Module 1 Lecture 3 - Cellular Metabolism: Respiration

Question 1

How many enzymatic steps are involved in glycolysis

Answer 1

10 enzymatic reactions

Question 2

What is the final result of glycolysis

Answer 2

Glucose broken into 2 3-carbon molecule (pyruvate)

Question 3

How many pyruvate molecules are made at the end of glycolysis?

Answer 3

2 pyruvate molecules

Question 4

How much ATP is made in glycolysis?

Answer 4

A net of 2 ATP; some was used to continue the glycolysis process

Question 5

How much NADH is made in glycolysis?

Answer 5

2 NADH

Question 6

Where does glycolysis take place and why?

Answer 6

Happens in the cytosol; the cytosol carries many intermediary metabolic enzymes

Question 7

What is McArdle’s Disease? How does it affect cellular respiration

Answer 7

The absence of an enzyme that converts glycogen to glucose; without glucose glycolysis cannot happen

Question 8

At the end of glycolysis where is most of the energy in?

Answer 8

The 2 3-carbon molecule (Pyruvate)

Question 9

What does pyruvate decarboxylation mean?

Answer 9

It means to remove a carbon

Question 10

Where does pyruvate decarboxylation take place?

Answer 10

In the mitochondrial matrix

Question 11

How many pyruvate molecules go through pyruvate decarboxylation?

Answer 11

2

Question 12

What is carbon removed in the form of in pyruvate decarboxylation?

Answer 12

CO2 through the cardio-respiratory system

Question 13

What is pyruvate catalyzed into?

Answer 13

Acetyl-CoA (2 carbon molecule)

Question 14

What is the final result of pyruvate decarboxylation?

Answer 14

2 CO2 and 2 NADH

Question 15

Is there any ATP made in pyruvate decarboxylation?

Answer 15

No

Question 16

What is the purpose of NADH and FADH2

Answer 16

They carry high energy electrons with the purpose of releasing them in the ETC

Question 17

Where do the acetyl-CoA go after decarboxylation?

Answer 17

TCA/Citric Acid/Krebs Cycle

Question 18

Where does Krebs cycle take place?

Answer 18

Matrix of Mitochondria

Question 19

How many reactions take place in the Krebs cycle?

Answer 19

8 reactions

Question 20

What two molecules make citric acid in the Krebs Cycle?

Answer 20

Oxaloacetate and acetyl-CoA

Question 21

How is Acetyl-CoA used up in the Krebs cycle?

Answer 21

The 2 carbon Acetyl-CoA combines with the 4 carbon Oxaloacetate; the 2 carbons are lost in the cycle

Question 22

What are the carbons that are lost turned into? (Krebs)

Answer 22

CO2

Question 23

Where does the CO2 go from once it leaves the matrix (pyruvate decarbox. and krebs)?

Answer 23

Outside the cell => blood => lungs => expelled out

Question 24

Oxygen is used when forming CO2 in these reactions. Where does it come from?

Answer 24

The oxygen comes from the reactions, not from inhaling it in

Question 25

Which reactions are the carbons lost in?

Answer 25

d-isocitrate => alpha-ketogluterate & alpha-ketogluterate => Succinyl-CoA

Question 26

Which reactions are NADH made in (Krebs Cycle)?

Answer 26

d-isocitrate => alpha-ketogluterate & alpha-ketogluterate => Succinyl-CoA & Malate => Oxaloacetate

Question 27

Which reactions are FADH2 made (Krebs Cycle)?

Answer 27

Succinate => Fumarate

Question 28

Through which process is ATP made in the Krebs cycle?

Answer 28

Substrate-level phosphorylation

Question 29

How is GTP made?

Answer 29

Enzyme CoA is removed from Succinyl-CoA and replaced with a phosphate group. The phosphate group is then used to make GDP into GTP

Question 30

How is ATP made in the Krebs Cycle?

