Mitochondria LECTURES overview
A. Mitochondria LECTURES overview
The arrangement of membranes: distinct inner and outer membranes, The location of ATPase, DNA and ribosomes
Fatty Acid Oxidation
B.Ê THERMINOLOGY Ê
Chemiosmosis - the production of ATP by coupling the transfer of H+ across a membrane, down their concentration to the phosphorylation of ADP.
Mitochondrial Structure öÊ (a) Cristae ÷ the folds of the inner mitochondrial membrane. (b) Matrix ÷ the space in the mitochrondria internal to the cristae.
Oxidation - loss of electrons from a substance involved in a redox reaction.
Oxidative phosphorylation - the production of ATP making use of the proton motive force across the inner mitochondrial membrane.
Proton-motive force - the potential energy contained in the electrochemical gradient produced by the vectoral transport of protons across biological membranes.
Reducing agent ÷ a molecule that transfers electrons to reduce another molecule.
Reduction - the gain of electrons by a substance involved in a redox reaction.
Substrate-level phosphorylation - when ATP is made by transferring a phosphate group from another molecule to ADP
ATP is the most readily accessible chemical energy store for use in metabolic reactions; ATP is a high energy molecule because the bonds between the three phosphate groups are unstable, and release a lot of energy when broken; ATP provides energy to a reaction by transferring a phosphate to an intermediate and increasing its energy level.
Glycolysis is the conversion of glucose to pyruvate (plus 2ATP plus 2NADH) in the cytosol of a cell.
NAD+ accepts a pair of electrons to become NADH. NADH is a reducing agent in many reactions.
The Krebs cycle occurs in the matrix of the mitochrondria;The first step of the Krebs cycle adds two carbons from acetyl CoA to oxaloacetate (4C) to make citrate (6C). As the cycle is completed, oxaloacetate is regenerated, 1 ATP, 3 NADH and 1 FADH2 are produced, and two CO2 released per pyruvate molecule.
The electrons from the NADH and FADH2 produced in glycolysis and the Krebs cycle are passed through the electron transport chain in the inner mitochondrial membrane. The vast majority of the ATP produced indirectly, as a result of the electron transport chain.
The electrons are passed to a series of carriers, each one more electronegative than the next.
O2 is the most electronegative, and is the final electron acceptor in the mitochrondrial ETC.
The electrochemical gradient contains potential energy, which is used by ATP synthase to phosphorylate ADP as protons are allowed to move from the intermembrane space to the matrix.
1. Anoxic glycolysis results in the formation of how many moles of ATP from ADP and Pi (per mole of glucose)
2. Glycolysis leads to the production of ____________ and two molecules of ATP. In the absence of oxygen, fermentation leads to the production of ______________. Glycolysis plus the citric acid cycle can convert the carbons of glucose to _________ , storing the energy as ATP, _____________ and ___________.
a. lactic acid, pyruvate, CO2, NAHD, FADH2
b. pyruvate, lactic acid, CO2, NADH, FADH2
c. CO2, lactic acid, pyruvate, FADH2
d. O2, lactic acid, pyruvate, FADH2
e. glucose, lactic acid, CO2, FADH2
3. At the end of glycolysis, each molecule of glucose has yielded 2 molecules of _______, 2 molecules of ________, and a net of 2 molecules of _________.
a. FAD, NAD+, ATP
b. CO2, NAD+, ADP
c. Lactic acid, ethanol, CO2
d. pyruvate, NADH, ATP
e. H2O, CO2, ATP
4. In the absence of oxygen, the primary purpose of fermentation is to:
a. produce amino acids for protein synthesis
b. generate a proton gradient for ATP synthesis
c. oxidize glucose to generate reduce electron carriers
d. generate alcohol for beverages
e. regenerate NAD+ from NADH allowing glycolysis to continue
5. The inside part (analogues to the cytosol of a bacterium) of a mitochondrion is called:
c) intermembrane space
6. Porins may be found:
a) in the outer membrane of gram-negative bacteria
b) in the outer membrane of chloroplasts
c) in the outer membrane of mitochondria
d) in the inner membrane of mitochondria
e) in a), b) and c) but not d)
7. The terminal electron acceptor during mitochondrial respiration:
8. During TCA cycle, the conversion of succinate to fumarate
a) in oxidation that passed electrons fo FAD to make FADH2
b) is a reduction that passes electrons to FAD
c) is a reduction that passes electrons to NAD+
d) ia a isomerization
e) none of the above
9. The major production of ATP during aerobic metabolism occurs when electrons from __________ and _____________ are transferred to _______________.
