Download 4 Cell Resp Part 2 NT

Metabolism/ Notes #4 - Cellular Respiration – Part 2
Date_____
Objectives

Explain how 36 ATP are made from one glucose molecule.

Understand how ATP synthase works.

Begin to understand chemiosmosis.
Key Vocabulary
Cristae
Intermembrane Space
Krebs Cycle
NADH
Oxygen
Matrix
FADH2
ATP Synthase
Endosymbiosis
Electron Carriers
Chemiosmosis
Acetyl CoA
ETC
Cellular Respiration - Stage 2 & 3: Oxidation of Pyruvate - Krebs Cycle
Glycolysis is only the start

Glycolysis

Pyruvate has more energy to yield
 3 more C to strip off __________________
 _________________________________________
 enzymes of Krebs cycle complete the full oxidation of sugar to CO2
Mitochondria — Structure

Double membrane energy harvesting organelle
 Smooth outer membrane
 Highly folded inner membrane

________________
 ___________________________

fluid-filled space between membranes
 __________________________

inner fluid-filled space
 DNA, Ribosomes
 enzymes

free in matrix & membrane-bound
Mitochondria – Function


What is evidence of endosymbiosis? __________________________________
_____________________________________________________________
What is the advantage of the highly folded inner membrane? ___________________
_______________________________________________
Oxidation of pyruvate

Pyruvate enters mitochondrial matrix
 3 step oxidation process
 Releases 2 CO2 (count the carbons!)
 Reduces _______________________________________
 Produces ____________________________
 Acetyl CoA enters __________________________
Pyruvate oxidized to Acetyl CoA - Yields: __________________________________________
Krebs cycle

aka Citric Acid Cycle
 in ____________________________
 8 step pathway


each catalyzed by specific enzyme

step-wise _______________________________
___________________________________
 does that make evolutionary sense?

bacteria 3.5 billion years ago (glycolysis)

free O2 2.7 billion years ago (photosynthesis)

eukaryotes 1.5 billion years ago (aerobic respiration = organelles ---mitochondria)
Count the carbons!
pyruvate
3C
2C
6C
4C
This happens
twice for each
glucose
molecule
4C
acetyl CoA
citrate
oxidation
of sugars
CO2
x2
4C
4C
6C
5C
4C
CO2
AP Biology
Electron Carriers = Hydrogen Carriers

Krebs cycle produces large quantities of _____________________
 NADH
 FADH2
 go to _____________________________
Energy accounting of Krebs cycle
Net gain =
__________________
=
________________________
Value of Krebs cycle?

If the yield is only 2 ATP then how was the Krebs cycle an adaptation?
 _____________________________


electron carriers & H carriers

reduced molecules move electrons

reduced molecules move H+ ions.
To be used in the ____________________________________
What’s the point?? _________________
And how do we do that?

ATP synthase
 set up a H+ gradient
 allow H+ to flow through ATP synthase
 powers bonding of Pi to ADP

ADP + Pi  ATP
But have we done that yet????
Cellular Respiration - Stage 4 - Electron Transport Chain
ATP accounting so far…

_____________________

_____________________

Life takes a lot of energy to run, need to extract more energy than 4 ATP!
There is a better way!

Electron Transport Chain
 Series of proteins built into ________________________________________

along _________________________

transport proteins & enzymes
 transport of electrons down ETC linked to pumping of H+ ions to create H+ gradient
 yields ____________________________________
 only in presence of O2 (__________________________________________)
Mitochondria

Double membrane
 outer membrane
 _______________________

highly folded _______________

enzymes and transport proteins
 intermembrane space

fluid-filled space between membranes
Remember the Electron Carriers?
What are they? _________________
Electron Transport Chain
What is building the proton gradient? ____________________________
Stripping H from Electron Carriers

Electron carriers pass electrons and H+ to ETC
 ________________________________________
 _____________________________________________________

electrons passed from one electron carrier to next in mitochondrial membrane (ETC)

_______________________________________
 Transport proteins in membrane pump H+ (_____________________) across inner membrane to
__________________________________________
But what “pulls” the
electrons down the ETC?
H2O
O2
AP Biology
electrons
flow downhill
to O2
oxidative phosphorylation
Electrons flow downhill

Electrons move in steps _________________________________________
 each carrier more electronegative
 _________________________
 _________________________
We did it!

Set up a __________________

Allow the _______________________________

____________________________
___________________________
Chemiosmosis

___________________________________________
 Build up of proton gradient just so H+ could flow through ATP synthase enzyme to build ATP

Chemiosmosis links ______________________________________
Summary of cellular respiration

Where did the glucose come from? _________________________

Where did the O2 come from? _____________________________

Where did the CO2 come from? ___________________________

Where did the CO2 go? __________________________

Where did the H2O come from? ___________________________

Where did the ATP come from? ___________________________________

What else is produced that is not listed in this equation? _____________________

Why do we breathe? __________________________________________
Taking it beyond…

What is the final electron acceptor in Electron Transport Chain? _______________

So what happens if O2 is not available?
 __________________

Nothing to pull electrons down chain

NADH and FADH2 can’t unload H+
 ____________ production ceases
 _________________________________
 __________________________________