Lecture 8

Question 1

What is the difference in location of the proton gradient in porkaryotes and eukaryotes?

Answer 1

the proton gradient is established across the cytoplasmic membrane, while in eukaryotes, it’s across the inner mitochondrial membrane

Question 2

What energy molecules are being produce from glycolysis?

Answer 2

glucose –> pyruvate
* releasing ATP and NADH

Question 3

What are energies being produce from citric acid cycle?

Answer 3

• NADH, FADH, CO2, GTP
• Actyl-CoA –> citric molecule –> oxalacetate –> reused when combined with another pyruvate cycle

Question 4

What does electron transportion look like?

Answer 4

• protons (electron carriers) get pushed out –> proton gradient/motive force –> generate ATP
• exergonic - oxygen turning water and creating energy

Question 5

electron transport

What if you don’t have oxygen?

Answer 5

• need another molecule during anaerobic conditions (taking place of oxygen; final electron acceptor)
• ex: nitrate reductase can be used to pass electrons to nitrate (NO3-) to become nitrite (NO2-)

Question 6

What is chemoorganotrophic metabolism?

Answer 6

• organic compounds are being reacted upon to create ATP (O2, CO2)
• without oxygen - need anaerobic respiration (Sulfur, nitrate, sulfate, organic electron acceptors)

Question 7

What is chemolithotrophic metabolism?

Answer 7

• use carbon as a carbon source (not related to metabolism)
• alot of same electron acceptors (aerobic, anaerobic)
• ATP is from inorganic compounds

Question 8

What is phototrophic metabolism?

Answer 8

• light is powering ETC (so don’t need molecules to accept electrons) –> proton motive force –> ATP
• photoheterotrophy - using organic compounds –> biosynthesis (not related to metabolism)
• photoautotrophy - carbon –> biosynthesis

Question 9

What is the difference between substrate level phosphorylation with aerobic and anaerobic respiratory mechanisms for generating ATP?

Answer 9

Substrate-Level Phosphorylation—fermentative mechanism in which ATP is synthesized at discrete reaction steps.

Oxidative Phosphorylation—respiratory mechanism in which ATP is synthesized by harnessing the proton motive force.

SLP will be less efficient than oxidative phsophorylation

Question 10

What is the flow of energy through aerobic metabolism?

Glycolysis, citric acid cycle, electron transport chain

Answer 10

glycolysis - 2 pyruvate, 4ATP, 2NADH
* SLP - 2 ATP (x2)
* OP - 6 ATP

CAC - 3 CO2 + 4 NADH + FADH, GTP
* SLP, OP –> 15 ATP (x2)

Glycolysis + CAC –> 38 ATP per glucose

SLC - substrate level phosphorylation
OP - oxidative phosphorylation

Question 11

What is the difference between inhibitors and uncoupleers of ATP synthesis?

Answer 11

Inhibitors block electron transport, preventing the establishment of a proton gradient. Examples are carbon monoxide and cyanide.

Uncouplers allow protons to pass across the membrane (by making them “leaky”), bypassing the use of ATPase. (Example: dinitrophenol).