Chapter 9 pt: 4,5

Question 1

What is the Electron transport chain?

Answer 1

• A network of proteins in the inner mitochondrial membrane.
• These proteins complex with molecules that are electronegative, meaning they readily accept electrons
• These proteins are arranged so that each step in the chain is slightly more electronegative than the previous one.

Question 2

Where are electrons passed from prior to entering the chain?

Answer 2

• NADH or FADH2

Question 3

What happens to potential energy and the energy state as you move further down the electron transport chain?

Answer 3

Decreases

Question 4

What are the functional groups of the electrons transport chain that receive electrons?

Answer 4

• FMN: flavin-containing prosthetic group in flavor protein.
• Fe-S: protein with an iron-sulfur cofactor
• Cyt: protein with a heme prosthetic group
• Q: ubiquinone, a nonprotein coenzyme

Question 5

At the end of complex one where do the electrons get picked up?

Answer 5

• inner membrane space by ubiquinone.

Question 6

Where does the electron transport chain take place in?

Answer 6

Inner membrane of the mitochondria.

Question 7

Where are the protons that are produced using the energy from the electrons donated by NADH found?

Answer 7

• the complex’s proton pump moves them from the mitochondrial matrix to the intermembrane space.

Question 8

where does ubiquinone move the electrons from complex one?

Answer 8

Complex three.

Question 9

What picks up the electrons in the inner membrane space following complex three?

Answer 9

Cyt-c swoops

Question 10

Where does Cyt-c take the electrons?

Answer 10

Complex four

Question 11

What happens to the electrons after complex four uses their energy to make protons?

Answer 11

• O2 outside the complex nabs the electrons and uses them to reduce it’s to water.

Question 12

What was the point of the electrons in step four of the electron transport chain?

Answer 12

Create a proton gradient.

Question 13

How do the journey of the electrons from FADH differ from those in NADH?

Answer 13

• they begin at complex 2, following complex two they are picked up by ubiquinone and then taken to three… (same path from this point on)
• Purpose is also the same.

Question 14

Where are the differences in charges as a result of the proton concentration gradient?

Answer 14

+: intermembrane space

• : mitochondrial matrix
• Creating a large gradient across the inner mitochondrial membrane

Question 15

What is the Proton-Motive force?

Answer 15

It is the large proton gradient in the inner mitochondrial membrane that represents a large amount of potential energy.

Question 16

What is Chemiosmosis?

Answer 16

• It is the potential energy that is from the proton motive force, and it is used for the creation of ATP.

Question 17

How is the Chemiosmosis mediated?

Answer 17

• ATP synthesis.

Question 18

What is happening during chemiosmosis coupling?

- Same thing as chemiosmosis?

Answer 18

• protons enter the channel, which releases energy as they move down the gradient.
• that energy is used to turn the F1 unit
• The F1 unit moves ADP and Pi closer together to form an ATP molecule.

Question 19

What is oxidative phosphorylation?

Answer 19

• It is ATP that is produced from the energy of the proton motive force that was generate via the ETC.

Question 20

The efficiency of cellular respiration is dependent upon what?

Answer 20

• wide variety of factors, most of which pertain to its cell type.

Question 21

What is the avg yield for ATP from one glucose molecule in the cellular respiration process?

Answer 21

29

Question 22

what percent efficiency is cellular respiration in terms of efficiency?

Answer 22

31

Question 23

What is a catabolic pathway?

Answer 23

• A pathway that breaks down macromolecules

Question 24

What does an anabolic pathway do?

Answer 24

• Creates macromolecules, or makes larger things

Question 25

What can cells pull from the citric acid cycle in order to make amino acids

Answer 25

• substrates for amino acids.

Question 26

What happens if oxygen isn’t present to serve as the final accepter in the electron transport chain?

Answer 26

• if there is no oxygen available than the electrons in complex four have no where to go.
• starting a traffic jam, nothing in or out of complex four.
• Then this causes serious back up through out all complexes, as NADH and FADH2 can no longer give off or accept electrons.
• Therefore, the cell can no longer give off NAD+.

Question 27

In eukaryotes what is always the final electron acceptor?

Answer 27

Oxygen, reduces to make water.

Question 28

In prokaryotes what is/can be the final electron acceptor?

Answer 28

• Typically some other electronegative molecule (sulfur containing)
• Oxygen

Question 29

If the cell can no longer reduce NADH to NAD + because a lack of oxygen as the final accepter in the ETC what is the cause?

Answer 29

• you lose an important substrate that is vital for the process of making ATP.

Question 30

Without oxygen as the final accepter in the ETC, how does the cell reduce NADH to NAD +?

Answer 30

Fermentation: process that is a branch from cellular respiration, this follows glycolysis. This provides an alternate way for a NADH back to NAD +.

Question 31

In humans were do we carry hour fermentation?

Answer 31

Latic acid pathway: pyruvate accepts electrons from NADH

Question 32

What is proton leak?

Answer 32

It is a leak in the Mitochondrial membrane that allows protons to move down the electrochemical gradient, but none of this energy is being captured.

• Wasteful
• this wasted energy is turned to heat.

Question 33

Why is the wasted energy that is converted to heat sometimes beneficial?

Answer 33

Brown fat: type of tissue that is specialized for heat production.
- Concentration decreases as you age.