 15

What are the inputs/outputs of the Kreb’s cylce and where does this occur in the cell?

Answer 15

Inputs: 2 pyruvic acid

Outputs: CO2, acetyl-coA

Location: Inner-matrix of the mitochondrion

Question 16

Which chemical reactions in the Kreb’s cycle yield NADH2?

Answer 16

pyruvic acid → acetyl-coenzyme A
Isocitrate → α-ketoglutarate
α-ketoglutarate →succinyl-coenzyme A
malate → oxaloacetate

Question 17

How does pyruvate enter the mitochondrion?

Answer 17

Facilitated diffusion with transport protein present.

Question 18

Where does the electron transport chain occur?

Answer 18

It occurs in the cristae (inner membrane of mitochondiron)

Question 19

What is the purpose of the electron transport chain?

Answer 19

To bring NADH and FADH2 back in the form of NAD and FAD by removing protons

Question 20

How does the electron transport chain produce ATP?

Answer 20

Energy is formed by moving protons in the intermembrane matrix

Question 21

How can you measure the efficiency of ATP production?

Answer 21

Use P/O ratio: # of ATP molecules formed PER atom of oxygen reduced to H2O

Question 22

How do animals make energy when there is no oxygen in the environment? What happens to the electron transport chain?

Answer 22

They use ANAEROBIC metabolism

1. impaired ATP synthesis
2. potential redox disruptions (can only remove e- as fast as e- are being made)

Question 23

What does LDH do to aid in anaerobic metabolism?

Answer 23

Allows pyruvic acid to be transformed into lactic acid without the need for oxygen.
-produces NADH2 → NAD
-primary determinant of whether the cell can carry out
anaerobic glycolysis at a substantial rate

Question 24

What is an isoenzyme?

Answer 24

Different molecular forms of an enzyme

Question 25

What fuels are used for anaerobic metabolism?

Answer 25

Glucose

Question 26

How many ATPs are generated in aerobic metabolism vs. anaerobic metabolism?

Answer 26

Aerobic: 24 - 32 ATP Anaerobic: 2 ATP

Question 27

How is the electron transport chain and oxidative phosphorlyation coupled?

Answer 27

The electron transport chain uses the electrons from electron carriers to create a chemical gradient that can be used to power oxidative phosphorylation.

Question 28

What is cellular respiration?

Answer 28

The process necessary for producing energy that cells can use.

Question 29

What is the difference between steady state and non-steady state ATP production?

Answer 29

Steady state ATP production: cells remain constant in their level of ATP (produces ATP as fast as it is used), go on indefinitely, free of intrinsic limitations i.e. aerobic metabolism Non-steady state ATP production: cell's supplies deplete, they do not make ATP as fast as it is being used, they cannot persist for very long i.e. anaerobic metabolism

Question 30

What is the role of phosphagens in ATP formation? Where are they found?

Answer 30

Phosphagens are compounds that serve as temporary stores of high energy phosphate bonds, they are found in skeletal muscles of vertebrates and muscles of invertebrates. (able to transfer ADP into ATP anaerobically) i.e. creatine phosphate is phosphagen of vertebrate muscles

Question 31

What are FOUR methods for ATP production?

Answer 31

1. Aerobic Catabolism from O2 in Environment : steady state (takes oxygen from environment and turns it into energy) 2. Anaerobic Glycolysis: non-steady state 3. Phosphagen Use: non-steady state (transfers ADP into ATP without oxygen) 4. Aerobic Catabolsim Using O2 Preexisting in Body: non-steady state

Question 32

Which is the best method for ATP production?

Answer 32

Aerobic Catabolism from O2 in the Environment - in presence of O2 - get the most amount of ATP, it may be a bit slower but it yields more energy and it is an indefinite source of obtaining energy as long as O2 is present

Question 33

Researchers have asked whether the ratio of fiber types (slow oxidative: SO or fast glycolytic: FG) can be altered during one's lifetime or they are fixed genetically. Why would a change in ratio of fiber types be of interest?

Answer 33

Muscle fatigue: exercise-induced reduction in the muscle's ability to generate peak forces and maintain power output -vertebrates are said to have a heterogeneous mixture of FG & SO fibers -FG: have MORE LDH, fatigue quickly, less myoglobin present (white) -SO: more mitochondrion, relatively resistant to fatigue, more myoglobin present (red) It is important to note when consider different animals and their abilities, cheetah and gazelle for example.

Question 34

Why is it important to distinguish temporary electron acceptors (hydrogen) in cells from final electron acceptors (oxygen)?

Answer 34

They play different roles, H+ id important for creating the chemiosmotic relationship, while O2 generates energy and makes water at the final step of aerobic catabolism.

Question 35

What are the unique advantages of O2 as the final electron acceptor?

Answer 35

1. Generate ATP and H2O 2. Carries electrons to transform NADH2 & FADH2 to NAD & FAD whihc can be used in the cell for energetic purposes