Krebs Cycle

The Krebs cycle requires oxygen, because..

• Without oxygen, glycolysis cannot take place to provide the starting materials for the Krebs cycle

• Without oxygen, ATP cannot be synthesized by substrate level phosphorylation

• Without oxygen, coenzyme A is unable to be added to the pyruvate molecule to make acetyl CoA

• Without oxygen NADH cannot be oxidized to continue receiving electrons as NAD+

Tags

NGSS.HS-LS1-7

NGSS.HS-LS2-5

How many turns of the Krebs cycle per glucose molecule

• 3

• 2

• 1

• 4

Tags

NGSS.HS-LS1-7

In one turn of the cycle, how many of the products are formed?

• 1 ATP, 3 NADH, 1 FADH2, 2 CO2

• 1 ATP, 2 NADH, 2 FADH2, 1 CO2

• 2 ATP, 3 NADH, 2 FADH2, 2 CO2

• 2 ATP, 2 NADH, 1 FADH2, 1 CO2

Tags

NGSS.HS-LS1-7

NGSS.HS-LS2-3

Where does the Krebs cycle take place?

• Chloroplast

• Cytosol

• Mitochondrial Matrix

• Cristae

Tags

NGSS.HS-LS1-7

What is the starting material for the Krebs Cycle?

• G3P

• Pyruvate

• Acetyl CoA

• Glucose

Tags

NGSS.HS-LS1-7

NGSS.HS-LS2-5

How does the Krebs cycle allow for ATP synthesis ?

• The rotation of the Krebs cycle turns a “rotor” in the cell to synthesize ATP

• ATP is synthesized by substrate level phosphorylation during the removal of the coenzyme A upon entrance into the cycle

• High energy electrons are stored in NADH and FADH2 to shuttle to the ETC to generate a proton gradient

• Krebs cycle completes the breakdown of glucose to release the energy and store it in the form of ATP

Tags

NGSS.HS-LS1-7

What is the difference between NADH and FADH2?

• Both are electron carriers, FADH2 occurs in the Krebs cycle and NADH occurs in glycolysis

• Both are electron carriers, FADH2 holds higher energy electrons

• Both are electron carriers, NADH occurs in glycolysis and FADH2 occurs in the Krebs cycle.

• Both are electron carriers, NADH holds higher energy electrons

How much of the glucose is left after Krebs cycle?

• 75%

• 0%

• 50%

• 25%

Tags

NGSS.HS-LS1-7

Predict the effect of an inhibitor that stops the oxidation of NADH or FADH2

• Increase of cellular respiration; more ATP is synthesized

• Decrease of cellular respiration; less ATP is synthesized

• Decrease of cellular respiration; more ATP is synthesized

• Increase of cellular respiration; less ATP is synthesized

Tags

NGSS.HS-LS1-7

How are electrons extracted during the Krebs cycle transferred to the electron transport chain (ETC)

• CO2

• NADH

• FADH2

• ATP

Tags

NGSS.HS-LS2-3