Unit 4: Celluar Respiration

Question 1

What are the 3 steps of pyruvate oxidation?

Answer 1

• Decarboxylation
• oxidation
• conjugation to CoA (coenzyme A)

Question 2

Where does pyruvate oxidation occur?

Answer 2

In the mitochondria

Question 3

Where does the Krebs cycle occur?

Answer 3

In the mitochondrial matrix

Question 4

What are the products of pyruvate oxidation?

Answer 4

acetyl CoA, CO2 and NADH

Question 5

What are the products of the citric acid cycle and where do they go afterwards?

Answer 5

• NADH and FADH2 are used in ETS
• GTP is also produced, which can be turned into ATP
• CO2

Question 6

What is the electron transport system?

Answer 6

• electron transport complex
• a series of redox reactions
• eventually transfer electrons to O2

Question 7

What happens when electrons are transferred?

Answer 7

Energy is released. The energy is used by protons to transport H+ from matrix to intermembrane space.

Question 8

What does ETS create?

Answer 8

A proton gradient

Question 9

What are the characteristics of complex 1?

Answer 9

• Inside mt inner membrane
• uses NADH dehydrogenase
• transfers electrons from NADH to Q
• proton pump

Question 10

What are the characteristics of Q?

Answer 10

• ubiquinone
• lipid
• free within mt membrane
• transfers e from I to III OR II to III
• carries 2 e
• reduced form is QH2

Question 11

What are the characteristics of complex II?

Answer 11

• within inner mt membrane
• uses succinate dehydrogenase
• transfers electrons from FADH2 to Q
• IS NOT A PROTON PUMP

Question 12

What are the characteristics of complex III?

Answer 12

• within inner mt membrane
• uses cytochrome reductase
• transfers e from Q to cytochrome c
• proton pump

Question 13

What are the characteristics of cytochrome c?

Answer 13

• within mt inner membrane
• faces intermembrane space
• transfers e from III to IV

Question 14

What are the characteristics of complex IV?

Answer 14

• within inner mt membrane
• uses cytochrome oxidase
• transfers e from cytochrome c to O2
• proton pump

Question 15

What happens if there is no oxygen present once the e gets to complex 4?

Answer 15

The electrons don’t move and then nothing works.

Question 16

What are the 2 ETS reactions?

Answer 16

1) I –> Q –> III –> cyt. c –> IV

2) II –> Q –> III –> cyt. c –> IV

Question 17

How are molecules across mt membrane?

Answer 17

a) through outer membrane into intermembrane space

b) through inner mt membrane–into matrix

Question 18

What does the movement of molecules across the outer membrane entail?

Answer 18

• the use of porins–channel-forming proteins

- allow most small molecules to cross outer membrane

Question 19

What does the movement of molecules through the inner mt membrane?

Answer 19

• diffusion of O2 (enters) and Co2 (exits)
• translocases
• NADH transfers H to shuttle

Question 20

What is the purpose of chemiosmosis?

Answer 20

ATP production using ATP synthase

Question 21

What are the structures used in chemiosmosis?

Answer 21

• F0= cylinder within inner mt membrane
• F1= water soluble catalytic complex (matrix side inner mt membrane)
• y (gamma) subunit acts as a rod that turns
• there are 4 other subunits

Question 22

How does ATP synthesis work in chemiosmosis?

Answer 22

• Binding-change mechanism protons flow down electrochemical gradient through F0
• Causes y to rotate
• causes conformation changes
• allows Pi to add on to ADP
• ATP is synthesized

Question 23

What is the process of creating ATP called?

Answer 23

Oxidative phosphorylation

Question 24

How many ATP molecule are formed for every NADH from the CAC? FADH2?

Answer 24

3 ATP per NADH

2 ATP per FADH2