L11- Electron Transport Chain

Question 0

What are the four stages of Aerobic Respiration?

Answer 0

step 1- pyruvate decarboxylation - matrix
step 2- krebs/citric acid cycle - matrix
step 3- electron transport chain - cristae
step 4- ADP to ATP - cristae

Question 1

What does the term OXIDATIVE PHOSPHORYLATION refer to?

Answer 1

the combined processes of the ELECTRON TRANSPORT CHAIN and ATP SYNTHASE PHOSPHORYLATION

Question 2

Saying Proton or Hydrogen Ion is the same thing, what is the shorthand for this?

Answer 2

H+

this is just a hydrogen atom striped of its electron so it has a positive charge

Question 3

What is the shorthand for Electron?

Answer 3

e-

Question 4

What is the shorthand for Oxygen?

Answer 4

O2

Question 5

What do we get from PYRUVATE DEHYDROGENASE/DECARBOXYLATION?

Answer 5

1 NADH
1 CO2
1 acetyl group which enters the krebs via ACA

Question 6

What is released during KREBS CYCLE?

Answer 6

3 NADH
1 FADH2
2 CO2
succinic acid
(all released into the matrix)

Question 7

What is the result of the ELECTRON TRANSPORT CHAIN?

Answer 7

transferring electrons through the ETC creates a buildup of H+ ions

Question 8

What is produced from ATP SYNTHASESPHORYLATION?

Answer 8

ATP is produced from matrix supply of ADP by harnessing the H+ gradient

Question 9

Concentrated H+ in the inter membrane space is allowed to leak back into the mitochondrial matrix by ATP SYNTHASE. What occurs via this desire of H+ to equilibrate?

Answer 9

ATP Synthase phosphorylates ADP TO ATP

Question 10

The ETC is a series of how many enzyme complexes?

Answer 10

4 enzymes complexes: I II III IV
the primary pathways is I-III-IV (electrons transported through UBIQUINONE, then complexes III and IV)
the second pathway II-III-IV (succinic acid passes electrons on to complexes III and IV)
very basic summary

Question 11

The ETC is a series of how many enzyme complexes?

Answer 11

4 enzymes complexes: I II III IV
the primary pathways is I-III-IV (electrons transported through UBIQUINONE, then complexes III and IV)
the second pathway II-III-IV (succinic acid passes electrons on to complexes III and IV)
very basic summary

Question 12

What cofactors are used during NADH dehydrogenase in Complex I?

Answer 12

flavin mononucleotide (FMN)
Fe-S clusters

Question 13

How many H+ are pumped from the matrix into the intermembrane space in Complex I?

Answer 13

4 H+ are pumpbed from the matrix into the intermebrane space

Question 14

What happens to the Ubiquinone when it gets the electron from complex I?

Answer 14

It is hydrolyzed into ubiquinol (QH2)

Question 15

What is Ubiquinone?

Answer 15

a non polar vitamin like coenzyme and antioxidant.
CoQ10
since it is non polar it diffuses laterally through the non polar layer (in the phospholipid bilayer) of the cristae membrane to transport its electrons to complex III

Question 16

What accepts the electrons from the Ubiquinol and passes them on to complex III?

Answer 16

Iron Sulfate Clusters

Fe-S

Question 17

An electron is highly polarized. How does it get into the non polar environment of the cristae?

Answer 17

using Fe-S (iron sulfur) clusters transports the electron.
When the Fe-S gets an e- it transports it into the innermembrane to the ubiquinone, where the electron makes QH2 (ubiquinol) which helps to move the electron laterally through the non polar membrane.

Question 18

After the ubiquinol brings the electron to complex III, what happens? - in a very simplified way

Answer 18

Cytochrome C takes the electron from the Ubiquinol and leaps out of complex III to complex IV via it’s heme ring center. The Ubiquinol is further broken down.

Question 19

What happens in complex IV? - in a highly simplified way

Answer 19

Complex IV is - Cytochrome C Oxidase, a multi subunit quaternary enzyme complex.
Last complex of the Electron Transport Chain.
accepts electrons from cytochrome c which reduces oxygen.
It then makes water from O2 and H+ in a complex process.

Question 20

What cofactors does complex IV need?

