Electron transport chain

Question 1

ETC is found in the ______ mitochondrial membrane.

Answer 1

Inner

-Takes electrons from NADH & FADH2:

-passes them down a chain of electron carriers with increasing electron affinity.

-Eventually donates them to oxygen to make water

Question 2

Energy from electron movement used to pump H+ into the intermembrane space.

Answer 2

Creates an H+ gradient that is used to drive the production of ATP.

Question 3

ATP synthase:

H+ gradient is used to drive the production of ______

Answer 3

ATP

Question 4

ATP generated:

Each NADH:
Each FADH2:

Answer 4

NADH = 3 ATP
FADH2 = 2 ATP

Question 5

Why do you suppose FADH2 generates less ATP?

Answer 5

Location in the ETC:
released at complex I

Energy released per electron: FADH2 has less energy to release compared to NADH

Question 6

How does the ATP generated by ATP synthase get to the cytosol?

Answer 6

Adenine nucleotide translocate antiporter exchanges ATP for ADP

We also need a phosphate translocate symporter which brings the phosphate group into the mitochondrial matrix.

Question 7

During glycolysis, ____ NADH are produced.

Answer 7

2;
-The NADH must cross into the matrix of the mitochondria to enter the ETC

-But inner mitochondria membrane is impermeable to NADH

Question 8

There are two shuttle systems in place to transport NADH from cytosol to mitochoondria:

Answer 8

1) Malate aspartate shuttle
2) Glycerol Phosphate shuttle

Question 9

In the case of reb blood cells (no mitochondria) or anerobic conditions, what happens to the NADH?

Answer 9

Pyruvate is converted to lactate.

Enzyme: lactate dehydrogenase
NAD+: is regenerated.

Lactate travels via the blood to the liver, where it enters gluconeogenesis.

This cycle is called the cori cycle.

Question 10

Malate aspartate shuttle:

Answer 10

1) ADH from glycolysis

2) Malate can cross the I.M.M. via an anti-porter

3) NADH is regenerated and can enter the ETC at complex I

4) Transamination reactions

5) Aspartate can cross the I.M.M via an anti-porter

6) Transamination reactions

Question 11

Glycerol phosphate shuttle:

Answer 11

1) NADH is produced in glycolysis

2) DHAP is reduced to glycerol 3-phosphate regenerating NAD+ for glycolysis

3) Glycerol 3-P can enter the minter-membrane space

4) Glycerol 3-P is converted back to DHAP by mitochondrial glycerol-3-P DHG (embedded in the I.M.M)

5) FADH2 directly enters the ETC

Question 12

NADH using glycerol phosphate shuttle, generates 1 less ATP: Why?

Answer 12

Because FADH2 enters at complex II which is less efficient at proton pumping. It requires more energy.

FAD is used in this complex which carries fewer electrons.

Question 13

Complete oxidation of glucose:

Answer 13

Question 14

Beta Oxidation:

Answer 14

Occurs in the mitochondrial matrix, so no shuttle systems are required.

Question 15

Within each round of beta oxidation:

_____ FADH2 produced
_____ NADH produced
& ____________ produced

Answer 15

1 FADH2
1 NADH
1 acetyl CoA

Question 16

FADH2 enters the ETC at complex _____ in each round of the beta oxidation.

Answer 16

Complex II

Question 17

NADH enters the ETC at complex ____ in each round of beta oxidation.

Answer 17

Complex I

Question 18

Acetyl CoA in beta oxidation cycle enters ______.

Answer 18

CAC

Question 19

Technically FADH2 from beta oxidation enters via an enzyme complex:

Answer 19

ETF: Q oxidoreductase

Question 20

The CAC occurs in the ____________.

Answer 20

Mitochondrial matrix.

(No shuttle required)

Question 21

Within each cycle of the CAC there are:

____ FADH2 produced
____ NADH produced

Answer 21

1 FADH2
3 NADH

Question 22

FADH2 enters the ETC at complex ____ in the CAC.

Answer 22

Complex II

Question 23

NADH enters the ETC at complex ____ in the CAC.

Answer 23

Complex I

Question 24

How many ATP are generated when acetyl CoA is oxidized to CO2 and H2O within the CAC?

Answer 24

12 ATP

Question 25

How many ATP are generated when pyruvate is oxidized to CO2 and H2O within the CAC?

Answer 25

15 ATP

Question 26

Electrons are passed from one complex to another until they are finally passed to ___ to make ____.

Answer 26

O2 to make H2O

Question 27

Since the electron carriers are in order of increasing electron affinity, energy is released with each pass of the electrons and then….

Answer 27

this energy is used to pump H+ from the mitochondrial matrix to the intermembrane space.

Question 28

The resulting _________ or ___________ gradient is then harnessed to generate ____ as H+ re-enters the mitochondrial matrix through the __________

Answer 28

chemiosmotic or electrochemical

ATP

ATP synthase

Question 29

If an individual is anoxic how does this affect ATP synthesis?

Answer 29

Anoxia, or the absence of oxygen, significantly impacts ATP synthesis. Cellular respiration, the process that generates ATP, relies on oxygen as the final electron acceptor in the electron transport chain (ETC). Without oxygen, the ETC cannot function efficiently, and ATP production is severely reduced.

Question 30

If the cell has adequate ATP how does this affect ATP synthesis, ETC, and the Citric Acid Cycle?

Answer 30

When a cell has adequate ATP levels, it regulates its ATP production pathways to maintain a balanced energy state. This regulation involves feedback mechanisms that control the activity of enzymes involved in glycolysis, the citric acid cycle (CAC), and the electron transport chain (ETC).

Question 31

Non-shivering thermogenesis:

Answer 31

Newborn babies, hibernating animals and cold-adapted animals need to generate more heat than is produced by normal metabolism.

-Have lots of brown fat: due to large number of mitochondria.

-Contains thermogenin, a protein that uncouples the ETC by translocating H+ back to the matrix.

(H+ in the intermembrane space move back into the matrix through thermogenin instead of through ATPase: heat is produced rather than ATP)