Chapter 7 - Part 2 (Electron transport / Chemiosmosis)
Explain the steps of alcohol fermentation:
1) Pyruvate is converted to ethanol by releasing carbon dioxide from Pyruvate, which is converted to acetaldehyde. 2) acetaldehyde is reduced by NADH to ethanol
Chemiosmosis:
(Diffusion of H+) Process in which energy stored in the form of H+ is forced across the membrane in order to drive cellular work
How much ATP is generated through cellular respiration?
30-32 ATP
What percent of potential chemical energy in glucose gets transferred to ATP?
34%
What is ATP synthase made of?
4 main parts, each made of multiple polypeptides
How can cells generate fuel without oxygen?
Anaerobic respiration and fermentation
What is the difference between the two?
Anaerobic respiration involves an electron transport chain
Facultative anaerobes:
Can make enough ATP to survive using fermentation or respiration
How goes the H+ gradient work?
Electron transport chain uses the exergonic flow of electrons from NADH and FADH2 to pump H+ across the membrane
Chemiosmosis:
Energy-coupling mechanism that uses energy stored in the form of an H+ gradient across a membrane to drive cellular work
Where does the energy for gradient formation come from?
Exergonic redox reactions
Most energy flows in what sequence?
Glucose --> NADH --> Electron transport chain --> Proton motive force --> ATP
What does fermentation consist of?
Glycolysis plus reactions that regenerate NAD+ by transferring electrons to Pyruvate or derivatives of Pyruvate
Why would oxidative phosphorylation cease?
If the oxygen's electronegative pull on electrons down the electron transport chain didn't exist (without oxygen)
Where is the electron transport chain?
In the folding of the inner membrane of the mitochondria (cristae)
Where does the rest of the energy stored in glucose go?
Lost as heat
Which molecules account for most of the energy from glucose?
NADH and FADH
Does the electron transport chain make ATP directly?
No, it eases the fall of electrons to oxygen, breaking it into smaller steps that release small amounts of energy
Prosthetic groups:
Nonprotein components essential for the catalytic functions of certain enzymes
Obligate anaerobes:
Only carry out fermentation or anaerobic respiration
ATP synthase:
Protein/enzyme in the inner membrane of mitochondria that makes ATP from ADP and inorganic phosphate
Explain lactic acid fermentation:
Pyruvate is reduced directly by NAHD to form lactate, with no release of CO2
Why are the number of ATP molecules generated inexact?
Ratio of NADH to ATP is not a whole number, ATP yield varies depending on shuttle used, use of proton movie force
Proton-motive force:
The H+ gradient used to perform chemiosmosis
What is the power source for ATP synthase?
The difference in concentration of H+ on opposite sides of the inner mitochondrial membrane
What establishes the H+ gradient across the inner mitochondrial membrane?
The electron transport chain
What happens to electron carriers during electron transport?
They alternate between reduced and oxidized states as they accept and donate electrons