Answer 30

Indirectly; GDP is turned into GTP which is a similar energy molecule to ATP but cannot be used. It (GTP) then gives its phosphate to ADP to make ATP

Question 31

What does the energy transfer process from GTP to ADP look like? (Reaction process)

Answer 31

ADP + GTP => <= ATP + GDP

Question 32

What is the purpose of removing hydrogens and adding them to NAD+ and FAD?

Answer 32

By removing these hydrogens and attaching them to these energy carriers, they can be used in the ETC to generate ATP

Question 33

After the Krebs cycle where is the energy now that the carbons are gone?

Answer 33

Energy is being held by the molecule carriers (NADH and FADH2)

Question 34

What does one cycle of Acetyl-CoA in the Krebs cycle make?

Answer 34

3 NADH, 1 FADH2, 1 ATP

Question 35

How many times is the Krebs cycle used?

Answer 35

Twice

Question 36

Where do the energy carriers go after the Krebs Cycle?

Answer 36

Electron Transport Chain

Question 37

Where does the ETC take place?

Answer 37

Inner mitochondrial membrane

Question 38

What do the energy molecule carriers do in the ETC?

Answer 38

They release high the high energy electrons which in turn releases free energy

Question 39

Why are proteins anchored on the inner mitochondrial membrane?

Answer 39

They allow for much more energy to be generated

Question 40

How many protein complexes are there?

Answer 40

4; 5 if we count ATP synthase as complex 5

Question 41

What releases the high energy electrons in the ETC

Answer 41

Hydrogens on NADH and FADH2

Question 42

What can the free energy released by the electrons be utilized for?

Answer 42

Hydrogens from NADH and FADH2 can harness that energy to move across the protein complexes

Question 43

Where do the hydrogens move from and go to in the ETC when they harness enough energy?

Answer 43

Move from the matrix, through the complex in the inner mitochondrial membrane to the intermembrane space

Question 44

Which complex is the only one that does not span the entire inner membrane?

Answer 44

Complex 2

Question 45

Which complex does NADH release its electron and subsequently its hydrogen?

Answer 45

Complex 1

Question 46

Which complex does FADH2 release its electron and subsequently its hydrogen?

Answer 46

Complex 2

Question 47

Why does NADH make more ATP than FADH2

Answer 47

FADH2 drops its electron off at complex 2 which has to shuttle over to complex 3 to let the hydrogen through; it contributes less than NADH to passing hydrogens through the complex

Question 48

Where do the electrons finally go at the end of the ETC

Answer 48

Oxygen; the final electron acceptor

Question 49

Where do the hydrogens accumulate?

Answer 49

Inner membrane space to go through ATP Synthase

Question 50

How does ATP synthase make ATP?

Answer 50

The high concentration of H+ ions move from the inner membrane space to the matrix; this allows ATP synthase to combine ADP with inorganic phosphate

Question 51

What is the term used for allowing the passage of H+ ions through ATP synthase?

Answer 51

Chemiosmosis

Question 52

How much ATP does one NADH molecule make? How many NADH molecules are overall made?

Answer 52

2-3 ATP (2.5 on average); 10 NADH molecules were made in cellular respiration

Question 53

How much ATP does one FADH2 molecule make? How many FADH2 molecules were made in cellular respiration?

Answer 53

1-2 ATP (1.5 on average); 2 FADH2 molecules

Question 54

What link does NADH and FADH2 represent

Answer 54

The link between TCA and ETC because after being converted back to NAD+ and FAD they can go and collect more hydrogens

Question 55

If cellular respiration occurred without oxygen how far could it go?

Answer 55

It could only go till Glycolysis because pyruvate instead of being converted into ACoA it turns into lactate

Question 56

How does lactate work in anaerobic respiration?

Answer 56

It uses up the NADH and turns it back into NAD+ so that molecules can go back to glycolysis and repeat the same process

Question 57

How much energy is produced in anaerobic respiration? Also why is it bad?

Answer 57

2 ATP; it's bad because not enough energy is being made plus lactate is toxic to our bodies

Question 58

Could our bodies make energy if there was no glucose?

Answer 58

Yes; fatty acids (fatty acid beta oxidation) and in severe cases proteins too