Exam 2 Vocab

Question 1

Oxidative phosphorylation

Answer 1

The phosphorylation o/ ADP to form ATP driven by the transfer o/ electrons to O2 in bacteria and mitochondria

• Involves generation o/ a proton-motive force during electron transport
• Subsequent use to power ATP synthesis

Question 2

Aerobic oxidation/respiration

Answer 2

The respiratory process that converts nutrient energy into ATP when O2 is available and is used as the final recipient o/ electrons transported via the ETC

Question 3

Steps of glucose oxidation in eukaryotes

Answer 3

1. Glycolysis
2. Citric Acid Cycle (Krebs Cycle)
3. Electron-Transport Chain (ETC)
4. ATP Synthesis

Question 4

What is the citric acid cycle?

Answer 4

In mitochondria (in matrix)….
- Oxidation o/ pyruvate to CO2 is coupled to the generation o/ high-energy electron carriers (NADH & FADH2) which stores energy for later use

Question 5

What is glycolysis?

Answer 5

In cytosol…
- On 6-carbon glucose molecule is converted by a series o/ reactions to 2 3-carbon pyruvate molecules
- Net: 2 ATPs produced for each glucose molecule metabolized

Question 6

What is the electron-transport chain?

Answer 6

High-energy electrons flow down their electron potential gradient from NADH & FADH2 to O2 via membrane proteins that convert the energy released into a proton-motive force (H+ electrochemical gradient)
- Energy released from the electrons pumps protons across a membrane, thus generating a proton gradientWh

Question 7

What is ATP synthesis?

Answer 7

Proton-motive force powers the synthesis o/ ATP as protons flow down their concentration and electrical (voltage) gradients through ATP-synthesizing enzyme (ATP synthase), which is embedded in a mitochondrial membrane
- For each og glucose molecule, an estimate 28 additional ATPs are made by this mechanism (stages II-IV)

Question 8

Catabolic reactions

Answer 8

Break molecules down (releasing energy)

Question 9

Anabolic reactions

Answer 9

Build molecules up (using stored energy)

Question 10

What is the net of glycolysis?

Answer 10

2 NADH + 2 ATPs

Question 11

What is the net product of the citric acid cycle?

Answer 11

• 5 reduced coenzymes which fuel ATP synthesis (30+ ATPs)
• 4 NADH + 1 FADH2 molecules from one pyruvate

Question 12

Complex I (NADH dehydrogenase)

Answer 12

Carriers: FMN, FeS

• Catalyze transfer o/ electrons from NADH –> ubiquinone
• Transports 4 H+ per pair o/ 3-

Question 13

Complex II (succinate dehydrogenase)

Answer 13

Carriers: FAD, FeS

• Catalyze transfer o/ electrons from succinate –> FAD –> ubiquinone (no transport o/ H+)

Question 14

Complex III (cytochrome bc1)

Answer 14

Carriers: FeS, heme

• Catalyzes the transfer o/ electrons from ubiquinone –> Cyt C
• Transports 4 H+ per pair o/ e-

Question 15

Complex IV (cytochrome c oxidase)

Answer 15

Carriers: Cu, heme

• Catalyzes transfer from Cyt C –> O2
• Transports 2 H+ across inner membrane
• Cyt C + ubiquinone shuttle electrons between complexes

Question 16

Types of electron carriers

Answer 16

1. Flavoproteins
2. Cytochromes
3. 3 copper atoms
4. Ubiquinone
5. Iron-sulfur proteins

Question 17

Flavoproteins

Answer 17

Polypeptides bound to either FAD or FMN

Question 18

Cytochomes

Answer 18

Contain heme groups bearing Fe or Cu metal ions

Question 19

3 copper atoms

Answer 19

Located within a single protien complex and alternate between Cu2+/Cu3+

Question 20

Ubiquinone (coenzyme Q)

Answer 20

Lipid-soluble molecule made o/ 5-carbon isoprenoid units

Question 21

Iron-sulfur proteins

Answer 21

Contain Fe in association w/ inorganic sulfur