a. FADH2, NADH, H20
b. O2, FADH2, NADH
c. FADH2, O2, NADH
d. NADH, O2, FADH2
e. FADH2, NADH, O2
10. Glyoxylate shunt
a) provide extra electrons to make ATP
b) produce additional intermediates in the TCA cycle
c) prepare precursosrs for FA synthesis
d) prepare glucose for fermentation
e) provide signal to neighboring cells
11. In the presence of an uncoupler, one may expect:
a) rate of electron transport to decrease
b) rate of electron transport to increase
c) ATP synthesis to stop
d) Both a and c
e) Both b and c
12. Which of the following statements about mitochondria is false? Ê
a. They contain an inner and an outer membrane.
b. The region enclosed by the inner membrane is termed the matrix.Ê
c. They contain DNA and ribosomes.Ê
d. They are an important site for energy production in cells.Ê
e. They contain stacked internal thylakoid membranes.
13. If you isolate mitochondria and place them in buffer with a low pH they begin to manufacture ATP. Why?
a. Low pH increases the concentration of base causing mitochondria to pump out H+ to the inter membrane space leading to ATP production.
b. The high external acid concentration causes an increase in H+ in the inter membrane space leading to increased ATP production by ATP synthetase.
c. Low pH increases the acid concentration in the mitochondrial matrix, a condition that normally causes ATP production.
Low pH increases the
14. In eukaryotic cells during aerobic respiration, most ATP synthesis occurs associated with
a) at the cellâs unit membrane
b) at the endoplasmic reticulum
c) at the mitochondrial outer membrane
d) in the folds of the mitochondrial inner membrane
e) in the thylakoids of the mitochondrion
15. The electron transport chain is located predominantly in the:
a. Outer membrane of the mitochondria.
b. Intermembrane space of the mitochondria.
c. Inner membrane of the mitochondria
d. Matrix of the mitochondria
e. Cytoplasm of the cell
16. What cellular compartment becomes acidic (high concentration of hydrogen ions) during mitochondrial electron transport? Ê
a. Mitochondrial stroma
c. Endoplasmic reticulum.
d. Space between inner and outer mitochondrial membranes
e. Thylakoid membranes
17. ATP synthase can produce ATP using as a direct energy source:
a) energy from the conversion of glucose to pyruvate. Ê
b) energy from the oxidation of pyruvate producing CO2 and H20
c) energy from a proton gradient established in mitochondria
d) energy derived from the breakdown of NADH and FADH2
e) energy from the metabolism of amino acids
18. In the F-type ATP-ase, the catalyc site(s) at which ATP binds is:
a) in the Fo portion
b) in the F1 portion
c) in the F3 portion
d) in the F3 portion
e) none of the above
19. Synthesis of one ATP by the F-type ATPase is accomplished by:
a) the complete rotation of the gamma subunit
b) 120 degree of rotation of the gamma subunit
c) 180 degree of rotation of the gamma subunit
d) substrate-level phosporylation
e) none of the above
20. ATP is synthesized in the F-type ATPase when the binding site is in:
b) the F configuration
c) the T configuration
d) the O configuration
21. Which of the following activities in mitochondria require proton-motive force?
a) ATP synthesis
b) Phosphate transport
c) ATP transport
d) ADP transport
e) all of the above
Correct Answers:ÊÊÊÊ 1b, 2b, 3d, 4e, 5d, 6e, 7e, 8a, 9e, 10b, 11e, 12e, 13b, 14d, 15c, 16d, 17c, 18b, 19b, 20, 21e
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