Answer 20

copper, zinc and magnesium

Question 21

In Complex II, What are the dual uses of Succinate Dehydogenase? Where is it made and where is it found?

Answer 21

Made in the Krebs Cycle.
Found embedded in the cristae (only enzyme from krebs to do this).
1) passes Hydrogen from succinate in the krebs directly into the ETC.
2)the succinate donates Hydrogen to FAD to become FADH2 which then carries the Hydrogens into the ubiquinone which makes it ubiquinol and enters the ETC in complex III.

Question 22

Why is complex II special?

Answer 22

it is the only complex that does not pump H+ into the intermembrane space. It also doubles the efficiency of the Electron Transport Chain.

Question 23

What is the enzymatic process happening in Complex I of the Electron Transport Chain?

Answer 23

NADH Dehydrogenase

Question 24

What is the enzymatic process happening in Complex II of the Electron Transport Chain?

Answer 24

succinate dehydrogenase

Question 25

What is the enzymatic process happening in Complex III of the Electron Transport Chain?

Answer 25

Cytocrome C Oxidoreductase

Question 26

What is the enzymatic process happening in Complex IV of the Electron Transport Chain?

Answer 26

Cytochrome C Oxidase

Question 27

How many subunits does Complex I - NADH Dehydorgenase have? Where is it found? Simply, what happens here?

Answer 27

46-subunit enzyme found in the cristae. It oxidizes NADH and passes the electrons from the hydrogen through the flavin mononucleotide (FMN) and the Fe-S clusters into Ubiquinone creating Ubiquinol while H+ is being pumped into the intermembrane space

Question 28

When Ubiquinol is stripped of its electrons onto Cytochrome C in complex III - cytochrome C Oxidoreductase, what happens to the ubiquinone?

Answer 28

it is recycled and picks up more hydrogen/electrons from complex I and complex II.

Question 29

What is Complex I in the ETC?

Answer 29

NADH dehydrogenase

Question 30

What is ATP synthase and where is it located?

Answer 30

a giant quarternary (4°) enyme embedded in the cristae membrane.

Question 31

What is the function of ATP synthase?

Answer 31

It channels H+ through the complex. The complex rotates in response to the low pH of the intermembrane space. This rotation catalyses the synthesis of ATP from ADP which is released into the matrix and transported out of the mitochondrion into the cytoplasm of the cell making it available for cellular function.

Question 32

How many ATP are released per glucose molecule in Glycolysis (anaerobic respiration)?

Answer 32

2 ATP

Question 33

How many ATP are released in aerobic respiration when it is operating efficiently per glucose molecule?

Answer 33

38 ATP

Question 34

True or false: aerobic respiration is very efficient

Answer 34

false: there are inefficiencies in aerobic respiration

Question 35

Where is the superoxide molecule formed?

Answer 35

In complex I, it needs superoxide dismutase to reduce it. this is an example of an inefficiency.

Question 36

Much ATP is needed to shunt the substrates of aerobic respiration into the mitochondrion via transport proteins. Name some of these substrates.

Answer 36

``` pyruvate ACA vitamins ADP mineral ions etc this is an inefficiency of aerobic respiration ```

Question 37

What do we use to build new enzymes damaged by respiration?

Answer 37

ATP - an example of inefficiency in respiration

Question 38

what must be properly eliminated to keep the pH balance in the cell? What happens if the pH changes in the cell?

Answer 38

CO2 | enzymes do not function correctly at incorrect pH levels. This causes people to feel dysfunctional.

Question 39

What is complex II in the ETC?

Answer 39

Succinate dehydronase

Question 40

What is Complex III in the ETC?

Answer 40

Cytochrome C Oxidoreductase

Question 41

What is Complex IV in the ETC?

Answer 41

Cytochrome C reductase

Question 42

True or False: The ETC's basic function is to transport electrons through membrane proteins which then produce H+.

Answer 42

True

Question 43

What is the function of Fe-S clusters in Complexes I, II, and III?

Answer 43

they transport electrons

Question 44

True or False: The end of the ETC in Complex IV means electrons are acted upon by copper, accepted by O2, and forms H20.

Answer 44

True

Question 45

Cytochrome C transports an electron between which two complexes in the ETC?

Answer 45

Complex III and IV