Glycolysis and Redox reactions

Question 1

What is cooperative allostery?

Answer 1

Two or more subunits work on an enzyme

It is a cooperative transition involves two shape changes

Question 2

Why do catabolic pathways need to be long?

Answer 2

It allows them to release energy slowly- that is the only for cells to properly capture some of the energy

Question 3

Burning Glucose to carbon dioxide- what is more efficient way to do it?

Answer 3

It is best to split reaction into many steps- only releasing small amount of energy at a time (enough to keep reaction going and store some energy).

Question 4

When glucose is oxidized, how much energy goes wehre?

Answer 4

• 1/2 is collected in ATP
• 1/2 is released as heat
• 686 kcal/mol total

Question 5

What are the two types of glucose oxidation?

Answer 5

• Aerobic (cellular respiration)

- Anaerobic (fermentation- absence of oxygen)

Question 6

Where do electrons go in regards to the carbon atom in the oxidation of glucose?

Answer 6

Electrons move further away from the carbon atom

- Number of C-H bonds decreases and number of C-O bonds increases

Question 7

How do we recognize oxidations?

Answer 7

• Increase in charge! (ex: 2+ -> 3+)

Question 8

In what form is oxidation energy stored?

Answer 8

• In the intermediate form NAD, which is reduced to NADH

Question 9

How does NADH behave?

Answer 9

• Comes from the reduction of NAD
• When it is oxidized it releases energy
  It is a temporary electron carrier

Question 10

Formula for oxidation and reduction of Nad+/Nadh

Answer 10

NAD+ + H+ + 2e -> NADH
red->
ox

Question 11

What is redox potential?

Answer 11

The tendency to lose or gain electrons

Question 12

What is the best electron acceptor?

Answer 12

Oxygen

Question 13

What are the 2 stages of glycolysis?

Answer 13

• Investment of ATP to activate the sugar. It is the splitting of C6 into 2 C3 (ENERGY CONSUMING)
• Oxidation of the C3, giving NADH (reduction of NAD+). This releases a lot of free energy.

Question 14

How much ATP do cell resp and fermentation yield?

Answer 14

Cell resp yields 29 ATP

Fermentation yields 2 ATP

Question 15

What is the name of the 6C and 3C it becomes during glycolysis? What aids this reaction?

Answer 15

Glucose splits into 2 pyruvate
This is aided by phosphate
Produces 2 ATP

Question 16

Where does oxidation of Pyruvate take place?

Answer 16

The mitochondria

Question 17

Where does glycolysis take place?

What is the end product of glycolysis and where does it go?

Answer 17

The cytosol

End product is pyruvate- which is then oxidized in the mitochondrial matrix to acetyl coA

Question 18

What is acetyl coA?

Answer 18

Acetyl coA is a an energy carrier

transfers 2C group to another molecule at start of citric acid cycle

Question 19

What is the purpose of the citric acid cycle?

Answer 19

Finishes oxidation of glucose by converting acetyl CoA to 2 CO2

Question 20

What catalyzes the citric acid cycle?

Is it a redox reaction?

Answer 20

Dehydrogenases

It is NOT a redox reaction

Question 21

What is the end result of citric acid cycle?

Answer 21

• 3 NADH, 1 FADH2, 1 GTP (ATP)

Question 22

Where does NADH go after citric acid cycle?

Answer 22

NADH goes to the electron transport chain!
Converts to NAD+ to continue citric acid cycle
Makes ATP

Question 23

What takes up electrons from FADH2?

Answer 23

• Ubiquinone takes up e from FADH2 from complex 2

- It carries electrons from one complex to the next

Question 24

How is ATP “spent”

Answer 24

ATP is converted to ADP via hydrolysis- a phosphate is kicked off and replaced by OH, releasing energy

Question 25

3 steps of cell resp

Answer 25

• Glycolysis
• citric acid cycle
• ETC

Question 26

Fermentation

Answer 26

Anaerobic respiration

• Pyruvate is used as electron acceptor due to lack of Oxygen
• Uses bacteria