Quiz 11

Question 0

ATP for cellular energy

Answer 0

–  Driving enzymatic anabolism and catalysis
–  Driving membrane transport proteins
–  Driving molecule and macromolecule manufacture

Question 1

Four Stages of Aerobic Respiration

Answer 1

All this activity takes place in the mitochondrion
Step 1 – Pyruvate Decarboxylation – matrix
Step 2 – Krebs/Citric Acid Cycle – matrix
Step 3 – Electron Transport Chain – cristae
Step 4 – ADP to ATP Phosphorylation – cristae

Question 2

Oxidative Phosphorylation

Answer 2

combined processes of the Electron Transport Chain and ATP Synthase Phosphorylation

Question 3

Proton, hydrogen ion and H+

Answer 3

all the same thing

Question 4

1.  Pyruvate Decarboxylation step:

Answer 4

1 NADH and 1 CO2 released to matrix, 1 acetyl group enters Krebs via ACA

Question 5

2.  Krebs Cycle step:

Answer 5

3 NADH, 1 FADH2, 2 CO2 released to matrix; succinic acid is produced as a step and released to the matrix

Question 6

Electron Transport Chain step:

Answer 6

Transfer of electrons through the ETC produces an abundance of H+ ions

Question 7

ATP Synthase Phosphorylation step:

Answer 7

ATP produced from matrix supply of ADP byharnessing H+ gradient

Question 8

The ETC concentrates H+ ions (protons) in the mitochondrial intermembrane space by

Answer 8

a complex process of passing electrons (e–) through the 4

membrane enzyme complexes — I, II, III and IV.

Question 9

ATP synthase

Answer 9

allows The concentrated H+ in the intermembrane space to leak back into the mitochondrial matrix

Question 10

This desire of H+ to equilibrate across the membrane concentration gradient

Answer 10

drives the enzyme to phosphorylate ADP to ATP — adding a phosphate group to adenosine diphosphate.

Question 11

Electron Transport chain

Answer 11

a series of 4 enzyme complexes (along with cofactors — iron-sulfur clusters, metal ions, cytochrome c and ubiquinone)

Question 12

where is ETC embedded

Answer 12

in the cristae–inner membrane of the mitochondrion

Question 13

what does the ETC do?

Answer 13

These are large and varying complexes (I, II, III,IV) remove electrons from hydrogen which creates H+ for oxidative phosphorylation. They are also H+ pumps.

Question 14

The primary pathway is I - III - IV.

Answer 14

(80% of electrons are transferred here)
Complex I begins the transport of electrons, which then pass through ubiquinone (coenzyme Q10), Fe-S clusters, Complex III, Cytochrome C, and Complex IV respectively.

Question 15

The second pathway II - III - IV

Answer 15

succinic acid passes electrons to Complex II, then to ubiquinone, to complexes III and IV.
The electrons are finally reacted with oxygen in complex IV,
forming water. Thus oxygen, as O2, is utilized in two different
steps two different ways in aerobic respiration.

Question 16

Complex I is NADH

Answer 16

It performs several operations to move electrons, using flavin mononucleotide (FMN) and Fe-S clusters as cofactors. It pumps 4 H+ from the matrixinto the intermembrane space. Additionally, it oxidizes NADH (and FADH2) and passes those hydrogen onto ubiquinone. It hydrolyzes the ubiquinone to ubiquinol (QH2).

Question 17

Ubiquinone

Answer 17

is a non-polar, vitamin-like coenzyme and
antioxidant, found primarily in mitochondria. It accepts electrons
from NADH dehydrogenase (as hydrogen) and becomes ubiquinol (QH2). Since it is non-polar, it diffuses laterally through the non-polar layer of the cristae membrane and unloads its electrons to Complex III, the Cytochrome bc1 complex.

Question 18

Iron Sulfur Clusters

Answer 18

are embedded in Complex I, II, and in the Rieske iron-sulfur protein subunit of Complex III. The Fe-S clusters accept the electrons (of hydrogen) from ubiquinol, and pass them into the other subunits of
Complex III.

Question 19

Cytochrome C

Answer 19

is highly water soluble (polar). This property is utilized in the electron transport chain Cytochrome C moves through the intermembrane space to transport electrons to Complex IV, from Complex III. It carries 1 electron with its iron-heme center.

Question 20

Cytochrome C Oxidase (complex IV)

Answer 20

This enzyme complex takes O2 and uses it as an electron acceptor — neutralizing the transported electrons from Complex I & III by making H2O from O2 and H+. Thus, there is a second use of oxygen in aerobic respiration as an electron acceptor.

Question 21

NADH

Answer 21

complex I

Question 22

Cytochrome C Oxidoreductase

Answer 22

complex III

Question 23

Cytochrome C Oxidase

Answer 23

complex IV

Question 24

Succinate Dehydrogenase

Answer 24

complex II

Question 25

Step 4. ATP Synthase and OxidativePhosphorylation

Answer 25

The final step in energy/ATP generation utilizes thehighly acid (H+) environment of the intermembrane space as a battery of potential energy.

Question 26

ATP Synthase

Answer 26

is a giant quaternary (4°) enzyme embedded in the cristae membrane, with an opening on the intermembrane space where it channels H+ through the complex. ATP synthase is a Matrix
complex enzyme that 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 Cristae Membrane ADP & PO4 mitochondrion to the cytoplasm.

Question 27

review

Answer 27

Glycolysis (anaerobic respiration) releases a net 2 ATP per glucose molecule
–  Aerobic respiration releases (at peak efficiency) a
net 38 ATP per glucose molecule
–  There are inefficiencies in aerobic respiration
–  Superoxide molecules form at Complex I and need superoxide dismutase to reduce them
–  Much ATP is needed to shunt the substrates of aerobic respiration into the mitochondrion via transport proteins —pyruvate, ACA, vitamins, ADP, mineral ions, etc.
–  Much ATP is used to build new enzymes damaged by respiration
–  Carbon dioxide must be properly eliminated to keep pH balance in the cell